School Science Lessons
Food Gardens 4
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Table of Contents
16.0 Agricultural chemicals
16.0.01 Agricultural chemicals
16.8.16 Acaricides
16.8.7 Arboricides
16.6.0 Fungicides
16.7.0 Herbicides, weedicides
16.2.0 Insecticides
16.1.0 Pesticides
3.10.0 Poisons and First Aid (Table)
16.9.0 Sprays, dusts, white oils

16.6.0 Fungicides
16.8.12 Fungicides
16.6.2 Bordeaux mixture
16.6.3 Captan
16.6.4 Copper oxychloride
16.6.5 Chlorothalonil
16.8.10 Dinoseb
16.6.12 Lime sulfur, CaSx
16.6.7 Metam-sodium
16.6.11 Potassium permanganate
16.6.8 Quintozene
16.6.9 Sulfur, wettable sulfur
16.6.10 "Yates Anti Rot Phosacid"
16.6.6 Zineb

16.7.0 Herbicides, weedicides
16.8.13 Herbicides, weedicides, dishwashing liquids
16.7.6 (2, 4-D) (2, 4-dichlorophenoxyacetic acid)
16.7.7 (2, 4, 5-T) (2, 4, 5-trichlorophenoxyacetic acid)
16.7.8 Acetochlor
16.7.1 Bifenox
16.7.2 Dalapon
5.21 Diseases of plants
16.8.11 DCMU
16.7.3 Glyphosate, herbicide
16.7.5 MCPA
16.7.4 Paraquat
9.88.1 Phosphonates, Ethephon, Glyphosate

16.2.0 Insecticides
16.8.14 Insecticides
9.2.0 Bti insecticide, as powder or spray, controls some caterpillars
16.2.3 Inorganic chemical insecticides
5.20 Insect pests of plants
16.18.12 Insecticide types, contact, ingestion, systemic
16.2.1 Organochlorine insecticides (prohibited in schools)
16.2.2 Organophosphate and carbamate insecticides, (prohibited in schools)
16.5.0 Plant extract insecticides

16.2.1 Organochlorine insecticides
16.3.0 Organochlorine insecticides, organochlorides, chlorinated hydrocarbons
16.4.01 Cyclodiene pesticides, aldrin, chlordane, dieldrin, endosulfan, endrin, heptachlor
16.3.1 DDT
16.3.3 Lindane, gammexane, BHC, benzene hexachloride
16.3.2 Methoxychlor Piperonyl butoxide

16.2.2 Organophosphate and carbamate insecticides
16.4.1 Acephate Carbaryl Bendicarb
16.4.8 Methiocarb
16.4.2 Dimethoate
16.4.3 Malathion, Maldison
16.4.4 Naled
16.4.5 Tetrachlorvinphos
16.4.6 Trichlorophon

16.1.0 Pesticides
Websites, Plant protection, pests and diseases
16.18.0 Pesticides
16.18.4 Active constituent
16.8.5 Chemical pesticides, poisons
5.22 Control of pests and diseases
16.8.11 DCMU, Diuron
16.8.10 Dinoseb
16.8.4 Integrated pest management (IPM)
16.6.12 Lime sulfur, CaSx
16.6.13 Mancozeb
16.6.14 Maneb
Neem oil, Azadirachta indica, Meliaceae
16.18.6 Persistence
16.18.2 Insect repellents
16.18.10 Pesticide safety
16.18.11 Pesticide safety, FIRST AID
16.18.12 Insecticide types, contact, ingestion, systemic
Pherome traps, species specific female sex hormone
16.18.5 Resistance to pesticides
16.7.0 Safety of herbicides, weedicides, and pesticides 16.18.7 Surface-acting agents
16.18.3 Withholding period

16.5.0 Plant extract insecticides
16.1.1 Pyrethrin, Plant extract insecticides
16.1.2 Rotenone

16.9.0 Sprays, dusts, white oils
16.9.0 Sprays, dusts, white oils
16.9.1 Chilli spray
16.9.4 Diatomaceous earth absorbacide
16.18.8 Emulsifying agents
16.9.2 Garlic spray Granules Fumigants Synergists W / V, W / W
16.9.3 Nicotine spray
16.19.0 Sprayers and dusters

5.20 Insect pests of plants
See diagram 9.303: Plant pests
Before starting to teach this and the next lesson, make a collection of pests and diseases from your garden.
They can usually be preserved in methylated spirits.
Also, collect diagrams of different pests.
make sure that your garden is a good example of pest and
disease control.
Check your spray equipment and pesticides.
A field visit may be useful for this lesson.
Show the students the examples of pests and diseases that you have collected from the garden.
To obtain the greatest possible production and cash income from your crops you must control loss by pests and diseases.
Pests are animals that eat your crops or infect your crop plants with diseases.
Pests may live in the ground, be attached to infected plants or may fly or walk to your crop.
Diseases are any change in the plant such as spots or holes in the leaves, wilting of the plant, rotting of the living plant.
They are caused by living things that may be so small that they cannot usually be seen by eye.
Diseases are carried by wind and water, infected plants, and pests.

The main pests of crops:
1. Nematode worms or eel worms: They are small worms pointed at both ends and have S-shapes.
They attack plant roots and may live in lumps on the roots.
They attack papayas, tomatoes, and bananas.
Killing nematodes or eel worms in the soil is very difficult.
2. Snails and slugs: Slugs are like snails with no shell.
They eat plant leaves and stems.
They can be controlled by picking off by students or by spraying with "Cuprox".
3. Spiders: Tiny red spiders called mites attack the leaves of beans and eggplant.
A chemical that kills them is called an acaricide, e.g. wettable sulfur.
4. Flies: Small white worms called larvae eat flowers and leaves, e.g. bean fly larvae.
5. Caterpillars: Some butterflies lay their eggs on the leaves and later caterpillars hatch out and eat the leaves.
They attack cabbages, tomatoes and beans.
6. Mole crickets and grasshoppers: They attack Chinese cabbage and lettuce.
7. Beetles: Beetles have hard shiny outer wings, e.g. Pumpkin beetle on pumpkins and sweet potato, Rhinoceros beetle on coconut
8. Bugs: Bugs have soft wings, e.g. vegetable bugs.
9. Rats: They eat root crops and fruit.
They can be controlled by destroying their nests and using poisonous bait, e.g. Warfarin.

5.20.1 Silverleaf white fly
Silverleaf white fly, sweet potato white fly, Bemisia tabaci, attacks sweet potato, tomato, cucumber, eggplant, poinsettia, okra, bean.
It sucks nutrients from phloem or lower leaf surfaces leaving chlorotic spots and withered leaves.
It produce a sticky substance, "honeydew", on which sooty moulds can grow, which reduce light to plant.
It is also vector for plant diseases, e.g. lettuce yellows virus, tomato yellow leaf curl virus,
and African cassava mosaic, and cassava brown streak virus.
There is no easy way to control it except by removing weeds near the crop.

5.21 Diseases of plants
| See diagram 6.0.1: Sterilizing soil
| 9.0.0 Fungi
| 4.0.0 Bacteria
Before the lesson walk out in the garden and look for examples of infected plants to show the students.
Show the students different examples of plants infected by diseases.
When a disease attacks a plant you say the plant is infected with the disease.
The three main causes of disease in crops:
1. Fungus diseases: A fungus is like a plant with a body of threads, is not green, and can attack and digest green plants.
Many fungi live in the damp soil.
Chemicals that kill fungi are called fungicides, e.g. "Captan".
1.1 Damping off fungus disease: This fungus attacks germinating seeds and makes all the seedlings fall over and die.
It can be prevented by heating the soil to kill all the fungi before planting seeds.
This is called soil sterilization.
1.2 Collar rot fungus disease: It attacks the stem near the ground.
Leaf and stem fungus diseases.
There are many of these diseases.
They appear as yellow or brown spots that may later join, then the leaf or stem dies.
1.3 Powdery mildew: It looks like white threads on leaves or stems of pumpkins and cucumbers.
2. Bacterial diseases: Bacteria are tiny living things that are much too small to be seen.
They can attack plants and cause them to rot. They live in damp places.
They cause many diseases, e.g. wilting of tomato plants, rotting of the heart of lettuce.
These diseases cannot usually be cured, but they can be prevented by soaking seeds in very hot water for a short time.
3. Virus diseases: Viruses are even smaller than bacteria and these diseases cannot be cured.
Viruses may cause yellow patches on leaves and later the plant dies, e.g. in taro and bananas.
These diseases cannot be cured but if the virus is carried by insects they may be controlled.
The best way to deal with bacterial or virus diseases is to burn the infected plant or part of the plant.
4. Diseases are carried to plants in four ways:
4.1 Wind can carry diseases a short distance.
4.2 Disease can be carried in running water or in the splash of rain drops.
4.3 Infected plants can pass disease to healthy plants if the plants are touching.
4.4 Disease can be carried by insect pests that can then infect healthy plan.

Diseases of plants, revision questions
1. Give an example of a virus disease. [Yellow patches on taro or banana leaves]
2. What are the four ways in which diseases are carried to plants? [By wind, by water or raindrop splash, by infected plants or soil,
by insect pests]
3. What does "infected" mean? [It means that a disease is attacking a plant.]

5.22 Control of pests and diseases
Websites, Plant protection, pests and diseases
| 16.0 Agricultural chemicals
In this lesson teach the students that you must be looking at your crops ever day for signs of pests and diseases.
Then you must be ready to decide what to do about the pests or diseases.
Often the pest or disease is harmless or does not do much damage
so it is best to either leave it alone or just pick off insects or diseased leaves by hand.
Yet you must still teach the students to look at the crops every day.
If the pest or disease is damaging your crop so much that you will not get enough to eat from it,
or you cannot sell it, then be prepared to use pesticide sprays or dusts.
Contact the agricultural field officer and ask for advice.
Clean your spray pump and try it with water first.
Check that you have enough of the right kind of spray.
The only really safe pesticides to use in schools are as follows:
Captan, Mancozeb, Maneb, Methoxychlor, Quintozene, Sulfur, Zineb.
Mix the pesticide according to the instructions on the label.
Do the spraying yourself or supervise an older student very closely.
Keep the students away from the spray.
Do not spray on a windy day.
Wash your hands and face (using soap) after spraying.
Clean out the sprayer after use, do not leave any pesticide in the sprayer.
Store pesticides and chemicals in a safe place
away from students.
The teacher should show the correct way of spraying or dusting of pesticides in the garden
Show the students examples of good preparation.
Pests and diseases can be controlled by good preparation before you plant the crop.
Good management after you have planted the crop.
There are five methods of good preparation for control of pests and diseases.
Use healthy planting material.
Seeds and cuttings should be clean and free of insects or disease spots.
Imported seeds in sealed silver packets will be free of disease.
Select planting material and seeds from plants known to be resistant to disease.
In village gardens some kinds of yams resist disease and some are attacked by disease.
Prepare the land properly so the plants can grow well.
Dig the soil deeply and dig drains near by so the roots can grow strongly in the drained soil.
Fertilize the plants to provide enough plant nutrients.
Sick plants are damaged more by pests and diseases than healthy plants.
Dig out and burn all plants from the previous crop, weeds, and other stray plants, such as male papaya trees.
If you get rid of all unnecessary plants, then pests and diseases will not live on them ready to attack your crop.
Destruction of diseased or useless plants is called garden hygiene.
Soil for seed beds or seed boxes can be sterilized by heating the soil in an oil drum all day to kill pests and diseases.
The five methods of control are as follows:
1. Use healthy planting material
2. Select resistant planting material
3. Good land preparation
4. Garden hygiene
5. Sterilize soil for seed beds and boxes.

5.22 Pests and diseases, revision questions
What are the five methods of control of pests and diseases by good preparation for the crop?
[Use healthy planting material, select planting material known to be resistant to pests and disease,
prepare the land properly, garden hygiene, sterilize the soil.]

16.0.01 Agricultural chemicals
Agricultural chemicals are chemicals used in agriculture, including insecticides, herbicides, and fungicides, but can also include
hormones and chemical growth agents, inorganic fertilizers and organic products, e.g. blood and bone manure and concentrated raw
animal manure.
Many agricultural chemicals can damage the environment and injury or harm to humans, farm animals and wild life.
Agricultural chemicals should be used correctly and stored and disposed of safely.
Farm workers should wear protective clothing and be trained in the use of all agricultural chemicals.

16.0.0 Pesticides and herbicides safety
Pesticides are chemicals used for destroying insects or other organisms harmful to cultivated plants or to animals.
Pesticides may be harmful to humans and farm animals and should be used correctly and stored and disposed of safely.
Farm workers should wear protective clothing and be trained in the use of all agricultural chemicals.
Pesticides can be divided into the following:
1. Baits and traps, e.g. sticky tapes and glues, barrier paints, fruit fly traps, which may be indiscriminate and affect beneficial as well as
harmful insects,
2. Contact poisons to be absorbed through the cuticle by spraying or by walking on sprayed fruit and leaves, e.g. pyrethrum, rotenone,
3. Desiccants that wear away the waxy exoskeleton or dissolve the waxy coating on the exoskeleton, e.g. soap sprays and
diatomaceous earth,
4. Fumigant gases that must be breathed in,
5. Oils that suffocate small insects, e.g. vegetable oils with dishwashing detergents,
6. Stomach poisons that require, e.g. rotenone and diatomaceous earth.
Pesticides used in schools
The contents below are for information only and do not constitute advice on how any particular agricultural chemical should be used in
any school garden.
Before using any agricultural chemical in a school garden, the supervisor should obtain advice from a Field Officer of the Department
of Agriculture and should obtain permission from the school principal.

16.1.1 Pyrethrin, Plant extract insecticide
Pyrethrin, Chrysanthemum monocarboxylic acid pyrethrolone ester, C21H28O3, is a yellow-brown liquid with distinct odour, that sinks in water.
Pyrethrins are two almost identical organic compounds extracted from the pyrethrum flower Chrysanthemum cinerariaefolium.
Pyrethrins have an immediate knock down effect on flying insects, but a second poison may be needed to kill them.
They have low toxicity to mammals.
Allethrin insecticide is an organic compound that is the same as pyrethrin, but made in a factory.
Permethrin is an organic compound that is similar to pyrethrin, but is made in a factory.
Chilli, pyrethrin and permethrin are stomach poisons and contact insecticides.
They are safe to use, but some people are made sick by them.
They are not persistent and there is no withholding period.
These poisons kill most pests quickly and so are called knockdown sprays.
They also repel insects, stopping them from coming near plants.
They can kill such a wide range of insects that some people spray them only in the early evening when bees have returned to their hives. Piperonyl butoxide
Synthetic pyrethroids contain natural pyrethrum with the synergist piperonyl butoxide, but these products are not allowed in some places.

16.1.2 Rotenone, derris
See diagram 16.1.2: Rotenone
Rotenone, C23H22O6, polycyclic ketone, toxic, crystalline, odourless, colourless, crystalline, isoflavone, a rotenoid, piscicide,
insecticide, in Lonchocarpus nicou, dried rhizome and root of Derris elliptica, Pachyrhizus erosus, jicama, also in many Fabaceae
Rotenone from derris dust, kills aphids, thrips, chewing insects, and is toxic to fish and birds.
Rotenone is an organic compound obtained from roots of the legume Derris and other local bean plants.
This chemical is a contact and stomach poison.
Rotenone can be used to repel insects, control chewing insects and lawn grubs, and as an acaricide.
It is often used to kill fish, but it is toxic to earthworms and can also affect pigs.
It is effective for short periods only because it is broken down by oxygen and sunlight.
It is not persistent and must be sprayed every three days.
It does not store well.
This is a good insecticide, but repeated applications are needed.
If applied as "derris dust" the plant leaves must not be too shaded.
Insects are never resistant to this poison.
It can control beetles, weevils, slugs, looper caterpillars, thrips, flies.
Rotenone is also used to poison fish.
Rotenoids are natural substances, with a cis-fused tetrahydrochromeno [3, 4-b] chromene nucleus, e.g. rotenone insecticide from derris.

16.2.3 Inorganic chemical insecticides
These chemicals are persistent stomach poisons that kill chewing insects, e.g. caterpillars, but not sucking insects, e.g. aphids,
Other inorganic chemicals are used as attractants, repellents and synergists.
Inorganic insecticides are usually heavy metal compounds, particularly of lead, mercury, e.g. dimethyl mercury antifungal agent and
insecticide, arsenic and antimony.
Also, some are fluoride salts, e.g. NaF, sulfur, polysulfides and borax.
1. Borax (Na2B4O7) is used as a cockroach and ant poison and is harmful to mammals.
2. Copper chrome arsenate (CCA), Treated timber, wood:
Copper chrome arsenate (CCA) is used to preserve fence posts and garden furniture giving a green colour.
Such treated timber is safe for normal use, but the sawdust and smoke from burning may contain dangerous levels of arsenic.
The white powder seen on some newly purchased timber is probably harmless sodium sulfate.
3. Copper (II) sulfate and lime is used in Bordeaux mixture.
Copper (II) sulfate can causes vomiting.
4. Lead arsenate (PbHAsO4) is a heavy metal compound that is insoluble in water and so not readily absorbed by plants on contact.
It is effective only by .
The lead blocks essential sites on enzymes and so it is non-specific.
It is toxic to all living systems and extremely persistent.
Sodium arsenite is no longer used as a cattle dip against ticks.
5. Sodium fluoride (NaF) and cryolite (Na3AlF6) liberates fluoride ions to precipitate Mg2+ as fluorophosphate thus affecting
magnesium-dependent enzymes.
It is non-specific and toxic to animals.
6. Sulfur as elemental sulfur, S, and the soluble lime sulfur (CaS) experiences aerial oxidation to SO2, to act as a safe fungicide and
It has some use as an insecticide.
7. Petroleum oils, petroleum oil spray (PSO) are also "white oil", and "summer oil", and "winter oil".
These chemicals are poisonous to some scale insects.
They are fairly safe to use.
There should be a one day withholding period before harvest of the sprayed crop.
The classification of petroleum oils is based on the temperature at which 5% of the constituents boil, e.g. C21, C23, C24 oils.
The latter has less phytotoxicity.
The oil droplets on the plant must all join together to kill all the insect pests.
These oils are used in 2 ways:
1. They can control scale insects on citrus trees.
2. They can be mixed with other insecticides, e.g. Carbaryl, to spread them better on plants.
Concentrations: 0.25% = 250 mL oil in 100 L water, 2% = 2 L oil in 100 L water.

16.3.0 Organochlorine compounds, organochlorides (chlorinated hydrocarbons)
1. The following organochlorine compounds have been banned in Australia and must not be used in schools:
Aldrin, BHC, Chlordane, DDT, Dieldrin, Endrin, Heptachlor, Hexachlorophene, Isodrin, Lindane,
Pentachlorophenol (PCP) C6HCl5O, 2, 4, 5-T.
2. The following pesticides are too dangerous for use in school food gardens:
2.1 Organochlorine compounds: DDT, benzene hexachloride (Lindane, gammexane BHC), aldrin (chlordane, dieldrin, heptachlor
epoxide, endrin).
Organochlorines are composed only of carbon, hydrogen and chlorine.
They are biologically very active, but not easy to breakdown, hence persistent.
They have one or more chlorine atoms attached to the carbon atoms, replacing hydrogen.
The term "organochlorine" refers to a wide range of organic chemicals, which contain chlorine and sometimes several other elements
that have been used in Australia as herbicides, insecticides, fungicides and industrial chemicals, e.g. polychlorinated biphenyls (PCBs).
They are very stable compounds that can be distributed in the environment where they persist long after their original use.
They degrade slowly and being fat soluble, accumulate in the food chain, eventually ending up in the fat of your body.
The key properties of organochlorines that cause concerns are persistence and toxicity.
While organochlorine pesticides were manufactured for their toxicity, the fact that they were also persistent had advantages in that they
remained effective against target pests for prolonged periods.
So they are used to protect crops, livestock, buildings and households from the damaging effects of insects.
Commonly used OCP insecticides were DDT, Lindane, chlordane, dieldrin, aldrin and heptachlor.
Fungicides included hexachlorobenzene (HCB) and chlorinated phenols, e.g. pentachlorophenol.
Herbicide 2, 4, 5 -T was also used.
Hexachlorobenzene (HCB) used in the past as a fungicide (seed disinfectant, seed paint), but now banned in Australia, appears as a
widespread contaminant in many environments.
It was deregistered for general use between 1985 and 1987.
Chlorinated phenols, e.g. pentachlorophenol (PCP) have been widely used in Australia to protect softwood timber from decay.
Also, 2, 4, 5-T was used in the past as a herbicide against broad leaf woody plants, as a defoliant.
The use of almost all the chemicals mentioned above is now banned in Australia.

16.3.1 DDT
DDT, the new chemical name is 1, 1-bis(4-chlorophenyl)-2, 2, 2-trichloroethane.
The old name was dichlorodiphenyltrichloroethane, hence "DDT".
DDT is a organochlorine contact insecticide that kills by acting as a nerve poison is a highly effective insecticide, both by contact and
by, and is of very low toxicity to mammals.
It is odourless and tasteless, has a high persistence, and is chemically stable.
However, insects can develop resistance to DDT by natural selection of surviving members with enzymes that can detoxify it.
DDT and its metabolic breakdown product can accumulate in the fat of birds and fish, and even people, at the end of the food chain.
It may cause birds to produce thin shell eggs that break easily.
So the advantage of it being chemically stable is now seen as a major disadvantage.
It was also used in large quantities in the control of mosquitoes, which caused malaria in tropical countries.
There has been a total ban on the use of DDT in Australia since 1987.
The technical product "DDT", which is a mixture of isomers, principally p, p'-DDT, with lesser amounts of o, p'-DDT.
Isomers are chemicals with the same molecular make-up, but with differing three-dimensional structure.
Small amounts of the breakdown products DDD and DDE can also be found in the formulation.
Once stored in fatty tissue, DDT residues are sequestrated and stabilized unless they are mobilized either through lactation or
significant weight loss, which burns fat DDT, DDD and DDE are all strongly suspected of being environmental endocrine disruptors,
i.e. chemicals that affect the hormonal system.

16.3.2 Methoxychlor
See diagram 16.2.2: Methoxychlor
Methoxychlor, C16H15Cl3O2, is an organochlorine insecticide.
It is a contact and stomach poison, very safe to use, and has long persistence.
Methoxychlor is pale yellow powder and has a fruity or musty odour.
It is used to kill flies, mosquitoes, cockroaches, chiggers and others.
Methoxychlor is a general insecticide for food crops, household pests, farm animals, pets and grain storage and is available as W.P.,
E.C., dusts, and in aerosol cans.
It has oestrogenic effects on mammals
Methoxychlor is a biodegradable analogue of DDT.
While non-polar compounds, e.g. DDT, stay dissolved in the fat of the body, polar substances, e.g. methoxychlor, are water soluble
and can be excreted to be further attacked by other organisms.
DDT and pyrethrins keep open the sodium channel of the insect nerve cell, but not the mammal nerve cell, so sodium ions leak in
causing continuous transmission of nerve impulses and the insect dies of exhaustion.
You can observe the frantic activity of house flies sprayed with DDT.
When DDT sprays were introduced an advertisement stated "They fly outside to die".
Methoxychlor can enter your body when you breathe contaminated air, eat contaminated food, get it on your skin and use gardening
products or pet sprays.
High doses of methoxychlor could cause damage to the nervous system, but low levels of methoxychlor will leave the body so quickly
that this type of damage is not likely.
The US Environmental Protection Agency (EPA) has set a reference dose (RfD) for methoxychlor at 0.005 milligrams per day. Piperonyl butoxide, PBO, C19H30O5
See diagram 16.2.2: Piperonyl butoxide
DDT, methoxychlor, and pyrethrins are more efficient if piperonyl butoxide is added to the insecticide to give a synergistic effect.
This additive is not itself an insecticide, but deactivates enzymes for detoxification of the pesticide in the insect.

16.3.3 Lindane
Lindane, gamma-hexachlorocyclohexane (╬│-HCH), gammaxene, [wrongly-named, benzene hexachloride (BHC)], variant of
hexachlorocyclohexane (HCB), benzene hexachloro
See diagram 16.13.3: Benzene hexachloride, chlorothalanil, DCPA, dalapon
Lindane, is an insecticide with different names made by the addition of chlorine to benzene.
The 7-isomer is the insecticide of the nine isomers formed.
Detoxification is by elimination of HCl.
Lindane has been used to treat lice in children.
The insecticide Lindane is more than 5-20 times more toxic to insects than DDT.
It was mainly used against plant-eating insects, but had various medical and veterinary applications in treating skin parasites.
It was used in the control of insect pests in stored seed to control white grubs in pineapples, against ectoparasites on food, and head
lice in humans.
It was deregistered for general use in 1985.
Lindane is a chemical that kills insects, including head lice and was the active ingredient in lice shampoo, which is no longer sold.
Generic Lindane is still available by prescription for head lice.
Shampoo with Lindane can be dangerous if swallowed, especially for children.
It appears that Lindane is not as effective against lice as it once was.
One of the safest and most effective methods for controlling head lice is by combing hair with a good lice comb with 3 or 4 rows of
closely-spaced metal teeth.
There are currently no commercial uses of hexachlorobenzene in Australia.
Hexachlorobenzene has been used as a pesticide, but is no longer registered for this use in Australia.
It was also used in the production of fireworks, ammunition, rubber, aluminium, and dyes, and in wood preservation.

16.4.0 Organophosphate and carbamate insecticides
See diagram 16.13.2: Organophosphorus insecticides
2. The following pesticides are too dangerous for use in school food gardens:
Organophosphorus insecticides: chlorpyrifos, parathion, malathion, dimethoate, dichlorvos, mevinphos.
High persistence chlorinated pesticides are being replaced by the organophosphorus group that has a range of activity, persistence,
specificity and function.
Their general formula is (RR'X) P = 0, where R and R' are short chain groups and X is a leaving group that it is easily removed from
the molecule either after a reaction in the body so persistence is reduced, e.g. carbaryl.

16.4.01 "Cyclodiene" pesticides, aldrin, chlordane, dieldrin, endrin, heptachlor
See diagram 16.13.4: Chlordane, aldrin, dieldrin, heptachlor, endosulfan
Hexachloropentadiene, C5Cl6 (Diels-Alder reaction) --> cyclodienes, e.g. aldrin C12H8Cl6, chlordane C10H6Cl8, dieldrin C12H8Cl6O,
endrin C12H8Cl6O, endosulfan, C9H6Cl6O3S, heptachlor C10H6Cl7.
These pesticides are now banned in most countries.
They are broad spectrum insecticides, highly toxic to insects and mammals, and with high persistence.
They also accumulate in body fats and act on the central nervous system.
The compound may itself be non-toxic, but is converted to a toxic form in the body.
They remain in the mammal body, measured as a half residence time, to be detoxified in the liver and excreted by the kidneys, but
leaving some stored in body fat to be released during illness, stress and lactation, maternal milk.
Aldrin and dieldrin have not been produced in the United States since 1974.
Aldrin and dieldrin are active against insects by contact or .
Their primary use was for the control of termites around buildings, corn pests by application to soil and in the citrus industry, termite
proofing of plastic and rubber coverings of electrical and telecommunication.
In 1970, the US Department of Agriculture cancelled all uses of aldrin and dieldrin based on the concern that these chemicals could
cause severe aquatic environmental change and are potentially carcinogenic.
Aldrin and dieldrin are classified as hazardous wastes.
That should be incinerated.
Chlordane, dieldrin, aldrin and heptachlor, were marketed to complement DDT.
Chlordane was used for instance to control termites, various types of ants, borers, lawn beetles, curl grubs, cut worms and black beetles.
Dieldrin was widely used against locusts and argentine ants, in the protection of electricity and telephone cable, soil treatment in farm
and industrial premises for control of termites, and control of termites in buildings, fences and similar structures.
Aldrin was used as a soil treatment, usually pre-planting, for crops, e.g. sugar cane, it was used in ant control as well as
subterranean termite control, the protection of power poles from termites, farm, industrial and domestic control of fleas, flies, lice and
Heptachlor, a persistent organic pollutant, was used similarly to chlordane.
It was also commonly used in soil treatment in crops for control of funnel ants and grubs of the grey-black beetle in cane growing areas,
and banana beetle borer in banana plantations.
In some countries it has a limited use to control fire ants.
Endosulfan was used widely to control insect pests, but is now banned or is being banned in most countries because of its acute
neurtoxic properties.

16.4.1 Acephate
See diagram Acephate
Acephate is a contact poison that is also systemic in some plants.
It is fairly safe to use.
There should be a 7 days withholding period before harvest of the sprayed crop.
It persists for some time.
It may burn young leaves.
Acephate can be used to control many insect pests and some people say it is the best general purpose insecticide for use in the tropics.
It can control aphids and thrips, caterpillars, leaf miners, rice hoppers, diamond-backed moth on cabbages, cutworms, and many
other insects.
Acephate is usually available as a wettable powder.
It is also available as a dust.

16.4.2 Dimethoate
See diagram Dimethoate
Dimethoate, C5H12NO3PS2, "Pestanal", organophosphate insecticide, systemic poison, dangerous if mist is breathed in or swallowed.
There should be a 7 days withholding period before harvest of the sprayed crop.
It may damage some fruit trees.
Dimethoate can be used to control aphids and all sucking insects, but it will not control chewing insects, e.g. grasshoppers.
It can control leaf miner in hibiscus cabbage (aibika) cabbages, okra, and sweet potato, aphids and thrips on plants of the pumpkin
family, cabbages, spring onions, tomato and bean, heliothis corn ear worm on bean, and plants of the tomato family, mites and red
spider on plants of the tomato family, taro, banana, bean and cassava, bean fly, vegetable bugs, pod borer on bean, and fruit fly.
When insects are first seen spray a solution of 5 mL of concentrate in 5 litres of water.
Make sure that the whole plant is sprayed.
Dimethoate is usually available as emulsifiable concentrate (E.C.).
It is also available as dusts, wettable powder (W.P.) and granules.

16.4.3 Malathion, Maldison, C10H19O6PS2
See diagram Malathion
Malathion is a wide spectrum aliphatic organophosphate.
Malathion is a synthetic phosphorous compound and cholinesterase inhibitor allowing acetylcholine to accumulate at cholinergic synapses and enhancing cholinergic receptor stimulation, leading to insect death.
Malathion is a widely-used agricultural chemical to control corn earworm, sucking insects, including mosquitoes and head lice.
Contact with skin, inhalation of spray or swallowing may be harmful.
Malathion, maldison, is a contact poison that is also weakly systemic in some plants.
It is fairly safe to use, but the concentrate is dangerous if swallowed, breathed in, or allowed to remain on the skin.
There should be a 7 days' withholding period before harvest of the sprayed crop.
It persists for some time.
Malathion can be used to control many different insect pests that eat leaves and stems, but some insects have become resistant to it.
It can control aphids, mole crickets, grasshoppers, cutworms, scale insects on
citrus trees, bugs on plants of the pumpkin family, bean and eggplant, taro leaf hopper, spider mites.
When the insects are first seen spray a solution of 10 mL of "Malathion 50" in 4 litres of water, and repeat the spray when necessary.
Malathion is usually available as a concentrate.
It is also available as aerosols, granules and dusts.
For control of scale insects mix with white oil, e.g. Albarol, and water.
For control of pests of stored products, use as a dust.

16.4.4 Naled
See diagram 16.13.5: Naled
Naled, C4H7Br2Cl2O4P, bromochlorphos, is a contact and stomach poison.
It is dangerous to use.
Naled can be used just before harvest.
It can control caterpillars, cutworms, bugs on eggplants, red spider mite on cassava and other crops.
Naled is available as an emulsifiable concentrate (E.C.), and a dust.

16.4.5 Tetrachlorvinphos
See diagram 16.13.5: Tetrachlorvinphos
Tetrachlorvinphos, C10H9Cl4O6P, "Rabon", "Gardona" is a contact and stomach poison.
It is fairly safe to use.
This chemical is not allowed to be used on crops in the US.
Tetrachlorvinphos can be used to control caterpillars and other pests of leafy vegetables, but other insecticides are better for this
It can be used to kill parasites of animals and to kill pests in agricultural buildings and is used in dog collars to control fleas.
Tetrachlorvinphos is usually available as emulsifiable concentrate (E.C.) oil solution and dusts.

16.4.6 Trichlorophon
See diagram 16.13.5: Trichlorophon
Trichlorphon, C4H8Cl3O4P, "Dipterex", "Chlorophos", is a stomach poison and contact insecticide for certain insects.
It also is used to kill flies and cockroaches.
It is dangerous to use.
There should be a 2 days withholding period before harvest of the sprayed crop.
Trichlorphon can be used to control cutworm of cabbage and other crops, white fly on taro, corn ear worm, bean fly, bugs, leaf
hoppers, banana scale moth and fruit fly.
Not effective for control of diamond backed moth.
Trichlorphon is available as wettable powder (W.P.) emulsifiable concentrate (E.C.) and dusts. Carbamates, Carbaryl
See diagram Carbaryl, 1-napthyl methylcarbamate, "Sevin", "Carbamine", "Dicamba", "Bugmaster", C12H11NO2
Carbaryl is a contact poison that is also weakly systemic in some plants.
It is fairly safe to use, but the concentrate is dangerous if it is swallowed, breathed in or allowed to remain on the skin.
There should be a 7 days withholding period before harvest of the sprayed crop.
It has a short persistence.
It may burn young leaves.
Carbaryl can be used to control many different insect pests that eat leaves and stems, but you may need a following spray of another
insecticide to kill all the insect pests.
It can control leaf miner on hibiscus cabbage (aibika), okra, tomato and sweet potato, caterpillar on cabbage and other leafy vegetables,
28-spotted ladybird on plants of the pumpkin family, tomato leaf miner, pod borers in bean, bugs on bean and eggplant, green looper
caterpillars on bean and tomato, diamond-backed moth on cabbages, taro leaf hopper, white fly on taro and other crops, army worm,
pumpkin beetle, moths on fruit trees, potato moths.
When the insects are first seen, spray a solution of 5 g of Carbaryl in 4 litres of water, and repeat the spray when necessary.
Carbaryl is usually available as a wettable powder.
It is also available as granules and dusts.
For control of scale insects mix it with white oil (petroleum oil). Carbamates, Bendicarb
Bendicarb, C11H13NO4, insecticide, Acutely toxic, Registration cancelled in USA 1999, "Ficam", "Multimat".

16.4.8 Carbamates, Methiocarb
See diagram 16.13.7: Methiocarb, mercaptodimethur, 4 methyl thio-3, 5-xylyl methylcarbamate, C11H15NO2S
Methiocarb, a white crystalline powder with a mild odour, is a contact and stomach poison insecticide, acaracide,
molluscicide and bird repellent.
It is dangerous with long residual activity, but as no systemic action.
Methiocarb is used mainly as snail bait and repellent for snails and slugs.
It also controls grasshoppers, mites and many insects.

16.6.2 Bordeaux mixture,
Bordeaux mixture, CuSO4.3Cu(OH)2.3CaSO4, "Bordo Mixture", is a mixture of copper (II) sulfate and calcium hydroxide, (slaked
lime, hydrated lime).
It is a protective fungicide that is safe, unless eaten.
The two chemicals are often bought separately and mixed in a plastic bucket and used immediately.
It may burn leaves and metal and is hard to use properly.
Bordeaux mixture can a wide range of fungus diseases, including rots, downy mildew and leaf spots.
It repels many insects.
It can kill the eggs of mites.
Copper (II) sulfate may be used by itself to control leaf spots and other diseases.
Use Bordeaux mixture to kill moss.

16.6.3 Captan
See diagram 16.13.6: Captan
Captan is ethanethiol or ethyl mercaptan.
Captan contains chlorine and sulfur.
A protective fungicide, safe to use, but may irritate the skin, used mainly as a dust on seeds to prevent damping off disease, also used
on vegetables and other crops and as a dip for stored products, 1 day withholding period.
It is a good all purpose fungicide for controlling mildew and leaf spots and damping off fungus on seeds.
Captan can control root and stem rot of bean, fungus diseases in carrots, peanut and sorghum, and leaf spot of yams.
It kills fish.
Seed that has been dusted with it must not be eaten.
Captan is available as dusts and WP, and in special soil fungicidal products.
In 1989 Captan was phased out of general usage as a pesticide in USA.

16.6.4 Copper oxychloride, ClCu2H3O3
Copper oxychloride is made from copper and chlorine.
It is a protective fungicide.
It is safe to use.
There should be a 1 day withholding period before harvest.
Copper oxychloride is a good fungicide for leaf diseases.
It can control a wide range of fungus diseases, including anthracnose, leaf rots, leaf spots, downy mildew, and powdery mildew.
Copper oxychloride is available as wettable powder (W.P.) and dusts.

16.6.5 Chlorothalonil
See diagram 16.13.3: Chlorothalonil
Chlorothalonil, C8Cl4N2, contains chlorine.
It is a protective fungicide.
It is safe, but it makes some people sick.
Its effect lasts a long time.
This is the best fungicide for fungus diseases of tomato.
Chlorothalonil can control leaf spots, powdery mildew, downy mildew and other fungi on plants.
It does not kill all soil fungi.
It can kill fish.
Chlorothalonil is available as wettable powder (W.P.) and tablets.

16.6.6 Zineb
See diagram 16.13.10: Zineb
Zineb, C4H6N2S4Zn, contains zinc.
It is a protective fungicide.
It is safe to use, but it may cause skin irritation.
It may damage young seedlings.
There should be a 7 days withholding period before harvest of the sprayed crop.
This is the best general purpose fungicide.
Zineb can control many vegetable fungus diseases including downy mildew on plants of the pumpkin family, leaf spots and rust diseases.
It is available as a wettable powder (W.P.) and as dusts.

16.6.7 Metam-sodium
See diagram 16.13.10: Metam-sodium
Metam-sodium fungicide, C2H4NNaS2, often just called "metam", is a carbamate salt containing sodium,
which is used to kill fungi, insects, nematode worms and weeds in the soil.
It is a yellow to light yellow-green solution with an odour of amine and sulfur that varies in intensity,
and is fairly safe to use, but may irritate eyes and mouth.

16.6.8 Quintozene
See diagram 16.13.5: Quintozene
Quintozene, C6Cl5NO2, is a protective fungicide for seed and soil.
It is safe to use, but may cause skin irritation.
It may burn young leaves.
This can be used as a soil drench after planting to control various fungus diseases, e.g. damping off fungus and rots.
It is applied to soil before sowing or after sowing to treat both seeds and soil.
It can be used to treat soil at transplanting and treat seeds of cabbages.
Seeds that have been treated with it must not be eaten.
It does not kill many kinds of fungi.
It cannot be used to control bacterial wilt.
It is available as dusts, granules, and pastes.

16.6.9 Sulfur, wettable sulfur
It is a non-metallic element and is used as "Wettable sulfur".
It is a fungicide and acaricide.
It is very safe to use, but it irritates the eyes and skin.
It may damage leaves of plants in the pumpkin family.
There is no withholding period.
It can control mites on capsicums, citrus hibiscus cabbage and tomato.
Also it can control powdery mildew, downy mildew and some rust diseases, but it is not effective for other fungus diseases.
Sulfur is available as a dust, wettable powder and sulfur paste.
Some people mix wettable sulfur with canola oil to make a spray.

16.6.10 "Yates Anti Rot Phosacid"
The phosphorous acid in "Yates Anti Rot" Phosacid inhibits the growth of fungus and enhances the defence system of plants.
It breaks down in soil and does not harm the environment.
It controls collar rot in citrus and ornamentals, root rot in citrus, avocados and ornamentals (including native plants, luculias, daphne
and proteas), and downy mildew in grapes.
It is sprayed over the foliage where it is absorbed into the plant.
It has no withholding period, so it can be sprayed up to harvest.

16.6.11 Potassium permanganate, Condy's crystals
Potassium permanganate, KMnO4
Potassium permanganate solution controls powdery mildew.

16.6.12 Lime sulfur, CaSx
Lime sulfur, calcium polysulfide, lime sulfur, CaSx, orange-red, pH 10-12, [Ca(OH)2 + S], agricultural fungicide
It contains calcium and sulfur.
It is a fungicide, acaracide and insecticide that is sprayed or dusted on plants.
It can be dangerous to use and causes skin irritation.
It may burn leaves and metal.
It can control many fungus diseases, e.g. leaf spots and powdery mildew and it can control red spider and mite and scale insects.
This is a hard spray to use properly.
It may damage plants in the pumpkin family.
Lime sulfur is available as a solution or a powder.
Use lime sulfur, CaSx to kill moss.

16.6.13 Mancozeb
Mancozeb, ethylene bisthiocarbamate (EBDC), a dithiocarbamate (C4H6N2S4Mn)x.Zny, (a combination of Maneb and Zineb),
e.g. Pestanal«, Dithane«, protective fungicide, against many fungal diseases, including potato blight, leaf spot, downy mildew, and
used for seed treatment of cereal grains, low risk to humans, but irritates, eyes, skin, respiratory tract, toxic to aquatic organisms.

16.6.14 Maneb, manganese ethylene bis(dithiocarbamate (C4H6MnN2S4), fungicide, controls blight, leaf spot, downy mildew,
ámarine pollutant.

16.7.0 Safety of herbicides, weedicides, and pesticides
Always store keep these chemicals in their original containers!
In many countries it is against the law to decant them into bottles or other containers that originally contained other substances,
e.g. food or drink.
A herbicide is a substance used to destroy plants or to slow down their growth.
The formulation is the form in which the pesticide is supplied by the manufacturer for use.
The half-life is the time required for half the amount of substance to be reduced by natural processes.
The LC50 is the concentration in air, water, or food that will kill 50% of the subjects, usually laboratory rats.
Mutagenicity is the ability to cause genetic changes.
Non-target animals or plants other than those that the pesticide is intended to kill.
Persistence is the tendency of a pesticide to remain active after it is applied.
Residual activity is the remaining amount of activity as a pesticide.
Bees gathering nectar and pollen may be directly exposed to pesticides or they may carry contaminated pollen back to nests and hives
and expose other bees to it.
Copper (II) sulfate solution, dilute sulfuric acid and dinitro-o-cresol can each kill some weeds without causing injury to crops.
S7 Poisons: Nemacur, Bifenthrin
S6 Poisons: Bromoxynil, Metaldehyde (100%), Hortico blackberry and tree killer, Warfarin, Pindone, Propoxur, Diazinon, Dichlorvos
S5 Poisons: Ametryn, Dicamba, Pyrethrum, Pyrethrins, Baysol snail and slug bait, Yates Blitzem snail bait, Boric acid,
Unscheduled chemicals: White oil, Lime sulfur spray fungicide, Dipel HG bioinsecticide.

16.7.1 Bifenox
See diagram 16.13.5: Bifenox
Bifenox, C14H9Cl2NO5, contains chlorine.
It is a contact poison.
It is fairly safe, but irritates the eyes.
It remains a long time in the soil.

16.7.2 Dalapon
Dalapon, C3H4Cl2O2, 2, 2-dichloropropionic acid, "Dowpon"
See diagram: 16.13.3: Dalapon
Dalapon is a herbicide that kills grasses in many crops and drainage ditches.
Dalapon Na is a selective poison that is taken in by the plant and moves through it to kill all parts, including the roots.
It acts slowly over 2-3 weeks.
It is safe to use, but causes irritation to the eyes and skin of some people.
Dalapon can control most annual and perennial grasses.
It will kill every plant it touches.
Dalapon is available as a water soluble powder.

16.7.3 Glyphosate, herbicide
Glyphosate, N-(phosphonomethyl) glycine (C3H8NO5P), (HO)2P(O)CH2NHCH2CO2H, "Roundup", "Rodeo", "Accord", "Zero"
Glyphosate phosphonate, broad spectrum systemic herbicide, may be carcinogenic
See diagram: 16.13.6: Glyphosate
16.2.6 Phosphorous compounds, organophosphorus insecticides, See 2.
1. Glyphosate, gives non-selective control of all grasses and broadleaf weeds, as well as onion weed, bamboo, lantana, blackberry
and unwanted trees.
It is used for economical and easy control of weeds when clearing garden beds before planting.
It is non- residual. Use 200 mL of the concentrated formula to make up to 50 L of spray.
It is absorbed by the foliage then translocated down to the roots to destroy roots and the whole plant.
The first signs after spraying are a gradual yellowing and wilting of the plant then a complete browning of the entire weed and the
death of the root.
It is less effective if the weeds are not actively growing and the dry soil causes the stomata to close, poor leaf cover on weeds,
e.g. waxy leaves, rainfall up to 6 hours after application and if sprayed late in the afternoon.
To allow translocation down to the roots and the chemical to take effect, the weeds should not be disturbed or cut after spraying.
2. Commercial glyphosate products may contain inert ingredients, i.e. anything added to the product other than an active ingredient,
e.g. glyphosate 41%, polyethoxylated tallow amine surfactant 15% and water 44%.
It may contain the contaminant N-nitrosoglyphosate (NNG).
The registered use status is "General Use".
It can control many difficult weeds, e.g. nut grass, couch grass, Johnson grass (Sorghum halepense), paspalum, kikuyu grass, blady
grass, Guinea grass and purslane.
It is used in forestry and noxious weed control to control grasses, herbaceous plants, but not all broadleaf woody plants.
It is absorbed by leaves and prevents production of an essential amino acid and inhibits plant growth.
It is broken down by some plants to mainly aminomethylphosphonic acid.
Do not allow spray drift to contact desirable plants! It is safe to operators and has no residual activity in the soil because glyphosate
and the surfactants used in commercial formulations are strongly adsorbed by the soil.
However, it remains unchanged in the soil depending on soil texture and organic matter content until soil micro-organisms break it
Glyphosate and the surfactant are not absorbed from the soil by plants.
It may be harmful to fish, but it does not build up, bioaccumulate, in fish.
It is usually non-toxic to birds, mammals and bees.
In tests in male and female rats, the acute oral LD50 was 4320 mg / kg.
It does not cause genetic damage or birth defects, and no noticeable effect on fertility, reproduction, or development.

16.7.4 Paraquat
See diagram: 16.13.6: Paraquat
Paraquat, C12H14N2+2, is the trade name for N, N'-dimethyl-4, 4'-bipyridinium chloride.
Paraquat is a poisonous dipyridilium compound used as contact herbicide.
Concentrated solutions of Paraquat causes irritation of the skin, cracking and shedding of the nails, and delayed healing of cuts and wounds.
It is a contact fast action poison.
Paraquat is a very dangerous chemical
It can kill people if swallowed.
It is not poisonous after touching the clay in soils.
There is no persistence in soil.
There should be a 9 day withholding period before harvest.
It controls most broad leaf annual weeds and grasses.
It works best when weeds are 2-15 cm high.
It is not very effective on perennials with good root system.
It kills water weeds.
Keep livestock away when spraying.
Paraquat is available as water solution.
Mix with water and immediately spray on leaves.
Paraquat, Diquat and Cyperquat are quaternary ammonium herbicides related to cationic surfactants that kill by contact with the plant
foliage and cannot enter the plant via its roots because they are very strongly adsorbed onto clay and soil particles.
They are used to kill weeds between crops or just before a crop emerges.
They are toxic to humans.

16.7.5 MCPA
MCPA, C9H9ClO3, 4-Chloro-2-methylphenoxyacetic acid, 2-Methyl-4-chlorophenoxyacetic acid (MCPA), S5 poison
See diagram 16.13.11: MCPA
Phenoxyacetic acids can mimic the natural auxin, plant hormone, indole acetic acid and are not destroyed by the plant.
They can also be used in setting unfertilized fruits and promoting root growth.
When used in excess they can be used as herbicides.
For MCPA is used to kill dicotyledon weeds in monocotyledon cereal crops.
Equal amounts are absorbed by weeds and cereals, but the cereals remain unharmed because of the differences in their growing shoot

16.7.6 (2, 4-D) (2, 4-dichlorophenoxyacetic acid)
See diagram 16.13.11: 2, 4-D
(2, 4-D), 2, 4-dichlorophenoxyacetic acid, Cl2C6H3OCH2CO2H
The phenoxyacetic acid herbicides are 2, 4-D and 2, 4, 5-T and its precursor 2, 4, 5-trichlorophenol (TCP).
The selective herbicide 2, 4-D is toxic to broad leafed plants, but less harmful to grasses.
This hormone weed killer 2, 4-dichlorophenoxy acetic acid is an aryloxyalkanoic acid known also as a "phenoxy herbicide", which
includes MCPA, mecoprop, triclopyr and 2, 4, 5-T.
Their actions against weeds resembling those of auxins (growth hormones).
Absorbed 2, 4-D is translocated within the plant and accumulates at the growing points of roots and shoots where it inhibits growth.
The principal use is for the control of broad leaf weeds in cereal crops, including wheat, maize, rice, sorghum, grassland and turf areas.
It is also widely used in mixtures with other herbicides to provide weed control in forestry, orchards and non-crop areas, and for the
control of aquatic weeds.
2, 4-D is a WHO Class II "moderately hazardous" pesticide, in the same class as endosulfan, lindane, paraquat and toxaphene.
It has an LD50 of 375 mg / kg in the rat with evidence suggesting a similar level of toxicity in human.
Occupational exposure to 2, 4-D has produced serious eye and skin irritation, nausea, weakness and fatigue, and inflammation of
nerve endings.
The various chemical forms of 2, 4-D can have different toxic effects.
Orthocarboxylic acids, e.g. picloram, can behave in a similar manner and is more potent than 2, 4-D.

16.7.7 (2, 4, 5-T) (2, 4, 5-trichlorophenoxyacetic acid)
plant growth regulator, Cl3C6H2OCH2CO2H
(TCDD), 1, 4, 7, 8-tetrachlorodibenzo-p-dioxin, 2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin, C12H4Cl4O2 (and other formulations)
(2, 4-D), 2, 4-dichlorophenoxyacetic acid, Cl2C6H3OCH2CO2H
See diagram 16.13.11: 2, 4, 5-T | 16.14.0: Dioxins, "Agent orange", PCBs:
It was used to kill noxious weeds, e.g. privet and blackberry.
At first it caused birth defects in animals and chloracne rash in workers due to a dioxin impurity TCDD
(2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin), but this impurity can be controlled to an acceptable limit.
Production of 2, 4, 5-T was contaminated with the carcinogenic dioxin TCDD.
Agent Orange was used first by the UK military in Malaysia and later by the US military to defoliate jungle regions in Vietnam.
Abnormal foetal skeletal development, increased foetal mortality and other reproductive effects may be associated with exposure to
phenoxy-acid herbicide and their dioxin contaminants.
2, 4-D has low soil absorption and a high potential for leachability and 2, 4-D residues have been recorded in groundwater and
surface water.
Some formulations of 2, 4-D are highly toxic to fish.
2, 4, 5-T, 2, 4, 5-Trichlorophenoxyacetic acid, "Weedone", Acetic acid (2, 4, 5-trichlorophenoxy)-555, C8H5Cl3O3.
This herbicide was formerly used for industrial sites, lumber yards and vacant lots, range land and rice, lawns and turf, aquatic use,
home use, recreation areas, food crops for humans.
2, 4, 5-T is used post emergence alone or with 2, 4-d for the control of shrubs and trees.
It is also used for girdling, injection or cut stump treatment.
It has been used as a growth regulator to increase size of citrus fruits and reduce excessive drop of deciduous fruit, weed control in
lakes and ponds at 22-45 kg / ha, and along ditches and irrigation networks.
The use of 2, 4, 5-T in the United States has been cancelled since 1985.
It is odourless, but is an irritant to eyes, nose, and throat.
The persistence of 2, 4, 5-T does not exceed one full growing season.
Biodegradation of 2, 4, 5-T to 2, 4, 5-trichlorophenol appears to be the dominant removal mechanisms.
2, 4, 5-T is was one of the most rapidly decomposed herbicides.
2, 4, 5-T has been qualitatively identified in drinking water.

16.7.8 Acetochlor, C14H20ClNO2, herbicide may be carcinogenic, Environmental pollutant
In chloroacetanilide family of herbicides, used to control annual grasses in corn (maize) and soybean in USA by inhibiting growth of
seedling shoots, applied just before or just after planting of crop.
Often used in combination with atrazine.
Pollutant in Minnesota streams but to date (2017), not prohibited in USA.

16.8.4 Integrated pest management (IPM)
Teachers should adopt an IPM approach to the control of pests on school farms.
IPM is a process of selecting a range of control strategies and using them jointly in the removal of agricultural pests, or in reducing
their presence to an acceptable level.
Pest control methods that do not rely on the use of chemicals include the following:
1. Physical or mechanical control, e.g. hand picking, fly swats, mouse traps, fly screens, using light traps, using ultrasound, the hand
chipping of weeds.
2. Cultural or managerial control, e.g. farm hygiene, crop rotation, companion planting, adjusting the time of planting and harvest, the
use of sealed storage containers
3. Genetic control, e.g. the use of plants that are resistant to the pest
4. Exclusion, e.g. the erection of fences to keep out rabbits, the isolation of sick animals from a healthy herd or flock, the careful
inspection of animals before allowing them entry to a school farm
5. Biological control, i.e. the use of other living organisms to reduce the activities of pests, e.g. the control of the cabbage white,
butterfly with the bacterium Bacillus thuringiensis.
Bacillus subtilis, suppresses fungus Alternaria helianthi seedling blight of sunflowers

16.8.5 Chemical pesticides, poisons
1. S7 Poisons, "Dangerous poison, highly toxic".
Not to be taken.
Keep out of reach of children.
Must be stored in a locked poisons cupboard.
Apply the chemical strictly in accordance with the manufacturer's instructions given on the label, product instruction sheet and the
Use MSDS to determine the Dangerous Goods Packing Group.
Use chemical eye protection goggles eye and skin protection when splashes can occur or when spraying., e.g. Bayer Nemacur,
2. S6 Poisons "Poison, moderately toxic".
Not to be taken.
Keep out of reach of children.
Must be stored in a locked poisons cupboard.
Apply the chemical strictly in accordance with the manufacturer's instructions given on the label, product instruction sheet and the MSDS.
Use MSDS to determine the Dangerous Goods Packing Group.
Use chemical eye protection goggles eye and skin protection when splashes can occur or when spraying, e.g. Bromoxynil, Diazinon,
Dichlorvos, Hortico blackberry and tree killer, Metaldehyde (100%.), Pindone, Propoxur, Warfarin.
3. S5 Poisons, "Caution, low toxicity".
Apply the chemical strictly in accordance with the manufacturer's instructions given on the label, product instruction sheet and the MSDS.
Use MSDS to determine whether the pesticide is a hazardous substance and / or a dangerous good.
Use eye and skin protection when splashes can occur, e.g. Ametryn, Baysol snail & slug bait, Boric acid, Dicamba, MCPA,
Pyrethrum, Pyrethrins, Yates Blitzem (snail bait), Zero weed spray (glyphosate).
4. Unscheduled chemicals, "very low toxicity".
Use in accordance with the safety instructions on the label, e.g. Lime sulfur spray fungicide, Dipel H G Bio-insecticide, white oil.

Glyphosate 95% TC, 62% IPA salt SL, 41% IPA salt SL
Dimethoate 40% EC
Alpha-cypermethrin 10% EC
Clopyralid 75% WG/ WDG
Paraquat 42% TC, 20% SL
Mancozeb TC, 80% WP.

16.8.7 Arboricides
Arboricides are chemicals used to kill trees.
The most widely used arboricide for the destruction of individual trees is sodium arsenite, Na3As, which is highly poisonous to humans
and other mammals.
Arboricides should be used correctly and stored and disposed of safely.

16.8.10 Dinoseb
Dinoseb (2-sec-butyl-4, 6-dinitrophenol), C10H12N2O5, is a dinitrophenol fungicide and insecticide.
It is used as a contact herbicide for post-emergence weed control in cereals, undersown cereals, seedling lucerne and peas.
Dinoseb is also used as a corn enhancer and an insecticide and miticide.
The use of dinoseb is banned in some countries because it is known to cause birth defects and sterility if it gets into the drinking water.
However, the EPA in USA determined that the 0.007 mg/L or 7 ppb MCLG and 0.007 mg/L or 7 ppb MCL for dinoseb are still
protective of human health.

16.8.11 DCMU
DCMU, C9H10Cl2N2O, [(1, 1-dimethyl, 3-(3, 4-dichlorophenyl) urea)], diuron, inhibits photosynthesis.
It is a broad-spectrum residual herbicide and algicide used for pre-emergent and post-emergent control of both broadleaf and grass
weeds in agriculture.
It is used to control weeds in pineapples, sugarcane and cotton plantations.
It is also used to control weeds and algae in and around water bodies and is a component of marine anti-fouling paints.
The use of diuron on tropical crops, e.g. tea, coffee, and pawpaw is restricted in Australia.

16.8.12 Fungicides
Fungicides are chemicals that kills fungus.
Fungicides may be harmful to humans and farm animals and should be used correctly and stored and disposed of safely.
Farm workers should wear protective clothing and trained in the use of all agricultural chemicals.

16.8.13 Herbicides, weedicides, dishwashing liquids
Herbicides, weedicides, commonly called weedkillers, are chemicals that are poisonous to plants and are used to kill unwanted plants.
Some herbicides cause a range of health effects ranging from skin rashes to death.
Herbicides should be used correctly and stored and disposed of safely.
Dishwashing liquids contain surfactants (surface-acting agents), that may be added to herbicides to reduce the surface tension on the
leaves of sprayed plants to allow the herbicide to stick evenly to the leaf surface and ensure maximum absorption.
This process is valuable when spraying leaves with a wax or hair surface because it stops the formation of beads of weedicide held
apart from the leaf surface.
However, some dishwashing liquids may neutralize the effect of the active ingredient of the weedicide by binding chemically with it .
Also, dishwashing liquids may cause excessive foaming to damage spraying equipment.
Non-ionic surfactants, "non-ionic wetters", are recommended to replace dishwashing liquids added to weedicides.
If the weedicide already contains a "built-in" surfactant, there is no need to add more surfactants to the weedicide.
Granular formulations of weedicide require the addition of non-ionic surfactants to work correctly.
However, surfactants may be toxic to fish and frogs, but some "aquatic safe" herbicide formulations are commercially available.

16.8.14 Insecticides
Insecticides are chemicals used to kill eggs, larvae and adult insects by direct contact or by the insect eating the treated plants.
Pyrethrum and neem (Azadirachta indica), are natural insecticides.
Insecticides based on the nicotine from cigarette butts are now banned.
Insecticides may be harmful to humans and farm animals and should be used correctly and stored and disposed of safely.

16.8.15 Rodenticides
Rodenticides, commonly called rat poisons, are chemicals used to kill rodents, i.e. rats and mice.
Rodenticides are poisonous and may harm people.
Great care needs to be taken when using rodenticides to kill pests.
Rodenticides should be used correctly and stored and disposed of safely.
Farm workers should be trained in the use of all agricultural chemicals.

16.8.16 Acaricides
These chemicals are used to kill red spider, mites and other 8-legged pests.
See diagram 16.13.5: Dicofol
1. Dicofol, C14H9Cl5O, contains chlorine.
It is a contact poison of mites only with long residual action, does not harm insects, is fairly safe, is not systemic, but may burn eggplant
(Aubergine) and other fruit.
There is a 7 days withholding period.
Dicofol can control mites on citrus trees and red spider mite on passion fruit, banana, cassava and other crops, but Dimethoate is better.
Highly inflammable, do not smoke near it.
Dicofol is available usually as E.C., it is also available as W.P. and dusts.
2. Formaldehyde (formalin) can be used as a soil drench that prevents damping off disease of seedlings.
It will irritate eyes and nose.
3. Naled: 16.4.4
4. Dimethoate: 6.4.2
5. Sulfur, Wettable sulfur: 16.6.9
6. Methiocarb: 16.4.8.

16.9.0 Sprays, dusts, white oils
1. Basil leaf spray deters insects.
2. Compost that is mature is soaked in water, filter water and use as a spray.
3. Eucalyptus leaf spray deters insects.
4. Lettuce leaves, boil and spray on cabbages, cauliflower, Brussels sprouts to deter white cabbage moth.
5. Lime sulfur (it may stain paint)
6. Nettle leaf spray deters insects
7. Red peppers crushed in a household blender, strained + rubbing alcohol + half cup of hot water
8. Rhubarb leaves chopped into boiling water
9. Sabadilla lily for control of stink bugs
10. Seaweed sprays control fungus diseases
11. Soap sprays, using pure soap not detergent, break down waxy layer of exoskeletons on small insects.
12. Spearmint leaves spray
13. Talcum powder for control of corn ear worm
14. Tomato leaves crushed in a household blender, strained + corn starch + water.
Crushed tomato leaves contain solanine fungicide.
Dusts are best applied either in a proper duster or a tin with a stocking over the end.

Oil sprays
1. One cup vegetable oil to half a cup of water.
2. Scale, aphids, smooth skinned caterpillars, mites and young grasshoppers suffocate when their bodies are covered with white oil.
Oil sprays also deter the citrus leaf miner.
In a blender, combine 2 cups of vegetable oil with a cup of dishwashing liquid.
Blend it up until it is mixed well.
Store this concentrate in a jar.
Label it and include the dilution rate on the label.
Dilute 1 tablespoon in a litre of water, mix it well and spray the pest as well as both sides of the foliage thoroughly.
Always follow this dilution rate, because you can burn the foliage if it is too strong.
Do not apply it in hot weather.
Do not use it on plants with hairy foliage, ferns, palms and cycads as this can also cause leaf burn.
Never use it on your trees in winter.
3. Use 500 mL vegetable oil, 1 cup pure liquid soap, blend thoroughly in a mixer, store in a labelled jar in a cool place.
For use, dilute 1 tablespoon (15 - 20 mL), of the mixture with 1 litre of water.
Oil sprays can suffocate mites, scale insects and other small soft bodied insects and deter leaf miners and small grasshoppers.
The spray may not work on hairy leaves.
Do not use the spray during very hot weather.
4. Use 1 teaspoon (about 5 mL), liquid dishwashing detergent (as a wetting agent), 1 cup (about 200 mL) vegetable oil, 1 quart
about 1 litre) tap water all purpose spray for mites, aphids.
It is a contact insecticide so it must contact all the insects.
Test it first on small leaves because it may cause leaf tip burn.
Some people prefer soap suds, using soft potassium soap, instead of dishwashing detergent.
Also some people add ammonia or vinegar to attack scale insects.
5. Use 2 cups vegetable oil + 1/4 cup of dishwashing detergent in blender to form the concentrate then use 1 tablespoon,
(15 - 20 mL), to 1 litre of water.
Spray both sides of leaves until all leaves are dripping wet.
6. Use 160 mL dishwashing liquid + 15 mL glycerine in 4 L water
7. Use 4 parts vegetable oil, e.g. canola + 1 part dish-washing detergent, blend in electric blender until homogeneous, dilute 1:50 with
water, spray from above and below
8. Use 750 mL canola oil + 45 mL detergent, e.g. "Sill" + 1, 250 mL water
9. Use 300 mL canola white oil + 300 mL vinegar + 300 mL water 4 + "Alginox" to kill algae.
Spray during overcast weather or in the evening.
10. Use commercial white oil for scale insects, aphids, smooth skinned caterpillars, mites, young grasshoppers, citrus leaf miner,
mealy bugs, mites on roses, ornamentals, citrus, fruit trees.
White oil contains petroleum distillates oil in dewaxed light paraffin emulsifiers.
Spray white oil every 4 weeks.
Do not store above 35oC.
Do not use on citrus late autumn / winter and use not later than one day before edible harvest.
Small insects suffocate when bodies covered.
White oil is more expensive than the above general contact sprays.
11. Use 45 mL sodium bicarbonate + 35 ml white oil + 4.5 litres of water, spray weekly, saturate the leaves until runoff, for aphids,
black spot, powdery mildew
12. Use 5 mL of cooking oil + 5 mL household detergent + 500 mL of water.
Use the solution as a spray to control sooty mould.
13. Use 4 mL of sunflower oil + 10 cc sodium bicarbonate + 1 drop household detergent + 1 litre of water.
Use the solution as a spray to control black spot on roses.

16.9.1 Chilli spray
Chilli Project
1.1 Chilli spray contain an organic compound that repels insects.
Grind chillies, but be careful not to put it in your eyes, and add soapy water or detergent as a sticker.
Wear gloves and spray on leafy vegetables.
Repeat the spray regularly.
Label and store in a safe place away from children.
The spay deters ants, aphids and small soft body insects.
1.2 Use 50 small hot chillies or chilli powder or chilli paste, 2 litres of water, 5 g of pure soap flakes dissolved in hot water
or 5 drops of liquid soap.
Put the chillies and 1 litre of water in a household blender, strain the puree mixture, add the soap and 1 litre of water.
Spray the mixture without dilution.
Label and store in a safe place away from children.

16.9.2 Garlic spray
Garlic (Allium sativum var. sativum), Amaryllidaceae.
1. Soak garlic and onion in hot water.
Garlic oil may be effective against the larvae of mosquitoes and houseflies.
2. Use 3 crushed garlic cloves, 1 tablespoon (15 - 20 mL), of vegetable oil, 1 litre of water, 1 teaspoon of liquid soap
3. Mix 3 cloves of macerated garlic + 5 mL of household detergent + 500 mL of water.
Use solution as a spray to deter aphids, slugs, and beetles.
4. Slice 100 g of garlic cloves and add 2 teaspoons (30 mL), of paraffin oil.
After two days, add 600 mL of water and 1 teaspoon liquid soap detergent. Strain this concentrate into a plastic bottle.
For spraying, add 1 teaspoon of this concentrate to 600 mL of water.
The spry kills different pests including cabbage moth.

16.9.3 Nicotine spray
Nicotine, C10H14N2
Tobacco plant (Nicotiana tabacum), Solanaceae.
See diagram 16.1.0 3: Nicotine
Tobacco water, cigarette, butt water, colour of brown tea, kills underground pests.
Nicotine is an organic compound obtained from the leaf of the tobacco plant.
It can be made by putting non-filter cigarette, butts in hot water.
This poison is a stomach poison for many insects.
Nicotine chemical is too dangerous for use in schools.

16.9.4 Diatomaceous earth absorbacide
1.0 Class Bacillariophyceae (Diatomophyceae) (Phylum Bacillariophyta), diatoms
Diatomaceous earth is sold as a fine dusting powder that kills insects by absorbing the protective coating of wax and oil.
Also, it is rich in minerals, so it both protects and feeds plants when added to garden soil.

16.18.2 Insect repellents
See diagram 16.13.8: Deet, DMP
Natural insect repellents contained strong smelling oils, e.g. citronella, that repel insects after contact with the repellent.
The most effective insect repellents is deet, NN-diethyl-m-toluamide.
Also, DMP, dimethylphthalate, is an effective mosquito repellent, but it dissolves the plastic in watch glass and spectacles.
Other effective repellents are E-Hex, ethyl hexanediol, C8H18O2, and Indalone, butyl 3, 4-dihydro-2, 2-dimethyl-4-oxo-2H-pyran-6-carboxylate!
The best repellent for bush flies and sand flies is di-n-propyl isosinchomeronate with the addition of the pyrethrum synergist
N-octyl bicycloheptenedicarboximide, NN diethyltoluamide, di-N-propyl isocinchomeronate.
An attractant for pantry moth is "biolure" (2, E)-9, 12-tetradien-1-yl acetate.
Java oil contains geraniol and citronellal.

16.18.3 Withholding period
This is the recommended time between spraying the crop and harvesting the crop so that people will not be made sick by eating the
pesticide still on the plants.
Make sure that crops that have been sprayed are not harvested within the withholding period.
A sprayed crop must be washed thoroughly before being eaten.

16.18.4 Active constituent
Pesticides are usually a mixture of chemicals.
The chemical that kills the pest is called the active constituent.
The other chemicals in the pesticide just make it easier to use and are called the inert ingredients.
Some active constituents are inorganic compounds, e.g. copper oxychloride and some are organic compounds, compounds of carbon.
Thus an organic chloride compound contains a carbon compound and chlorine, and an organic phosphate compound contains a
carbon compound and phosphorus.
The name of the active constituent is always written on the label.
Pesticides are made by many different factories in different countries and each factory gives the pesticide its own special name called
a trade name, e.g. Glyphosate weed spray, N-(phosphonomethyl) glycine, "Roundup", "Rodeo", "Accord", "Zero", S5 poison
So it is possible or pesticides with different names to contain the same active constituent and be used to kill the same pests.

16.18.5 Resistance to pesticides
It often happens that pesticides do not kill all the pests.
Some get sick, but remain live.
These pests may produce offspring which will not be affected by the pesticide because they have developed resistance to this pesticide.
So it is not wise to always use the same pesticide. Instead the pesticides should be changed from time to time.
So when you use up all of one type of pesticide, try using another type.

16.18.6 Persistence
Some pesticides and weedicides remain active for a long time, even in the soil.
The time they remain active is called "persistence".
Pesticides that persist for a long time may be dangerous because their poisonous properties may affect later insects, animals and crops.

16.18.7 Surface-acting agents
Surface acting agents are chemicals that may already be added to the pesticide or that can be added to the pesticide.
They include detergents, soaps, wetting agents, spreaders and stickers.
These chemicals spread the pesticide over the plants better and may make them stick to the plants.
The label on the pesticide will tell you whether to mix with a surface active agent, a surfactant.
There are many commercial surface active agents or use any washing detergent.

16.18.8 Emulsifying agents
An emulsifying agent is a chemical similar to soap that helps oil and water to mix and form an emulsion.
When two liquids can mix they are called miscible.
Wettable powders (W.P.) are a mixture of an active constituent, e.g. sulfur, an emulsifying agent, and inert materials, e.g. clay.
Water is mixed with the wettable powder to make a spray solution.
Emulsifiable concentrates (E.C.) are a mixture of active constituent, an emulsifying agent, and oil.
Water is mixed with the emulsifiable concentrate (E.C.) to make a spray solution.
Emulsifiable concentrates and wettable powders should never be mixed together.
The label on the pesticide tells you which other pesticides can be mixed with it. Granules
Granules are very small pieces of rock with pesticides stuck to them.
They are usually used when the pesticide has to be put in the soil. Fumigants
Fumigants are poisonous gases used to kill pests in stored crops or soil.
They are very dangerous and should not be used in schools.
Some Departments of Agriculture use the dangerous poison ethylene dibromide on agricultural products that carry disease. Synergists
Synergists are chemicals added to pesticides to make them more poisonous, e.g. piperonyl butoxide makes the insecticide pyrethrum
more poisonous. W / V, W / W
W / V This means weight per volume or the weight of active constituents in a certain volume of pesticide.
So 30% W / V emulsifiable concentrate means 30 grams of active constituent in every 100 mL of the emulsifiable concentrate.
This may also be written as 300 g / L (grams per litre).
W / W. This means weight per weight or the weight of active constituents in a certain weight of pesticide.
So a 50% W / W wettable powder means 50 grams of active constituent in every 100 grams of wettable powder.
This may also be written as 500 g / kg (grams per kilogram).

Before teaching this project, discuss the content of the lessons with a field officer of the Ministry of Agriculture,
and get advice on planting material, planting distances, site for planting, approved mulch, composting, and control of pests and diseases.
Use only the procedures, agricultural chemicals and insecticides recommended by the local field officer of the Ministry of Agriculture.