Biological Pest and Disease Control

Some people expressed interest in how I control pests and diseases in a biological way. Therefore I will post a few recipies on how to make these dawas at home before I continue on the chicken series. I will sort the recipies by main ingredient. Thereby you can see what you have got available and how you can use it.

All these recipes are useful, cheap and easy to produce, the most important factor in biological pest and disease control however is the general state of your crop. Diseases and pests are opportunistic, they always go after the weakest plants. It is therefore important to keep your crop strong by managing your soil well. Keep the crop well irrigated and supplied with adequate nutrients to give it the best start. Ensure microbial life in the soil is abundant by using plenty of compost regularly. Microorganisms in the soil are your best ally in controlling pests and diseased. For every harmful nematode, fungus or bacteria there are thousands of beneficial ones that assist in feeding your crop, keeping it healthy and controlling harmful ones. These biological controls are meant as as prevention of disease and should be used early to avoid spread and bigger damage. That means the farmer has to monitor his crop very regularly.  

Artemisia

Artemisia

Mix 1 kg dried Artemisia leaves into 10 litres of water. Boil for 20 min. Leave overnight, then filter it through a cloth and add 2 Tblsp of liquid soap.
Spray as a repellent against aphids, worms, bugs and slugs.

Ash

Sprinkle 1 tsp of ash into the emerging sheaths of plants, which are prone to attacks from worms or bugs. Especially effective against maize stalkborer and termites.

Ash & Castor Oil

Mix 2-3 kg of ash into 1 litre of castor bean oil. Spread over a seedbed of about 100m2 Repeat 2-3 times at weekly intervals. Prevention against soil-borne diseases.

Ash & Tumeric (binzari)

Fresh and Dried Turmeric

This is one treatment I use all the time. Turmeric powder can be bought as a spice from supermarkets.
Mix 200g of turmeric powder with 800g of wood ash. Apply during early morning hours over plants that are easily affected by powdery mildew (tomatoes, cucumbers, melons, peas, etc.) I use a sieve to dust it over all the leaves and repeat this treatment regularly especially during times when day and night temperatures differ greatly.

Powdery Mildew

What is the difference between powdery mildew and downey mildew? Powdery mildew grows on the upper surface of the leaves as if they were dusted with baby powder (powdery). Downey mildew grows on the underside of the leaves (it is easy to remember if you say it is down > downey mildew). Both are a fungus. Therefore ash and turmeric can also be used against other fungal diseases but it doesn't work too well for downey mildew as it will not stick to the underside of the leaves.

Chili-Garlic

Making this one is a bit tricky as grinding the chili really hurts your eyes and throat. Better cover your mouth with a cloth and wear rubber gloves to protect yourself.
Grind together 50g chili and 50g garlic. Mix with 10 litres of water. Filter through a cloth if you want to use a sprayer otherwise apply directly using a soft broom or leafy branch from a tree, dip it into the mix and flick it over the crops. Use against aphids and jassids.

Aphids

Jassid

You can increase the concentration of this spray by using only 5 litres instead of 10 litres of water. You can also substitute all or part of the garlic by more chili.

Coriander (dhania/giligiliani) seeds

Coriander Seeds

Boil 200g crushed coriander seeds for 10 min in 1 litre of water. Filter through a cloth and add 2 litres of water.
Spray as an antifungal and repellent against spider mite.

Spider Mite Damage

Garlic

Mix 1 crushed garlic bulb with 4 litres of water and soak overnight. Filter through a cloth and add 1 tsp of alcohol. Spray on the soil in spots where you suspect root-knot nematode infection. Do this before the nematodes spread over larger areas.

Root-knot Nematode Damage

Ginger (Tangawizi)

Mix 20g of ginger powder into 1 litre of water and mix well. Spray thrice at fortnightly intervals against powdery mildew, Drechslera oryzae, Rhizoctonia solani, Sclerotium oryzae and Sclerotium rolfsii. (Hover the curser over the pictures below to display the names.)

Drechslera oryzae

Rhizoctonia solani

Sclerotium oryzae

Sclerotium rolfsii

Gliricidia sepum

Gliricidia sepum is not a common tree species in East Africa. If you can get your hands on a seedling however it is a very worthwhile tree to plant in your farm. It is a very versatile plant.

Gliricidia sepum

Grind 500g Gliricidia leaves and/or bark and soak in water for 1-3 days. Filter through a cloth and dilute with water to make 20 litres. Spray against pests in cucumber, as a fungicide in tomatoes, and as a general fertilizer and insect repellent .

Lemon Grass (Mchai chai)

Grind 50g of lemon grass and mix with 2 litres of water. Leave to soak for several hours. Strain through a cloth and spray as a bactericidal on carrots, lettuce and on tomatoes against blight.

French Marigold (Tagetes)

Marigolds are very beautiful and useful plants that every farmer should have in abundance on his/her farm. They can grow as an intercrop even between the rows and will provide some crop protection as such. In case no French Marigold is available a farmer can also use the wild growing Tagetes minuta, which is often falsly considered a weed.

Tagetes patula

Tagetes minuta

Pound 250g of Tagetes leaves and flowers and cover with water. Leave to soak overnight. Strain through a cloth and fill up to 1.8 litres of water.
Spray against bean pod weevils, aphids, leafhoppers and against blight in tomatoes.

Neem Leaves or Neem Seeds

A friend of mine in Dar es Salaam experimented with crushed Neem seeds as a repellent with very convincing results. The problem with Neem seeds is that they rot very fast and are difficult to store over a longer period. But if you have Neem trees or can get some seeds it is definitely worth making some excellent repellent out of them.

Leaves and fruits of a Neem tree

1kg Neem leaves and/or seeds. Pound the leaves and/or crush the seeds. Cover with water and leave overnight. Strain through a cloth and take 5 litres of the original liquid and add 15 litres of water. Add 1 Tblsp of liquid soap. Spray against whitefly, aphids and locusts every 4 days.

Neem Oil

Neem oil is even more effective than Neem leaves. It is available in East Africa but unfortunately not very cheap. Try to find it in pharmacies, Health shops or at good agrovets.

Mix 30-40ml of Neem oil into 1 litre of water and stirr well. Use immediately.
Spray against sucking insects like aphids, whitefly and stem borers.

Onion

Remove the base from an empty and washed 2-litre cooking-oil bottle and place 2 chopped onions in the head-over bottle (cap on). Pour 2 litres of hot water over the onions and let them soak for 24 hours. Bore a hole in the cap and place the bottle head-over into the soil so that the onion concotion slowly seeps into the soil.

Place in an area where ants are a problem. The smell repells them, Also helps against Alternaria tenuis, Colleotrichum ssp., Fusarium ssp. and Helminthosporium ssp. Hover the curser over the pictures to display the names of the diseases.

Alternaria Leafspot

Colleotrichum

Fusarium wilt

Helminthosporium

Pawpaw Leaves

Rust is very difficult to control. I suggest for all perennial crops like green asparagus and lemon grass, which are prone to rust, that at first all leaves be cut back behind the point where the rust is visible. New growth should then be sprayed with this concoction weekly to control new outbreaks.

Rust on Maize

Rust on Asparagus

Chop and pound 1kg of pawpaw leaves and add 1 litre of water. Leave for 6 hours. Strain through a cloth and add 2 Tblsp of liquid soap. Dilute at a rate of 1:4.
Spray against rust every 3 days early mornings or late afternoons.

Rhubarb Leaves

Rhubarb plants are available in East Africa but not widely common. Try to get a plant so that you can produce one of the most powerful pesticides at home for free. The stems of rhubarb are edible and make the delicous rhubarb crumble or rhubarb compote. The leaves however are poisonous and must not be eaten!
Boil 1 cup of chopped rhubarb leaves in 6 cups of water. Leave to cool. Strain through a cloth. Add 1 Tblsp of liquid soap.
Spray against thrips or other sucking insects.

Thrips damage

Note: this is poisonous! If you store it mark clearly on the bottle that this is a poison. Don't spray on plants, which are to be harvested for consumption soon.  

Tobacco

Tobacco is another plant that is poisonous and must be handled with care. It is important to avoid skin contact and to protect the respiratory system by wearing a mask. Plants may not be eaten for 3-4 days after application!

Tobacco plant

Boil 250g chopped tobacco leaves in 4 litres of water for 30 minutes. Filter through a cloth. Dilute at a rate of 1:4 and add 2 Tblsp of liquid soap.
Spray against caterpillars, beetles, leaf miners, stemborers, aphids, thrips, cutworms and rust.

Tomato

Pound 250g of tomato leaves and stems and soak in 4 litres of water for a few hours. Filter through a cloth. Add 2 Tblsp of liquid soap.
Spray against diamondback moth caterpillars. Start spraying when the larvae begin to develop.

Diamond back moth

Larvae and pupae

Vinegar and honey trap

Mix 1 cup of vinegar, 2 cups of water and 1 Tblsp of honey. Mix and shake well. Fill into a blue plastic bottle and drill small holes into the bottle just above the liquid level. Alternatively cut off the top and stick it head over back into the bottle (without the cap). This will make a trap. The smell of the liquid and the blue colour of the bottle will attrackt fruitflies who will not be able to leave the bottle again and drown in the liquid.

Fruitfly Trap

Place in areas where you want to attrackt fruitflies away from fruit trees, cucumber, zucchinis and melons.

Yellow Sticky Traps

Yelow sticky traps are the only reliable remedy against whitefly that I know of. Chemical control is almost impossible as the whiteflies are very mobile and just fly off when being sprayed. They are however strongly attracted to bright yellow and will settle on anything of that colour. This is used in yellow sticky traps. These are small yellow plastic sheets or long yellow plastic bands covered in a very sticky glue that doesn't dry out for several weeks. Whitefly and also leafminer flies and fruitflies get stuck on the non-poisenous coating and die.

Yellow sticky trap

Trap bands in greenhouse

Place a good number of sticky traps near any plants at risk, like tomatoes, lemon trees, pawpaws, etc. or distribute them all over the greenhouse. They are available from the internet or from Koppert in Nairobi http://www.koppert.com/distribution-koppert-products/kenya/
It is also noteworthy that whiteflies are a typical drought pest. They always attack plants that are stressed. It is therefore important to ensure sufficient irrigation to avoid plants getting stressed. A greenhouse should also always be constructed in a way that whiteflies can't enter (Double door entrance, small netting size, etc.) Once they have infested a greenhouse it is almost impossible to eradicate them again. They will weaken the plants further and spread diseases.