Flour preparation

Flour preparation can be used against the following pests (clicking on underlined pests takes you to pests' page): Aphids, Spider mites. Flour and soap can also be used against Thrips, Whiteflies, Downy mildew on cucumbers in greenhouses.

General Information on Flour Preparation

Flour mixed in water is said to be very effective against aphids and spider mites. It should be applied in the morning taking care to spray underside of leaves. As the heat of the sun increases, the mixture dries out and the insects are left encrusted in flour, shrivel and die. The coating of flour falls off the leaves so that their ability to photosynthesise is not essentially affected (Stoll 1988). 

According to Ellis and Bradley (1992) starch like ordinary baking flour is an old pest control remedy, whereas numerous products made as non poisonous insect control from potato starch, are currently on the market in the US and India. Reportedly potato starch apart from killing aphids, red spider mites, white flies and thrips also acts as an inhibitor to downy mildew on cucumbers in glasshouses.

Recipes for Flour/ Starch Preparations

Flour preparation I: 

A spray made from 2 cups of fine white flour well stirred into 5-10 litres of water is said to be very effective against aphids and spider mites. 

Flour Preparation II: 

Stir together vigorously 1 cup of buttermilk with 8 cups of fine white flour and 50 litres of water. Spray this onto the affected crop taking care to treat the underside of the leaves. This mixture destroys eggs, larvae and adult mites. Four applications have been shown to kill 95 % of red spider mite infestation (Stoll 1988).

Flour and Soap III: 

- Add 2 - 4 tablespoons of wheat or potato or any baking flour into 4 cups of warm water. 
- Stir well. 
- Add 1 teaspoon of soap as sticker. 
- Stir the filtrate again prior to application. 

Recipe for potato starch remedy

Commercial potato flour is not on the market in Kenya, but it is very easy to produce at home. 
Finely shred a few Irish potatoes and mix in a bowl of water. Leave to stand for some hours, then stir the mixture and sieve out the potato flesh. Remaining in the bottom of the bowl will be a white layer of potato starch. If not to be used right away, the water can be decanted, and the starch dried for later use.

Potato starch spray: mix 2-4 tablespoons of potato starch in 1 litre of water and add 2-3 drops of liquid dish soap. Shake the mixture and spray to cover the leaves well. Very close to recipe for flour and soap III.

Information Source Links

  • Ellis, B. W. and Bradley, F.M. (1992). The Organic Gardener's Handbook of Natural Insect and Disease control. Rodale Press. ISBN 0-87596-753-1
  • OISAT: Online Information Service for Non-Chemical Pest Management in the Tropics. www.oisat.org 
  • Stoll, G. (1998). Natural crop protection in the tropics. Margraf Verlag. Weikersheim

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