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FACTSHEETS FOR FARMERS


www.plantwise.orgCreated in Zambia, September 2016


Baking soda against powdery mildew in okra

Recognize the problem

Powdery mildew is a fungal disease. Plants affected by powdery mildew look

like they have been dusted with flour. The disease first starts off as circular

powdery white spots which can appear on leaves, stems and sometimes fruits.

Later it usually covers the entire upper part of the leaves. It affects the older

leaves first. At the end, the leaves turn yellow and dry out.


Background

Powdery mildew affects a wide variety of crops and takes away a plant’s

nutrients. This causes the plant to become weak and the growth rate becomes

slow.

Baking soda (sodium bicarbonate) is a common powder found in almost all the

super markets. It can be used in organic farming. Baking soda works by

creating a harsh environment for the fungus to survive on the leaf. If

available, use potassium bicarbonate which is more effective than sodium

bicarbonate (baking soda). The spray of water and potassium bicarbonate will

kill and prevent the powdery mildew to some extent. When 6-10 out of 100

okra plants are showing the initial spots of whitish powdery growth on the

leaves, potassium bicarbonate solution may be sprayed. When the problem is

expected to become severe, such sprays may not be efficient enough. When

most leaves are covered with the mildew, all actions, even chemical sprays, are

too late.


Management

• Wear gloves

• Mix 9-10 tablespoons (bottle top lid) of potassium bicarbonate with 16


litres of water in a knapsack sprayer.

• Add 3-4 tablespoon vegetable oil or any available cooking oil. This helps


the spray to stick to the leaves.

• Add 9-10 tablespoons of soft dish washing soap (such as sunlight™)

• Close the sprayer well and shake.

• Spray on both the top and bottom of the leaves using a knapsack


sprayer

• Spray once a week for three weeks and switch to 11-12 tablespoons if


fungus is still growing or spreading.

• Spraying should be done in the morning or evening when the leaves are


still moist

• Do not spray on okra that is soon to be harvested


Scientific name(s) > Podosphaera spp.


The recommendations in this factsheet are relevant to: Democratic Republic of the Congo, Malawi, Tanzania, Zambia


Authors: Jacqueline Mweembe

Ministry of Agriculture

tel: mweembejay@gmail.com email: +260977478715


Edited by Plantwise


Plantwise is a global initiative led by CABI


ZM075En


Lose Less, Feed More


Whitish powdery mildew attack on

okra leaves. (Photo by Scot Nelson)


Baking soda. (Photo by Melissa

Baldwin)

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