News and knowhow for farmers

Sh60 can save farmers up to 80 per cent harvest loss


With as little as Sh60 per growing season, greenhouse horticultural farmers can save up to 80 per cent of their produce lost to aphids and other small pests using biological remedies.

The biological, environmental friendly methods also reduce to zero the chemical component of the produce, a factor that increases likeability in major export markets like the European Union.

Aphids attack capsicum, roses, tomatoes, cucumber, courgette, pepper, pumpkin, eggplant, cabbages and kales, African black nightshade, among other greenhouse crops.

Fruit trees like citrus, beans, peas, barley, wheat, are just but a few outdoor crops affected by the aphids.


Catherine Gacheri of Dudutech, a Naivasha-based integrated pest management solutions international institution, says the pest is deadlier in greenhouses than in the open fields.

In outdoor farming, aphids account for 25 per cent loss. This is because continuous showers help in controlling colony multiplication and effects.

“The yield loss, however, goes up in dry seasons since aphid colonies build up without interference from environmental elements like rain. In enclosed spaces like greenhouses, they can easily lead to produce loss of more than 80 per cent if not controlled,” she says.

Dudutech supplies Aphidius spp, Beauvitech and Lecatechve biological solutions for eradicating aphids, thrips, white-flies among other pests.

Do the maths

For open field application, one acre of the crop requires 100mg of fungal based products such as Beauvitech and Lecatech. Two hundred and fifty milligrammes of the two products costs Sh2,000.

It costs Sh119 to spray a 30m by 80m standard greenhouse, which is equivalent to 0.0593 acres. The protection will last until harvest.

For Aphidius spp, a farmer will require 500 insects per hectare, costing Sh2500. This translates to 200 insects per acre, costing Sh1,000.

If this amount is broken down to a greenhouse of 30m by 80m, the farmers incurs about Sh60 for about 12 insects. These insects will provide protection into the next growing season if there is a natural plantation nearby the field.

But Dudutech will not segment the product to this level, but the farmer can use is on another piece or time.

Cancer danger? No export

Besides chemical pesticides being hazardous to the farmer while applying, they reduce export market appeal of the produce.

In 2012, the EU banned importation of horticultural produce containing dimethoate chemical levels exceeding 0.02 parts per million. The chemical, which is an ingredient of most pesticides, is linked to cancer.

The EU consumes about 80 per cent of fruits and vegetables as well as 42 per cent of flowers from Kenya.

Approved effective solution

Pests undergo genetic mutation to survive consistent chemical application with time.

“There is no way that pests are going to be resistant to biological insets unless they migrate before they are destroyed. Biological control is sustainable,” Gacheri says.

As the global horticultural market turns eyes to organic farming, biologically produced harvest would attract more market and higher prices than chemical-residue-containing harvest.

The biological control organisms are affordable and approved by the Kenya Plant Health Inspectorate Service.

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