Project Everest

Work Update

Push- Pull Pest Management in Malawi

by
Roya Ghodsi
Roya Ghodsi | Jul 27, 2017 | in Agriculture Assessment

The research conducted by the Malawi Agriculture Assessment team this month has revealed the poor pest- management methods used by smallholder farmers which pose significant threat to their food and income security. The surveys we conducted with smallholder farmers in the Nancholi area identified chemical pesticides as being one of the largest contributors to farmers’ input costs, particularly this dry season during which there has been an influx of pests and diseases. This excessive use of chemical pesticides is unsustainable given the already low disposable income level of most of these farmers, and particularly since the extensive costs put towards these pesticides are not being recovered by the return profit from their crops. Some farmers have predicted a loss of up to 25 per cent of their produce (and subsequently their income) this upcoming harvest due to their lack of capacity to respond to the unexpected influx of pest infestation. Most pesticides have also proven to be largely ineffective.

These issues of poor pest-management practice suggest a need for sustainable intensification within the Experimental Farm model that will be implemented in Malawi in December. Sustainable intensification is the incorporation of scientific principles of ecosystem management into farming practices to maximise crop production with minimal external input costs. Sustainable intensification methods include Integrated Pest Management, nutrient cycling, improving on-farm biodiversity, and enhancing nitrogen fixation – all which increase agricultural productivity while minimising adverse environmental effects. Integrated Pest Management (IPM) looks specifically at managing pest populations using cultural and biological controls rather than chemical pesticides in order to naturally impede the pest’s ability to thrive in a certain environment.

The most common pest we observed on smallholder farms was the stem borer Brusseola fusca (Noctuidae), a lepidopteran species (moth) whose larvae damage the leaves, stem, and grain of the maize crop; contributing to 88% of maize crop losses. The ‘Push-Pull’ strategy is an IPM strategy already developed in Africa for the control of stemborers in maize farming systems, which if implemented in the Experimental Farm in Malawi, has the potential to significantly increase resilience to pest infestations.

The ‘Push-Pull’ strategy essentially exploits the natural production of semio-chemicals by plants to manipulate pest behaviour and therefore control their distribution and abundance. In this strategy, the pests are deterred away from the Maize by the use of repellent ‘push’ plants. These plants produce the same chemical as maize does when an insect feeds and damages its plant structure, tricking other pests into thinking that the maize habitat is already occupied. The pests are simultaneously attracted using chemical stimuli to other areas such as trap ‘pull’ plants where they become concentrated, enabling their management by the farmer.

Desmodium is an example of a ‘push’ crop grown in Africa which defers pests from the maize crop once they detect its semio-chemicals, of which it produces 100 times more than maize. If Desmodium were to be sown between maize in each bed of the Experimental Farm, it would deter pests out of the field to a trap ‘pull’ crop on the field’s border (perhaps Napier grass). This is because the pest species will assume the area is overpopulated and therefore is less likely to lay eggs in the field.

Given that Desmodium is a legume which can fix 100kg of nitrogen per hectare, its planting will also serve as a natural fertiliser to improve soil fertility and enhance nutrient cycling. This will further increase crop yields and reduce farmers’ dependency on external inputs such as synthetic fertilisers.

This push-pull system is just one example of an IPM strategy that has potential for success if implemented into the Experimental Farm. Not only could it reduce production costs and crop losses associated with pests, but it would feed directly into Project Everest’s vision for an entirely self-sufficient and eco-based farm model.

I’d love to hear any feedback or further input, particularly from any Trekkers with greater Ag expertise than myself who could help assess the viability of this idea.

edited on Jul 27, 2017 by Roya Ghodsi

Andrew Vild Jul 27, 2017

This is fantastic! Very impressed with the technical knowledge and the fact you've done background research. It might be useful if you attached any files with the articles you used for research or included links or references for future use.

I would also be interested to see how this applies to crops such as pigeon peas, which have the larvae eggs planted inside the casing and the peas themselves are a meter or more off the ground.

Hoping to see feedback from some aggies (Lisa, Zoe!)

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Zoe Paisley Jul 27, 2017

Seriously love this system Team! You've done some amazing research and I'm super impressed.

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Zoe Paisley Jul 27, 2017

The great thing is Lisa and I have studied Helicoverpa on cotton, so we have some resources we can talk to about specific pest management on Maize. Something to consider would be having desmodium in between the beds and then the pigeon pea in the beds, climbing on the fencing to flow over onto the path or just in the centre of the bed. This way you couple the push plant and the nitrogen fixing plant both in the path and bed.

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Isaac Crawford Jul 27, 2017

This could gain some serious momentum for one of the Malawian experimental farms, as it currently fully occupied with pigeon pea shoots.

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Zoe Paisley Jul 28, 2017

We can definitely work with the pigeon pea.

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Campbell Chesworth Dec 4, 2017

Hey Zoe, would you be able to elaborate on this/provide some resources on how this could/should look?

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Isaac Crawford Jul 27, 2017

Natural, non chemical solutions are going to be the way forward in Malawi. There is certainly a need to limit input costs for smallholder farmers in order for them to be able to use their currently limited income on alternative things to farming, such as health services. Increasing soil health through crop rotation and nitrogen fixing, rather than input intensive fertiliser dependence is something that will stem from this proposed IPM system. Your example of Desmodium is perfect, as currently based off our recent soil samples many smallholder farmers have issues with nitrogen deficient soil. Excited to see Malawi's agricultural knowledge and expertise develop with time!

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Lisa Paisley Jul 30, 2017

I honestly love IPM's. They mimic the natural ecosystem and have so many benefits for the farmer, community and environment.

You touched on it in the post but one of the key aspect of this system is the pull crop. From the study that most of this research is based off, Napier Grass was found to be the most effective crop to use. Not only does it attract the moth to lay its eggs on the plant rather than corn, Napier grass also produces a sap when larvae feed. This means the insects are physically trapped on the plant and can not survive. Its sick.
Also Napier grass is a native to Sub Saharan Africa meaning that very few inputs like water or fertilisers would be required to optimise growth.
But the major benefit is that Napier grass can be used as feed for livestock. This means that farmers can either harvest the grass then sell this as hay or sillage to a fellow producer OR they can start including livestock on their farm. The latter is ideal as this diversifies the production system and creates a buffer for the producer meaning that if their crops fail they can still have some income by selling their livestock.

Basically this is super exciting and something I've wanted to implement for a while now, so I can't wait for it to be up and running in Malawi.

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Amber Johnston Jun 30, 2018

Status label added: Work Update

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