Chemical war on armyworms


Since fall armyworms arrived in Malawi December of 2016, government and development partners have developed strategies to effectively control this pest.

The national response plan adopted last year spells out various activities to control the armyworms.

Pesticides certainly have a place in the government’s plan for large-scale adoption of an integrated pest management (IPM).

Applying pesticides can be dangerous of people and the environment.

A leaf damaged by fall armyworms

“In an ideal world, only trained extension workers and lead farmers would be spraying,” says entomologist George Phiri, the assistant programmes representative at Food and Agriculture Organisation (FAO).

Government and donors have spent considerably on personal protective clothing, sprayers and safe pesticide use training.

But some farmers can be seen applying pesticides with bare hands using water bottles and other makeshift spraying devices—“without any supervision”.

“Others do not even know the names of the pesticides they apply and the precautions they should take to protect themselves from the potential dangers,” he says.

Even the efficacy of chemical control varies considerably.

Presently, there are unsubstantiated reports of fall armyworms developing resistance to Cypermethrin, the initial pesticide government distributed to control the pest. This may have to do with spraying techniques, timing, dilution and whether the spraying was targeted or non-targeted.

The stage of the life cycle at which the pest is sprayed can also determine the effectiveness of pesticides.

At advanced stages of development, the worms actually hole up in parts of the maize plant where they are protected from the pesticides.

Pesticides are expensive and are not cost-effective if improperly used.

Farmers who use chemicals — whether purchased from agrodealers or distributed for free or on subsidized terms— receive varying information on how to apply them.

This leaves plenty of room for human error and exposure.

According to Dimitri Giannakis of Farmers World, a leading supplier of farm inputs, most formal and informal agro-dealers are not specifically trained in helping farmers make better choices.

He says: “Many have basic knowledge of prices, and which chemicals are usually applied to which crop, but in most cases agro-dealers do not have enough information to differentiate between the effectiveness of the chemicals.

“Even formal retailers have challenges in ensuring that farmers get the right information.”

Farmers World has created Farm Services (FSU) Unit to help formal agrodealers in their network gain the technical knowledge they need to properly advise farmers.

They also help farmers weigh the costs and benefits of spraying.

FSU coordinator Caitlin Shaw says: “For example, failure to alternate chemicals can be extremely counterproductive and expensive for a smallholder.

He reckons in pest management, the importance of training alongside purchasing is even higher.”

Farmers World has deployed an extension agent at each point of sale to mitigate the risk faced by the farmer.

But more work is needed nationally.

“The bottom line is:  spraying alone is not enough to tackle aggressive pests like fall armyworms,” warns European Union agricultural scientist Jean-Pierre Busogoro.

He adds: “In the longer term, an IPM strategy is affordable and thus, accessible for the majority of farmers and can help promote consistent agricultural messaging.”

Busogoro favours working through farmer field schools, a participatory extension approach that involves farmers in developing and assessing technologies. They call it “learning by doing.

While the initial inputs for farmer field schools may cost more up front, Busogoro  says, they may prove more sustainable in the long-term as communities are empowered and easily accessible, already organised into groups.

“Learning-by-doing can bring lasting impact to farming communities by allowing farmers to develop their own solutions adapted to local conditions,” he says.

Phiri explains that adoption of recommended agronomic practices—including timely planting, before build-up of the armyworms’ populations—is an integral part of dealing with in the long term.

“The older a crop gets beyond the vegetative stages, the lower the chances of successful control of the pest,” explains Phiri.

Early planting and early-maturing varieties can help.

Intercropping and more diverse cropping systems can also help slow the spread of fall armyworms and other pests and diseases by creating a barrier from the crop that are edible by the pests.

According to the International Centre of Insect Physiology and Ecology (Icipe), the“push-pull” intercropping technique has proven particularly successful in controlling fall armyworms.

Originally developed for controlling the cereal stem-borer, another pervasive pest,   push-pull involves growing a cereal crop—like maize, millet or sorghum—with insect-repellent legumes in the Desmodium genus.

Such intercropping ‘pushes’ pests away from the prone cereal crop.

The cereal crop is simultaneously intercropped with Napier grass or other vegetative plants which serves as an enticing border that ‘pulls’ the pests away from the cereal crop.

While fall armyworms represents a new and tricky challenge to Malawian farmers, Malawi is no stranger to pests.

For solutions. We can also look to the successful local control of African armyworm.

Since 2014, the GoM and FAO have successfully build capacity at the community-level to monitor and predict outbreaks of African armyworm in hotspots.

While we know that FAW is here to stay, Malawi can rise to the challenge through early planting, intercropping, biological control, use of botanical pesticides, reduced use of hazardous pesticides and utilising farmer field schools.

The Ministry of Agriculture, Irrigation and Water Development also plans research on various solutions, including the impacts of conservation agriculture on fall armyworms’ population. n

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