Look beyond chemicals in locust control

The Horn of Africa is going through the worst desert locust invasion, which is expected to continue at least until the end of the year.

Kenya is working to control the invasion, but the methods being used are harmful to the people and the environment.

Despite the existence of more efficient alternatives, the government has continued to use toxic chemical pesticides through aerial and ground application.

According to the Food and Agriculture Organisation, 193,000 litres of pesticides have been imported to date. At the onset of the invasion, toxic pesticides were applied, including fipronil, which has been withdrawn in Europe due to its high toxicity towards pollinators.

Human health

The pesticides in use – mostly deltamethrin and to a smaller extent fenitrothion – are also toxic to other insects, fish, wildlife and human health. Unfortunately, no monitoring study has been undertaken to assess the impact of these pesticides on soil, water quality, pollinators, wildlife and human health.

Another challenge is what to do with the unused pesticides once the locusts have been controlled. Bayer East Africa recently donated 170,000 litres of pesticides worth Sh100 million despite a pilot project on biopesticide in Turkana having found out that, besides killing the hoppers, biopesticides would drastically reduce other problems related to toxic pesticides.

There is need to develop long-term, integrated pest control strategies so as to protect people, non-target organisms and ecological processes to ensure food security and food safety. This strategy should look beyond chemicals.

Some useful mechanical methods include digging ditches to collect and bury hoppers as well as finding eggs and digging them out. These methods work well during early infestation.

Microbial biopesticides

Perhaps more promising are biological control mechanisms. Natural predators such as wasps, birds and reptiles may prove effective in controlling small swarms.

For managing more established swarms, newly developed targeted microbial biopesticides, such as the fungus-based Novacrid, offer a solution.

This fungus kills locusts and grasshoppers only. It is, however, not yet registered for locust control in Kenya and only a small quantity has been imported.

There is an argument that it is more expensive. However, with 1kg, you can treat up to 20 times larger area than with one litre of a chemical pesticide. Secondly, transport costs are lower and there are no external environmental and human health costs.

Other biopesticides which could be used alongside Novacrid are oils extracted from natural products, especially the neem tree —which has other advantages to the soil and the environment.

The main active chemical in neem oil, called azadirachtin, disturbs locust metamorphosis and reduces general activity of the hoppers. Neem oil can also be applied as a repellent since locusts dislike its taste and smell.

The fact that the neem tree keeps its leaves during drought periods increases its importance as a source of biomass for mulching.

In a pastoral system, neem is beneficial to the soil, provides shade and improves fodder productivity in the dry season.

Neem can also help in controlling more than 200 other pest species. Currently, there is not enough neem oil in Kenya, but farmers can be helped to produce it.

Finally, there should be research on sustainable, long-term plans to empower farmers and pastoralists with skills in integrated pest management and prevention.

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