Beauveria bassiana: a golden opportunity for vegetable farmers

Adult of Plutella xylostella, commonly known as Diamondback moth. Photo from Wikimedia Commons.
Adult of Plutella xylostella, commonly known as Diamondback moth. Photo from Wikimedia Commons.

One of the biggest threats to cabbage farming in West Africa is Plutella xylostella, commonly known as the Diamondback Moth (DBM). For years, DBM has been devastating both smallholder and commercial cabbage farms in the region, affecting incomes and market prices of the crop.

To address this, we developed and field tested a biopesticide based on the fungus Beauveria bassiana 5653 against DBM. Aside from effectively controlling DBM, cabbage yield in plots treated with Bba5653 was almost three times higher compared to plots treated with the insecticide bifenthrin or to untreated plots.

Songhai Center—a Private Voluntary Organization for training, production, research and development of sustainable agricultural practices—have been involved in the testing and highly recommends the product.

Bba5653 can control DBM on cabbage and its cousin kale, regarded as high-value cash crops. Compared to other vegetables such as carrot and lettuce, farmers say returns are higher with cabbage cultivation.

Cabbage damaged by DBM. Photo by Ignace Godonou, IITA.
Cabbage damaged by DBM. Photo by Ignace Godonou, IITA.

For the past few years, thousands of farmers in West Africa had to abandon cabbage production because of DBM. Consequently, market prices for African cabbage have jumped because of dwindling supplies.

The high costs of synthetic pesticides do not help either. The most common chemical pesticides—bifenthrin and deltamethrin—require about 19 applications within three months prior to harvest. The expense is prohibitive for most farmers.

Farmers, like Louis Awandjinou who has been cultivating the crop since 1986, have also observed that the chemical pesticides have been less and less effective against DBM over the years.

Alternatively, farmers have been using botanical pesticides, mostly extracts from the seed of the neem tree, against DBM and a wide range of other arthropod pests, but the approach has had limited success.

Used in integrated pest management, B. bassiana­-based biopesticide offers a cost-effective and environmentally-friendly solution to DBM. The fungus has a narrow range of target pests and persists in the environment with the ability to remain active for several months after initial application, B. bassiana could end the frequent application, high costs, and risks associated with the use of chemical pesticides. It could also preserve beneficial insects, and, by extension, biodiversity.