Bean leaf eating bug

Hi, can anyone help.
We have intercropped beans and cowpeas with maize and sorghum but we have a major problem with a type of bean leaf eating bug. Does anyone have an effective recipe for a natural pesticide for these bugs that are devouring our bean and cow-pea leafs. We are in Malawi. See picture.

Hi Martin!

I reached out to our local insect ID lab and they suggested the following:

They look like a type of leaf beetle (family Chrysomelidae). I’m not familiar with the species in that area, but in a quick web search I came across a species called Ootheca bennigsen that looks like a good possibility. I also found a paper from Tanzania [Cammell and Knight, 1992] that may have some management information:

Control options I could find include:

  • sloping planting areas and border hedgerows reduce wind speed and therefore reduce landings (Cammell and Knight, 1992)
  • Paul et al. (2007) found organic extract of Vernonia lasiopus leaves and new stems to be effective(see methods on page 191 of paper linked below). These researchers also tried cow urine with some effectiveness
  • 2% neem seed extract sprayed at 11-day intervals (Karel, 1989)


Cammell, M.E. and Knight, J.D. (1992) Effects of Climatic Change on the Population Dynamics of Crop Pests. Advances in Ecological Research, 22, 117-162.

Karel, A. K. (1989). Response of Ootheca bennigseni (Coleoptera: Chrysomelidae) to extracts from neem. J. Econ. Entomol. 82, 1799-1803.

Paul, U.V., J.K.O Ampofo, A. Hilbeck. and P. Edwards. (2007) Evaluation of organic control methods of the bean beetle, Ootheca bennigseni, in East Africa. Arable Crops Evaluation of organic control methods of the bean beetle <i>Ootheca bennigseni</i> in East Africa | New Zealand Plant Protection

Thanks Stacy for the info. I will pursue it.

It is about 10 days since we made the OP using Vernonia lasiopus leaves. We also added some chilli. It reduced the pest considerably so that it was not a problem anymore. We have had heave rains and it is on the increase again, so we will retreat.
Thanks again for the help.

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I’m very glad to have been helpful! Thank you for sharing your experience trying the Vernonia leaves with chili.