Scientists at the Nairobi-based International Centre for Insect Physiology and Ecology (Icipe) have discovered ‘smart’ maize varieties that defend themselves from the destructive stemborer by summoning the natural enemies of the pest.

 The varieties have genetic markers which allow them to ‘call for help’ when attacked, attracting wasps- biological enemies of stemborers.

Icipe researchers working in collaboration with their counterparts from Keele University, UK, and the International Crops Research Institute for Semi-Arid Tropics (ICRISAT), believe that the findings, recently published in Scientific Reports, present strong possibilities for developing maize varieties that are resistant to the pest.

 Common in Africa, stemborers, during the larval stage, remain concealed in the stem, where they make extensive tunnels that disrupt the flow of nutrients. Other larva drill into the cobs, ruining the grains and increasing the chances of aflatoxins.

Attacks can lead to losses of between 10-100 per cent. “When stemborers lay eggs on the maize cultivars, a defense reaction is triggered in the plants, which release odours that attract wasps that parasite on the stemborers,” explained Dr Amanuel Tamiru, a scientist at Icipe.

According to Dr Tamiru, the maize plant recruits both the egg and larval parasitic wasps that kill the stemborer eggs before they hatch into larvae, as well as attack any larvae that may emerge, pre-empting damage of the crop.

“Our findings could be used by maize breeders to promote stemborer resistance in maize cultivars, preferred by farmers because of other desirable traits,” said Prof. Toby Bruce of Keele University

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