Worldwide distribution. In tropics. On bean, including French bean, cowpeas, pigeon peas and yard long beans. An important pest.
Caterpillars have two rows of black dots on the back.
At first, caterpillars feed in the flowers making webs, then bore into the pods to eat the seeds. Look for frass – waste matter – at entry holes.
Cultural control: avoid planting near old crops; handpick flowers with webbing; grow maize/sorghum between bean rows; collect debris and destroy; check AVRDC for tolerant varieties.
Chemical control: aim to kill caterpillars in flowers as difficult for chemicals to enter pods. PDPs: neem, derris, pyrethrum, or chilli; use spinosad or Bt (Bacillus thuringiensis). Alternatively, synthetic pyrethroids, but may kill natural enemies.