A survey of vegetable-infesting aphids in Sri Lanka, and their natural enemies
Keywords:Aphids, Vegetables, Natural enemies
AbstractAphids (Homoptera: Aphididae) that infest vegetables and their natural enemies were collected during a survey carried out in 18 vegetable-growing areas in six different agro-ecological regions. The survey covered 90% of the vegetable types grown in Sri Lanka, of which more than half are grown world-wide. Eighteen species of aphids belonging to 11 genera were collected from 51 vegetable species. All of the aphids collected were cosmopolitan, polyphagous species, with only Dysaphis carategi (Kaltenbach) recorded for the first time in Sri Lanka, being restricted to carrots. Fifteen of the collected aphid species are potential viral vectors; yet only six species of vegetables infested either by Aphis gossypii or Aphis spiraecola showed probable signs of viral infection. Weeds growing around vegetable plots harboured six species of aphids, which were present on vegetables as well. Eleven species of coccinellids and one species of chrysopids were predatory on six species of aphids on 12 vegetables. Two species of parasitoids (Family Braconidae) were collected from colonies of Myzus persicae infesting cabbage and radish. Host-specific aphid species and natural enemies of aphids were few on vegetables.