Insects associated with medicinal crops under shade nethouse conditions

Abstract

The insects feeding on medicinal plants were collected from the shade-nethouse of Department of plantation, spices, medicinal and aromatic crops, College of Horticulture, Mudigere during 2017-18. The insect taxonomist has identified insect specimen viz. black aphid Aphis craccivora Koch on chamomile Matricaria chamomilla L., long scale insect Coccus longulus (Douglas) on ashoka Saraca asoca (Roxb.) Wild., scale insect Saissetia coffeae (Walker) on madhunashini Gymnema sylvestre R. Br., Aphis gossypii Glover on mehindi Lawsonia inermis L., scale insect Coccus sp. on soapnut Sapindus trifoliatus L., Saissetia oleae (Oliver) on Adhatoda vasica Nees. The highest infestation was observed on S. asoca plants (96.08%), M. chamomilla (87.50%) and the infestation was 60 per cent on G. sylvestre plants. The infestation was lesser extent in other medicinal plants viz. Aphis gossypii on L. inermis (28.85%), Coccus sp. on S. trifoliatus (26.92%) and Saissetia oleae on A. vasica was the least (11.67%). The infestation of aphids and scale insects caused symptoms like curling, yellowing, leaf drop, weak plants and severe infestation caused death of medicinal plants. Black ant, Polyrhachis exercita (Walker 1859) was associated with A. craccivora on chamomile M. chamomilla. Small ant, Lophomyrmes quadrispinosus was associated with scale insects on S. asoca, G. sylvestre, S. trifoliatus and A. vasica.