The impact of adjacent habitats on population dynamics of red cotton bugs and lint quality.

Abstract

Red cotton bugs [Dysdercus spp. (Hemiptera: Pyrrhocoridae] are among the most destructive pests of cotton and many other crops. Red cotton bugs (RCBs hereafter) damage cotton plants by sucking sap and deteriorate lint by staining. The incidence of RCBs causes boll injury along the field margins neighboring with various peripheral areas. The adjacent habitat/crops strongly mediate the population dynamics of RCBs. However, limited is known about the impact of adjacent habitat on population dynamics of RCBs and lint quality. This two-year field study evaluated the impact of adjacent habitat (okra, unpaved road, water channel and Eucalyptus trees) on population dynamics of RCBs and lint quality of cotton. The RCBs were sampled weekly from margins to 4 meter inside the cotton field. The RCBs' populations were monitored and plucked cotton bolls were examined for internal damage. The highest incidence of RCBs was recorded for cotton field adjacent to okra and water channel. Similarly, the highest number of damaged bolls were observed for the field side neighboring with okra and water channel. Furthermore, the highest number of unopened bolls were recorded for okra and water channel sides with higher percentage of yellowish lint. Field sides bordering with Eucalyptus trees and unpaved road had lower RCBs incidence and lint staining. Nonetheless, RCBs incidence was higher at field margins compared to field center indicating that population was strongly affected by adjacent habitat. It is concluded that sowing okra and weedy water channels adjacent to cotton would support RCBs population and subsequent lint staining. Therefore, water channels must be kept weed-free and okra should not be sown adjacent to cotton. Nonetheless, detailed studies are needed to compute monetary damages caused by cotton pests to the crop. Furthermore, effective management strategies must be developed to manage RCBs in cotton to avoid lint-staining problem.