Influence of Morphological Traits on Spotted Pod Borer, Maruca vitrata Resistance in Pigeonpea

摘要

Pigeonpea (Cajanus cajan L) is a tropical grain legume mainly grown in India, ranks second in area and production and contribute about 90% in the world's pulse production. In Andhra Pradesh, it is cultivated in an area of 6.38 lakh ha with a production 2.65 lakh tonnes (AICRIP Report, 2012). It is attacked by more than 250 species of insects of which legume pod borer or spotted pod borer, Maruca vitrata Geyer is a serious pest of pigeonpea in tropic and sub-tropics, because of its extensive host range, destructiveness and distribution on cowpea, mungbean, urdbean and field bean (Shanower et al., 1999). The larvae feed on flowers, buds and pods and the entrance hole is plugged with excreta. It is basically a hidden pest and completes its larval development inside the web formed by rolling and tying together leaves, flowers, buds and pods. Host plant resistance being one of the most exploited methods, fits well in any integrated pest management programmes. Several morphological and structural features of plants like type of trichomes and their orientation, trichome length and density, pod wall thickness, number of pods per cluster, pod length, plant type and branching pattern play an important role in providing resistance against pod borers (Jeffree, 1986; David and Eswaramoorthy, 1988; and Haider et al, 2006). Similarly, trichome exudates on plant surfaces play an important role in the host selection process of insect herbivores (Bemays and Chapman, 1994). Keeping all these in view, the present studies were undertaken to assess their role in host plant resistance.