Cowpea cultivars screened for resistance to insect pests.
The resistance of 20 cowpea (Vigna unguiculata) cultivars to 9 different insect pests was evaluated in field-plot tests in Georgia, USA, in 1980. The cultivars differed significantly in their degree of susceptibility to aphids (Aphis craccivora Koch and A. gossypii Glov.), thrips (mainly Frankliniella tritici (Fitch), but also F. bispinosa (Morg.), F. fusca (Hinds) and Sericothrips variabilis (Beach)), Lygus lineolaris (P. de B.), Anticarsia gemmatalis Hb., Nezara viridula (L.) and Chalcodermus aeneus Boh. A. gemmatalis was the most abundant lepidopterous pest, and a positive linear relationship between population density and the resultant estimated defoliation was noted. In the case of C. aeneus, percentage damaged pods correlated significantly with both the number of punctures on peas and the number of eggs and larvae. It was thought that the chances of finding a cultivar resistant to several of these pests were poor.