Insect pest incidence in seed pods of pigeonpea genotypes in on-farm trials in southern Malawi

In 1999, pod pest surveys were conducted within the Blantyre Shire Highlands Rural Development Project (RDP) Area, at on-farm trial sites in Nansadi and Mangunda sections of Matapwata Extension Planning Area (EPA) and Lirangwe section of Chiradzulu North (Mombezi) EPA. This article reports results of the surveys in Mangunda section. At crop maturity, pigeon pea (Cajanus cajan) pods as well as pods from Crotalaria ochroleuca, Tephrosia vogelii, Dolichos and other plant hosts were collected and examined for infestation. The results from medium duration genotypes indicated that pod-sucking bugs are a major problem for all genotypes. There were some indications that Chilinga and ICEAP 00073 showed less damage to borers compared to ICEAP 00068 and ICP 6927. Results from long duration genotypes showed that pod-sucking bugs are also a major constraint later in the season. ICP 9145 showed less pest damage in intercrops compared to sole crops, but the differences were not significant. With respect to overall damage and damage by pod-sucking bugs, the ICEAP genotypes performed slightly worse than ICP 9145. The odds of damage were significantly different between the locations, with higher values for the humid and cool sites (Matapwata) compared to the warm and semi-humid sites (Mombezi). The pests were identified as the noctuid Pardasena virgulana that was occasionally parasitized by Cotesia sp. and the tortricid Leguminivora ptychora. L. ptychora and Etiella zinckenella were also collected from Tephrosia pods. Within pods of both pigeon pea and Crotalaria a large chalcidoid wasp (Eurytoma sp.) was abundant. Parasitism of Lampides boeticus by Neotypus intermedius (Ichneumonidae) was high, particularly on Crotalaria. Maruca vitrata parasitization by Braunsia sp. (Braconidae) was also greater on Crotalaria than on pigeon pea