Some aspects of pod characteristics predisposing pigeonpea (Cajanus cajan (L.) Millsp.) to infestation by Callosobruchus chinensis (L.)

Investigations with pigeonpea (Cajanus cajan) genotypes ‘Apio-elina’ and ‘PI-397566’ showed that certain pod characteristics influenced both infestation in the field by Callosobruchus chinensis and damage caused by this pest. Compared to pods with no or sparse hair, pods with thick hairs suffered greatly reduced field infestation due to the barrier effect of the hairs on oviposition and larval penetration. Even on pods with no or few hairs, the pod wall appeared to offer some resistance to both larval penetration and adult emergence. High levels of infestation by C. chinensis were recorded on pigeonpea pods with no or few hairs, those with pods damaged through shattering, and those with pods that had been previously damaged by pod borers. From the results of the study, it was recommended that pigeonpea selection should include screening for high pod hair density and thicker pod wall

Effect of field infestations of immature pigeonpea (Cajanus cajan (L.) Millsp.) pods on production of active (flight) and sedentary (flightless) morphs of Callosobruchus chinensis (L.)

A study conducted in Uganda on Callosobruchus chinensis showed that adults emerging from dry seed-infested and immature pod-infested pigeonpea differed in a number of morphological and biological characteristics in one or both sexes. Adults emerging from dry seed-infested pigeonpea were more or less uniform in a number of these characteristics; in contrast, adults emerging from green pod-infested pigeonpea differed depending upon when they emerged: the differences were greatest between those emerging during the 2nd to the 6th days from first emergence, and those emerging from the 8th to the last days of emergence. In one or both sexes, these differences were expressed in terms of elytral hue and size, body length, distance between the compound eyes, length of pygidium, body water content, pre-maturation periods, fecundity and adult longevity. We suggest that these differences are due to polymorphism, and specifically the predominance of flight forms among late emergers from pod-infested pigeonpea. The differences observed in the two morphs of C. chinensis and ascribed to the flight and flightless forms, are thought to be adaptations for survival and propagation under field and storage conditions, respectively. The predominance of emerged adults of the flightless forms from dry seed and the flight forms from green pods were associated with low moisture content in dry seed and high moisture content in green pods, respectively. These observations show that bruchid control measures are needed in the field as well as in storage

Diseases and pests of pigeonpea in eastern Africa: a review

Pigeonpea is one of the major legume crops grown in eastern Africa but has been relatively neglected in terms of research and development. The peas are a rich source of protein and the crop is nitrogen-fixing and drought tolerant. It is an ideal crop for the semi-arid areas of Africa and there is great potential for it to be more widely grown. The large number of pests and diseases which attack pigeonpea in Africa (and elsewhere) is perhaps the main constraint to increased production. The most important pest worldwide is the pod borer, Helicoverpa armigera, but the flowers and pods are attractive to a wide range of insect pests. The most important disease in eastern Africa is Fusarium wilt (Fusarium udum) and considerable effort has been devoted by ICRISAT to developing wilt-resistant pigeonpeas, adapted to cultivation in the region. This paper reviews the literature on pests and diseases of pigeonpea with special reference to eastern Africa and presents some new information on distribution and damage levels for the key pests and disease

Path coefficient analysis of yield and its components in pigeonpea

(African Crop Science Journal, 1998 6(2): 143-148

Effect of solar drying period of beans on seed viability, cooking time and injuriousness of Acanthoscelides obtectus Say

(African Crop Science Journal 1998 6(4): 417-421