Field infestation of cowpea ( Vigna unguiculata ) pods by beetles of the families Bruchidae and Curculionidae in Northern Nigeria

摘要: An account is given of a study infestation cowpea pods in the field Northern Nigeria by weevil, Piezotrachelus varius (Wagn.), and Bruchids, Bruchidius atrolineatus (Pic) Callosobruchus maculatus (F.). Oviposition Bruchids did not commence until were fully formed light green colour, whilst P. originated young pods. Observations indicated that high level parasitism Bruchid eggs occurred, but majority Hymenopterous parasites emerging from within related to . When harvested at regular intervals, large numbers emerged early harvests only. B. was predominant species emerging, particularly harvests. In case single final harvest pods, , higher than collected recorded. Shelling four batches mean 11 per cent, seeds attacked harvests, only 3·5 as became dry. It concluded considerable improvement quality would result an adoption latter method farmers, provided some control respect introduced. From observations made it true pest, primarily pest able continue store very limited extent, C. its build up rapidly during immediate post-harvest storage period. The normal manner cultivation precludes use methods oviposition peaks suggest elimination secondary hosts might be worthwhile. A reduction treatment stored cowpeas growing areas, period, should considerably reduce this species.