Insect pests of cowpeas vigna unguiculata(l.) walp. and studies on cowpea yieldassessment under different chemical sprayregimes and minimum use of insecticidesagainst the dominant insect pest speciesat Katumani dryland rese4rch station, Kenya
Abstract
Studies to identify major insect pests
attacking cowpea, Vigna unguiculata (L.) Walp.,
in the field and to assess cowpea yields under
different chemical control regimes were conducted at
Katumani, Kenya during th'e short and the long rainy
seasons of 1978 and 1979 respectively_
From materials collected in unsprayed plots,
the cowpea crap was found to be attacked by a total
of 43 species of insects which were classified into
seven orders: Diptera (1),Co1eoptera (10), Heteroptera
(15), Homoptera (3), Lepidoptera {8},Or t h o p t e ra (4) and
Thysanoptera (2). Only a few of these were considered
major pests, ,namely, Acanthomia horrida Germ, Agrotis
segetu D and S, Anoplocnemiscurvipes F., Aphis
craccivora Koch, Callosobruchus maculatus Fab.,
Heliothis armigera Hb, Lagria villosa Fab , , Maruca
testulalis Geyer. Megalurothrips sjostedti Trybom,
Nezara viridula L.
Maximum seed yields were obtained from cowpea
I plots sprayed with gamma BHC insecticide after
flowering. There were no significant ·differences i,n
yields between plots sprayed with insecticide before
flowering and those of the untreated plots. insecticidal treatments applied four times after flowering at 14
days interval, starting at the appearance of first
flowers,gave significantly higher yields than spraying
two times after onset of flowering at 45 days apart.
Mean seed yield of the ten varieties of cowpea
used differed significantly between treated and
untreated cowpea plots. The local" varieties KAT 1,
KAT 2 and KAK 1 constantly performed ell producing
higher yields than the exotic varieties except
VITA 4.
Aphids which were one of the most important
pests of cowpea at Katumani preferred to colonize
prostrate varieties to erect ones in growth habit.
When gamma BHC insecticide was applied to plots
attacked with aphids there was no correlation between
insecticide application and cowpea varietal yields.
Citation
Mabonga, F.R.A.(1983).Insect pests of cowpeas vigna unguiculata(l.) walp. and studies on cowpea yieldassessment under different chemical sprayregimes and minimum use of insecticidesagainst the dominant insect pest speciesat Katumani dryland rese4rch station, KenyaSponsorhip
University of NairobiPublisher
Department of Plant Science and Crop Protection, University of Nairobi
Subject
Insect pestsCowpeas
Vigna unguiculata(l.) walp
Cowpea yield
Chemical spray
Katumani dryland research station
Kenya
Description
Msc Thesis