Effects of sowing date modification and intercropping on thedistribution of Aphis craccivora Koch (Hemiptera: Aphididae) ingroundnut (Arachis hypogaea) in the Nigerian Sudan Savanna andimplications for management
2005
Sastawa, B.M. | Maina, Y.T. | Lawan, M.,University of Maiduguri(Nigeria). Dept. of Crop Protection
Field trials were conducted during the 2001 and 2002 croppingseasons to determine the distribution pattern of Aphis craccivora ingroundnut fields in Maiduguri, Nigeria. The factorial experiment consistedof four sowing dates of groundnut (31 July and 7, 14 and 21 August in2001 and 21, 28 July, 4 and 11 August in 2002), four intercrop patterns(3:1, 2:1, 1:1 and 0:1) of miller to groundnut and 2 intercrop systems ofmillet- groundnut (MG) and millet-groundnut-soybean-cowpea (MGSC)arranged in split-split plot design. Aphids and their predator(Cheilomenes vicina) were present in groundnut fields for about fiveweeks in both 2001 and 2002. However, the numbers of aphids and thoseof their predator were not significantly (p greater than 0.05) correlated.The distribution pattern of aphids in groundnut sown on the differentdates and as intercrops was regular (b greater than 1) according toTaylor's Power Law; conversely, aphids in sole groundnut assumed aclumped (b greater than 1) distribution. There were significant (p lessthan or equal to 0.05) correlations between mean number of aphids/plantand percent incidence of infestation. Differences between the expectedand the observed proportions of groundnut plants infested by aphidswere not significant (p greater than 0.05) over the two croppingseasons.
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