CONTROL OF' GROUNDNUT ROSETTE VIRUS AND ITS VECTOR, APHIS CRACCIVORA KOCH.

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Date
1986-10
Authors
ABUBAKAR, YAHAYA MAFARA
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Abstract
The study was conducted .with a view to determine the effects of plant population, sowing aates, insecticides and interaction between the three factors on the epidemiology and control of groundnut rosette virus and its aphid vector, Aphis craccivora Koch. Results obtained show that irrespective of planting date or plant density, peak populations of Aphis craccivora are attained between the last week of July and first week of August. Groundnuts are found to be colonised starting at germination especially when planted late. During the two years of trials, rosette incidence was about 2%. However, the severity was higher and the disease spread much faster on control plots than on insecticide treated plots. Insecticide treatment did not prevent primary infection of rosette. Cheilomenes sulphurea, C. vicina and Scymnus sp, (Coccinellidae) and Xanthogramma aegypticum, Paragus borbonicus (Syrphidae) were the most commonly recorded aphid natural enemies, but did not exert significant suppressing effect. Their role in the integrated control of the aphids as vectors is discussed. Fewer aphids and higher pod yield and shelling percentage were recorded on insecticide treated, earlier and more densely planted groundnuts. Planting date had stronger--influence on groundnut-yield than spacing or insecticide treatment. Carbofuran applied as Furadan 3G proved superior to ethiofencarb (Croneton 500 E.G.), pirimicarb (Pirimor ED Spray) and carbosulfan (Marshall 5% Dust) in aphid control. Application of carbofuran at 0.75kg a.i./ha proved as effective as 1.0 and 1.5kg a.i./ha during the first 30 days of planting. The various interactions of planting date, plant population and insecticide treatments on aphids and other parameters such as yields are discussed.
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A thesis submitted to the Faculty of Agriculture, Ahmadu Bello University in partial fulfillment of the requirements for the degree of Master of Science in Crop Protection. Department of Crop Protection Faculty of Agriculture Ahmadu Bello University Zaria. October, 1986.
Keywords
CONTROL,, GROUNDNUT,, ROSETTE,, VIRUS,, VECTOR,, APHIS CRACCIVORA, KOCH.
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