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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/4713

Title: Effects of Two Neem Kernel Extracts in the Control of Whitefly (Bemisia Tabaci) on Tomato
Authors: Appiagyei, Francis
Issue Date: 13-Jun-2010
Abstract: Whiteflies (Bemisia tabaci Genn.) are major insect pests of tomato plants in Ghana. The danger of these insect pests developing resistance to most synthetic insecticides has necessitated the need for alternative methods of controlling them. Neem products which are practically non-toxic and relatively harmless to man and beneficial insects are the best alternative against the control of these pests. Field trials were conducted in the minor rainy season of 2008 and major season of 2009 to assess the effectiveness of different neem-based products namely, aqueous neem kernel powder extract (ANKPE) and neem kernel powder extract (NKPE) against and B. tabaci and on the yield of tomato (Lycopersicon esculentum Mill.). Karate (Lambdacyhalothrin) was used as reference synthetic pesticide. The field design used was the Randomized Complete Block Design (RCBD) and there were four treatments with three replications. Data were collected on insect numbers, number of damaged leaves and the number of plants infected with tomato yellow leaf curl virus. The field trial was conducted on an experimental farm near the Sewage Treatment Plant at the Kwame Nkrumah University of Science and Technology, Kumasi in the Ashanti Region of Ghana. B. tabaci was detected on the tomato plants two weeks after transplanting in both seasons. The number of whiteflies was significantly lower (F = 194.06; P < 0.0001) in the neem - treated plants compared to the control plants but significantly higher than the karate - sprayed plants in the minor season. During the major season, the number of whiteflies on the karate - sprayed and neem - treated plants was significantly lower (F = 96.38; P < 0.0001) than the control plants. There was significant difference (P < 0.001) between ANKPE and NKPE in the minor season. However, there was no significant difference between the neem extracts in the major season. The number of damaged leaves on the control plants was significantly more (F = 27.92; P < 0.0001) than the karate - sprayed and neem - treated plants. The number of plants infected with tomato yellow leaf curl virus in the control was significantly (F = 11.54; P < 0.0001) more than the karate and ANKPE - sprayed plants but did not differ significantly from NKPE. The number of plants infected with tomato yellow leaf curl virus (TYLCV) in NKPE did not differ significantly from ANKPE - sprayed plants in the minor season. No infection of tomato yellow leaf curl virus (TYLCV) was observed on all treatments during the major season. There was no significant difference (F = 3.11; P < 0.0887) in terms of yield among all the treatments in the minor season and in major season (F = 0.19; P < 0.897). Karate (Lambdacyhalothrin) did not prove superior to ANKPE and NKPE in the minor and major seasons. B. tabaci proved to be susceptible to the two neem extracts in the minor and major seasons. The neem extracts can therefore be used in the control of B. tabaci.
Description: A Thesis submitted to the Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology, Kumasi in partial fulfillment of the requirements for the degree Master of Science in Environmental Science, June-2010
URI: http://hdl.handle.net/123456789/4713
Appears in Collections:College of Science

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