The 2005 ESA Annual Meeting and Exhibition
December 15-18, 2005
Ft. Lauderdale, FL

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Friday, December 16, 2005 - 9:54 AM
0325

Development of bioassay methodology for sweetpotato weevils Cylas punticollis and Cylas brunneus

Moses Ekobu, ekobum@yahoo.com, Makerere University, Crop Science, P.O. Box 7062, Kampala Uganda, Kampala, Uganda

Abstract Sweetpotato (Ipomoea batatas, L) is a staple food for the people of Uganda and is consumed in many parts of the Eastern African region. Most of the crop is produced organically by resource-poor farmers, who get yields of only 4.2 ton/ha, below the world’s average of 15.5 tons/ha. Sweetpotato weevils, Cylas puncticollis and C. brunneus (Coleoptera: Apionidae) are the major pests of sweetpotato and contribute to between 60 -100% of the yield reduction. Current efforts therefore, are geared towards developing methods to increase yield of quality root to satisfy household nutritional needs and for the market. The objective of the study was to develop an artificial diet for rearing sweetpotato weevils and to subsequently screen the efficacy of various toxins against the sweetpiotato weevils. The artificial diet formulations mainly consisted of the diet for Euscepes postfasciatus (Coleoptera: Curculionidae) and various proportions of sweetpotato powder, were formulated and used to rear the weevils at the laboratory. A survival rate of up to 80% was shown in the best diet (one with the highest sweetpotato powder). The diet also supported the development of the weevils from 1st instar to adulthood. The adults also continued feeding on the diet for three months. These data are important in guiding in the development of genetically modified sweetpotato varieties for weevil resistance. Chemicals that are attractive to the insects can also be incorporated into the diet, thus opening windows for integrated pest management options.


Species 1: Coleoptera Apionidae Cylas punticollis
Species 2: Coleoptera Apionidae Cylas brunneus
Keywords: Artificial diet

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