Kampani, D.V. 1992 . Studies on the effect of buprofezin against the cassava mealybug Phenacoccus manihoti in Malawi. Ph.D. thesis, London, Imperial College of Science and Technology. London

Notes: (Ph.D. thesis, London, Imperial College of Science and Technology.) Buprofezin was evaluated for its toxicity to different stages of the cassava mealybug Phenacoccus manihoti Mat-Ferr. and its natural enemy Epidinocarsis lopezi (de Santis). Direct mortality of eggs treated with 0, 0.1, 1.0, 10, 100 and 1000 ppm of buprofezin was low particularly in the presence of the ovisacs. Treatment of eggs closer to the time of hatch increased mortality. Treatment of eggs did not affect later stages. When the first, second and third instars were treated at doses ranging from 0-3.0 g a.i./cm^2, moulting was unsuccessful. The highest mortality occurred at the next moult. Later instars were more susceptible to buprofezin, ED_50 values being 0.39, 0.09 and 0.004 g a.i./cm2 for first, second and third instars respectively. Treatment of first instars never affected subsequent development of later instars but buprofezin applied to second and third instars did. Direct mortality of first instars treated with buprofezin six days after hatching was 31 and 19%, for the wettable powder and oil formulation respectively, lower than treatment at two days after hatching. Mortality at moulting time however was 8 and 27% higher in treatment applied six days after hatching than at two days. Hatching of eggs from subsequent adults was severely reduced when buprofezin was applied to second and third instars. The number of eggs laid was not affected nor was the first moult of the second generation first instars. Less than 7% of eggs laid by adult mealybugs treated with buprofezin hatched but this improved with time while adults placed on treated plants laid fewer eggs of which less than 5% hatched in the first week following treatment. The effectiveness of buprofezin lasted up to 25 days under semi-controlled conditions causing up to 40% moult failure of first instars introduced on the treated plants. The wettable powder formulation was less phytotoxic to cassava than the oil formulation.