Abstract:
The European red mite, Panonychus ulmi (Koch) (Acari: Tetranychidae) is an important pest of apple in many countries of the world. Occasional outbreaks of the pest mite also occur in the North Rhine area, Germany, where a number of insecticides and fungicides have been applied each year in apple orchards. The present laboratory studies, conducted in 2003 at Department of Entomology and Plant Protection, Institute of Plant Diseases, University of Bonn, Germany. The objectives of study were to find toxicities (LC50) of some of the commonly applied pesticides in this area against different stages of P. ulmi and the level of resistance developed by the pest mite against these pesticides. The results revealed variations in toxicities of different pesticides used against P. ulmi adult females of pesticide-treated population. After 48h, the pesticides Apollo (100%), Metasystox (98.04%), Masai (87.72%) and Ordoval (100%) were found highly toxic, while Confidor (53.75%) slightly toxic. The P. ulmi adult females collected from pesticide-treated apple trees showed many fold resistance against different pesticides, where 21.2 and 23.3 fold higher resistance was recorded against Confidor and ME 605, respectively. Lower resistance of 6.3, and 1.7 fold was found in P. ulmi adult females against Masai and Ordoval, respectively. The eggs, nymphs and adult non-mated as well as mated females of P. ulmi from pesticide-treated population showed variations in susceptibilities to the same and different pesticides. The egg stage was found most susceptible, while the adult non-mated females were found most tolerant against different pesticides. Apollo was found comparatively toxic against the egg (LC50 0.067) and nymphal stage (LC50 0.125), while Ordoval against the mated- (LC50 0.214) and non-mated adult females (LC50 0.275) of P. ulmi.
Page(s):
125-130
DOI:
DOI not available
Published:
Journal: Sarhad Journal of Agriculture, Volume: 22, Issue: 1, Year: 2006