SUSCEPTIBILITY OF SOME COTTON VARIETIES TO TETRANYCHUS URTICAEKOCH INFESTATION, WITH REFERENCE TO ITS PREDACOUS MITES AND SPIDERS IN BENI-SUEF GOVERNORATE.

The populations of the spider mites Tetranychus urticae Koch (different stages), and their natural enemies i.e. predacious mites (families, Stigmaeidae, Tydeidae and Phytoseiidae) and the true spiders (families Saltisidae, Philrodomidae, Miturigidae, Thomisidae, Lycosidae and Araneidae) were studied in Beni Suef governorate during the cotton cultivated seasons, 2010 and 2011.The population differed according to the different sampling dates on the different cotton varities, Giza 80, 90 × ost, Dandra, Giza 83, Giza 89, Giza 90 and Giza 91 varities.The cotton (Giza 90 variety) was the most susceptible to the spider mite infestation in the two seasons, as, it harboured 96.625 and 83.5 mite individuals, per leaf in the seasons 2010 and 2011,respectively. The statistical analysis of obtained data indicated that the least significant differences for different varities were 39.559 and 19.779 in case of season effect. Also, Giza 80 and Giza 83 varities harboured more predacious mites during 2010 (6.5) individuals for each, while each of Giza 80 and Giza 90 harboured during 2011, 6 predacious mites. The average collected numbers of the spiders was 12.25 individuals on Dandra variety during 2010 while on Giza 83 variety during 2011 season was 8.25 individuals. The study indicated that there was generally positive correlation between the two spotted spider mite and their associated natural enemies. [ABSTRACT FROM AUTHOR]