The determination of sex ratio of dominant natural enemies and parasitism rate of (Nipaecoccus viridis Newstead) on sour orange and oleander trees in Shiraz, Iran

ABSTRACT: During two continuous years in different places of Shiraz, the sex ratio of natural enemies of this mealybug and the parasitism rate of two kind of natural dominant factor, Anagyrus pseudococci girault and Dicrodiplosis manihoti harris were determine. The average of the sex ratio for the parsitoid wasp, for all places was 0.65 and in 2011, it was 0.67. About the sex ratio of D. manihoti in various places, the average for female mosquitos was 0.46 in 2010 and in 2011, it was 0.57. Among the sampling places, the most percent of parasitism in the first peak was about 62%. In most places, the percent of parasitism of A. pseudococci was reduced on the sour orange trees by the appearance of Marietta picta andre and D. Manihoti and after that, because of the warm weather in august, this reduction continued until September. In most places, from the beginning of September, the percent of parasitism was increased again and in the middle of October, the second peak of parasitism percent was reached. The reason of the increasing of the parasitism percent in fall in some places was the reduction of the population of ant in these places and also, the disappearing of M. picta.