THE EFFECT OF THE EGG PARASITOID PSEUDOLIGOSITA BABYLONICA ON DOBAS INFESTATION IN DOAAN, SHICHAWI AND ASID (HUDRAMOUT, YEMEN)

The best and most efficient method of biological control is the use of egg parasitoids, and most species used were from the family Trichogrammatidae, and the name of the dobas egg parasitoid (DEP) in Yemen is [(Pseudoligosita babylonica n. sp. (Hymenoptera: Trichogrammatidae)]. We have followed the existence and the impact of this parasitoid in Hadramout since 2005, we recognized it in 2007 in Gail Al-Halikah, it was identified in France (CIRAD) at the end of 2008 and it turned out to be the same type found in Iraq, which was found also in 2005, during 2008 and 2009. In the four generations of the dobas insect we followed the spread in Douan, Asid and Shichawi. We found that it exists in all villages of these regions. The proportion of parasitism differs from one area to another, significantly at the level of 5% and the percentage of parasitism declined from 23.6% in January 2008 to 2.53% in August 2009 in all the 13 villages in Douan. The heavy rain in October 2008 influenced the parasitism because it washed the honey dew from the leafs which is the mean food of the parasitoid, and in the district of Ridh Gosaiar where there was a clear significant difference between Wadi Asid and Chkawi; it was only 6% in Asid and 17% in Chkawi, which led to its effect on the severity of the injury, accordingly it was in Chkawi 6.5 eggs/leaflet, while it reached to 9.3 in Asid which confirms the clear relationship and positive impact in reducing the injury.
The adults of the DEP were present all the time of the dobas egg periods and approximately it moves from the old egg masses to the new for the second generation. It was also noted that the parasitoid was present in all plant heights of different palm trees up to more than 15 meter.