أمجد أحمد سعد باقويقو

ملخص الدراسة

فهرس الـمحتويات

Summary

      Study the spread of Dobas eggparasitoid

PseudoligositababylonicaViggiani

 (Hymenoptera – Trichogrammatidae )

In Date PalmAreas of Coastal Hudramout and the possibility of rearing it on other hosts inthe laboratory

            Thespread of Dobas egg parasitoid Pseudoligosita babylonica Has beenstudied in the Coastal region of Hadramout in general and particularly in thedepartments of Doan and Ridh / Gosaiar , during the period from July 2009to  July 2010 . The study showed that theparasitoid existed in all areas of date palm cultivation in the departments ofthe coastal  Hadramout and vary theproportion of parasitism from each department to another one,  and reached the highest in the Directorate ofHadibo island of Socotra (44.5%), followed by the Directorate of Ridh/Gosaiar(40%) and the Directorate of Al-Dees al-Shargiyah (39.2%) while the lowestparasitism was recorded in the Directorate of Gil Benyameen (8.5%), and whenstudying the presence of parasitism in areas of the Directorate of Doanand like of Ridh/Gosaiar, the results showed that the percentage of parasitismwas differ in the growing areas of palms which infected by Dobas bug and it was significant differences at 5% duringthe four generations, reaching the highest in Rihab /Doan (25.74%) and thelowest in Gar-beleswad( 0.55%),  In Ridh / Gosaiar has reached the highestin the region of Al-Atim ( 34.03%) and the lowest in Almlahis (14.17%0), andthe effect was clear of the parasitoid on the severity of injury during thesefour generations of the study.

The study alsodemonstrated that there was a remarkable effect of the irrigation methods inthe parasitism with a significant differences , the parasitism on Dobaseggs  has increased in the areas withsustained  irrigation compared with thatareas of spate irrigation and this means that the sustainable irrigation  provide a good  conditions for the multiplication of theparasitoid throw the intercropping of different crops between the date palmtrees. The study also showed that the Dobas Egg Parasitoid has the ability toaccess to it’s host at all levels of palm altitude, which reached to 20meters so it is possible to put all parasitoid release cards at any level ofpalm heights. The study also demonstrated that the female of the parasitoidprefered parasitism on eggs laid in the leaflets than the  eggs laid between the leaflets, this habit ofparasitism may be because the thickness of the leaflets is very thin comparedwith that areas between the leaflets.

 The studyshowed that the Dobas Egg Parasitoid in the circumstances of coastal Hadramoutexists throughout the months of the year and has two peaks, first in January /February and the second in June/ July, because of the presence of dobas  eggs along the months of the year. Theparasitism behavior of the female was studied too, after the emergence of thefemale through a side vents with irregular edges, the female starts to cleanit’s self and wait until the male emerge from the same Dobas egg , and the mating occurs for less than two minutes , after that the female start searchingfor healthy Dobas eggs. It was recorded a strange behavior of parasitism forthe female , it inserted the eggs laying machine  in the plant tissue which ended to the softpart of the dobas egg.

The results ofthe study explained the successful of breeding the parasitoid on it’s main host the Dobas  eggs on date palm seedlings in thelaboratory, this is the first work carried out successfully at the level of theRepublic of Yemen for the eggs parasitoids, and its life-cycle take 31days and each egg of dobas give two of the parasitoid adults , female andmale  with a sex ratio 1: 1 . thereproduction to produce only males was recorded in the dobas egg parasitoid,the unfertilized female can produce only one male from each dobas egg .

For rearingDobas egg parasitoid on another alternative hosts, the Mediterranean flour moth(( Ephestia kuehniella ))has been searched, it was found in and outsidethe same area of the study . It was successfully reared in the laboratory ongroats of wheat, and the eggs where collected from the rearing boxes designedfor this purpose. Also eggs of Sitotroga cerealella  where brought from the biological controlunit of Wadi Hudramout Agric. Department. when rearing the parasitoid on thesetwo hosts , the parasitism failed , and may be due to the special behavior ofthe parasitoid, this was supported by the failure of parasitoid to lay eggs inthe Dobas eggs outside the plant tissue .

There where somerecords during the study , e.g. a external parasite on the Dobas nymphs in thelaboratory and the field, which can be Bocchus hyalinus , and a blackparasitoid similar to P. babylonica but may be Aprostocetus sp.Also the parasitoid P. babylonica was recorded on a wild plantssurround the date palm fields ( wild cotton Gossypium sp , ) Jimsonweed Datora stramonium ) and Caster Bean Plant Ricinus stramonium , allthese plants where infested by the leaf hoppers (Jassid).