تأثير الإطلاق المتكرر للمتطفل Trichogramma cacocaie Marchal في خفض كثافة دودة ثمار التفاح Cydia pomonella (L.)‎ في بساتين التفاح في محافظة السويداء، سورية

الملخص EN

Field experiments were conducted in 2012, 2013 and 2014 on apple trees in the fields of the Scientific Agricultural Research Center of Sweida, Syria, and another field in State Farms in Mafaele region.

Three treatments were used to study the efficacy of the recurrent release of the parasitoid Trichogramma cacocae Marchal, the impact of traditional insecticides in reducing codling moth damage and an untreated control.

In the biological control treatment, a weekly release of T.

cacocae was conducted during the growing season until harvest time.

The boundary trees which surrounded the biological control treatment were treated with traditional insecticides (Delta permethrin, Dimethoate and Chlorine perfos ethyl) throughout the growing season.

The trees treated with Trichogramma which were adjacent to the chemical treatment were considered separately representing the dual action of the direct impact of Trichogramma and indirect effect of insecticides.

Results were evaluated according to the levels of fruit damage, productivity and efficacy of biological and chemical treatments during the season and at harvest.

The highest and lowest pest density were recorded in the fields’ number 14 and 19, respectively.

Significant differences in infestation rates by codling moth were observed between control and each of the other treatments (biological control and chemical treatments).

In the third year, significant differences of productivity were recorded in all sites between treatments and the control.

Highest production average of 77.99 and 37.83 kg/tree were obtained in the field of Mafaele and field 5, respectively, treated with chemical insecticides.

Average production of 49.77 and 17.55 kg/tree was obtained in the biological control treatment, and 54.17, 23.31 kg/tree in the combined treatment as compared to 11.16 and 3.18 kg/tree in the control, in the two fields, respectively.

In the Third season at harvest time, the recorded efficacy values of Trichogramma were 56.01 and 65.04% in field 5 and Mafaele, respectively, and the highest efficacy values of using Trichogramma in the successive three seasons in field 19 were 52.08, 72.7 and 72.69%, respectively.