ANBAR JOURNAL OF AGRICULTURAL SCIENCES

Abstract

Laboratory and field studies were conducted to evaluate the effect of the growth regulator Applaud on population structure of the green peach aphid Myzus persicae Sulz. ,and on the parasitoid Diaeretiella rapae (Mcintosh). The combined effect of the parasitoid and the growth regulator with the insecticide Actara (Thiamethoxam) was also studied. Results indicated that the growth regulator had detrimental effect on all aphid stages. The winged form was reduced to an average of 0.5 insect/ plant on all treated cabbage cultivars except the cultivar royal on which the average was 2.4 insect/plant compared to about 6 individuals/plant on non treated pants for all cultivars after one week of treatment. The winged form disappeared from the plant during the third week after treatment. Infestations were reduced after two weeks of application to an averages of 5.0, 18.6, 12.3 and 6.0 individual/plant for the treated cultivars, Kandura, Royal, Dabana and Red respectively compared to an averages of 75.2, 65.5, 52.3 and 22.6 individuals/ plant before the treatment for the mentioned cabbage cultivars respectively. The percentages of parasitism by D. rapae on aphid were also influenced by cabbage cultivar and the growth regulator . The highest percentage was 90% recorded on aphid fed on nontreated Kandura cultivar reduced to 70.1% on the same cultivar treated with Applaud. The lowest percentages were 25 and 19.5% recorded for aphid on nontreated and treated Red cabbage cultivar .Results also showed that Applaud and the parasitoid treatment was the best combination for controlling this aphid. Therefore, these biological means could be taken in consideration in the management program of green peach aphid in the field.