Effect of Vermicompost on Some Biological parameters of the Melon Aphid, Aphis gossypii Glover and the Predatory Gall Midge Aphidoletes aphidimyza Rondani on Two Greenhouse Cucumber Cultivars

Agricultural practices such as application of fertilizer and various cultivars of host plant can affect population parameters of the pests and their natural enemies. In this research, effects of using different vermicompost: soil ratios (0:100, 10:90, 20:80 and 30:70 %) as a growth medium of two cucumber cultivars (Khasib and Karim) were investigated against biological parameters of the melon aphid, Aphis gossypii Glover and its predator gall midge, Aphidoletes aphidimyza Rondani. The experiments were carried out in a growth chamber at 25 ± 2°C, 65 ± 5 % RH and a photoperiod of 16:8 h (L:D). The longest and shortest longevity of the aphid was obtained at 0:100 % ratio of Khasib and at 30:70 % ratio of Karim. The highest total fecundity of the aphid were at 0:100 % ratio for both Khasib and Karim and lowest fecundity of it was at 30:70 % ratio of Karim. The shortest incubation period of A. aphidimyza was observed at 20:80 and 30:70 % ratios of Karim and at 30:70 % ratio of Khasib. The shortest larval period was also at 30:70 % ratio of Karim. The total fecundity of predator increased with increasing the vermicompost ratios. The results revealed that most biological parameters of the A. gossypii and A. aphidimyza were affected by the type of cultivar and dosage of vermicompost fertilizer. Therefore, intergration of the both cultural methods and natural enemy can lead to better controlling of the melon aphid in integrated pest management programs especially in greenhouse cultures.