Effects of certain environmental factors on population fluctuations of Aphis gossypii in cucumber fields at Assiut Governorate

Ibrahim,I.L¹; AbdEl-Ghaffar.M.M²;Abdel-fttah.O.A³and Khttab.H.M4

Abstract

Field experiments were conducted in the farm of Agriculture faculty, AL-Azhar university at Assuit governorate throughout two successive seasons 2014 and 2015 to survey the insects associated with cucumber crop ( Cucumis sativus .L ). Results indicated existence of 10 insect species related to 9 families of 6 orders. The important Insect pests recored on cucumber were Leafhoppers ,Empousca spp ,thrips Thrips tabaci (Lind.), the melon aphids Aphis gossypii (Glover) , the tomato whitefly, Bemisia. tabaci , the cucurbit fruit flies, Dacus ciliates and cucurbit leaf fly (leaf-miner) Liriomyza bryoniae (Kalt.),. However the common associated natural enemies inhabiting cucumber field were, Coccinella septempunctata L.; Chrysopela carnea (Steph)., Orius spp and C. undecimpuctata . The effects of certain environmental factors (maximum temperature , minimum temperature, relative humidity) and C. undecimpuctataand numbers on the population fluctuation of A. gossypii were studied .Results indicated that C. undecimpuctata had significant correlation with population of aphid during the two seasons 2014 and 2015. The previous environmental factors were responsible for about 51.75% & 91.62% of the variability in the populations of aphid in summer and Nili plantation at 2014 respectively , while they were responsible for about 78.08% & 94.65% respectively in 2015.

Key words

survey the insects Empousca spp ,thrips effects of certain environmental