ABUNDANCE OF CERTAIN INSECT PESTS AND ASSOCIATED PREDATORS IN COTTON FIELDS. | ||||
| Journal of Plant Protection and Pathology | ||||
| Article 4, Volume 29, Issue 11, November 2004, Page 6625-6642 PDF (5.03 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jppp.2004.240065 | ||||
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| Author | ||||
| M. G. M. Ragab, | ||||
| Plant Protection Res. Institute, Agric. Res. Center, Dokki-Giza, Egypt. | ||||
| Abstract | ||||
| The abundance of certain cotton insect pests and associated predators was studied on Giza 89 cotton variety under field conditions of Middle Delta during 2002 and 2003 seasons. Weekly count of total number of insects/1 00 seedling (or leaves or plants or bolls)chosen at random indicated that: During early- to mid-season of 2002 and 2003, Aphis gossypii (Glover) showed one peak of abundance in first of May, while Emp < /em>oasca spp. had one peak in late of May, 2002 and first of June 2003. Thrips tabaci (Lind.) had two peaks through May and June and it was the most abundant pest followed by A. gossypii, Empoasca spp. and Bemisia tabaci (Genn.). Coccine/la undecimpunctata (L.) reached its highest abundance in may, while the rest predators peaked through June synchronizing with the higher numbers of aphids and thrips. The most abundant predator was C. undecimpunctata; while, Chrysoperfa camea (Steph.) was the least abundant one, A. gossypii positively correlated with B. tabaci and T. tabaci, while Empoasca spp. negatively correlated with A. gossyp < /em>ii and B. tabaci. Relative humidity affected A. gossyp < /em>ii and B. tabaci positively in 2002 and negatively in 2003, but the reverse correlation was observed with Empoasca spp., and T. tabaci. Temperature positively affected Empoasca spp., in the two early to mid- seasons, and T. tabaci in 2002 one only, but it negatively affected A. gossyp < /em>ii and B. tabaci in both seasons. A. gossyp < /em>ii and B. tabaci were more influenced by total predators than Empoasca spp. and T. tabaci. During mid- to late-season of 2002 and 2003, A. gossyp < /em>ii showed one peak of abundance in late July and another peak in late August, while B. tabaci peaked twice through August and September. Also, Emp < /em>oasca spp. reached their highest abundance through August, while the maximum abundance of Pectinophora gossyp < /em>ie/la (Saund.) and Earias insulana (Boisd.) population were occurred in the end of both seasons. All insect pests except P. gossyp < /em>ie/la were more abundant in 2002 season than the same insects in 2003. B. tabaci was the most abundant pest during 2002 season and A. gossypii during 2003 one, while E. insulana was the least abundant pest during the two seasons. C. undecimpunctata peaked through August of 2002 and 2003 seasons; while, the rest predators mostly peaked through July and August of the two seasons. Paederus alfierii (Koch) was the most abundant predator, while Orius sp. and C. camea were the least one through 2003. The correlation between all insect pests themselves were positive except Emp < /em>oasca spp., which correlated negatively with P. gossypie/la and B. insulana in the two seasons. Relative humidity affected A. gossyp < /em>ii and P. gossypie/la positively in 2002 season, while B. tabaci and Empoasca spp. influenced by it positively in 2002 and 2003. On the other hand, E. insulana negatively correlated with it in the two seasons. Temperature affected A. gossyp < /em>ii and B. tabaci positively on 2003 and negatively in 2002, while the correlation was positively with Empoasca spp. and negatively with P. gossyp < /em>ie/la and E. insulana in the two seasons. Total predators were more effective on A. gossyp < /em>ii, B. tabaci and P. gossyp < /em>ie/la during 2003 season than 2002 one. While, these predators were more effective on Empoasca spp. and E. insulana during 2002 season than 2003 one. These findings have a great importance in cotton integrated pest management. | ||||
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