SUSCEPTIBILITY OF SOME EGYPTIAN COTTON VARIETIES TO INFESTATION WITH SUCKING INSECTS | ||
| Egyptian Journal of Agricultural Research | ||
| Article 10, Volume 75, Issue 2, July 1997, Pages 383-391 PDF (2.13 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejar.1997.404765 | ||
| Authors | ||
| EL-SAYED M. E. KHALAFALLA; RAMADAN M. SALEM; SAMIRA H. MITRI | ||
| Plant Protection Research Institute, Agricultural Research Centre, Dokki, Giza, Egypt | ||
| Abstract | ||
| Nine Egyptian cotton varieties were evaluated for their susceptibility to infestation with certain sucking insects under field conditions of north Delta during 1995 season. Weekly count of total number of insects per 25 seedlings or leaves chosen at random, showed that peak aphid populations on the different varieties occurred during the period from the 2nd week of July to the 3rd week of August. The highest numbers of aphids existed on cotton variety Giza 83, while Giza 70 harboured the least numbers. On the other hand, cotton variety Giza 83 was the least infested variety with jassids and whiteflies, which showed highest affinity to varieties Giza 70 and Giza 85, respectively. In most tested varieties, the total populations of the three sucking insects correlated positively with temperature, and relative humidity, while this correlation was negative with wind speed in all tested varieties. The combined effect of the three climatic factors was more pronounced on the populations on Giza 45 and Giza 80 than on other varieties since it was responsible for 86.8 and 80.33% of variability in the populations, respectively. On the other hand, the total populations were less affected by the three climatic factors collectively on Giza 76, Giza 83 and Giza 77, where it was responsible for 28.00, 21.75 and 19.80% of variability in the populations, respectively. | ||
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