Effect of biotic and abiotic factors on the population dynamics of wheat greenbug, Schizaphis Graminum (rondani) (hemiptera: aphididae)under Sohag governorate conditions [electronic resource]

Includes bibliographic reference

The present study was carried out in the Agriculture Experimental of Shandaweel Agriculture Research Station, Sohag Governorate
during two successive seasons of 2015/2016 and 2016/2017. Results of both seasons showed the population fluctuation of S. graminum.
The obtained results revealed that greenbug increased from 0.60, 0.63 nymphs/tiller on 3rd, 4th week of January respectively,
to reach a peak of 82.80, 66.40 nymphs/tiller in 2nd,3rd week of March respectively. Aptera of S. graminum started to appear
in 4th week of January and increased to reach a maximum of 11.00, 4.7 individuals/tiller on both seasons respectively.
The peak of alatae reached 3.90, 4.70 individuals/tiller respectively, in the 4th week of March. The population of all morphs
started declining in the last week of March from field and disappeared by 1st week of April. The grubs and adults of
Coccinella septempunctata Linné appeared on the crop during the beginning of February and their population increased
with the increase in aphid population. Its abundance was maximum on the 4th week of March with average of 7.80, 9.06
individuals/tiller on both seasons respectively. The population of aphids had significant positive correlation with maximum,
minimum, mean temperature were 0.6524, 0.481, 0.542 in first season and 0.5687,0.472, 0.364 in the second season respectively.
But it showed negative correlation with humidity in both seasons -0.454, -0.391 respectively. The studies evaluate in detail
the abiotic and biotic factors regulating the wheat aphid populations.

Keywords: Wheat aphid, Schizaphis graminum (R), biotic and abiotic factors.

Summary in Arabic