Seasonal abundance of some insect pests and associated natural enemies on fenugreek plants
2009
Afsah, A.F.E.
. Thrips tabaci recorded one peak on the second week of March and terminal buds harboured the highest numbers. During the first season, simple correlation (r) value was significantly positive between its population and both temperature and wind velocity, while it was insignificant for RH% but in the second season (r) value was insignificantly positive except with temperature that proved to be insignificantly negative. Berseem leaf weevil, Phytonomus bruneipennis had three peaks on 14th and 28th of February and 14th of March. Simple correlation values (r) between the insect population and the three weather factors were insignificant during both years. Liriomyza spp. showing three peaks on 24th of January, 28th of February and 28th of March and positively correlated with both temperature and wind velocity during two seasons. In the first season both, Aphis craccivora and Myzus persicae showed two peaks on (31st January, 7th March) and (14th February, 14th March), respectively but A. pisum showed four peaks on mid and late February, mid March and late April. A. craccivora, A. pisum and M. persicae recorded three peaks for each during the second season. The effects of the three weather factors on aphid populations had insignificant influence during the two seasons except in the relation between A. pisum and temperature degree, it was highly significant and significant in the first and second seasons, respectively. Two natural enemies were associated to pests infesting fenugreek plants. Coccinella spp. which began to appear in the first week of February and second half of January during the first and second seasons, respectively. Simple correlation values were not significantly positive for both temperature and wind velocity, while they were negative for RH% during two seasons..
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