Population Fluctuation, Host Preference, Damage And Control Of Western Flower Thrips, Frankliniella occidentalis (Pergande) On Some Vegetable Crops In Egypt.

Document Type : Original Article

Author

Plant Protection Research Institute, ARC, Dokki, Giza.

Abstract

Four vegetable host plants,cucumber, Cucumis sativus L; Squash, Cucurbita pepo L; eggplant, Solanum melongena L. and kidney bean, Phaseolus vulgaris L.were cultivated at Namoul village, Toukh district, Qalyoubia Governorate for two successive summer seasons throughout 2014 and 2015 to study the population fluctuation, host preference, damage percentages and control of western flower thrips, Frankliniella occidentalis.
The obtained results revealed that the occurrence of F. occidentalis was recorded during the whole period of flowering stage from May, 10th to July,5th and the population density was increased and concentrated from the period between May, 24th to June, 28th on all the four tested crops. The population fluctuation of F. occidentalis was differed according to host plant. Two peaks were recorded on squash and kidney bean flowers during the two studied seasons. While, 2&3 peaks were observed on both cucumber and eggplant flowers in both seasons, respectively.
Cucumber flowers was infested by significantly highest numbers of F. occidentalis rather than the other three tested crops and considered as the susceptible crop, as the seasonal mean numbers were 8.03 and 7.48 individuals / flower in the two seasons, respectively. On the contrary, kidney bean flowers infested by the significantly lowest numbers of this pest, 1.87 and 3.26 individuals / flower in the two tested seasons, respectively.
During the two tested seasons, F. occidentalis caused a significant damage in the flowers of all studied crops. The significantly heaviest damage percentage was recorded on cucumber flowers, being 29.12 and 26.66 % in the two seasons, respectively. While, the lightest damage was determined on kidney bean flowers, showing 6.66 and 11.78% in the two seasons, respectively.
Acetamiprid (Mospilan 20% SP) and Thiamethoxam (Actara 25 % WG) gave the significant highest reduction of F. occidentalis infesting cucumber flowers, as the average of their reductions after 14 days of spraying 81.80 and 75.17%, respectively. Carbosulfan (Marshal 20% EC) and Spinosad ( Tracer 24 % SC) gave considerable results in reducing the population density of the thrips ( 68.70 and 67.13% after 14 days, respectively).While, Spinetoram (Radiant 12% SC) gave the significantly lowest reduction after 14 days (60.03%).

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