Relationship Between Bemisia tabaci and Aphis gosspyii Infestations with Certain of Plant Diseases, Plant Enzyme Activities, Dissection Structures and Natural Enemies on Squash Plant.

Document Type : Original Article

Authors

Plant Protection Research Institute, Agricultural Research Center, Giza, Egypt

Abstract

The whitefly Bemisia tabaci and cotton aphid, Aphis gosspyii are considered as the most harmful insect pests to squash, Cucurbita pepo L. crop. Beside the direct damages, white fly transmits pathogenic virus and induces plant physiological disorders, as the silver leaf disorder and cotton aphid transmits mosaic virus. In this study, we evaluated the development of leaf silvering and mosaic virus in squash plant exposed to the infestation of B. tabaci and A. gosspyii, respectively. An experiment was conducted under field conditions, in Mansheyet Saqqara village, Giza, Egypt, during the summer seasons, 2016 and 2017.
The activity of some plant enzymes, such as Alpha Esterase, Peroxidase & Phenoloxidase and chlorophyll contents were correlated with B. tabaci and A. gosspyii infestations. The associated predators, mirid bug, Nesidiocoris tenuis and ladybird, Coccinella  undecimpunctata were collected and their relation was also studied. The leaf silvering degrees were also determined during this study.
The results indicated that induced silver leaf in squash cultivar was similar to a systemic phytotoxemia, mild symptoms in which silvering along the main and secondary veins. While, sever symptoms included completely silvering were observed on the upper leaf surface. Inversely, the lower leaf surface appeared normal.

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