Response of squash varieties to Tetranychus urticae (Acari : Tetranychidae)‎ and Bemisia tabaci (Hemiptera : Aleyrodidae)‎ infestation in relation with its leaf chemical compositions

Abstract EN

Immature fruit of squash (Cucurbita pepo L.) is a popular vegetable in Egypt.

It can be produced almost as year– round crop.

Field studies were carried out to evaluate four squash varieties i.e.

Arkan, Dafn, Sama 740 and Andro 174 for their liability to the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) and the whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) infestation during 2015 and 2016 seasons at Beni Suief Governorate, Egypt.

Andro 174 variety was the most susceptible during the both seasons, while Sama 740 and Arkam varieties were the most tolerant during the investigated period.

Metrological phenome as temperature and humidity played a key role in the T.

urticae and B.

tabaci infestations on the tested squash varieties.

On the other hand, the sensitivity of squash varieties to the pest injury relies mainly on the phytochemical contents which varied from variety to another, which affect on pest density levels on squash leaves.

A positive relationship was found between pest infestations and squash leaf contents i.

e., nitrogen, total proteins, total carbohydrates and reducing sugar.

In addition, the effect of potassium content, total phenols and tannins was negative effect on the T.

urticae and B.

tabaci populations, in where these target pests increased as the leaf content of these components decreased.

It is concluded that the obtained results should be taken into account in planning of integrated pest management programs in squash plants.