The homopterous insects are considered polyphagous pests on some cucurbitaceous crops. The objective of aim study was to survey the aphids, leafhoppers and whitefly insect species infesting certain varieties of squash plants i.e.(hybrid Otto, hybrid Daphne and hybrid Aziad) and also to study the seasonal abundance of the dominant species as well as to evaluate the effect of different varieties and their chemical constituents on the population density of the aforementioned homopterous insects during the studying period. The present experiments were carried out at the experimental farm belonging to the faculty of agriculture , zagazig university during 2016 and2017 seasons. The least susceptible variety of squash was Aziad hybrid variety, while the highest susceptible variety was Daphne hybrid variety and the certain chemical constituents in all tested varieties were associated with the insects infestation. The resistance variety should be used as an effective factor in integrated pest management programs which played an important role in depressing the population of the tested insects.