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The aimed of this investigation was to estimate the seasonal abundance and activity periods of the cotton mealybug, Phenacoccus solenopsis Tinsley and its associated parasitoid on okra plants. The present experiment was conducted at Hihhya distract, Sharkia Governorate during two consecutive seasons 2017 and 2018. Plant samples were taken weekly to calculate the population density of different stages of tested pest and its parasitoid, the effect of some weather factors, the number of generations and the best leaf surface. The present work was found a reverse relation between the populations of the cotton mealybug (CMB) and its associated parasitoids. The population dynamic of CMB was high while the population of its parasitoids was low in the first season. On the other hand, the opposite results were obtained during the second season. The P. solenopsis had two to three generations during the first and second seasons, respectively. There was significantly positive correlation between maximum temperature and the population females of this insect whereas, a significant negative correlation was found with mean of relative humidity during the period of this investigation. The results of this study may help the researchers for designing a comprehensive pest management program and prediction models for the cotton mealybug to restrict their further spread.

from May to September 2017 on navel orange leaves infested with the Parlatoria black scale, Parlatoria ziziphi (Lucas) to calculate economic threshold and economic injury levels depending on the loss of leaves chlorophyll content. Simple correlation and partial regression were calculated between numbers of insect and chlorophyll loss percentage in infested and uninfested units (inch 2). Positive highly significant correlation was recorded between numbers of insect and percentage of chlorophyll loss. Chi-square (X 2) was used to calculate economic threshold and economic injury levels of P. ziziphi that causes economic damage in disk chlorophyll content which were 9 and 14 individuals per inch 2 , respectively.

Entomology Journal publishes original research papers and reviews from any entomological discipline or from directly allied fields in ecology, behavioral biology, Field experiments were conducted on cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Sternorrhyncha: Coccoidea: Pseudococcidae) which infested eggplant at Hihhya distract, Sharkia Governorate during two successive seasons 2015 and 2016. The population density, activity periods, the effects of some weather factors, number of insect generations and preferable leaf surface of of P. solenopsis were considered. The obtained results revealed that the total numbers of a live stages had four peaks of activity during the first season. They were in third week of June, third week of July, fourth week of August and second week of September. While, during the second season, three peaks of activity were noticed in the last week of June, first week of August and second week of September. The total effects of some weather factors such as maximum and minimum air temperature (˚C) and relative humidity percentage (R.H.%) showed positive significant relationship with the cotton mealybug population. P. solenopsis had three generations during the first and second seasons the first generation was taken seven weeks. While, the second and third generations took sex weeks. The first generation was during the period extended from the third week of May till the end of June, the second one took place from the first week of July till the second week of August and the third one was during the period extended from the third week of August till the third week of September. The insect pest preferred the lower leaf surface than the upper one during the first and second seasons.

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