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Larvae of spiny bollworm, Earias insulana and pink bollworm, Pectinophora gossypiella treated with Trichoderma harzianum liquid filtrate and spores of the fungus was investigated. In addition, the toxic effect of salicylic and tannic acids on the two insect species was studied. Bioassays were performed using a fungal filtrate 1, 0.5 and 0.25 ml (V/V) and spores suspension concentrations (2 × 10 5 , 1 × 10 5 and 0.5 × 10 5 spores / ml). The results showed that the mortalities of E. insulana and P. gossypiella larvae were closely related to the rates of the filtrate and the spores of T. harzianum. After infection with the fungal filtrate for 3 days, the three tested rates recorded the same mortality 60% of E. insulana. But, the mortality of P. gossypiella was 40, 33.33 and 31.67% for 1, 0.5 and 0.25 ml, respectively. On the other hand, after the same period of infection the concentrations of T. harzianum spores 2 × 10 5 , 1 × 10 5 and 0.5 × 10 5 spores / ml gave 60, 53.33 and 50% mortality and 80, 76 and 75% mortality for E. insulana and P. gossypiella, respectively. The toxic effect of salicylic acid on P. gossypiella was higher than its toxicity against E. insulana.

Laboratory studies were conducted for evaluate the effect of Dipel 2×, (Bacillus thuringiensis Kurstaki) against pink bollworm Pectinophora gossypiella (Saund.), and Biover® (Beauveria bassiana) (Balsamo) against spiny bollworm, Earias insulana (Boisd.).The accumulated mortalities of both pink bollworm, Pectinophora gossypiella and spiny bollworm, Earias insulana larvae, after six days of treatment, were represented as the acute toxicity were, Dipel 2× attained 17.18±0.63 % larval mortality at 32×10 6 IU concentration against P. gossypiella larvae while Biover® resulted in 15.55±0.59% larval mortality against Earias insulana larvae comparing with 0.00% larval mortality in untreated check. At the same time the tested biocide Btk (Dipel 2×) caused different influences on all biological aspects of pink bollworm which decreasing larval duration, pupal weight, pupation percentage, adult emergence, oviposition periods, adult longevity, female fecundity decreased strongly which recorded 149.75±5.23 egg/female comparing with that 362.00±2.31 egg/female in untreated check. The tested biocide Btk (Dipel 2×) also decreasing hatchability percentage that exhibited 73.16±1.15 % as compared with 88.09±0.57 % that achieved in untreated check. Also, results cleared that the effect of Biover® fungi attained decreasing in all biological aspects, except the male and female longevity and oviposition periods compared with untreated check. Female fecundity was moderately influenced when spiny bollworm larvae treated by Biover® that achieved 60.33±11.66 eggs compared with 78.33±5.78 eggs laid /female deposited by check females. Hatchability percentage of spiny bollworm also decreased vigorously which attained 41.12±6.45% as compared with that 82.33±7.51% in untreated once.

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.

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