The striped mealybug Ferrisia virgata (Ckll.) (Hemiptera: Pseudococidae) attacks many host plants including shrubs and trees in Egypt. The aim of this work is to study the population densities of striped mealybug and the effect of biotic and abiotic factors on the insect population and the preferable direction for the insect stages on ornamental corn shrubs, Dracena fragrans in Al-Zohria gardens at Cairo during two successive years (2014-2015) (2015-2016). The results showed that the highest number of F. virgata insects occurred during Sep. in the first year, while it occurred during Nov. in the second year, with average (93.5 and 42.1 insect / sample) in the first and second years respectively. The general mean number of F. virgata has of 24.7 during the first year while it was 16.6 in the second year of investigation. The results showed that the insect population was highest in autumn with average (64.3 and 44.6 insect/ sample) in the first and second year respectively, whereas the lowest mean was in spring (2.7 and 1.5 insect / sample) during the two successive years. The data revealed insignificant relation between daily maximum, range and minimum of temperature and natural enemies on population activity. On the other hand the relation between the relative humidity and the population activities was highly significant positive correlation in both two years. In respect to preferable direction, results showed that the northeastern direction was the preferable direction for the population activity in the both years of the study.

The cotton mealybug Phenacoccus solenopsis Tinsley (1989) (Hemiptera: Pseudococcidae) is one of the invasive species recently introduced to Egypt and nowadays it is wide spread among various parts of the country. The aim of this study shed light on certain biological aspects of the cotton mealybug and the effect of three host plant species i.e. ("potato", "tomato" and "cotton") as food source on certain biological aspects under the laboratory conditions. The results showed that the female and male of the cotton mealybug are not equal in numbers of moulting and nymphal duration. The life cycle of cotton mealybug was greater for males compared to females may be due to the additional moult and the pupal stage in the male, and it was significantly affected by different host plants, the females lasted 24.2±2.7, 22.1±3.1 and 20.0±2.7 days on potato, tomato and cotton plants leaves, respectively, while the males life cycle lasted 25.2±2.6, 22.9±3.1 and 21.4±2.9 days on potato, tomato and cotton plants leaves, respectively. Adult females lived longer than males, the female longevity lasted 31.2±2.5, 26.8±3.6 and 23.1±3.2 days on potato, tomato and cotton plants leaves, respectively, while males lived 3.1±1.3, 2.1±0.9 and 2.0±1.0 days on potato, tomato and cotton plants leaves, respectively. The cotton mealybug fecundity was significantly affected by different host plants; the females laid 163.3±48.5, 212.8±55.1 and 265.8±57.7 Eggs/female when adults reared on potato, tomato and cotton plants leaves, respectively. Sex ratio between females and males of P. solenopsis reared on potato, tomato and cotton plants leaves are not affected by the host plant. From the motioned results, it could be concluded that the cotton mealybug, P. solenopsis preferred cotton plant than the other two host plants.

The predatory mite Cydnoseius negevi (Swirski & Amitai), (Family Phytosidae), is a predaceous mite of different mite and insect pests, such as two-spotted spider mite and castor whitefly. This work aimed to study the role of C. negevi in controlling the four arthropod pests, Spodoptera littoralis (Boisduval), Trialeurodes ricini (Misra), and Anagasta (Ephestia) kuehniella (Keller) as well as spider mite Tetranychus urtica (Koch) compared with date palm pollen as food options under controlled conditions. The predatory mite C. negevi can feed and complete its life span successfully on these foods. Trialeurodes ricini and A. kuehniella eggs prolonged the life cycle of C. negevi. Likewise, the shortest period observed when male and female fed on eggs of T. urtica. Egg production of the tested mite was the highest when it fed on pollen, while oviposition was lower when the predatory mite fed on T. ricini. Food sources also affected all life tables where spider mite eggs and pollen grains were the most favorable foods increased Ro, rm, erm and GRR values. Insect eggs prolonged T and Dt times of the tested mite C. negevi. Therefore, C. negevi could be reared successfully on date palm pollen and eggs of S. littoralis, T. ricini, A. kuehniella and T. urticae.

Certain biological aspects of the Egyptian praying mantis Miomantis paykullii (Stal, 1871) were studied in the laboratory. Results indicated that ootheca contained an average of 52.4 nymphs, with a mean length of 15.0 mm. The total duration period of nymphal stage required 64.1±10.54 and 54.8±6.54 days for female and male respectively. The generation period was 99 days at daily mean of temperature 25.9Cº and relative humidity percentage 45.0%. Six nymphal instars were recorded for male whereas, seven instars were found for female. The fecundity of M. paykullii through the oviposition period was 336.2±56.78 nymph per female.

This study was carried out to survey the main piercing-sucking insect species that infesting maize plants in Zagazig district, Sharkia Governorate, Egypt during 2020 and 2021 seasons, in addition to estimate the effects of potassium fertilization on populations of aphid, leafhopper and planthopper insects. Plant samples, sweeping net, yellow sticky broad traps were used to collect these piercing-sucking insects from different potassium fertilized maize plants. Results showed that aphid species that infesting maize plants were Rhopalosiphum maidis, R. padi, Aphis gossypii, the leafhoppers were Empoasca decipiens, E. decedens, Cicadellina chinai, C. bipunctella zea and Balclutha hortensis, and the planthoppers were Sogatella vibix and S. furcifera. Potassium fertilization of maize plants influenced the population density of the aforementioned homopterous insect species. The highest mean number of the aforementioned homopterous insect species occurred with F1 (zero potassium fertilization) treatment, while the lowest population density was recorded with F4 (150 kg. Potassium sulphate/feddan). Chemical analysis showed a reverse relationship between protein and carbohydrate contents and aphid, leafhopper and planthopper populations on all tested potassium fertilized maize plants, while a positive relationship between pH values and the aforementioned insect populations was obtained.