Mealybugs comprise some of the worst pests of fruit and shade trees in many parts of the world, especially in tropical and subtropical countries. Hibiscus mealybug, Maconellicoccus hirsutus (Green) at outbreak densities can be quite extensive actually killing hibiscus and ornamental landscape planting. M. hirsutus attacks a wide variety of host plants. It attacks grapes, guava and it was recorded on the roots of some date trees, ornamental and fruit crops.
In order to achieve a successful biological control in any area, searching for the well established and most efficient biological agents should be involved. The natural enemies (predators and parasitoids) showed differences of their searching characteristics in response to host plant species.

Ecological studies were carried out on four mango varieties (Shmama, Balady, Holman and Alphonso) in Inshas El-Raml district, Sharkia Governorate during the two successive years (2007-2008 and 2008-2009) to survey the important scale insects and mealybugs which attack mango varieties and their associated natural enemies. Seven species of scale insect and mealybugs belonging to four families, five parasitoids species and predacious specie were recorded. Seasonal abundance, number of generations, effect of climatic factors, preferable level, preferable leaf surface, distribution and susceptibility of the mango varieties to infestation for both Kilifia acuminata (Signoret) and Aulacaspis tubercularis (Newstead) and its associated natural enemies were studied. The relationship between insects infestation and chemical composition of leaves of mango varieties were also considered.

The present work was carried out to evaluate the toxicity of the extracts against Tetranychus urticae Koch, its predatory mite, Amblyseius gossipi El Badry and aphid, Aphis gossypii under laboratory and field conditions. Obtained data indicated that the spider mite females were more susceptible than females of the predacious mite to the toxic effect of all tested extracts. Predacious mite females were sensitive to direct spray application than the indirect method on treated prey. Natural extracts showed high mortality percentage against aphid, A. gossypii adults. Seventy two hours after treatment mortality of aphid A. gossypii adults varied significantly among tested concentrations. The study included the repellency effect of four different concentrations on mite and aphid. All the tested extracts gave poor repellency effect to aphid compared with mite. Obtained data indicate that high significant reduction was recorded after 3 days of treatment against T. urticae adults but after 24 hr. against predatory mite, Euseius scutalis Athais-Henriot under field conditions. Although, the rate of infestation reduction percent of the tested concentrations was increased as well as increasing the rate used but the rate of increase in efficacy was not proportional with the increase in the rate of concentration applied for all the investigated periods after treatments. Also, the rate of infestation reduction was significantly reduced with the lapse of time. Toxicity of tested materials was far less against the predator compared with T. urticae. These natural extracts were succeeded as fertilizers that effected on plant growth characters which had an important and effective role on competition between plants in increasing total yield in cucumber.

Field studies were carried out on cotton plants for two years (2004 & 2005). Plants received application of five different treatments, i.e., EM (effective microorganisms), Dipel 2X (bioinsecticide), Mikrofol (foliar fertilizer), Pleo (new chemical insecticide) and Conventional Spray Program (Pestban, Sumigold and Telethon). The effect of these treatments on percentages of infestation & reduction, larval content in cotton bolls by Pectinophora gossypiella and Earias insulana. Also, % of opened bolls, seeded cotton yield, fiber quality, some biochemical components on cotton bolls and numbers of predators of bollworms were estimated.

Particular knowledge based on biological, ecological and control studied was contributed to the red palm weevil, Rhynchophorus ferrugineus (Oliv.). Laboratory and field studies revealed that the unit increase in temperature above threshold level was corresponded to the decrease in developmental parameter figures such as sex ratio, longevity and growth rates of R. ferrugineus survivors. Soft inner date palm tissues demonstrated the most preferendum food diet more than sugarcane stem slices and recommended artificial diet. Life table parameters revealed that temperature and food type strongly affected reproductive rate (R0), generation duration (Gt), intrinsic rate of increase (rm) and population doubling time (Dt).Field trials were completed on the changes in the population activity of this insect during two investigated seasons, i.e. 2001 & 2002. The careful integration of the data obtained revealed that adult occurrence in date palm fields took place all the year round thus extended from early of March until the end of November with distinct occurrence in summer months while scarce by numbers of R. ferrugineus adults were occurred during winter months. Monitoring the changes in the population cycle demonstrated two distinct broods; the 1st brood harbored the reliable numbers of adult and considered accordingly as period of ” effective occurrence during hot months, while the 2nd brood demonstrates few numbers of adults and accordingly identified as “ineffective emergence”. Four overlapping annual generations were assessed under field conditions.The combined effect of three main physical environmental factors governing the changes in the population activity of R. ferrugineus was studied by simply adopting the partial regression values were considered as dependant (Y) and independent variables x1, x2 and x3 . The ovicidal, larvicidal and adulticidal activities of four insecticides against eggs, larvae and adults stages of R. ferrugineus under laboratory conditions were estimated.Data revealed that profenofos (72% EC) proved to be the most potent compound followed by emamectin (5% SG), abamectin (1.8% EC) and lufenuron (50% EC) especially against one and two days old eggs. The advancement of embryogensis correlated negatively with the susceptibility of eggs to the four tested insecticides. Considering the larval stage, emamectin proved to be the most effective compound followed by profenofos, abamectin and lufenuron against all tested instars. The susceptibility of tested insecticides was negatively correlated with the progression of larval development. The efficiency of tested insecticides against adult stage showed that, emamectin was the most effective followed by profenofos, lufenuron and abamectin, respectively. As a general trend, larvae were the most susceptible stage followed by egg and adult stages, respectively. The obtained results revealed that there were significant differences between the tested compounds on the reproduction of females. The tested insecticides treated as LC50 against egg stage induced a drastic effect on the number of mature and immature oocytes in the ovaries of virgin females.

Some qualitative and quantitative traits were studied in order to differentiate between the involved parents and the derived hybrids to determine and know the best cross, which could be recommended for breeding under our conditions. Mean values of studied characters of tested races, their crosses and their reciprocals were compared.

The effects of the three insect growth regulators (IGRs) chlorfluazuron, flufenoxuron and pyriproxyfen on certain biological, biochemical and histopathological aspects of late 6th instars of S. littoralis treated as newly moulted 4th instars with the LC50 values of these compounds were studied.
The two chitin synthesis inhibitors, chlorfluazuron and flufenoxuron were the first and second most toxic IGRs, respectively for the larvae, whereas the juvenile hormone mimic, pyriproxyfen was the least toxic compound. Chlorfluazuron and flufenoxuron decreased the mean larval duration in the parental generation (the generation during which the treatment was carried out) and in both the first and second generations (the generations following the parental generation), as compared to non-treated larvae. This was slightly decrease, except for that obtained in the parental generation treated with chlorfluazuron where it was significant. This is also true for treatment with pyriproxyfen in the second generation the slightly decrease in the mean larval duration was obtained. In contrast, treatment with pyriproxyfen increased the mean larval duration in both the parental and first generations as compared to control. Nevertheless, such slight increase.
Chlorfluazuron and flufenoxuron slightlly decreased the mean pupal duration in the parental, first and second generations as compared to non-treated pupae. On the other hand, treatment with pyriproxyfen did not, approximately, affect the mean pupal duration in the three generations. The same pattern was more or less obtained for the mean pupal weight after treatment with the same three IGRs.
Both sexes of S. littoralis moths surviving 4th instars treated with the LC50 values of chlorfluazuron, flufenoxuron and pyriproxyfen lived shorter than non-treated moths in the three generations. Such decrease was significant only for the two sexes treated with chlorfluazuron in all the three generations, and for the male and female moths treated with flufenoxuron in both the parental and second generations, respectively. The percent of egg-hatch also was decreased as a result of treatment with the three tested IGRs in the three generations. However, chlorfluazuron exhibited the highest effect in suppressing the reproductive potentials of the female moths.
The two chitin synthesis inhibitors, chlorfluazuron and flufenoxuron significantly decreased the haemolymph glutamate¬oxaloacetate (GOT) and glutamate-pyruvate transaminases (GPT) activities of S. littoralis late 6th instars treated as 4th instars with the LC50 of these IGR's, as compared to non-treated larvae. However, pyriproxyfen slightlly increased and decreased GOT and GPT activities, respectively. In contrast, the three tested IGRs significantly increased the haemolymph acid and alkaline phosphatases activities of late 6th instars treated also as 4th instars, as compared to non-treated larvae. On the other hand, treatment with chlorfluazuron, flufenoxuron and pyriproxyfen decreased the haemolymph carbohydrases activity of late 6thinstarss as compared to non-treated larvae, except for an increases in invertase activity was obtained at treatment with pyriproxyfen only. The change in carbohydrases activity was significant at all treatments, except for the activity of invertase at treatment with both flufenoxuron and pyriproxyfen, and for the activity of trehalase at treatment with both chlorfluazuron and pyriproxyfen where theirs no change.
The total content of the haemolymph main nutrients (lipids, proteins and carbohydrates) of late 6'h instars showed a great variation with the different treatments. The total content of lipids was increased at treatment with both flufenoxuron and pyriproxyfen and was decreased at treatment with chlorfluazuron only. The total content of proteins was increased at treatment with both chlorfluazuron and pyriproxyfen, whereas it was decreased at treatment with flufenoxuron only. However, the total carbohydrate content was decreased at treatment with chlorfluazuron, flufenoxuron and pyriproxyfen as compared to non¬
treated larvae. This change in the main haemolymph nutrients was significant only for the total protein and carbohydrate contents at treatment with both chlorfluazuron and flufenoxuron.
The total haemocyte counts of late 6thinstars was increased due to treatment of 4th instars with the two chitin synthesis inhibitors, chlorfluazuron and flufenoxuron. The reverse was true for treatment with the juvenile hormone analogue, pyriproxyfen. The same pattern was also obtained for the viability of the haemocytes. There are five types of haemocytes in S. littoralis larvae: prohaemocytes, plasmatocytes, granulocytes, spherulocytes and oenocytoids. The most pronounced effect of treatment with the three tested IGRs was a significant increase in the number of both prohaemocytes and spherulocytes due to treatment with pyriproxyfen, and meanwhile a significant decrease and increase in the number of both granulocytes and spherulocytes respectively after treatment with flufenoxuron. Also, treatment with chlorfluazuron significantly increased the number of plasmatocytes, and meanwhile significantly decreased the number of both spherulocytes and oenocytoids, respectively.
Treatment of 4th instars of S. iittoralis with both flufenoxuron and pyriproxyfen resulted in severe histological changes in the integument, fat body and midgut of the surviving late 6th instarss. Chlorfluazuron disrupted the fonnation of endocuticle, whereas pyriproxyfen did not affect the cuticle formation, but it damaged only the hypodermis. These two IGRs caused collapsing and lysis of the fat cells with a higher magnitude in case of treatment with pyriproxyfen. The most prominent changes induced by these two compounds for the midgut was the vacuolation of the epithelial cells and disruption of the peritrophic membrane. Ultrastructural studies revealed that treatment with both chlorfluazuron and pyriproxyfen caused enhancement of lysosomal organelles in the midgut columnar epithelium, disruption of the microvilli, vacuolation of the cytoplasm of the columnar cells and fragmentation of the nuclear chromatin materials.

The study aimed to study the following points:
1-Survey of the different tydeid mites inhabiting different Egyptian fauna (52 different species)
2-Study the population dynamics of the different tydeid mites inhabiting some crops.
3-Study the different taxonomical characters of the collected tydeid mites allover the country.