No doubt, there are changes in insect pest problems facing the farmers in the newly reclaimed land as well as in the old valley in Egypt due to different reasons, e.g., pesticide misuse and pest resistance, secondary pest outbreaks, absence or inefficient presence of natural enemies, and climate changes. Since the 1990s, the Ministry of Agriculture and Land Reclamation emphasizes to spread the philosophy of integrated pest management (IPM) among the farmers to utilize all suitable means, techniques, and approaches for maintaining pest population levels below those causing economic losses. Among these means is understanding the role of natural enemies in the agro-ecosystem to preserve and encourage their presence and enhance their role in suppressing pest populations as a main factor among the IPM strategies. Thus, it is of essential need to know more about the existing natural enemies associated with the key pests of the economic crops representing different agro-ecosystems in Egypt to develop a successful utilization of biological control agents within the frame of such IPM programs. Thus, it was found necessary to update their recent status as natural resources in various agro-ecosystems. These data are considered a review article eagerly needed for strategies of IPM of serious insect and mite pests in Egypt. The role of the biological control agents, mainly parasitoids and predators in different economic crops, is highlighted.

Population dynamics of Ferrisia virgata on Acalypha macrophylla was studied throughout one year. Three annual generations occurred on early June, early July and early August; increasing gradually in size, respectively.F. rirgura overwinters during January-early June, probably as adult females in the cracks and junctions of trunk and large branches and on the fallen leaves. In the laboratory, females migrate to the soil in winter. The preferable cardinal directions for this pseudococcid are southern east in first generation and southern west in the other two generations. Significantly positive correlation was found between population density and daily minimum and maximum temperatures, but correlation with relative humidity was insignificant.

Interactions between different initial densities of the predator Allaeocrcmum biannulipes and its preys were investigated. Four initial densities (3, 6, 9 and 12 pairs/vial) and three preys, Corcyra cephalonica, Tribolium confusum and Anagasta kuehniella were checked at 15–26 °C and 45–60% r. H. Associating with the latter prey, the pest's population showed a negative response towards the increase of the initial density of the predator up to 9 pairs/vial. However, in association with the other two preys, a reverse trend took place. The appropriate initial density with which the predator could face its victim was checked against the prey A. kuehniella under two hygrotherimic conditions: 15–26 °C/45–60% r. H. and 22–23 °C/38–60% r. H. At the former conditions, the predator was most efficient as it was able, with the density of 6 pairs/vial, to build up its population and to suppress that of its prey. However, in summer months (22–23 °C/38–60% r. H.), conditions were in favour to the pest than to the predator and consequently, the highest density of the latter built with the intial density of 9 pairs/vial was associated with a relatively high density of the prey. Zusammenfassung Zur Wirkung der Raubwanze Allaeocranum biannulipes (Montr. et Sign.) auf die Populationen einiger vorratsschädlicher Insekten Es wurden die Beziehungen zwischen verschiedener Anfangsdichte der Raubwanze A. biannulipes und der Enddichte ihrer Beutetiere Corcyra cephalonica, Tribolium confusum und Anagasta kuehniella bei 15–26°C und 45–60% rel. LF untersucht. Letzterer Schädling reagierte auf eine Zunahme der Anfangsdichte der Raubwanze bis hinauf zu 9 Paar/Gefäß mit einer Verminderung der Dichte. Jedoch war bei den beiden anderen Schädlingsarten ein umgekehrter Trend zu beobachten. Die optimale Anfangsdichte der Raubwanze wurde bei 2 Temperatur‐Luftfeuchte‐Bedingungen (15–26°/45–60% und 22–23°/38–60%) ermittelt. Bei der erstgenannten Bedingung war der Prädator am wirksamsten: er baute seine Population von 6 Paar/Gefäß ausgehend auf und reduzierte die Dichte seiner Beute. Dagegen wirkten die Sommerbedingungen (22–23°/38–60% zugunsten des Schädlings: eine Anfangsdichte von 9 Paar/Gefäß hatte eine relativ hohe Beutedichte zur Folge.

Five generations of Ferrisia virgata (CKLL.) have been reared per year; singly on sprouting potato tubers, although the fifth generation was not completed because of cold weather. This method produces only parthenogenic females, while males and females may be produced by dense rearing. Copulation was never observed, while oviposition behaviour and hatching process were described. Eggs are deposited singly and the incubation period averages 2.11–2.62 hr. with no significant difference under various thermal conditions. Hatchability ranges from 96.2–99.1%. Total nymphal duration in females averages 43.2 and 92.6 days at 28.9 and 16.6°C., respectively, while that in males elapses 25.4 days at 25.1–26.5°CC. Duration of the three nymphal instars of females and the four ones in males are estimated in various generations. The differences in duration between generations and those between instars within each generation were highly significant. Rate of mortality during nymphal stadia in the autumn/winter generations is higher than that in the spring/summer ones; being 14.3–100 and 0–23%, respectively. Longevity of parthenogenic ovipositing and non‐ovipositing females as well as that of males is estimated. The total life period (from egg to adult death) averages 76.2–154.6 days in females opposite to 19–47 in males. Eggs laid by a female averages 64.1–78 eggs; producing 61.6–67.6 nymphs/female/life. Average number of eggs/female/day averages 3.4–4.5 eggs. Three hymenopterous parasites and five predators are found associated with F. virgata. However, numbers of these bioagents are considerably low compared to the relatively high population of the pest.

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