Chemical plant strengtheners find increasing use in agriculture to enhance resistance against pathogens. In an earlier study, it was found that treatment with one such resistance elicitor, BTH (benzo-(1, 2, 3)-thiadiazole-7-carbothioic acid S-methyl ester), increases the attractiveness of maize plants to a parasitic wasp. This surprising additional benefit of treating plants with BTH prompted us to conduct a series of olfactometer tests to find out if BTH and another commercially available plant strengthener, Laminarin, increase the attractiveness of maize to three important parasitic wasps, Cotesia marginventris, Campoletis sonorensis, and Microplitis rufiventris. In each case, plants that were sprayed with the plant strengtheners and subsequently induced to release volatiles by real or mimicked attack by Spodoptera littoralis caterpillars became more attractive to the parasitoids than water treated plants. The elicitors alone or in combination with plants that were not induced by herbivory were not attractive to the wasps. Interestingly, plants treated with the plant strengtheners did not show any consistent increase in volatile emissions. On the contrary, treated plants released less herbivore-induced volatiles, most notably indole, which has been reported to interfere with parasitoid attraction. The emission of the sesquiterpenes (E)-β-caryophyllene, β-bergamotene, and (E)-β-farnesene was similarly reduced by the treatment. Expression profiles of marker genes showed that BTH and Laminarin induced several pathogenesis related (PR) genes. The results support the notion that, as yet undetectable and unidentified compounds, are of major importance for parasitoid attraction, and that these attractants may be masked by some of the major compounds in the volatile blends. This study confirms that elicitors of pathogen resistance are compatible with the biological control of insect pests and may even help to improve it.

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.

Three rates of Coccinella undecimpunctata L. (Coleoptera: Coccinellidae) stages release in cucumber field for controlling Aphis gossypii Glover and Myzus persicae (Sulzer) (Hemiptera: Aphididae) was repeated 4 times at 15-day intervals. The tested rates were 12000 predator larvae/ feddan/releases, 6000 predator adults/feddan/releases and combination of 6000 larvae and 3000 adults/feddan/releases. The releases were conducted during 2007 and 2008 at a location in Qalubia Governorate. This release indicated the potential use of this predator to control the targeted aphis on cucumber. Reduction in aphids' populations and subsequent yields were significant. Highest reduction and yield gain was observed when combination larvae and adults were released.

A little attention has been given on molecular identification of thrips (Insecta: Thysanoptera) in Egypt. Thus, the primers ITS4A, 28S rRNA, 18S rRNA and the primer pairs COI-1 + COI-2 + COI-3 were used to identify the three dominant thrips species (Haplothrips cahirensis karny; Dendrothrips eremicola Priesener and Hydatothrips kassimanus Priesener). The samples were collected from a private olive grove during 2013 and 2014 at Ismailia governorate, Egypt. DNA sequence data for 28S rRNA gene showed a positive response to H. cahirensis and D. eremicola only, while 18S rRNA reacted with all species. ITS4A and COI-1 + COI-2 + COI-3 showed a negative response to the studied species. DNA sequences of the species based on 18S rRNA were recorded in the Gene Bank. The phylogenetic tree of the three thrips species was given also.

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