Ten Egyptian and imported entomopathogenic nematodes were evaluated for their pathogenicity to R. ferrugineus in both the laboratory and the field. In the laboratory, most nematodes were pathogenic to the pest larvae, pupae and adults. Larvae and adults were more susceptible to nematode infection (mostly 100 % mortality) than pupae enclosed in their cocoons. In the field however, the highest insect larval mortality was 66.67 % and most of nematodes failed in controlling the pest. Such failure could be due to hot weather, the tunnelling behaviour of the pest larvae and the too much sap in the infested sites in the trunks of palm trees.

The peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tiphritidae), is an economic insect pest attacking the fruits of mangoes, apricots, guava, citrus, and peaches. This pest is difficult to be controlled by the traditional chemicals due to the behavior of its larvae that hide inside the fruits or its pupae that pupate in the soil. The present study documented the molecular identification and the first record of the entomopathogenic nematode, Heterorhabditis marelatus D1 from Egypt. Environmental characterization showed that the new isolate was superior than the commercialized species, Heterorhabditis bacteriophora, in heat tolerance (higher more than five times), desiccation tolerance (higher than four times), and hypoxic tolerance (higher than about two times). Comparative virulence of the reference nematode to the larvae of the great wax moth, Galleria mellonella L., was carried out. When applied to the soil, the new isolate showed high potency in controlling B. zonata adults emerged from their pupae as it killed over 77% of the adults within 48 h after emergence.

Sugar beet, Beta vulgaris L. is a strategic crop of sugar industry in Egypt. It is threatened by several insect pests among most important of them is the beet beetle Cassida vittata. This work deals with the biological control of this insect using four Egyptian and imported entomopathogenic nematodes (EPNs). The nematodes included Steinernema carpocapsae S2, Heterorhabditis bacteriophora S1, S. feltiae and H. bacteriophora (1-3). Daily mortality of larvae, pupae and adults of C. vittata were recorded after treatment with serial concentrations (from 500 to 4,000 infective juveniles/ml) of each of four studied EPNs. Development of nematodes in insect bodies was followed up. S. carpocapsae S2 was chosen for the application against different stages of the pest in a sugar beet field. In the field, single application of S. carpocapsae S2 killed 65% of the larvae, 92% of the pupae and 57.3% of the adults of C. vittata within a week. This work is the first report on using the EPNs to control sugar beet beetle.

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