Commuting between kingdoms: The biosynthesis of the only nonplant stilbene 1 from Photorhabdus bacteria has been solved by identification of all the genes involved in its biosynthesis and by feeding experiments. Stilbene 1 is derived from the condensation of two β‐ketoacyl thioesters and is required for the normal development of Heterorhabditis nematodes, the natural host of Photorhabdus.

Ticks have numerous natural enemies, but only a few species have been evaluated as tick biocontrol agents (BCAs). Some laboratory results suggest that several bacteria are pathogenic to ticks, but their mode of action and their potential value as biocontrol agents remain to be determined. The most promising entomopathogenic fungi appear to be Metarhizium anisopliae and Beauveria bassiana, strains of which are already commercially available for the control of some pests. Development of effective formulations is critical for tick management. Entomopathogenic nematodes that are pathogenic to ticks can potentially control ticks, but improved formulations and selection of novel nematode strains are needed. Parasitoid wasps of the genus Ixodiphagus do not typically control ticks under natural conditions, but inundative releases show potential value. Most predators of ticks are generalists, with a limited potential for tick management (one possible exception is oxpeckers in Africa). Biological control is likely to play a substantial role in future IPM programmes for ticks because of the diversity of taxa that show high potential as tick BCAs. Considerable research is required to select appropriate strains, develop them as BCAs, establish their effectiveness, and devise production strategies to bring them to practical use.

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In order to establish a functional role for late embryogenesis abundant (LEA) proteins in response to stress conditions in Caenorhabditis elegans, we silenced the expression of an LEA (Ce-lea-1) gene and determined the survival of worms under stress conditions. Ce-lea-1 transcription was induced during dehydration of C. elegans dauer juveniles. Following partial silencing of Ce-lea-1 transcription, we demonstrated a specific and significant reduction in worm survival during induction of desiccation, osmotic and heat stress. Together, these results establish a functional role for Ce-lea-1 in stress survival of C. elegans and suggest that Ce-lea-1 may function as a component that is common to the responses to the examined stress conditions.

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This paper characterizes the 'surviving stage' of the entomopathogenic nematode and describes the survival mechanisms in relation to the main environmental factors. The implications of survival strategies on the utilization of steinernematid and heterorhabditid nematodes as biological control agents are also discussed.

This chapter deals with some methods and procedures developed and tested with specific entomopathogenic nematode strains as potential biological control agents. It is likely that for other species of nematodes, experimental conditions such as concentration, incubation period and incubation temperature may need to be optimized. The meal worm Tenebrio molitor has been suggested as an alternative model insect to Galleria mellonella for determination of nematode virulence. The bioassays described emphasize the potential of measuring quantitative behavioural responses as specific criteria for nematode virulence.

The pathogenicity of 4 species of entomopathogenic fungi (Hyphomycetes species: Beauveria bassiana, Metarhizium anisopliae, Metarhizium flavoviride, and Paecilomyces fumosoroseus) to various developmental stages of Rhipicephalus sanguineus (Acari: Ixodidae) ticks was compared under laboratory conditions. The most virulent isolate, M. anisopliae-108, caused 92-96% mortality to unfed larvae and nymphs on day 7 postinfection (PI) and 100% mortality to unfed adults and engorged females on day 21 PI. The pathogenicity of M. anisopliae-108 to engorged larvae and nymphs was lower--82.6 and 60%, respectively. All tested B. bassiana, M. flavoviride, and P. fumosoroseus isolates were significantly less virulent (P < 0.05) or avirulent toward most life stages of R. sanguineus. The M. anisopliae and M. flavoviride isolates also prevented or reduced the ability of the ticks to lay eggs several days before their deaths. Female ticks infected by the fungi achieved only 11.3-60.8% of their egg-laying capacity compared with the controls.