SummaryAt the turn of the century, damage by Otiorhynchus sulcatus was sporadic and limited to small areas. Increasing horticultural intensification and the adoption of husbandry techniques favourable to the weevil, such as the use of polythene mulches, increased its pest status. The development of the early inorganic pesticides reduced the number of serious outbreaks of this pest and weevil control was further improved by the development of the persistent organochlorine insecticides in the 1940's. The banning of a number of the more persistent insecticides over recent years has now left the horticultural industry in a very vulnerable position. O. sulcatus is now a pest on a range of horticultural crops throughout the temperate regions of the world. Infestations are most common in Europe (where it originated) and the USA, and nearly 150 plants species have been identified as potential hosts to O. sulcatus. Damage is most frequently caused by the root feeding larval stage. Populations as low as one larva plant can kill sensitive species such as Cyclamen. Severe damage by the leaf feeding adults is less common, although low levels of damage or contamination by adults may be unacceptable in certain situations. There is one generation a year. Oviposition by the flightless parthenogenetic females occurs over the summer months with oviposition rates of c. 500 and 1200 eggs adult‐1for outdoor and laboratory populations, respectively. O. sulcatus mainly overwinters as larvae, although significant numbers of adults may survive in areas where winter temperatures are not too severe.A number of natural enemies, such as hedgehogs, frogs and predatory beetles, help to maintain O. sulcatus populations at a low level in natural environments, but they are less successful in intensive horticultural systems where persistent chemicals have been heavily relied on to maintain the population below the economic threshold level. Increasing environmental concern is now forcing growers to consider new pest control strategies. Controlled release formulations of non‐persistent products, such as fonofos and chlorpyrifos, have shown potential as control agents for O. sulcatus larvae. Biological control agents, such as insect parasitic nematodes, have been developed commercially and new microbial control agents are in the process of development. Most of the new control products are directed towards control of O. sulcatus larvae. Adult vine weevils are nocturnal and a much more difficult target for the new control agents. It is likely that an integrated approach to pest control will be required to maintain O. sulcatus populations below their economic threshold level.

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Fungi have been suggested as agents for the biological control of insects for over a century, but their use remains extremely limited. This paper examines the biology of entomogenous fungi, highlighting their need for moisture, and reviews studies on the Entomophthoraceae, Beauveria bassiana, Beauveria brongniartii, Metarhizium anisopliae and Verticillium lecanii. It is suggested that current studies should be directed towards the control of pests living in humid micro‐climates and that moisture‐retaining formulations should be developed to reduce the reliance of fungi on moisture. Many entomogenous fungi produce insecticidal toxins in submerged culture and these compounds are of interest as a source of new toxophores. The most extensively studied toxins are the cyclic depsipeptides from M. anisopliae, termed destruxins, and their possible role in pathogenesis is discussed. Beauveria bassiana also produces the cyclic peptides termed beauvericin, beauverolides, and bassianolide. Toxins produced by V. lecanii, and the Entomophthoraceae are also described.

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