![]() ![]() A hole at the base of the partition allowed free movement of the molluscs. The ventilated plastic container (30 × 13 × 13 cm) was split in two equal halves by a cardboard partition. Test arena to evaluate mollusc repellent properties of Metarhizium brunneum volatile organic compounds (VOCs). There were three replicates per treatment and the whole study repeated twice. Leaf consumption based on residual weight was measured 24 and 48 h post‐treatment. brunnuem conidia and the other left untreated (control). Choice assays were as above with the following modifications, the test arena consisted of a 2.5 L ventilated plastic box (16 cm × 10 cm × 16 cm) and lettuce leaves in Petri dishes were placed next to each other with one treated with different doses of M. There were five replicates per treatment and the whole study repeated twice. The assays were performed in a 300 mL cylindrical plastic container at room temperature with leaf consumption based on residual weight being measured 24 and 48 h post‐treatment. Two snails, starved for 24 h, were placed in each test arena 24 h after inoculating the leaves with the fungal inoculum. ![]() Controls consisted of leaves not treated with conidia. In no choice assays, the garden snail was provided lettuce leaves (4 g wet weight) pre‐coated with different doses (0.4, 0.2, 0.04 g) of dry conidia of M. brunneum conidiaĬhoice and no‐choice assays were conducted to see if molluscs avoided M. The potential for development of these ubiquitous volatiles as novo molluscicides is discussed.Ģ.3. 20, 29 This paper reports that these compounds are highly repellent or toxic to slugs and snails. 24, 25, 26, 27, 28 Exactly why entomopathogenic fungi produce these compounds is unclear but the fact that so many insects exhibit avoidance behavior suggest that they are responding to VOCs. 21, 22, 23 Most notable are 1‐octen‐3‐ol, 3‐octanone and 1‐octene, which are produced by a wide range of fungi including saprophytic molds, mushrooms and entomopathogenic fungi including species of Beauveria and Metarhizium. 20 Some compounds clearly possess pesticidal or repellent properties. Many fungal species produce low molecular weight volatile organic compounds (VOCs) with insect behavior modifying properties. ![]() Wood et al., 19 investigated the feeding behavior of the banana slug, Ariolimax columbianus Gould, on the sweetbread mushroom, Clitopilus prunulus Scop, and discovered that 1‐octen‐3‐ol released by this mushroom acted as an antifeedant. Of the limited number of studies, it is clear that slugs avoid or taste and reject the mushroom sporocarp. 13, 17, 18 Although many plant species have been screened to identify potential molluscicides very little attention has been given to fungi as a source of such compounds. 13, 14, 15, 16, 17 Whereas some compounds act as feeding deterrents others exhibit fumigant or contact toxicity. caffeine, neem, terpenoids, isothiocyanates) show promise as molluscicides and mollusc repellents. 10, 11 Live nematodes have been shown to elicit avoidance behavior in some slug species. 9 The nematode Phasmarhabditis hermaphrodita Schneider has been developed as a biological molluscicide but is considered expensive and ineffective against mature molluscs. 5, 6 However, metaldehyde will be withdrawn in the UK by 2020 in order to protect wildlife and to comply with the EC drinking water Directive 98/83/EC. 8 Metaldehyde‐based products by far dominate the molluscicide bait market worldwide but have corresponding ecotoxicological effects on non‐target species and lead to contamination of drinking water. 5, 6, 7Ĭurrent mollusc control is still heavily dependent upon the use of chemical pesticides such as metaldehyde, ferric phosphate, methiocarb and thiodicarb. 3, 4 The problem is often exacerbated by the accidental introduction of highly damaging invasive mollusc species such as the golden apple snails ( Pomacea canaliculate Lamarc k, Pomacea maculata Perry ), which have devastated rice crops in Asia and pose a serious threat to food security in the region. 2, 3 Their pest status is set to increase further due to legislative changes to pesticide usage and climate change with weather patterns favoring their population growth. Slug and snail population densities have increased over the years due to changes in crop management such as minimum tillage, direct drilling, and over‐wintering arable crops. nursery stock, root crops, salads) and hence their marketability. 1 Feeding damage can significantly reduce the aesthetic appearance of plants (e.g. Besides reducing plant stand and crop yield they increase the risk of infection by opportunistic plant pathogens. They cause feeding damage to both aerial and subterranean parts of the plant, including leaves, shoots, roots, tubers, corms, bulbs, flowers and seed. Snails and slugs are serious pests of agricultural and horticultural crops. ![]()
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