Insect are often seen eating plants and so are blamed for most plant damage. But the real culprits may be slugs and snails, which mostly hide by day and creep out at night, say biologists in Britain.
Mark Rees and Valerie Brown of Imperial College at Silkwood Park applied 'above-ground' and 'below-ground' insecticides and a molluscide to four annual crucifers, and observed how the insecticides affected fruit production. The crucifers were wild radish (Raphanus raphanistrum), shepherd's purse (Capsella bursa-pastoris), charlock (Sinapis arvensis) and hedge mustard (Sisymbrium officinale).
Rees and Brown found that although the insecticides reduced damage to leaves, the plants did not produce more fruit or grow larger. However, after the molluscicide was applied, plants increased both their size and fruit production by 37 per cent (Journal of Ecology, vol 80, p 353).
Even though slugs and snails were seen less often than insects, they were having a far ...
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