Horticulture under glass increasingly fights insects with natural enemies

In recent years Dutch horticulture under glass has started to make use of assassin bugs and parasites as pest control. The number of organic pest controls has been increasing substantially in growing tomatoes, cucumbers and paprikas. Ecological pest control is also increasingly used in growing flowers under glass. This increase started around 1995 .

Total number of pest controls for vegetables grown under glass

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New pest controls gaining ground

The number of ecological pest controls has been growing spectacularly in horticulture under glass. In 1992 Statistics Netherlands observed only seven different species, which had increased to 26 in 2000. The new ecological pest controls are well-received.

By 1995 the assassin bugs were introduced in growing tomatoes and a new kissing bug in growing paprikas. In 2000 these pest controls were used by nine in ten farmers growing these crops. Several natural enemies introduced in 1998 had also gained ground by 2000.

The ladybug, introduced in 1995 in paprika growing was less successful. The surface area on which it was used fell from 66% of the total in 1995 to 9% in 2000.

 New pest controls in horticulture under glass

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Tried and tested pest controls still popular

Most traditionally used pest controls have been successful throughout. The ichneumon wasp introduced in 1971 against white fly in tomatoes and the kissing bugs against thrips in cucumber and paprika introduced in 1981 are still used all over in 2000.

The kissing bug fighting red spider mite introduced in 1969 as the first organic pest control lost its popularity among cucumber growers. The number of users fell from 75% in 1998 to 50% in 2000. However virtually all paprika growers used it in 2000.

Ecological pest control increased in gerbera growing

Much ecological pest control is currently used in growing flowers under glass, especially in growing gerberas. In 2000 four species of ichneumon wasps, three species of kissing bugs and two species of gallfly were all used by more than 10% of all farmers. Ichneumon wasps were used against white fly by 74% of these holdings. But ecological pest controls are also increasingly used in growing roses, orchids and potted plants to fight red spider mite, aphids and thrips.

Tom Loorij