More Examples Of Cucurbit Pests

Two leaf miner species, namely Liriomyza trifolii and L. huidobrensis, can cause damage in cucurbits. Both are about the size of the vinegar flies that hang around overripe fruit in the kitchen. Females lay their eggs in the plant tissue after making openings with their ovipositors and drinking the sap. The larvae hatch and make serpentine tunnels within the leaf. As a result of their rapid life cycle, they breed very quickly.

- Bill Kerr

L. trifolii, which arrived in South Africa before the other species, is more active in warmer areas. L. huidobrensis is a slightly larger species with a wide range of hosts. It prefers to attack the midrib of leaves, and may even bore down the stems of newly emerged pumpkins.

BIOCONTROL

Fortunately, South Africa has several species of parasitoids (minute wasps) that are highly effective at controlling this pest.

The female wasp lays an egg in the tunnelling larva when the latter reaches a certain stage of development. The parasitoids breed faster than the leaf miners, and so eliminate this pest.

Other beneficial insects include certain ladybird species that feed on aphids and scale insects.