|
 
The adult sciarid flies live on and around the compost surface of pots, generally inside rather than outside. The flies themselves are an unsightly nuisance but most of the damage is caused actually by their young. The small white larvae live in the compost and feed on the tender roots of plants and cuttings. In our own nursery we have seen them nibbling at the edges of banana seeds, and preventing germination. Biological ControlsThere are two possibilities for biological control of sciarid. Both attack sciarid larvae. One is a predatory mite which crawls over the soil looking for prey, and the other is a nematode which is watered on, and which attacks the sciarid larvae underground. The mites have the advantage that they can crawl into crevices and onto surfaces that the nematodes can't reach. They are also good as a preventative measure, as they can survive with little food, or alternative food. On the other hand the nematodes are more effective if the sciarid population is high. Use both in a two-pronged attack!Predatory MitesThese are tiny brownish crawling beneficial mites (hypoaspis miles) which eat eggs and larvae of Sciarid flies. The soil temperature needs to be above 12°C, and they will be even more effective if the soil is warmer than that. Use as soon as possible after receipt, and within 48 hours. Store at 15-20° C until use. Keep out of direct sunlight. For more information about hypoaspis mites click here NematodesThese are tiny transparent worms (eelworms)which live in the soil. These nematodes are active at temperatures as low as 8°C, but the bacteria that they use to kill their hosts are not, minimum soil temperatures need to be 14°C for the nematodes to work effectively. For more information about nematodes click here |
||