Orthogalumna terebrantis Wallwork

The hydrophilic mite Orthogalumna terebrantis lays its eggs in the lower surface of the young leaves. Egg period lasts 7-8 days and 3 nymphal stages (proto, deuto and trito) together are completed in about 15 days at 25°C. Under field conditions 2,00,000 galleries per m (or 10,000 per plant) can cause serious damage to water hyacinth as observed in some tanks in Kerala and Karnataka.

O. terebrantis helps in hastening the collapse of water hyacinth. But in Kerala where Neochetina eichhorniae and N. bruchi are slow in establishing O. terebrantis on its own is providing effective suppression of water hyacinth in certain areas. The impact is more pronounced in partially shaded areas or under bridges.

Outdoor tanks / pools etc. as used for the weevils are employed for mass rearing of the mites also. Fresh plants are placed in to the pools and adult mites are released at the rate of about 10-20 adults per plant.