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June 2001. Orchidophilus aterrimus (Waterhouse) is a problem in some of orchid stocks at the National Capital Botanical Gardens, Port Moresby, Papua New Guinea. Several insecticides were applied over several months, but it was not possible to eliminate the problem. Information on insecticides was requested.
Sprays of Confidor (Imidacloprid) were suggested: 0.25 – 0.5 g/liter at two week intervals. It is a stomach poison, systemic and a rather long residual activity. It is also very active against aphids, mealybigs and scale insects. However, it was also said to to be very poorly absorbed through leaves so often the level control following foliar application is very poor. As a foliar application, it is highly persistent and highly
disruptive to IPM programs. Parasitoids are particularly susceptible. In shade house conditions, Confidor kills 100 % of parasitoids for sileverleaf whitefly for at least 21 days post spray. The only way to effectively use Confidor is as a soil application into the root zone.
The Northern Territory undertook a successful eradication program against the orchid weevil in the early to mid 1990’s. The approach involved quarantine, removal and burning of the less valuable infested plants, dipping all remaining Dendrobium and Vanda plants in dimethoate solutions, cover sprays with chlorpyrifos and good hygeine in the affected nursery property. It has been published.
There is a series of papers, mostly from Hawaii, on chemical control of this pest and several gave quite adequate control but could not eliminate the infestations.
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