Authors
Victoria L. Tenbrink, Research Associate
Arnold H. Hara, .Entomologist
Beaumont Research Center
Hilo, Hawaii
Hosts
Recorded hosts of the lesser orchid weevil include these genera of orchids: Vanda, Phalaenopsis, Renanthera, Grammatophylum (Swezey, 1945).
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Distribution
Lesser orchid weevils were first intercepted on orchids coming into Hawaii from the Philippines near the early part of this century. They were later found in an orchid house in Honolulu in 1928. Accidentally introduced on orchid plants from Asia, the lesser orchid weevil is recorded on Kauai, Oahu, and Hawaii. (Swezey, 1945, Nishida, 1992). It may occur on other Islands.
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Damage
Lesser orchid weevil larvae and adults have chewing mouthparts. They inflict similar damage to that of the orchid weevil.
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Biology
The biology of the lesser orchid weevil has not been studied in Hawaii.
Eggs
Information lacking
Larvae
Information lacking
Pupae
Information lacking
Adults
The lesser orchid weevil adult measures about 1/8th by 1/16th in. The body and wingcovers are opaque black. The striations on the wingcovers are much shallower and closer together than those on the orchid weevil, Orchidophilus aterrimus (Waterhouse).
The name derives from the relative smallness of the lesser orchid weevil, although in size the largest individuals overlap the smaller of the orchid weevils (Buchanan, 1935).
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Management
Non-Chemical Control
Biological control-Parasites
Information lacking
Biological control-Predators
Information lacking. Generalist predators such as spiders, toads, and birds can be expected to feed on lesser orchid weevils.
Sanitation
Plants with feeding damage should be immediately destroyed. This may prevent spread of an infestation if done soon enough.
Preharvest
Information lacking. However, this information on orchid weevil may apply. In bioassays, organophosphates and synthetic pyrethroids were effective against orchid weevils. Synthetic pyrethroids had greater residual activity, and some were superior to others in their effectiveness (Hata & Hara, 1991; Hata & Hara, 1992; Hara & Hata, 1994). Consult the University of Hawaii Cooperative Extension Service for effective, currently registered chemicals. Contact sprays must reach the insect, or the insect must encounter the residue. In the field, sprays tested were only effective against adults. Control was effective after 4 months of spraying every 3 weeks. (Hara & Mau, 1988).
Postharvest
A pyrethroid dip will help eliminate adults harbored in leaf axils but will probably not affect eggs, larvae and pupae inside stems or leaves. Material with feeding holes should be discarded.
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References
Buchanan, L. L. 1935. A new Genus and Species of Orchid Weevils (Coleoptera, Curculionidae, Barinae). Proc. Haw. Ent. Soc. 9: 45-48.
Hansen, J. D., A. H. Hara & V. L. Tenbrink. 1992. Insecticidal dips for disinfesting commercial tropical cut flowers and foliage. Tropical Pest Management 38: 245-249.
Hara, A. H. & R. F. L. Mau. 1988. The orchid weevil, Orchidophilus aterrimus(Waterhouse): insecticidal control and effect on vanda orchid production. Proc. Haw. Ent. Soc. 26: 71-75.
Hara, A. H. & T. Y. Hata. 1994. Residual activity of insecticides on dendrobium for control of orchid weevils, 1993. Insecticide and Acaricide Tests, 19: 369-370.
Hata, T. Y. and A. H. Hara. 1991. Control of Orchid Weevils on Dendrobium, Hawaii, 1990. Insecticide and Acaracide Tests 16: 252.
Hata, T. Y. and A. H. Hara. 1992. Control of Orchid Weevils on Dendrobium, Hawaii, 1991. Insecticide and Acaracide Tests 17: 348.
Nishida, G. M., ed. 1992. Hawaiian Arthropod Checklist. Bishop Museum Press: Honolulu.
DEC/1994.
O-PERRIG
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