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ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Crop and Commodity Protection Research » Research » Publications at this Location » Publication #223955
Title: Use of shaking treatments and pre-harvest sprays of pyrethroid insecticides to reduce risk of yellowjackets and other insects on Christmas trees imported into Hawaii

Author
item Hollingsworth, Robert
item CHASTAGNER, GARY - WASHINGTON STATE UNIV.
item REIMER, NEIL - HAWAII DEPT OF AG
item OISHI, DARCY - HAWAII DEPT OF AG
item Landolt, Peter
item PAULL, ROBERT - UNIV OF HAWAII, MANOA

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2008
Publication Date: 2/1/2009
Citation: Hollingsworth, R.G., Chastagner, G.A., Reimer, N.J., Oishi, D.E., Landolt, P.J., Paull, R.E. 2009. Use of shaking treatments and pre-harvest sprays of pyrethroid insecticides to reduce risk of yellowjackets and other insects on Christmas trees imported into Hawaii. Journal of Economic Entomology., Volume 102. pp. 69-78.

Interpretive Summary: Insects are commonly found by Hawaii’s quarantine inspectors on Christmas trees imported from the Pacific Northwest. To reduce the risk of importing yellowjacket (Vespula spp.) queens and other insects, an inspection and tree shaking certification program was begun in 1990. From 1993 to 2006, the annual percentage of shipped containers rated by Hawaii quarantine inspectors as moderately or highly infested with insects was significantly higher for manually shaken trees than for mechanically shaken trees. Between 1993 and 2001, a total of 343 insect species were recovered from Christmas trees. Live western yellowjacket [Vespula pensylvanica (Saussure)] queens were intercepted both from containers certified as manually shaken and from containers certified as mechanically shaken. The standard manual shaking protocol removed about one-half of the queens from Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] trees that were naturally infested with western yellowjacket queens. We investigated the use of pre-harvest sprays of permethrin as a complement to shaking procedures used to control yellowjackets and other insects. Western yellowjacket queens and honey bees (surrogates for wasp pests) were exposed to Noble fir foliage that had been sprayed in the field with permethrin more than six weeks before harvest. Pesticide residues provided complete control (moribundity or mortality) in both species. The sprays did not affect needle retention or quality of Noble fir foliage. We conclude that pre-harvest sprays of pyrethroid insecticides could be used in combination with mechanical shaking to greatly reduce the quarantine risk of yellowjacket queens and other insects in exported Christmas trees.

Technical Abstract: Insects are commonly found by Hawaii’s quarantine inspectors on Christmas trees imported from the Pacific Northwest. To reduce the risk of importing yellowjacket (Vespula spp.) queens and other insects, an inspection and tree shaking certification program was begun in 1990. From 1993 to 2006, the annual percentage of shipped containers rated by Hawaii quarantine inspectors as moderately or highly infested with insects was significantly higher for manually shaken trees than for mechanically shaken trees. Between 1993 and 2001, a total of 343 insect species were recovered from Christmas trees. Live western yellowjacket [Vespula pensylvanica (Saussure)] queens were intercepted both from containers certified as manually shaken and from containers certified as mechanically shaken. The standard manual shaking protocol removed about one-half of the queens from Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] trees that were naturally infested with western yellowjacket queens. We investigated the use of pre-harvest sprays of permethrin as a complement to shaking procedures used to control yellowjackets and other insects. Western yellowjacket queens and honey bees (surrogates for wasp pests) were exposed to Noble fir foliage that had been sprayed in the field with permethrin more than six weeks before harvest. Pesticide residues provided complete control (moribundity or mortality) in both species. The sprays did not affect needle retention or quality of Noble fir foliage. We conclude that pre-harvest sprays of pyrethroid insecticides could be used in combination with mechanical shaking to greatly reduce the quarantine risk of yellowjacket queens and other insects in exported Christmas trees.