Effectiveness of Bifenthrin (Onyx) and Carbaryl (Sevin SL) for Protecting Individual, High-Value Conifers from Bark Beetle Attack (Coleoptera: Curculionidae: Scolytinae) in the Western United States

Abstract

High-value trees, such as those located in residential, recreational, or administrative sites, are particularly susceptible to bark beetle (Coleoptera: Curculionidae: Scolytinae) attack as a result of increased amounts of stress associated with drought, soil compaction, mechanical injury, or vandalism. Tree losses in these unique environments generally have a substantial impact. The value of these individual trees, cost of removal, and loss of esthetics may justify protection until the main thrust of a bark beetle infestation subsides. This situation emphasizes the need for ensuring that effective insecticides are available for individual tree protection. In this study, we assess the efficacy of bifenthrin (Onyx) and carbaryl (Sevin SL) for protecting: ponderosa pine, Pinus ponderosa Dougl. ex. Laws., from western pine beetle, Dendroctonus brevicomis LeConte, in California; mountain pine beetle, Dendroctonus ponderosae Hopkins in South Dakota; and Ips spp. in Arizona; lodgepole pine, Pinus contorta Dougl. ex Loud., from D. ponderosae in Montana; pinyon, Pinus edulis Engelm. in Colorado and Pinus monophylla Torr. and Frem. in Nevada from pinyon ips, Ips confusus (LeConte); and Engelmann spruce, Picea engelmannii Parry ex. Engelm. from spruce beetle, Dendroctonus rufipennis (Kirby) in Utah. Few trees were attacked by Ips spp. in Arizona and that study was discontinued. Sevin SL (2.0%) was effective for protecting P. ponderosa, P. contorta, and P. monophylla for two field seasons. Estimates of efficacy could not be made during the second field season in P. edulis and P. engelmannii due to insufficient mortality in untreated, baited control trees. Two field seasons of efficacy was demonstrated in P. ponderosa/D. brevicomis and P. monophylla for 0.06% Onyx. We conclude that Onyx is an effective individual tree protection tool, but repeated annual applications may be required in some systems if multiyear control is desired.

Efficacy of Two Systemic Insecticides Injected Into Loblolly Pine for Protection Against Southern Pine Bark Beetles (Coleoptera: Curculionidae)

“…The experimental design used (Shea et al 1984) in these studies is regarded as a conservative test of efÞcacy and serves as a standard to determine the effectiveness of insecticide bole sprays (e.g., carbaryl, bifenthrin) for individual tree protection in the western United States (Fettig et al 2006). With bole sprays, bark beetles that land on target trees immediately contact the active ingredient before initiating host colonization.…”

“…In 2003, bifenthrin (Onyx) was registered by the EPA for protection of ornamental trees against several Dendroctonus species, including southern pine beetle, but so far this product has not been widely available to consumers. Fettig et al (2006) indicated that the registered rate (0.06% [AI]) may be too low for efÞ-cacy against some western bark beetle species. Two other products, carbaryl (Sevin) and permethrin (Astro), are registered and effective against western bark beetle species, but they have proven ineffective against southeastern bark beetle species (Zhong et al 1994).…”

Protection of spruce from colonization by the bark beetle, Ips perturbatus, in Alaska

“…Conversely, in our second study, none of the attractant + interruptant-treated trees was killed. Based on the results from the second study, the spruce trees were protected equivalent to a successful insecticide trial (Shea et al, 1984;Fettig et al, 2006).…”

“…Cost may vary in warmer areas, where it may be necessary to use multiple applications/year to maintain adequate release rates of the interruptant during the flight period of the pest. The limited environmental impact of the treatment should be considered when evaluating and comparing costs with conventional insecticide treatments [$10.80 (Onyx) or $14.00 (Sevin SL)/tree; excluding labor (Fettig et al, 2006)]. …”

“…This study investigated whether the combination of a beetle-produced compound (verbenone), a nonhost volatile (conophthorin), and the induction of a host defense mechanism by MJ, is effective in reducing the colonization density and, ultimately, mortality of P. Â lutzii associated with I. perturbatus. The long-term goal is to assess whether behavioral chemicals, induction of host resistance, or the dual application of behavioral chemicals and induced resistance could reduce tree mortality caused by bark beetles to levels equivalent to those of successful insecticide trials (Shea et al, 1984;Fettig et al, 2006).…”