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Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, trees and stands can be protected from Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (DFB)-caused mortality by application of synthetic formulations of the beetle's antiaggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH). A biodegradable formulation of MCH, SPLAT MCH, was developed and evaluated for protecting individual Douglas-fir trees and small stands from colonization and mortality by DFB. In an individual-tree experiment in Idaho, both MCH bubble capsules and SPLAT MCH significantly reduced the proportion of treated trees colonized and killed by DFB compared to untreated controls. SPLAT MCH was as effective as MCH bubble capsules for protecting individual trees. Both MCH bubble capsules and SPLAT MCH significantly reduced the proportion of trees colonized and killed by DFB within 0.04-ha circular plots surrounding each treated tree compared to untreated controls. In 0.41 ha stands in New Mexico, both MCH bubble capsules and SPLAT MCH significantly reduced the proportion of trees colonized and killed by DFB compared to untreated controls, again with no differences observed between MCH treatments. In a similar stand level trial in Idaho, neither MCH treatment significantly reduced the proportion of trees colonized by DFB, and only MCH bubble capsules significantly reduced levels of tree mortality compared to untreated controls, but no significant difference was observed between SPLAT MCH and MCH bubble capsules. Overall, the results indicate that SPLAT MCH is as effective as MCH bubble capsules for protecting individual trees and small stands of Douglas-fir from DFB-caused mortality., (© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

From 2009 to 2013, we tested four systemic insecticide formulations and five application methods against the invasive goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), in California. The insecticides were evaluated in three experiments: 1) 2009 remedial applications of emamectin benzoate (stem-injection) and imidacloprid (stem-injection and soil-injection); 2) 2009-2012 emamectin benzoate and imidacloprid initially applied at different times during the dormant season with varying injection technologies; and 3) 2013 dinotefuran applied to several tree diameter size classes. Adult leaf-feeding bioassays were used to assess the impact of systemic treatments against A. auroguttatus, whereas enzyme-linked immunosorbent assays determined the quantity of the active ingredient of insecticide residues in foliage. Imidacloprid (experiment 1) persisted at elevated levels in foliage of coast live oak, Quercus agrifolia Née, for 1.5 yr following stem injections. Stem injections of emamectin benzoate (experiment 2) sometimes significantly decreased survival in adults fed foliage from treated Q. agrifolia, and both the emamectin benzoate and imidacloprid treatments reduced adult feeding in some trials. Imidacloprid residues in Q. agrifolia and California black oak, Quercus kelloggii Newb., foliage remained at elevated levels (>10 µg/g) ∼2 yr postapplication. In 2013 (experiment 3), dinotefuran residues were highest in foliage collections 2 wk postapplication and greatest in smaller diameter oaks, but insecticide treatment had no effect on survival or frass production by adults fed foliage from treated trees. Systemic injections of emamectin benzoate and imidacloprid applied during the dormant season to uninfested or lightly infested oaks can reduce adult A. auroguttatus survival and maturation feeding., (Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

We tested 3-methylcyclohex-2-en-1-one (MCH) and an Acer kairomone blend (AKB) as repellent semiochemicals for area and single tree protection to prevent spruce beetle (Dendroctonus rufipennis Kirby) attacks at locations in Utah and New Mexico. In the area protection study, we compared host infestation rates of MCH applications at three densities (20, 40, and 80 g MCH ha-1) against a control treatment over 0.64 ha plots centered within ~1.25 ha treatment blocks. All treatments included two baited funnel traps within the plot to assure spruce beetle pressure. Following beetle attack, plots were surveyed for new spruce beetle attacks and to quantify stand characteristics. The probability of more severe spruce beetle attacks was significantly reduced, by ~50%, in each of the MCH area treatments compared with the control treatment but there was no significant treatment difference among the MCH deployment densities. For the single tree protection study, we compared attack rates of MCH, Acer kairomone blend (AKB), and MCH plus AKB on spruce beetle-baited trees against bait-only trees. Each treatment was applied over a range of host diameters to test for host size effects. Seventy-five percent of control trees were mass-attacked, about one-third of MCH- and AKB-alone spruce was mass-attacked, and no MCH plus AKB spruce were mass-attacked. These results suggest that MCH alone is a marginal area and single tree protectant against spruce beetle but that deployment with other repellents can significantly increase treatment efficacy., (Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

The goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), was linked in 2008 to ongoing tree mortality in oak woodlands of southern California. Mortality of coast live oak, Quercus agrifolia Née, and California black oak, Q. kelloggii Newb., continues as this exotic phloem borer spreads in southern California. Management options are needed to preserve high-value oaks and maintain management objectives. From 2009 to 2012, we tested four contact insecticide formulations in four experiments against A auroguttatus in California. The impact of contact insecticides was evaluated ∼<1, 8, and 12 mo postapplication against A auroguttatus adults in no-choice leaf-feeding or walking bioassays. At <1 mo postapplication, bifenthrin, carbaryl, lambda-cyhalothrin, and permethrin all reduced adult survival and feeding in leaf-feeding and walking bioassays. At 8 mo postapplication, only bifenthrin reduced adult feeding, but had no effect on survivorship. At 12 mo postapplication, adult A auroguttatus survived fewer days and fed less in leaf-feeding bioassays with bifenthrin, carbaryl, and permerthin. These results support the annual application of contact insecticides prior to A auroguttatus' flight period to reduce adult leaf maturation feeding and activity on the bark surface (e.g., oviposition), but additional studies are needed to show these contact treatments can prevent tree mortality from this invasive species., (Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the US.)

Movement of invasive wood-boring insects in wood products presents a threat to forest health and a management challenge for public and private land managers. The goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), is a new pest in San Diego and Riverside Cos., CA, believed to have been introduced on firewood. This beetle has caused elevated levels of oak mortality since 2002. From 2009-2011, we tested several sanitation methods, applicable to large and small land parcels, to reduce or prevent goldspotted oak borer emergence from infested oak wood. In most experiments, emergence of goldspotted oak borer adults from the positive controls demonstrated that the beetle could complete development in firewood-sized pieces of cut oak wood. In 2009, adult emergence from sun-exposed oak wood began and peaked 2- to 4-wks earlier at a low elevation site than at a high elevation site (late May to late June). However, there were no significant effects of elevation or host species on the emergence response of goldspotted oak borer by solarization treatment in this study. Solarization of infested wood with thick (6 mil) and thin (1 mil) plastic tarpaulins (tarps) did not significantly reduce emergence of adults despite recordings of greater mean and maximum daily temperatures in both tarped treatments and greater relative humidity in the thick-tarped treatment (all compared with nontarped controls). Grinding wood with a 3"-minus screen (< or = 7.6 cm) significantly reduced goldspotted oak borer emergence compared with control treatments, and this was the best method for reducing adult emergence among those tested. In a separate grinding study, no adults emerged when wood was ground to 9"-minus (22.9 cm), 2"-minus (5.1 cm), or 1"-minus (2.5 cm) screen sizes, but a low level of adult emergence from the positive controls limited any inferences from this experiment. Debarking cut wood pieces eliminated goldspotted oak borer emergence from the wood fraction, but adults emerged from the shaved bark and phloem.