Effects of Color Attributes on Trap Capture Rates of Chrysobothris femorata (Coleoptera: Buprestidae) and Related Species.

Chrysobothris spp. (Coleoptera: Buprestidae) and other closely related buprestids are common pests of fruit, shade, and nut trees in the United States. Many Chrysobothris spp., including Chrysobothris femorata, are polyphagous herbivores. Their wide host range leads to the destruction of numerous tree species in nurseries and orchards. Although problems caused by Chrysobothris are well known, there are no reliable monitoring methods to estimate local populations before substantial damage occurs. Other buprestid populations have been effectively estimated using colored sticky traps to capture beetles. However, the attraction of Chrysobothris to specific color attributes has not been directly assessed. A multi-color trapping system was utilized to determine color attraction of Chrysobothris spp. Specific color attributes (lightness [L*], red to green [a*], blue to yellow [b*], chroma [C*], hue [h*], and peak reflectance [PR]) were then evaluated to determine beetle responses. In initial experiments with mostly primary colors, Chrysobothris were most attracted to traps with red coloration. Thus, additional experiments were performed using a range of trap colors with red reflectance values. Among these red reflectance colors, it was determined that the violet range of the electromagnetic spectrum had greater attractance to Chrysobothris. Additionally, Chrysobothris attraction correlated with hue and b*, suggesting a preference for traps with hues between red to blue. However, males and females of some Chrysobothris species showed differentiated responses. These findings provide information on visual stimulants that can be used in Chrysobothris trapping and management. Furthermore, this information can be used in conjunction with ecological theory to understand host-location methods of Chrysobothris.

Evaluation of Systemic Imidacloprid and Herbicide Treatments on Flatheaded Borer (Coleoptera: Buprestidae) Management in Field Nursery Production.

The flatheaded appletree borer, Chrysobothris femorata (Olivier) (Coleoptera: Buprestidae), and related species are deciduous tree pests. Female beetles prefer to oviposit at tree bases, and larvae tunnel beneath the bark, which weakens or kills young or newly transplanted trees. In the first objective of this study, Discus N/G (2.94% imidacloprid + 0.7% cyfluthrin) applied at six lower-than-labeled rates (0.0, 0.98, 1.97, 3.94, 5.91, and 7.87 ml/cm of average trunk dia.) was evaluated for protection of field-grown maples. A second objective evaluated imidacloprid with and without herbicides to assess the impact of weed competition at the tree base on insecticide effectiveness. A third objective determined relative imidacloprid concentrations in leaf tissue samples with ELISA and related to insecticide rates, herbicide treatments, and the level of flatheaded borer protection. In two trials, higher rates of insecticide were more effective at protecting trees, with rates ≥3.94 ml product/cm trunk diameter performing equivalently. Weed-free trees had more borer attacks and grew faster than trees in weedy plots. Imidacloprid content in leaf tissues had a trend for higher concentrations in smaller, weedy trees in the first season, but that pattern disappeared in subsequent years. Based on fewer attacks in weedy versus weed-free trees (60-90% reduction), it was concluded that weed presence can reduce borer attack success in nurseries independent of insecticide treatment, but tree growth was reduced by weed presence. In addition, Discus applied at rates >3.94 ml/cm did not confer added borer damage protection in weedy plots.

Permethrin Residual Activity Against Ambrosia Beetle (Coleoptera: Curculionidae: Scolytinae) Attacks Following Field Aging and Simulated Rainfall Weathering.

Adult ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) bore into ornamental nursery trees resulting in trunk vascular tissue damage, which can potentially kill trees. Ambrosia beetle exposure to surface-applied insecticides is minimal after internal trunk galleries are formed, so effective management requires insecticide treatments to be applied near the time of infestation or to have residual activity on the bark. Tree trunk sections (bolts) were used to determine the effect of field aging or irrigation (i.e., simulated rainfall weathering) on permethrin residual activity against ambrosia beetles. In all experiments, 30-cm-long bolts from Liriodendron tulipifera L. (Magnoliales: Magnoliaceae) were hollowed and filled with 70% ethanol at field deployment to induce ambrosia beetle attacks over a 2-wk period. To evaluate insecticide residual activity, permethrin was sprayed onto tree bolts at 0, 8, 17, or 24 d before ethanol addition, and then bolts were deployed along a wooded border in fall 2017 and spring 2018. Tree bolts with permethrin residues ≤17 d old had significantly fewer ambrosia beetle attacks than bolts with 24-d-old residues or the non-permethrin-treated control bolts. To evaluate simulated rainfall weathering, permethrin was applied to tree bolts 8 or 22 d before ethanol (spring 2018) or 10 or 24 d before ethanol (fall 2018) with half of the bolts receiving regular irrigation events. Irrigation had no significant effect on permethrin residual activity against ambrosia beetles during either test. This study determined ambrosia beetle control was affected by permethrin residue age more than simulated rainfall weathering, and a reapplication interval of ≤17 d maximized beetle control.

Preharvest quarantine treatments of chlorantraniliprole, clothianidin, and imidacloprid-based insecticides for control of Japanese beetle (Coleoptera: Scarabaeidae) and other scarab larvae in the root zone of field-grown nursery trees.

Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), is an important quarantine pest of nurseries. Nursery plant movement from P. japonica-infested regions is regulated by the U.S. Domestic Japanese Beetle Harmonization Plan (DJHP), which classifies states by risk categories. Treatments for category 2 states include preharvest soil surface treatment of nursery plants grown in field soil using Discus SC, Marathon (1G or 60 WP), or Flagship (0.22G or 25 WG). In this study, Discus, Marathon 60 WP, or Flagship 0.22G DJHP standards were compared with labeled rates of non-DJHP-approved insecticides, including neonicotinoids clothianidin (Arena 50WDG), generic imidacloprid (Quali-Pro Imidacloprid 2 F T&O Insecticide, Mallet 2 F T&O Insecticide, and Lada 2 F Insecticide), and imidacloprid + bifenthrin (Allectus SC), as well as the anthranilic diamide, chlorantraniliprole (Acelepryn Insecticide). Arena provided 100% P. japonica control in May, June, and July over four test years, but had one larva recovered during August in two of those 4 yr. Acelepryn did not provide DJHP-acceptable P. japonica control. During July, Allectus provided 100% P. japonica control in three of four test years, but had four larvae in one test year. Other treatments tested only during July, which provided 100% P. japonica control, included Discus (five tests); Marathon, Quali-Pro, and Mallet (two tests); and Lada and Flagship (one test). Generic imidacloprid 2 F formulations were equivalent in P. japonica control to DJHP-approved insecticides. Insecticides generally performed poorly on other scarabs or curculionid larvae. The study supports Arena, Allectus, and generic imidacloprid 2 F products as suitable candidates for the DJHP.

Ethanol injection of ornamental trees facilitates testing insecticide efficacy against ambrosia beetles (Coleoptera: Curculionidae: Scolytinae).

Exotic ambrosia beetles are damaging pests in ornamental tree nurseries in North America. The species Xylosandrus crassiusculus (Motshulsky) and Xylosandrus germanus (Blandford) are especially problematic. Management of these pests relies on preventive treatments of insecticides. However, field tests of recommended materials on nursery trees have been limited because of unreliable attacks by ambrosia beetles on experimental trees. Ethanol-injection of trees was used to induce colonization by ambrosia beetles to evaluate insecticides and botanical formulations for preventing attacks by ambrosia beetles. Experiments were conducted in Ohio, Tennessee, and Virginia. Experimental trees injected with ethanol had more attacks by ambrosia beetles than uninjected control trees in all but one experiment. Xylosandrus crassiusculus and X. germanus colonized trees injected with ethanol. In most experiments, attack rates declined 8 d after ethanol-injection. Ethanol-injection induced sufficient pressure from ambrosia beetles to evaluate the efficacy of insecticides for preventing attacks. Trunk sprays of permethrin suppressed cumulative total attacks by ambrosia beetles in most tests. Trunk sprays of the botanical formulations Armorex and Veggie Pharm suppressed cumulative total attacks in Ohio. Armorex, Armorex + Permethrin, and Veggie Pharm + Permethrin suppressed attacks in Tennessee. The bifenthrin product Onyx suppressed establishment of X. germanus in one Ohio experiment, and cumulative total ambrosia beetle attacks in Virginia. Substrate drenches and trunk sprays of neonicotinoids, or trunk sprays of anthranilic diamides or tolfenpyrad were not effective. Ethanol-injection is effective for inducing attacks and ensuring pressure by ambrosia beetles for testing insecticide efficacy on ornamental trees.

Field evaluation of essential oils for reducing attraction by the Japanese beetle (Coleoptera: Scarabaeidae).

Forty-one plant essential oils were tested under field conditions for the ability to reduce the attraction of adult Japanese beetles, Popillia japonica Newman (Coleoptera: Scarabaeidae), to attractant-baited or nonbaited traps. Treatments applied to a yellow and green Japanese beetle trap included a nonbaited trap, essential oil alone, a Japanese beetle commercial attractant (phenethyl proprionate:eugenol:geraniol, 3:7:3 by volume) (PEG), and an essential oil plus PEG attractant. Eight of the 41 oils reduced attractiveness of the PEG attractant to the Japanese beetle. When tested singly, wintergreen and peppermint oils were the two most effective essential oils at reducing attractiveness of the PEG attractant by 4.2x and 3.5x, respectively. Anise, bergamont mint, cedarleaf, dalmation sage, tarragon, and wormwood oils also reduced attraction of the Japanese beetle to the PEG attractant. The combination of wintergreen oil with ginger, peppermint, or ginger and citronella oils reduced attractiveness of the PEG attractant by 4.7x to 3.1x. Seventeen of the 41 essential oils also reduced attraction to the nonbaited yellow and green traps, resulting in 2.0x to 11.0x reductions in trap counts relative to nonbaited traps. Camphor, coffee, geranium, grapefruit, elemi, and citronella oils increased attractiveness of nonbaited traps by 2.1x to 7.9x when tested singly, but none were more attractive than the PEG attractant. Results from this study identified several plant essential oils that act as semiochemical disruptants against the Japanese beetle.

Toxicity of botanical formulations to nursery-infesting white grubs (Coleoptera: Scarabaeidae).

The toxicity of eight botanically based biopesticides was evaluated against third instars of the scarab larvae (Coleoptera: Scarabaeidae) Popillia japonica Newman, Rhizotrogus majalis (Razoumowsky), Anomala orientalis Waterhouse, and Cyclocephala borealis Arrow. Soil dip bioassays were used to obtain concentration-mortality data 7 d after treatment of larvae, leading to the calculation of LC50 and LC90 values. A wide range in LC50 and LC90 values were exhibited among the formulations. The product Armorex was one of the most active formulations against P. japonica (LC50 = 0.42 ml/liter), R. majalis (LC50 = 0.48 ml/liter), A. orientalis (LC50 = 0.39 ml/liter), and C. borealis (LC50 = 0.49 ml/liter). Armorex is composed of extracts from diverse botanical sources, including 84.5% sesame oil, 2.0% garlic oil, 2.0% clove oil, 1.0% rosemary oil, and 0.5% white pepper extracts. The product Azatin, composed of 3% azadirachtin, also exhibited high toxicity to P. japonica (LC50 = 1.13 ml/liter), R. majalis (LC50 = 0.81 ml/liter), and A. orientalis (LC50 = 1.87 ml/liter). Veggie Pharm is composed of extracts from diverse sources, but this product showed the lowest toxicity to P. japonica (LC50 = 35.19 ml/liter), R. majalis (LC50 = 62.10 ml/liter), A. orientalis (LC50 = 43.76 ml/liter), and C. borealis (LC50 = 50.24 ml/liter). These results document the potential for botanical formulations to control white grubs, but blending extracts from diverse botanical sources does not ensure enhanced biological activity.

Surface-applied insecticide treatments for quarantine control of Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), larvae in field-grown nursery plants.

BACKGROUND: Japanese beetles, Popillia japonica Newman, are a quarantine challenge for nursery shipments from infested to non-infested states. Marathon (imidacloprid) and Discus (imidacloprid + cyfluthrin) are approved preharvest nursery treatments (US Domestic Japanese Beetle Harmonization Plan; DJHP). This study evaluated approved and non-approved (acephate, carbaryl, clothianidin, dinotefuran, halofenozide, thiamethoxam, trichlorfon) preharvest treatments, optimal rates (labeled 1x, 0.3-0.75 x or 2-3 x) and optimal timings (June, July, August and September) to control early-instar (grubs) P. japonica in field nurseries. RESULTS: Most insecticides effectively reduced grub densities, except for acephate, carbaryl and trichlorfon. Clothianidin, thiamethoxam and halofenozide provided grub control equivalent to DJHP standards during most years. Across all test years and timings, percentage grub reductions were: Marathon (1x: 59.2-100; 3 x: 78.9-100), Discus (1x: 60.7-100), clothianidin (1x: 96.1-100; 3 x: 97.4-100), thiamethoxam (1x: 75.0-100; 3 x: 80.0-100), halofenozide (1x: 70.0-100; 3 x: 90.0-100) and dinotefuran (1x: 13.2-88.2; 3 x: 71.1-93.4). CONCLUSIONS: July application was more consistent and effective than other timings, and higher rates (2x and 3 x) did not generally improve grub control. Overall, clothianidin, thiamethoxam and halofenozide (and dinotefuran applied in August) were equivalent to current DJHP standards. These insecticides may be suitable for DJHP Category 2 states, potentially lowering grower costs.

Drench treatments for management of larval Japanese beetle (Coleoptera: Scarabaeidae) in field-grown balled and burlapped nursery plants.

Insecticide drenches were applied to postharvest field-grown nursery plants harvested as 60-cm-diameter balled and burlapped (B&B) root balls for controlling third instars of Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae). Bifenthrin, chlorpyrifos, lambda-cyhalothrin, and thiamethoxam were drench-applied in fall and spring tests at volumes of runoff (1X; approximately equal 2.57 liters per drench per root ball) or twice runoff (2X). Tests also examined consecutive drenches (two, four, or six) and B&B rotation between drenches. Fall-applied drenches did not meet the Domestic Japanese Beetle Harmonization Plan (DJHP) standards of < or =1 grub and ranged from 0 to 90% control. However, most fall-applied drenches significantly reduced grub numbers relative to the untreated root balls. Spring-applied drenches were more effective than fall drenches: chlorpyrifos treatments gave 94-100% control, whereas other spring-applied treatments were less consistent, including thiamethoxam (83-100% control) and bifenthrin (61-100% control). Lambda-cyhalothrin was not effective. A higher drench volume (2X) did not significantly improve treatment efficacy; however, grub numbers decreased as the number of drenches increased for fall-applied chlorpyrifos and thiamethoxam and spring-applied bifenthrin. Rotation of root balls significantly reduced grub numbers compared with nonrotated treatments for fall-applied chlorpyrifos (six drenches) and bifenthrin (two or six drenches), but these treatments did not meet DJHP standards. The study indicates chlorpyrifos, bifenthrin, and thiamethoxam drenches can control Japanese beetle in the spring and may provide a new postharvest option to certify B&B plants for Japanese beetle.

Chlorpyrifos immersion to eliminate third instars of Japanese beetle (Coleoptera: Scarabaeidae) in balled and burlapped trees and subsequent treatment effects on red maple.

This study examined chlorpyrifos immersion of balled and burlapped (B&B) nursery trees for elimination of third instars of Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), and for phytotoxicity on red maple, Acer rubrum L. Trees were harvested as 45- and 60-cm-diameter B&B and immersed in chlorpyrifos at U.S. Domestic Japanese Beetle Harmonization Plan rate (0.24 kg active ingredient [AI/100 liters) or lower rates of 0.015, 0.03, 0.06, and 0.12 kg (AI)/100 liters. The 0.03, 0.06, and 0.24 kg (AI) rates provided 100% control of Japanese beetle grubs in both 45- and 60-cm B&B. The 0.015 and 0.12 kg (AI) chlorpyrifos rates were 100% effective in three tests. However, in another test, 0.015 and 0.12 kg (AI) chlorpyrifos treatments had four (93% control) and one (98% control) grubs recovered, respectively. Root ball soils consisted of loam, silt loam, or clay loam texture classifications. Trunk diameter and internode growth of red maple harvested as 45-cm B&B decreased linearly with increasing chlorpyrifos dip rate during the first year, but effects were unapparent in the second year. Chlorpyrifos rates had no measurable impact on growth of red maples harvested as 60-cm B&B. No visual phytotoxicity symptoms were detected for chlorpyrifos rate or root ball size treatments. In conclusion, results support lowering the U.S. Domestic Japanese Beetle Harmonization Plan chlorpyrifos dip rate for category 2 states to at least 0.03 kg (AI) for B&B diameters < or =60 cm. Chlorpyrifos rates < 0.24 kg (AI) will lower cost, reduce worker exposure, and lessen potential environmental contamination.