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Background Plants are thought to produce ecdysteroids as a means of protection from insect herbivores. Some insects will not feed on plants containing high amounts of phytoecdysteroids, and this response could be limited to monophagous and oligophagous insects. The aim of this study was to determine whether phytoecdysteroids could inhibit feeding in several species of beetles that range from monophagous to polyphagous. Results Here we demonstrate that phytoecdysteroids, including 20-hydroxyecdysone, prevent several beetle species from feeding on preferred host plants, including the polyphagous Japanese beetle Popillia japonica (Scarabaeidae). Phytoecdysteroids prevented feeding damage when sprayed onto soybean plants in no-choice and choice assays in a dose-dependent manner. Laboratory assays indicate that other plants could be protected from Japanese beetle herbivory, including linden, wild grape, elm, Virginia creeper and rose leaves. Additional beetle species tested in the family Chrysomelidae included the oligophagous Cerotoma trifurcata and Diabrotica virgifera virgifera and the monophagous Trirhabda canadensis. All species were prevented from feeding when their preferred host plants were treated with phytoecdysteroids. Conclusion This study demonstrates that beetles, representing polyphagous and monophagous feeding guilds, can be prevented from feeding when phytoecdysteroids are applied to the leaf surface. The phytoecdysteroids could be utilized in pest management towards a variety of beetles, including the more pestiferous polyphagous species, if the compounds are placed on the leaf surface. © 2016 Society of Chemical Industry.

Belowground herbivory under nutrient-poor conditions is known to significantly decrease plant biomass and root:shoot ratios. However, the mechanisms behind the changes in belowground plant–herbivore interactions that occur under different nutrient conditions remain unclear. We performed a pot experiment using Lolium perenne L. and the third-instar larva of Popillia japonica Newman. The experiment used a three-way factorial randomized-block design; the three factors were nutrient amount (rich/poor), nutrient heterogeneity (homogeneous/heterogeneous), and belowground herbivore (present/absent). Relative water content (RWC) of shoots under nutrient-poor conditions was smaller than that under nutrient-rich conditions, and a single herbivory significantly reduced the RWC under the nutrient-poor conditions. Plant biomass was larger under nutrient-rich conditions than under nutrient-poor conditions. A herbivore decreased plant biomass more under nutrient-poor conditions than under nutrient-rich conditions. Nutrient heterogeneity had no effect on plant biomass, but herbivory and nutrient amount interactively affected root proliferations to nutrient patches. Plants were smaller under nutrient-poor conditions; thus, a larger proportion of the roots was removed by a belowground herbivore. A loss of a larger proportion of roots would cause the small RWC, which restricts compensatory growth. Consequently, growth of L. perenne is more severely limited by a belowground herbivore under nutrient-poor conditions.

The Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae), was introduced into the United States in New Jersey in 1916 and now commonly occurs in the eastern and mid-western United States. The Japanese beetle has a wide host range and feeds on more than 300 plant species within 79 families (2), but it has not been reported to be a vector of plant viruses. Southern bean mosaic virus (SBMV; genus Sobemovirus) and Bean pod mottle virus (BPMV; family Comoviridae, genus Comovirus) are transmitted by several species of leaf-feeding beetles in the families Coccinelidae and Chrysomelidae (1). Japanese beetles, collected in northwestern Arkansas with a JB Jumbo insect trap (Great Lakes IPM, Inc., Vestaburg, MI), were tested to determine if they are able to transmit SBMV and BPMV. The beetles were given a 24-h acquisition access (individually in plastic petri dishes) to detached trifoliolate leaves of Phaseolus vulgaris ‘Black Valentine’ systemically infected with either BPMV or SBMV. Beetles that had fed on the infected bean leaves (as evidenced by feeding damage to the leaves) were caged individually in clear plastic cups on healthy ‘Black Valentine’ bean seedlings for a 24-h transmission access period. The test plants were grown in the greenhouse for 2 weeks after which they were evaluated for virus infection. In the first trial, BPMV was not transmitted (0 of 11 bait plants with feeding damage), whereas SBMV was efficiently transmitted (6 of 6 bait plants with feeding damage) as determined by agar-gel double-diffusion serology of test plants using polyclonal antibodies to SBMV and BPMV. In a second trial, with a different set of beetles, the transmission rate for BPMV was 3 of 46 (6.5%) and 33 of 43 (77%) for SBMV, and the test plants were evaluated for virus infection using Protein A ELISA. The higher transmission efficiency of SBMV by Japanese beetles when compared with BPMV is characteristic of these two viruses when they are transmitted by other leaffeeding beetles (1). These results are in contrast to an earlier report that Japanese beetles were not able to transmit BPMV from infected soybeans to healthy soybeans in Illinois (3). To our knowledge, this is the first report that the Japanese beetle, an introduced insect with a wide host range in the United States, is a vector of plant viruses. References: (1) J. P. Fulton et al. Ann. Rev. Phytopathol. 25:111. 1987. (2) D. W. Held. J. Aboricult. 30:328, 2004. (3) T. R. Mabry et al. Plant Dis. 87:1221, 2003.

Field-collected adults of three genera of turf-infesting scarabs, Japanese beetle ( Popillia japonica Newman), June beetles ( Phyllophaga spp.), and masked chafers ( Cyclocephala spp.), were exposed to experimental and commercial granule formulations of the entomopathogenic fungus Metarhizium brunneum (Petch) strain F52 to determine their relative susceptibility. Experimental granules contained microsclerotia produced by liquid fermentation with the ability to produce fresh conidia when rehydrated and commercial granules were Met 52 granular bioinsecticide. All three groups of scarab adults showed a positive dosage response to the fungus when exposed in cups of potting mix treated with the granules. LC 50 values for microsclerotia granules were 1.9 × 10 7 , 7.1 × 10 6 , and 3.2 × 10 6 conidia cup -1 for P. japonica , Phyllophaga spp., and Cyclocephala spp., respectively. LC 50 values for Met 52 granules were 5.9 × 10 7 , 5.1 × 10 7 , and 7.6 × 10 6 conidia cup -1 , respectively. The experimental granules containing microsclerotia show promise as a viable commercial control agent. They can be produced using lower cost fermentation methods and applied at lower dosages (97 g for 100 m 2 as opposed to 489 g per 100 m 2 for Met 52). If M. brunneum is applied to control the aforementioned white grubs, our data indicate the potential for the adult beetles to also be infected as they enter the soil to lay eggs.

Induction of cytochrome P450, glutathione S transferase (GST), and carboxylesterase (CoE) activity was measured in guts of the scarab Popillia japonica Newman, after consumption of single or mixed plant diets of previously ranked preferred (rose, Virginia creeper, crape myrtle and sassafras) or non-preferred hosts (boxelder, riverbirch and red oak). The goal of this study was to quantify activities of P450, GST and CoE enzymes in the midgut of adult P. japonica using multiple substrates in response to host plant suitability (preferred host vs non-preferred hosts), and single and mixed diets. Non-preferred hosts were only sparingly fed upon, and as a group induced higher activities of P450, GST and CoE than did preferred hosts. However, enzyme activities for some individual plant species were similar across categories of host suitability. Similarly, beetles tended to have greater enzyme activities after feeding on a mixture of plants compared to a single plant type, but mixing per se does not seem as important as the species represented in the mix. Induction of detoxification enzymes on non-preferred hosts, or when switching between hosts, may explain, in part, the perceived feeding preferences of this polyphagous insect. The potential consequences of induced enzyme activities on the ecology of adult Japanese beetles are discussed.

An evaluation was performed for host range of Bacillus thuringiensis tolworthi, kumamotoensis, and japonensis against the following scarab turfgrass pests (Coleoptera: Scarabaeidae) Anomala cuprea, Atenius sp., Cotinis sp., Cyclocephala borealis, Cyclocephala lurida, Cyclocephala pasadenae, Popillia japonica, Phyllophaga sp. Results showed Bacillus thuringiensis tolworthi and Bacillus thuringiensis japonensis to have activity against U.S. economic grub pests Cyclocephala borealis, Cyclocephala lurida, and Popillia japonica while Bacillus thuringiensis kumamotoensis was active against Cotinis sp. Other U.S. turfgrass pests tested, Atenius sp. and Phyllophaga sp. had no detectable susceptibility to any of the three isolates. Bacillus popilliae was inactive against Cyclocephala pasadenae. ' Dow AgroSciences, 5501 Oberlin Drive, San Diego CA 92121 ^ USDA-ARS Com Insects and Crop Genetics Research Unit, Genetics Laboratory, ISU, Ames, lA 50011 ^ Department of Entomology, Iowa State University, Ames, lA SOOl 1

White grub damages various crops, trees and they can also be one of the most serious pests of turf grass in golf courses. This study was conducted to determine the biocontrol of white grubs with 18 different kinds (anise, camphor, castor, cinnamon, clove oil, citronella, fennel, geranium, lavender, lemongrass, linseed, neem, peppermint, pine, rosemary, tea-tree, thyme, and turpentine) of plant essential oils in laboratory, green house and field. Anise oil (88.9%), linseed oil (100%), and teatree oil (88.9%) were highly effective among tested essential oils against 3rd instar of Bifurcanmala aulax in cap vial experiment. However, anise and linseed oils showed low mortality against 3rd instar of Popillia japonica in pot greenhouse experiment. Efficacy of anise, linseed oil, and tea-tree was also different depending on target white grub in field trials. Correlated mortality showed 32.6% only in tea-tree oil treatment against pupae of Adoretus tenuimaculatus however, correlated mortality of anise, linseed and tea-tree oil were 54.8, 51.6 and 56.5% respectively against 3rd instar of Exomala orientalis in the field trial in Adelscott Country Club in Hapcheon, Gyeongnam province.

Scarab beetles are agriculturally important worldwide, and as adults or larvae they may cause damage to the leaves, flowers, fruit, and roots of crops. Previous international studies showed that Japanese beetle ( Popillia japonica , Newman) lures, and structurally related chemicals, can attract numerous scarabs. Based on those studies, season-long trials in grape, cabbage, corn and soybean fields were conducted in 2012–2013 in NE China. Tests determined the attractiveness of the Japanese beetle floral lure (phenethyl propionate:eugenol:geraniol, 3:7:3) and sex attractant (Japonilure), alone, combined, or in a mixture with either (Z)-3-hexen-1-ol, anethole = 1-methoxy-4-propenyl benzene or benzyl alcohol, to local Coleoptera. Furthermore, control efficacies based on leaf, ear, and silk damage, as well as reductions of adults on plants, and overwintering larvae, were also determined. Eleven scarab species, and four non-scarab species, were captured. The addition of other chemicals increased the attractiveness of the two Japanese beetle lures to scarabs such as Potosia brevitarsis (Lewis), Oxycetonia jecunda Faldermann, Holotrichia diomphalia Bates et al., Popillia quadriguttata (Fabricius), Maladera verticalis (Fairmaire), and Metabolus impressifrons Fairmaire, and the chrysomelid beetle Chrysomela populi L. The floral lure, and floral lure plus Japonilure baited traps resulted in > 80% overwintering larvae and adult reductions in corn and cabbage fields, whereas the Japonilure traps gave similar results in the soybean fields. This indicates that the commercial Japanese beetle lure combination can be recommended for use by the Chinese farmers in the corn or soybean fields, and that the related chemicals can be used to increase the attractiveness of the Japanese beetle lures.

The effect of mycelial and conidial formulations of the insect pathogenic fungi, M. anisopliae , on the survival and behavior Japanese beetle, Popillia japonica Newman, larvae and ovipositing adults in turfgrass-soil microcosms was explored. Changes in Japanese beetle grub feeding site selection on sod roots, movement patterns, and survival in Metarhizium anisopliae inoculated soil were examined in greenhouse studies and through the use of radiographic analysis in the laboratory. Our studies indicate that the application of mycelial particles in soil affected the behavior of both larval and adult Japanese beetles. Japanese beetle grubs avoided soil that contained high concentrations of pathogen for up to 20 d after application. Conversely, the incorporation of mycelial particles increased oviposition in both choice and no choice studies. Our findings on scarab response to inundative applications of M. anisopliae mycelium may help explain some of the inconsistency in results that often occur when fungal pathogens are used to control insects in the field.

A new species of mermithid nematode, Hexamermis popilliae n. sp. (Nematoda: Mermithidae) is described from the Japanese beetle Popillia japonica Newman in Italy, an area of new introduction for this invasive pest. The combination of the following characters separates H. popilliae from other members of the genus Hexamermis Steiner, 1924: adult head obtuse; amphidial pouches slightly posterior to lateral head papillae in female but adjacent to lateral head papillae in males; amphidial openings large, well developed; amphidial pouches elliptical in females and oblong in males; cuticular vulvar cone well developed, vulvar lips greatly reduced or lacking, vagina curved at tip where meeting uteri, without reverse bend (not S-shaped), spicules slightly curved, with a slight bend in the basal portion, approximately equal to body width at cloaca. This is the first record of a species of Hexamermis parasitizing the Japanese beetle Popillia japonica. The only previous mention of mermithid nematodes from P. japonica was an undescribed species of Psammomermis in North America. Hexamermis popilliae will be evaluated as a potential biological control agent in an integrated control program of the Japanese beetle in Italy.

We conducted an experimental study of the effects of nutrient addition on the susceptibility of two species of willows (Salix eriocephala and S. sericea) and their hybrid to a pathogen and several herbivores. We hypothesized that the relative susceptibility of parental and hybrid willows would depend upon soil nutrient availability and vary among plant enemies. Using potted plants in a common garden, we found that S. eriocephala was significantly more susceptible to attack by a fungal rust (Melampsora sp.), a leaf-chewing beetle (Popillia japonica), and a leaf-folding sawfly (Phyllocolpa nigrita) than was S. sericea. Conversely, S. sericea was significantly more susceptible to attack by a spider mite (Tetranychus sp.) and a leaf-mining caterpillar (Phyllocnistis sp.) than was S. eriocephala. Hybrid susceptibility to Melampsora sp. and to Phyllocnistis sp. resembled S. eriocephala's, while hybrid susceptibility to Phyllocolpa nigrita, Tetranychus sp., and Popillia japonica resembled S. sericea's. Susceptibility to a sixth enemy, another leaf-mining caterpillar, Phyllonorycter salicifoliella, did not differ among the parents and hybrid. Susceptibility to herbivores and pathogens increased along a gradient of increasing fertilizer application, and this effect was independent of plant taxon or enemy. The results of our study point to the contrasting influences of a taxonomically and functionally diverse enemy community, reinforce the hybrid dominance model of enemy susceptibility, and demonstrate that physiological stress and enemy susceptibility can be inversely related.

Cerceris fumipennis Say (Hymenoptera: Crabronidae) uses a wide range of adult buprestid beetles to provision nests. Wasps seldom make ‘mistakes’ and attack beetles in other families. Bioassays showed that the wasps use contact chemical cues in the beetles’ epicuticle to discriminate buprestids from other beetles. Wasps rejected buprestids that had their cuticular hydrocarbons (CHC) removed by being washed in solvents. The washed, rejected buprestids became acceptable to 70% of wasps when they were coated with an extract of buprestids’ own CHC. Washed buprestids coated with extracts of non-buprestid beetle CHC were not accepted. Analyses of buprestid CHC profiles showed that they are relatively simple, consisting of five classes. Other coleopteran families that may co-occur in the arboreal hunting habitat of C. fumipennis have a broader range of CHC classes. Experiments adding buprestid hydrocarbons to a non-buprestid beetle, unwashed Popillia japonica Newman (Coleoptera: Scarabaeidae), suggested that wasps may be deterred by the presence of CHC classes not found in Buprestidae. Adding a synthesized dimethyl-branched hydrocarbon, a class of CHC found in Chrysomelidae but not Buprestidae, to the cuticle of unwashed buprestid beetles, caused wasps to reject the buprestid beetles. We propose that CHC act as a kairomone for C. fumipennis, triggering attack, whereas classes of CHC not found in Buprestidae disrupt this response, and thus help to determine the prey range of the wasp.

Popillia quadriguttata (F.) has caused extensive damage to ≍20 families and 25 species of plants in Asia, especially in China and Korea. Adult feeding causes serious damage to soybean leaves, and larvae develop on the roots of soybean, turf, and horticultural crops. As Japanese beetle (Popillia japonica Newman) lures have been used for trapping P. quadriguttata in a previous study, mass trapping this pest with various densities of the Japanese beetle pheromone, Japonilure, and floral lure, alone and in combination, were carried out during 2012-2013 in a northeastern China soybean field. Mass trapping in 2012 with Japonilure gave the best results with 72 and 75% adult and larval reduction, respectively. In 2013, mass trapping (30 traps per hectare) with Japonilure, floral lure, or the combination resulted in a 93, 70, and 74% reduction of adults trapped, and a 90, 77, and 93% reduction of overwintering larvae, respectively. In addition, field tests showed that almost twice as many beetles approached the lure combination compared with the floral lure alone, and the pheromone residual was ≍80% of the initial dosage after 30 d. Because reduction of overwintering larvae is the most critical parameter indicating treatment efficacy, the results here indicate that the lure or lure combinations can be recommended for use by Chinese soybean farmers.

Hand removal is often recommended as a method for small-scale control of Japanese beetles (Popillia japonica Newman). In this study, we investigated the effectiveness of daily hand removal for controlling damage by Japanese beetles on grape plants. We also investigated whether the timing of the removal (at 0800, 1400, or 1900 hours, or at all 3 periods) influenced the effectiveness of the technique. We found that hand removal significantly lowered the number of beetles on, and consequently the damage to, grape plants relative to nonremoval controls. Of the single removal treatments, removal of beetles at 1900 hours was most effective, with results similar to removing beetles three times per day. The majority of beetles removed from plants during the experiment were female, a pattern that matches our understanding of aggregation formation behavior in the species, and which may serve to enhance the benefits of hand removal. Hand removal seems to work by decreasing the number of feeding beetles, which in turn reduces the release of aggregation kairomones from the plant, and subsequently decreases the attractiveness of the plant to future beetles.

Japanese beetle, Popillia japonica Newman, and oriental beetle, Anomala orientalis (Waterhouse) (both Coleoptera: Scarabaeidae) are considered invasive species and have been reported as key pests of urban landscapes in the Northeastern USA. Tiphia vernalis Rohwer and Tiphia popilliavora Rohwer (Hymenoptera: Tiphiidae) were introduced as biocontrolagents against these beetles. Theseparasitic waspsburrowinto thesoil and search for grubs. When a host is found, thewaspattaches an egg in a location that is specific for the wasp species. It is unknown if these wasps can detect patches of concealedhostsfromadistanceabovegroundandwhatrole,ifany,herbivore-inducedplantvolatiles play in their host location. This study evaluated the responses of femaleT. vernalis and T. popilliavora togrub-infestedandhealthyplants inY-tubeolfactometer bioassays. Alsotheeffectofrootherbivory on the composition of turfgrass (Poaceae) volatile profiles was investigated by collecting volatiles from healthy and grub-infested grasses. Tiphia wasps were highly attracted to volatiles emitted by grub-infested tallfescue (FestucaarundinaceaSchreb.)andKentuckybluegrass(PoapratensisL.)over healthy grasses. In contrast, wasps did not exhibit a significant preference for grub-infested perennial ryegrass (Lolium perenne L.) as compared with the control plants. The terpene levels emitted by grub-infested Kentucky bluegrass and tall fescue were greater than that of control plants. Low levels of terpenes were observed for both test and control perennial ryegrass. The elevated levels of terpenes emitted by grub-infested Kentucky bluegrass and tall fescue coincided with the attractiveness to the tiphiid wasps. Here, we provide evidence that plant exposure to root-feeding insects P. japonica and A. orientalis resulted in an increase in terpenoid levels in turfgrasses, which strongly attracts their above-groundparasitoids.

Popillia quadriguttata (Fabricius), and Protaetia brevitarsis (Lewis) adults were captured with Japanese beetle, Popillia japonica Newman, sex attractant and floral lures at Changchun, China during July–August 2012. The floral lure (phenethyl propionate:eugenol:geraniol, 3:7:3) was attractive to male and female P. quadriguttata (AV: 1.2 ± 0.9; 1.1 ± 0.3; total: 2.3 ± 0.8), and was similar in attraction to the combination of the sex attractant (SA) [(R, Z)-5-(1-decenyl) dihydro-2(3H)-furanone] plus the floral lure for male (1.60 ± 0.2), female (1.30 ± 1.1) and total captures (2.9 ± 3.0). However, the SA alone captured only males in much higher numbers than when combined with the floral lure (10.0 ± 6.4). In a separate earlier test, the greatest number of P. quadriguttata males (12.5 ± 3.0), female (12.2 ± 1.5) and total captures (24.7 ± 2.5) was in yellow, laboratory-made, bottle traps. The floral lure also attracted female Pro. brevitarsis (10.0 ± 3.4), while the SA attracted only few male beetles (1.0 ± 0.2). The combination SA + floral lure captured similar females (11.0 ± 2.0) and total (14.2 ± 2.2) Pro. brevitarsis as the floral lure alone. Two butterflies, Colias erate poliographus (Motschulsky) and Pieris rapae (Linnaeus), were also attracted to the floral lure. These studies indicate a potential for replacing pesticides by using the Japanese beetle lures for monitoring and control of several insects in China, and that they would be useful in monitoring and eradication of two potential scarab pests, P. quadriguttata and Pro. brevitaris , in the United States and Europe.

Japanese beetle (Popillia japonica Newman) is an emerging silk-feeding insect found in fields in the lower Corn Belt and Midsouthern United States. Studies were conducted in 2010 and 2011 to evaluate how silk clipping in corn affects pollination and yield parameters. Manually clipping silks once daily had modest effects on yield parameters. Sustained clipping by either manually clipping silks three times per day or by caging Japanese beetles onto ears affected total kernel weight if it occurred during early silking (R1 growth stage). Manually clipping silks three times per day for the first 5 d of silking affected the number of kernels per ear, total kernel weight, and the weight of individual kernels. Caged beetles fed on silks and, depending on the number of beetles caged per ear, reduced the number of kernels per ear. Caging eight beetles per ear significantly reduced total kernel weight compared with noninfested ears. Drought stress before anthesis appeared to magnify the impact of silk clipping by Japanese beetles. There was evidence of some compensation for reduced pollination by increasing the size of pollinated kernels within the ear. Our results showed that it requires sustained silk clipping during the first week of silking to have substantial impacts on pollination and yield parameters, at least under good growing conditions. Some states recommend treating for Japanese beetle when three Japanese beetles per ear are found, silks are clipped to13 mm, and pollination is50% complete, and that recommendation appears to be adequate.

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 TO Insecticide, Mallet 2 F TO 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.

Early-season herbivory can cause plants to induce resistance to subsequent herbivores, and this ubiquitous plant defense strategy has been shown to be adaptive when subsequent vegetative-feeding herbivores impact plant fitness. However, a growing number of studies show that leaf herbivory can also induce defenses in plant reproductive tissues, which may deter mutualists such as pollinators and seed dispersers, or antagonists such as florivores and seed predators. Due to their direct interaction with plant reproductive tissues, deterrence of these mutualists or antagonists may have large negative or positive effects on plant fitness. Despite numerous predictions, we know little regarding the fitness consequences of leaf-to-reproductive tissue induction in nature. Here, using observations of natural populations and manipulative field experiments, we show that leaf herbivory by the invasive Japanese beetle (Popillia japonica) induces an accumulation of jasmonic acid and complex phenolics in reproductive tiss...

Larvae of scarab beetles (Coleoptera: Scarabaeidae) are important contaminant and root-herbivore pests of ornamental crops. To develop alternatives to conventional insecticides, 24 plant-based essential oils were tested for their acute toxicity against third instars of the Japanese beetle Popillia japonica Newman, European chafer Rhizotrogus majalis (Razoumowsky), oriental beetle Anomala orientalis (Waterhouse), and northern masked chafer Cyclocephala borealis Arrow. Diluted solutions were topically applied to the thorax, which allowed for calculating LD50 and LD90 values associated with 1 d after treatment. A wide range in acute toxicity was observed across all four scarab species. Of the 24 oils tested, allyl isothiocyanate, cinnamon leaf, clove, garlic, and red thyme oils exhibited toxicity to all four species. Allyl isothiocyanate was the most toxic oil tested against the European chafer, and among the most toxic against the Japanese beetle, oriental beetle, and northern masked chafer. Red thyme was also comparatively toxic to the Japanese beetle, oriental beetle, European chafer, and northern masked chafer. Interspecific variability in susceptibility to the essential oils was documented, with 12, 11, 8, and 6 of the 24 essential oils being toxic to the oriental beetle, Japanese beetle, European chafer, and northern masked chafer, respectively. Analysis of the active oils by gas chromatography-mass spectrometry revealed a diverse array of compounds, mostly consisting of mono- and sesquiterpenes. These results will aid in identifying active oils and their constituents for optimizing the development of plant essential oil mixtures for use against scarab larvae.

To examine how the major elements of global change affect herbivory in agroecosystems, a multifactorial experiment was conducted where soybeans were grown at two levels of carbon dioxide and temperature, including those predicted for 2050, under otherwise normal field conditions. Japanese beetles (Popillia japonica Newman) were enclosed on foliage for 24 h, after which the beetle survivorship, total and per capita leaf consumption, and leaf protease inhibitor activity were measured. The direct effect of temperature on beetle consumption and survivorship also was measured under controlled environmental conditions. No differences in total foliage consumption were observed; however, beetles forced to feed at elevated temperature in the field demonstrated greater per capita consumption and reduced survivorship compared to beetles feeding at ambient temperature. Survivorship was also greater for beetles that consumed foliage grown under elevated CO2 , but there were no interactive effects of CO2 and temperature, and no differences in leaf chemistry were resolved. Leaf consumption by beetles increased strongly with increasing temperature up to ∼37° C, above which increased mortality caused a precipitous decrease in consumption. An empirical model based on the temperature dependence of leaf consumption and flight suggests that the 3.5°C increase in temperature predicted for 2050 will increase the optimal feeding window for the Japanese beetle by 290%. Elevated temperature and CO2 operating independently have the potential to greatly increase foliage damage to soybean by chewing insects, such as Popillia japonica, potentially affecting crop yields.

Field-based bioassays were used to determine the relative impact of rainfall on the relative toxicity of four insecticides, phosmet, carbaryl, zeta-cypermethrin, or imidacloprid, from different chemical classes on adult Japanese beetles, Popillia japonica Newman, in highbush blueberries, Vaccinium corymbosum L. Bioassays were set up 24 h after spraying occurred and Japanese beetle condition was scored as alive, knockdown or immobile 1, 24, and 48 h after bioassay setup. All insecticides were significantly more toxic than the untreated control and zeta-cypermethrin consistently had the greatest toxic effect against the Japanese beetles. All insecticides experienced a decrease in efficacy after simulated rainfall onto treated blueberry shoots, although the efficacy of zeta-cypermethrin was the least affected by rainfall. This study will help blueberry growers make informed decisions on when reapplications of insecticides are needed in the field with the aim of improving integrated pest management (IPM).

Plants will experience increased atmospheric CO2 and drought in the future, possibly altering plant- insect dynamics. To investigate the combined effects of these components of global change on plant-insect inter- actions, three major hormone signaling pathways (jasmonic acid (JA), salicylic acid (SA), and ethylene (ET)) and related defenses were examined in undamaged soybean (Glycine max) leaves and after Japanese beetle (Popillia japonica) feeding; plants were grown under elevated CO2 and reduced soil water both independently and simulta- neously. Nutritional quality and Japanese beetle preference for leaf tissue grown under these different conditions also were determined. Elevated CO2 increased the concentra- tion of leaf sugars and dampened JA signaling transcripts but increased the abundance of SA compared with plants grown in ambient CO2. A mild reduction in soil water content had no effect on leaf sugars but stimulated the induction of transcripts related to JA and ET biosynthesis after herbivory. When applied in combination, elevated CO2 and reduced soil water content suppressed the expression of transcripts related to JA and ET gene tran- scription. Exposure to elevated CO2 alone increased sus- ceptibility of soybean to beetle damage. However, exposure to elevated CO2 in combination with reduced soil water content negated the impact of elevated CO2, leaving susceptibility unchanged. Predicting future crop resistance to pests must take into account interactions among indi- vidual components of global climate change.

We tested the effect of host density on entomopathogenic nematode efficacy in 1-L pots with grass and soil. In four experiments, combinations ranged from somewhat resistant hosts (oriental beetle, Anomala orientalis, or northern masked chafer, Cyclocephala borealis, with Heterorhabditis bacteriophora) over more susceptible hosts (Japanese beetle, Popillia japonica, with Steinernema glaseri) to a highly susceptible host (P. japonica and S. scarabaei). In each experiment, four larval densities were exposed to two nematode rates over a 14-day period. A significant effect of host density on nematode efficacy occurred only in the A. orientalis–H. bacteriophora combination, but there was no clear trend in the data. This suggests that an exhaustion of available nematode populations to less lethal levels by high host numbers was counteracted by other factors such as increased chances for nematode-host contact and increased host susceptibility due to stress via reduced food resources and increased aggress...

Poor livestock performance on tall fescue is linked to infection by a fungal endophyte that enhances grass resistance to stress, including herbivory, while producing ergot alkaloids toxic to vertebrate grazers. Novel ‘safe’ endophyte/grass associations produce no ergot alkaloids yet retain stand persistence, but they could be more susceptible to insect outbreaks. We tested the hypothesis that grass-feeding insects are more abundant in novel endophyte pastures compared with those containing common endophyte. Above- and below-ground herbivores were sampled across two growing seasons in pastures containing common strain endophyte (KY31), novel endophytes (MaxQ or AR584) or endophyte free. We also sampled natural enemies as an indicator of possible tritrophic effects. With a few exceptions, numbers of predatory, chewing (grasshoppers, crickets, caterpillars) or sucking insects (leafhoppers, planthoppers) were similar in common and novel endophyte pastures. Contrary to our hypothesis, Aphrodes spp. leafhoppers were more abundant in KY31 than other pasture types in 2008; their nymphs also were more abundant in KY31 than in MaxQ in 2009. Adults (but not total numbers or nymphs) of another leafhopper, Psammotettix striatus, were less abundant in KY31 than other pasture types in 2009. Popillia japonica and Cyclocephala spp. grubs did not differ in density, weight or instar among the endophyte-containing associations. In feeding assays, armyworm (Mythimna unipuncta) survival was higher on MaxQ and NE9301, and weight gain was higher on NE9301, suggesting armyworm outbreaks could be more severe on such grasses, but that result may not be attributable solely to alkaloids because common strain and endophyte-free grasses did not differ in either parameter. Caterpillar abundance did not differ among pasture types in the field. Our results suggest that re-seeding common strain endophytic pastures with livestock-safe novel endophyte/grass associations to alleviate fescue toxicosis is unlikely to promote markedly higher populations of plant-feeding insects.

Field-based bioassays and residue profile analysis were used to determine the relative toxicity, rainfastness, and field degradation over time of five insecticides from five insecticide classes on adult Japanese beetles, Popillia japonica Newman (Coleoptera: Scarabaeidae), in grapes, Vitis labrusca L. Bioassays assessed Japanese beetle condition as alive, knockdown, or immobile when exposed for 24 h or 7-d field-aged residues of phosmet, carbaryl, bifenthrin, thiamethoxam, or indoxacarb after 0, 12.7, or 25.4 mm of rain had been simulated. We found that the two most toxic insecticides to Japanese beetle were phosmet and carbaryl, followed by bifenthrin, thiamethoxam, and then indoxacarb. The efficacy of phosmet decreased because of rainfall, but not because of field aging. The efficacy of carbaryl decreased because of rainfall and field aging. The efficacies of bifenthrin and thiamethoxam were not affected by rainfall but decreased because of field aging. The efficacy of indoxacarb was not affected by rainfall or field aging. This study will help vineyard managers make informed decisions on when reapplications of insecticides are needed with the aim of improving integrated pest management programs.

Phenylacetonitrile, (E)-β-ocimene, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene and (E,E)-α-farnesene were identified as Japanese beetle, Popillia japonica, feeding-induced volatiles from the leaves of the giant knotweed, Fallopia sachalinensis, but not by mechanical damage. Volatile emission was also induced by treatment with a cellular signaling molecule, methyl jasmonate. These results suggest that volatiles will be synthesized de novo by a biotic elicitor from P. japonica oral secretion.

Root-feeding grubs (Coleoptera: Scarabaeidae) were sampled from damaged areas of 61 irrigated roughs on 32 Kentucky golf courses to determine species composition and natural enemy incidence, the first such survey in the United States' transitional turfgrass climatic zone. Masked chafers (Cyclocephala lurida Bland and C. borealis Arrow) and Japanese beetle (Popillia japonica Newman) accounted for ≈73 and 26% of grubs found in an autumn survey, with Cyclocephala spp. predominating at most sites, although mixed infestations were common. Only a few Phyllophaga spp., and no exotic species other than P. japonica were found. Cyclocephala spp. also predominated in seasonal and statewide surveys regardless of whether a course had cool- or warm-season grass fairways. Pathogenic bacteria, Paenibacillus and Serratia spp., and the autumn-active parasitoid Tiphia pygidialis Allen were the main enemies associated with Cyclocephala spp. Predominant enemies of P. japonica were Paenibacillus, Serratia, and Metarhizium spp. in autumn, and eugregarines, Stictospora sp. (probably S. villani Hays and Clopton) and Tiphia vernalis Rohwer in spring. Entomopathogenic nematodes and the microsporidian Ovavesicula popilliae Andreadis & Hanula were nearly absent in our samples. No predictive relationships were found between soil parameters and proportionate abundance of Cyclocephala or P. japonica, or with natural enemy incidence at particular sites. Although incidence of individual enemies was generally low (

Levels of atmospheric CO2 have been increasing steadily over the last century and are projected to increase even more dramatically in the future. Soybeans (Glycine max L.) grown under elevated levels of CO2 have larger herbivore populations than soybeans grown under ambient levels of CO2. Increased abundance could reflect the fact that these herbivores are drawn in by increased amounts of volatiles or changes in the composition of volatiles released by plants grown under elevated CO2 conditions. To determine impacts of elevated CO2 on olfactory preferences, Japanese beetles (Popillia japonica Newman) and soybean aphids (Aphis glycines Matsumura) were placed in Y-tube olfactometers with a choice between ambient levels of CO2 gas versus elevated levels of CO2 gas or damaged and undamaged leaves and plants grown under ambient levels of CO2 versus damaged and undamaged plants grown under elevated levels of CO2. All plants had been grown from seeds under ambient or elevated levels of CO2. Painted lady...

Elevated levels of CO2, equivalent to those projected to occur under global climate change scenarios, increase the susceptibility of soybean foliage to herbivores by down-regulating the expression of genes related to the defense hormones jasmonic acid and ethylene; these in turn decrease the gene expression and activity of cysteine proteinase inhibitors (CystPIs), the principal antiherbivore defenses in foliage. To examine the effects of elevated CO2 on the preference of Japanese beetle (JB; Popillia japonica) for leaves of different ages within the plant, soybeans were grown at the SoyFACE facility at the University of Illinois at Urbana-Champaign. When given a choice, JB consistently inflicted greater levels of damage on older leaves than on younger leaves, and there was a trend for a greater preference for young leaves grown under elevated CO2 compared to those grown under ambient CO2. More heavily damaged older leaves and those grown under elevated CO2 had reduced CystPI activity, and JB that consumed leaves with lower CystPI activity had correspondingly greater gut proteinase activity. Younger leaves with higher CystPI activity and photosynthetic rates may contribute disproportionately to plant fitness and are more protected against herbivore attack than older foliage. Cysteine proteinase inhibitors are potent defenses against JB, and the effectiveness of this defense is modulated by growth under elevated CO2 as well as leaf position. © 2009 Springer-Verlag. Fil: Zavala, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Illinois at Urbana; Estados Unidos. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Casteel, Clare L.. University of Illinois at Urbana; Estados Unidos Fil: Nabity, Paul D.. University of Illinois at Urbana; Estados Unidos Fil: Berenbaum, May R.. University of Illinois at Urbana; Estados Unidos Fil: Delucia, Evan H.. University of Illinois at Urbana; Estados Unidos

Invasive species' facilitation, or benefiting, of native species is rarely considered in biological invasion literature but could have serious economic consequences should a non-native herbivore facilitate injury by a native pest of high-value crops. Japanese beetle (JB),Popillia japonica, a polyphagous scarab, facilitates feeding by the obligate fruit-feeding native green June beetle (GJB),Cotinis nitida, by biting into intact grape berries that GJB, which has blunt spatulate mandibles, is otherwise unable to exploit. Here, we show JB further facilitates GJB by contaminating fruits with yeasts, and by creating infection courts for yeasts associated with GJB, that elicit volatiles exploited as aggregation kairomones by GJB. Traps baited with combinations of grapes and beetles were used to show that fruits injured by JB alone, or in combination with GJB, become highly attractive to both sexes of GJB. Such grapes emit high amounts of fermentation compounds compared with intact grapes. Beetle feeding on grape mash induced the same volatiles as addition of winemaker's yeast, and similar attraction of GJB in the field. Eight yeast species were isolated and identified from JB collected from grapevine foliage. Establishment and spread of JB throughout fruit-growing regions of the United States is likely to elevate the pest status of GJB and other pests of ripening fruits in vineyards and orchards.

Field and laboratory tests were conducted from 2001 through 2007 to assess the effectiveness of entomopathogenic nematode Heterorhabditis bacteriophora strain GPS11 applications targeted against different instars of the Japanese beetle, Popillia japonica . During summer flight, P. japonica adults were trapped and caged on turfgrass plots for oviposition. Larval development was monitored for the occurrence of each instar. Nematodes were applied in the field against each developing instar at 2.5 × 10 9 infective juveniles/ha. In 2001, field data obtained in October resulted in 75%, 53%, and 33% control with the applications targeted against the first, second, and third instars, 69, 28, and 9 days after treatment (DAT), respectively. In 2002 field trial, data obtained in October indicated 97%, 88%, and 0% control when the applications were targeted against the first, second, and third instars at 66, 43, and 14 DAT, respectively. Additional plots established in 2002 to determine efficacy against each instar at 14 DAT showed control of the first, second, and third instars to be 55%, 53%, and 0%, respectively. In laboratory tests conducted in 2002, 2004, and 2007, P. japonica collected from the field at the occurrence of each instar were exposed to H. bacteriophora at concentrations of 0, 10, 33, 100, 330, or 1000 infective juveniles/grub. Probit analysis of the mortality from three of the four sets of tests conducted showed the first instar to be significantly more susceptible to H. bacteriophora than the third instar at the LC 50 level and all tests showed the first instar to be significantly more susceptible than the third instar at the LC 90 level. In addition to the observed decrease in the third instar susceptibility to H. bacteriophora , soil temperatures in the mid-western United States during late September and October rapidly decline often reaching below 15 °C by the beginning of October when grubs are in the third instar stage of development. Therefore, we conclude that the applications of the nematodes made in August or September will provide higher control than those made in October, due to the more appropriate temperature for nematode activity and the presence of more susceptible larval stages. Early nematode applications may also provide an opportunity for nematodes to recycle and cause secondary infections.

The Japanese beetle, Popillia japonica Newman, has an unusually broad host range among deciduous woody plants, yet it feeds only sparingly, or not at all, on certain species in the field. We evaluated beetles' preference, survival over time and fecundity on eight woody plant species historically rated as susceptible or resistant and, after verifying those ratings, tested whether resistance is correlated with so-called quantitative defense traits including leaf toughness, low nutrient content (water, nitrogen, and sugars), and relatively high amounts of tannins or saponins, traditionally associated with such plants. We further tested whether species unsuitable for Japanese beetles are also rejected by fall webworms, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), the expected outcome if the aforementioned traits serve as broad-based defenses against generalists. Choice tests supported historical resistance ratings for the selected species: tuliptree, lilac, dogwood, and Bradford callery pear were rejected by Japanese beetles, whereas sassafras, cherry plum, Virginia creeper, and littleleaf linden were readily eaten. Rejected species also were unsuitable for survival over time, or egg-laying, indicating beetles' inability to overcome the resistance factors through habituation, compensatory feeding, or detoxification. None of the aforementioned leaf traits was consistently higher or lower in the resistant or susceptible plants, and plant species rejected by Japanese beetles often were not rejected by fall webworms. Specialized secondary chemistry, not quantitative defenses, likely determines the Japanese beetle's dietary range among deciduous woody plant species it may encounter.

Feeding damage by Japanese beetle (Popillia japonica Newman) was evaluated on 16 field-grown birch genotypes (Betula L.) under two irrigation regimes at Fayetteville, AR in 2003, 2004 and 2005. Percentage of total leaf area skeletonized by Japanese beetle was visually estimated, and leaf damage was rated as no damage, low damage, moderate or severe damage based on the percentage of leaf skeletonization. The average percentage of leaf skeletonization on all birch trees by Japanese beetles was 32% in 2003, 27% in 2004 and 25% in 2005. In 2005, well-watered trees had a higher percentage of leaf skeletonization than water-stressed trees. Betula utilis var. jacquemontii and Betula papyrifera 'Uenci', rated as severe damage in all 3 years, were estimated to have the highest percentage of leaf skeletonization followed by B. papyrifera, which was rated as moderate-to-severe damage. Betula maximowicziana, Betula nigra 'Cully', B. papyrifera 'Renci', and Betula platyphylla 'Fargo' were rated as low-to-moderate damage. Betula pendula 'Laciniata' had nearly no damage from Japanese beetle in all 3 years. The other birch genotypes were rated as low damage during the 3-year period.

Elevated levels of atmospheric carbon dioxide (CO 2 ), a consequence of anthropogenic global change, can profoundly affect the interactions between crop plants and insect pests and may promote yet another form of global change: the rapid establishment of invasive species. Elevated CO 2 increased the susceptibility of soybean plants grown under field conditions to the invasive Japanese beetle ( Popillia japonica ) and to a variant of western corn rootworm ( Diabrotica virgifera virgifera ) resistant to crop rotation by down-regulating gene expression related to defense signaling [lipoxygenase 7 ( lox7 ), lipoxygenase 8 ( lox8 ), and 1-aminocyclopropane-1-carboxylate synthase ( acc-s )]. The down-regulation of these genes, in turn, reduced the production of cysteine proteinase inhibitors (CystPIs), which are specific deterrents to coleopteran herbivores. Beetle herbivory increased CystPI activity to a greater degree in plants grown under ambient than under elevated CO 2 . Gut cysteine proteinase activity was higher in beetles consuming foliage of soybeans grown under elevated CO 2 than in beetles consuming soybeans grown in ambient CO 2 , consistent with enhanced growth and development of these beetles on plants grown in elevated CO 2 . These findings suggest that predicted increases in soybean productivity under projected elevated CO 2 levels may be reduced by increased susceptibility to invasive crop pests.

Combinations of the anthranilic diamide, chlorantraniliprole, and the entomopathogenic nematode Heterorhabditis bacteriophora were tested for control of third-instar white grubs in turfgrass. In greenhouse experiments, the combinations had a synergistic or additive effect on the oriental beetle, Anomala (= Exomala ) orientalis mortality, whether chlorantraniliprole was applied 1 week before H. bacteriophora or simultaneously. Combinations caused mortality to occur more rapidly than for the single agents. H. bacteriophora -chlorantraniliprole combinations had a synergistic effect on mortality of Japanese beetle, Popillia japonica , and northern masked chafer, Cyclocephala borealis , larvae in greenhouse experiments. Synergistic and additive effects on larval mortality were also observed in field experiments with A. orientalis and P. japonica . Across all experiments, synergistic interactions (based on a χ 2 test) were observed in 64% of the combinations. Significant control (based on ANOVA) was observed in 12% of the chlorantraniliprole alone treatments and 29% of the H. bacteriophora alone treatments, but significant control occurred in 76% of the combination treatments. H. bacteriophora progeny production per dead larva recovered in greenhouse experiments did not differ between H. bacteriophora alone and the combination treatments. Nematode densities were higher at 28 days after treatment in soil from the combination treatments due to the higher number of larvae succumbing to nematode infection. H. bacteriophora and chlorantraniliprole were compatible in tank mixes. Agitation in solution with up to 900 ppm chlorantraniliprole did not affect survival, infectivity, and reproduction of H. bacteriophora . H. bacteriophora -chlorantraniliprole combinations offer a safe and highly IPM compatible alternative for remedial white grub control.

BACKGROUND: An investigation was carried out to determine whether new neonicotinoid–nematode combinations and earlier applications against younger larval stages could increase the efficacy of synergistic neonicotinoid–entomopathogenic nematode combinations against white grubs. RESULTS: In the laboratory, combinations of the neonicotinoids imidacloprid and clothianidin and the nematodes Heterorhabditis bacteriophora Poinar and H. zealandica Poinar against third instars were compared. In Anomala orientalis (Waterhouse) and Popillia japonica Newman, H. bacteriophora–imidacloprid combinations showed the most consistent synergism but did not cause significantly higher mortality than H. zealandica–imidacloprid combinations. In Cyclocephala borealis Arrow, there was no clear trend as to which combinations caused the most consistent synergism, but H. zealandica–imidacloprid combinations tended to cause the highest mortalities. In the laboratory, imidacloprid–H. bacteriophora combinations provided more consistent synergism against third-instar than against second-instar A. orientalis, but mortality was higher in second instars. In field experiments, imidacloprid–H. bacteriophora combinations against A. orientalis and P. japonica provided more consistent synergism when applied in mid-September but more consistent control when applied in late August. CONCLUSIONS: Imidacloprid is a better synergist for entomopathogenic nematodes than clothianidin. Imidacloprid–nematode combinations are more effective against second instars than against third instars, allowing rate reductions of both agents to make this approach more competitive with full-rate applications of neonicotinoid alone. Copyright © 2008 Society of Chemical Industry

Bacillus thuringiensis serovar japonensis strain Buibui experimental formulations containing Cry8Ca1 δ-endotoxin were evaluated in the field for the control of oriental beetle, Anomala orientalis Waterhouse; Japanese beetle, Popillia japonica Newman; Asiatic garden beetle, Maladera castanea (Arrow); and European chafer, Rhizotrogus majalis (Razoumowsky) larvae infesting turfgrasses. In 17 fall applications, control of A. orientalis and P. japonica was achieved at rates as low as 100 g of toxin per ha; however, rates of 301 or 593 g/ha were consistently more effective. A. orientalis larvae were the most susceptible followed by P. japonica, R. majalis, and M. castanea. Two spring applications of 120 g of toxin per ha were not effective against oriental or Japanese beetles.

Japanese beetle traps baited with the Popillia japonica Newman (Coleoptera: Scarabaeidae) pheromone lure and a eugenol feeding attractant were placed at five golf courses in Korea to determine how well they work for detecting activity of a closely related species, Popillia quadriguttata (F.) (Coleoptera: Scarabaeidae), a turf pest in Korea. The traps also were used to determine the time of day and time of year that P. quadriguttata is most active. Nineteen scarab species of 13 genera were attracted to the Japanese beetle traps with P. quadriguttata clearly being the most abundant (383 beetles per trap), followed by Adoretus tenuimaculatus Waterhouse (10 per trap), Popillia flavosellata Fairmaire (seven per trap), Exomala orientalis Waterhouse (four per trap), and Maladera japonica (two per trap). Other scarab species were trapped at a rate of

We compared the virulence of the entomopathogenic nematodes Steinernema scarabaei, Heterorhabditis zealandica, and Heterorhabditis bacteriophora (GPS11 and TF strains) against third instars of the Japanese beetle, Popillia japonica, the oriental beetle, Anomala (=Exomala) orientalis, the northern masked chafer, Cyclocephala borealis, the European chafer, Rhizotrogus majalis, and the Asiatic garden beetle, Maladera castanea, in laboratory and greenhouse experiments. The virulence of the nematode species relative to each other differed greatly among white grub species. H. bacteriophora and H. zealandica had similar modest virulence to P. japonica, A. orientalis, C. borealis, and M. castanea. But against R. majalis, H. zealandica showed low virulence with a clear concentration response whereas H. bacteriophora caused only erratic and very low mortality. In contrast, S. scarabaei had modest virulence against C. borealis, but was highly virulent against R. majalis, P. japonica, A. orientalis, and M. castanea with R. majalis being the most susceptible and M. castanea the least susceptible.

Ground covers were tested for 3 consecutive yr for their effect on Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), abundance and behavior in a blueberry planting. Alsike clover (Trifolium hybridum L.), buckwheat (Fagopyrum esculentum Moench), pe- rennial ryegrass (Lolium perenne L.), and bare ground were compared within row-middles for their effect on abundance of adult female beetles, female beetle behavior after landing, density of larvae in the soil, and survival of larvae. Adult beetles were consistently most abundant on buckwheat, followed by clover and ryegrass, while they were generally absent from bare ground plots. Larval density was three times greater in ryegrass and clover than in buckwheat, with the fewest found in bare ground. There was high variability in larval survival within treatments, but overall survival was highest in plots with ryegrass. Observations of adult beetles revealed that the proportion of time spent feeding and the frequency of feeding were higher on buckwheat and clover than on ryegrass, and the average duration of digging bouts lasted longer on ryegrass than on the other two plant treatments. These results reveal that adult P. japonica behavior is affected by cover crops and that this behavior translates into variation in larval density of this pest.

American [ Castanea dentata (Marsh) Borkh.] × Chinese [ Castanea mollissima Blume] chestnut (Fagac, ae) hybrids are a novel system in which to study influences of phytopathogenic fungi and woody plant hybridization on herbivore susceptibility, as the hybrids are well characterized with regard to resistance to the chestnut blight fungus [ Cryphonectria parasita (Murr) Barr ( Endothia ) Diaporthales: Valsaceae] and variability is present. We chose two groups of resistance-rated backcross chestnut that shared an F1 parent and had different American parents. Foliage from both backcross groups and the parent trees was sampled on three dates for use in feeding assays with gypsy moth larvae [ Lymantria dispar (L.) [Lepidoptera: Lymantriidae], adult Japanese beetles [ Popillia japonica Newman (Coleoptera: Scarabaeidae)], and fall webworm larvae [ Hyphantria cunea Drury (Lepidoptera: Arctiidae)], respectively. Foliar analyses were performed concurrently and included carbohydrate, tannin, and nitrogen content, toughness, and density. Blight resistance had almost no effect on herbivore performance or foliar chemistry. When the parent trees and backcross groups were compared, however, significant differences in gypsy moth performance and Japanese beetle consumption were evident. There were no differences in fall webworm consumption. Most foliar characteristics measured differed among chestnut genotypes at some point in the season, and all varied seasonally. No clear pattern emerges with respect to the relationship among blight resistance, herbivore susceptibility, foliar properties, and plant genotype, and more research is needed to separate these effects.

A bioassay arena was developed to test the response of the Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), to various plant-derived factors that may influence the selection of oviposition sites. In choice experiments with natural and artificial plant cues, females preferred to lay eggs in ryegrass rather than in artificial resources. Artificial grass stems received more eggs on average than bare ground, indicating the role of vertical objects on the soil surface as oviposition cues. Popillia japonica females were able to discriminate between the quality and quantity of the artificial stems, as more eggs were laid in soil blocks that had larger diameter stems or a higher number of stems per soil block. Beetles were capable of evaluating plant characteristics on the soil surface and adjusted their investment accordingly; more eggs were laid in resources that were chosen more frequently. Observations of females in choice arenas revealed how surface cues influence digging behavior and the time spent under the soil surface. The number of digging events was not significantly different among the three treatments with surface cues (ryegrass, grass roots, and artificial grass), but beetles spent significantly more time in the soil under ryegrass than any of the other treatments. These findings suggest that oviposition by P. japonica is selective and is influenced by plant-derived cues evaluated before and after digging into the soil.

At 15 commercial highbush blueberry farms, fields where row middles were tilled had 72% lower larval density of Popillia japonica than fields with grass in row middles. Popillia japonica larval populations were similar in the perimeters of tilled and untilled fields. Soil parameters measured in these sites were not correlated with larval density of P. japonica. Samples of adult beetles on bushes showed that they were significantly less abundant in tilled fields compared with fields with grass in the row middles. The abundance of larvae inside fields during the spring was significantly correlated with early, but not late summer abundance of adult beetles on bushes. Comparisons of different tillage timings showed that grassy plots between rows of blueberry bushes that were tilled in spring and kept bare all year round had lower abundance of P. japonica larvae than those that retained perennial ryegrass. The effect of tillage timing on larval abundance was not consistent across 2 years, but most timings caused similar reduction in P. japonica larval density in the row middles. Tillage in the spring and in the autumn caused 50.5% and 68.8% reduction of larval density in each year respectively. These results indicate that tillage can reduce P. japonica larval and adult abundance in highbush blueberry fields.

The effect of insecticides on oviposition of Tiphia vernalis Rohwer and subsequent survival of parasitoid progeny to the cocoon stage was determined in the laboratory by using larval Japanese beetle, Popillia japonica Newman, as the host. Insecticides tested were imidacloprid, thiamethoxam, halofenozide, chlorpyrifos, and carbaryl at labeled rates. Female T. vernalis were allowed 2 d to parasitize P. japonica larvae after the parasitoids had received a 4-d exposure to insecticide-treated soil. Another group of female T. vernalis were allowed 2 d to parasitize P. japonica larvae that had been exposed to insecticide-treated soil for 3–4 d. Percentage of parasitism of P. japonica larvae in these trials after exposure of adult parasitoids to carbaryl, chlorpyrifos, halofenozide, or imidacloprid-treated soil (23.3–50.0%) or adult parasitoids to chlorpyrifos, halofenozide, or imidacloprid-treated grubs (33.0–56.7%) was not negatively affected relative to the control treatment (21.7–54.2%). A third grou...

Increased concentrations of CO2 and ozone are predicted to lower nutritional quality of leaves for insect herbivores, which may increase herbivory as insects eat more to meet their nutritional demands. To test this prediction, we measured levels of herbivory in soybean grown in ambient air and air enriched with CO2 or O3 using free air gas concentration enrichment (FACE). Under open-air conditions and exposure to the full insect community, elevated [CO2] increased the susceptibility of soybeans to herbivory early in the season, whereas exposure to elevated [O3] seemed to have no effect. In the region of the canopy exposed to high levels of herbivory, the percentage of leaf area removed increased from 5 to >11% at elevated [CO2]. We found no evidence for compensatory feeding at elevated [CO2] where leaf nitrogen content and C:N ratio were unaltered in plants experiencing increased herbivory. However, levels of leaf sugars were increased by 31% at elevated [CO2] and coincided with a significant increase in the density of the invasive species Popillia japonica Newman (Japanese beetle). In two-choice feeding trials, Japanese beetles and Mexican bean beetles (Epilachna varivestis Mulsant.) preferred foliage grown at elevated [CO2] to foliage grown at ambient [CO2]. These data support the hypothesis that the increased level of sugar in leaves grown at elevated [CO2] may act as a phagostimulant for the Japanese beetle. If these results apply more widely to soybean production, the expectation of agricultural yield increases as a result of increasing elevated [CO2] may need to be reevaluated.

We investigated the biology of Tiphia pygidialis Allen, a previously unstudied native parasitoid of masked chafer, Cyclocephala spp. grubs, in central Kentucky and the seasonal dynamics of Tiphia vernalis Rohwer, an introduced parasitoid of Japanese beetle, Popillia japonica Newman. T. pygidialis was active from mid-August to early October, parasitizing third-instar masked chafers, whereas T. vernalis attacked overwintered third-instar P. japonica from mid-April to early June. Adult T. vernalis were attracted to modified Japanese beetle traps and yellow pan traps and to 10% sugar water sprayed on tree foliage. Spraying sugar water directly on turf most effectively monitored T. pygidialis wasps. Parasitism rates as high as 33 and 58% were observed for T. pygidialis and T. vernalis, respectively. In the laboratory, T. pygidialis larvae progressed through five instars to cocoon formation in ≈22 d. They overwinter as prepupae. Field-collected female wasps lived 32 ± 4 d, parasitizing 22 ± 6 grubs. In...

We examined the effects of supplemental food sources on parasitism of turf-infesting white grubs (Coleoptera: Scarabaeidae) by tiphiid wasps (Hymenoptera: Tiphiidae). Survival of spring active Tiphia vernalis Rohwer and late summer active Tiphia pygidialis Allen, parasitoids of Japanese beetle, Popillia japonica Newman, and masked chafer, Cyclocephala spp., grubs, respectively, was significantly increased when wasps were provided with 10% sugar water in the laboratory. Presence of a grub for host feeding did not affect wasp longevity. Sugar sprays applied directly to turf were examined as a method for increasing grub parasitism rates. Large numbers of T. pygidialis visited turf sprayed with sugar water to feed. Parasitism of Cyclocephala spp. grubs by T. pygidialis was reduced in sugar-sprayed turf, but higher in turf plots located near sugar-sprayed turf. T. vernalis, which feeds on homopteran honeydew secretions, was never observed feeding on sugar-sprayed turf, nor did such treatments affect i...

Achieving predictability (i.e., consistency of control) is a key challenge in the use of entomopathogenic nematodes for pest control. As nematode species/strain plays a key role in the success of white grub control, two strains, Heterorhabditis zealandica X1 (Hz-X1) and Heterorhabditis bacteriophora GPS11 (Hb-GPS11), identified through laboratory assays to be the most virulent, were tested in a series of field trials against the second and third instar white grubs Popillia japonica and Cyclocephala borealis at different locations over a 2-year period. The HP88 strain of H. bacteriophora (Hb-HP88), the NJ and MB strains of Steinernema glaseri (Sg-NJ and Sg-MB) and a UK strain of Steinernema kraussei (Sk-UK) were also included for comparison in some tests. Overall, Hz-X1 and Hb-GPS11 strains were the most effective nematodes resulting in 73–98 and 34–97% control of P. japonica and 72–96 and 47–83% control of C. borealis, respectively. The Hz-X1 and Hb-GPS11 strains did not differ significantly between each other against either grub species in any of the tests. The Hb-HP88 provided 52 and 36% control of P. japonica and C. borealis, respectively. The Sg-MB provided 6–58% control of P. japonica, no control of C. borealis, and 54–74% control of mixed populations of the two species. The Sg-NJ provided 20% control of P. japonica. Doubling the nematode application rate from 2.5 × 109 to 5 × 109 infective juveniles/ha did not significantly increase control of a mixed population of P. japonica and C. borealis. Halofenozide (Mach 2 2SC) and imidacloprid (Merit 75WP) applied as preventative treatments in July provided 97 and 98% control, respectively, of P. japonica. Imidacloprid applied as a curative treatment in September provided 47% control of C. borealis but 0% control of P. japonica. Trichlorfon (Dylox 6.2G) applied as a curative treatment in September provided 29–92% control of P. japonica, 49% control of C. borealis, and 0–77% control of mixed populations of the two grub species. Grub control provided by the Hz-X1 strain was always equal to or better than trichlorfon and that by the Hb-GPS11 strain was equal to trichlorfon except for one occasion. The amount of post-application irrigation plus rainfall had a strong effect on nematode efficacy. A total of 10 cm of post-application irrigation plus rainfall was found to be optimum at which the Hb-GPS11 and Hz-X1 strains produced 83–97 and 96–98% control of the two white grub species, respectively. Combined analyses of the results from all 8 trials containing 46 treatments indicate that the consistency in the control of P. japonica and C. borealis by the new Hz-X1 and the Hb-GPS11 strains is equal to or better than the curative application of chemical insecticide standard, trichlorfon.