Japanese Beetle Grubs Research Articles

Mulches Used in Highbush Blueberry and Entomopathogenic Nematodes Affect Mortality Rates of Third-Instar Popillia japonica.

Simple SummaryJapanese beetle is a serious pest of many crops, including blueberry. While the adult beetles feed on leaves, the grubs (immatures) feed on plant roots and can cause wilting and reduced plant growth. Farmers rely on insecticides to control Japanese beetle, but nematodes that attack and kill grubs in the soil may be as effective as insecticides in some cases. Mulches of compost, woodchips, sawdust, and tree bark are commonly used in blueberry production, but it is not known how mulches affect Japanese beetle grubs or the effectiveness of beneficial nematodes to control grubs. We placed grubs in soil beneath different mulches in the laboratory and tested two nematodes. The species H. bacteriophora killed almost all grubs in all mulches, but S. scarabaei was not as effective and was more affected by mulch type. A mulch of compost + woodchips and sawdust caused 60% grub mortality without adding nematodes. In a field experiment during October, the nematodes caused 50% grub mortality, which was lower than expected and likely due to cool soil temperatures. We recommend using H. bacteriophora for Japanese beetle grub management in blueberry, regardless of the mulch type being used.Popillia japonica Newman (Japanese beetle) is an invasive, polyphagous pest in North America, as adults feed on plant foliage and larvae on roots. Management in crops relies on foliar and soil applications of insecticides, but entomopathogenic nematodes (EPN) are effective biocontrol agents. In highbush blueberry, mulches (composts, woodshavings, sawdust, bark) are used for weed control and fertility. Therefore, our objective was to determine the effects of Heterorhabditis bacteriophora and Steinernema scarabaei on third-instar P. japonica in substrates commonly used as mulches in blueberry. In containers in the laboratory, larval mortality was 90–100% with H. bacteriophora for all substrates, but rates with S. scarabaei were lower and variable among substrates. A mixture of municipal compost + woodchips/sawdust resulted in 60% larval mortality without adding EPN, but few nematodes were recovered, indicating other causes of death. In a field microplot experiment in October, larval mortality rates were 50% at most for all EPN and substrate type combinations, likely due to lower than optimal soil and substrate temperatures for EPN survival and infectivity. Overall, a compost and woodchip/sawdust mulch should help suppress P. japonica populations in blueberry, and applying H. bacteriophora when temperatures are optimal to mulches can provide excellent larval control.

Rhizobacterial treatments of tall fescue and bermudagrass increases tolerance to damage from white grubs.

Inoculation of hybrid bermudagrass with plant growth-promoting rhizobacteria (PGPR) can increase plant growth and influence relationships with above-ground herbivores like fall armyworms. However, few experiments have evaluated PGPR applications relative to root herbivory. Root-feeding white grubs cause severe damage to grasses, especially in tall fescue pastures, golf courses, and lawns. Since bacterial inoculants enhance root growth, the goal of this study was to determine if the inoculation of hybrid bermudagrass by rhizobacteria can increase the tolerance of tall fescue and hybrid bermudagrass to damage from white grub feeding, and if PGPR are compatible with neonicotinoid insecticides commonly used for white grub control. In trials with tall fescue and hybrid bermudagrass, grasses were treated with the PGPR strain mixture Blend 20 or nitrogen or left non-treated and were then infested with Japanese beetle grubs. Grasses treated with PGPR and nitrogen fertilizer produced significantly more top growth than the non-treated grub-infested controls. Tall fescue and hybrid bermudagrass treated with Blend 20 produced root mass similar to or greater than nitrogen fertilized grasses. Both grasses treated with Blend 20 had greater root mass than non-treated infested grass. No treatment negatively impacted grub survival, and weight gains of grubs were similar for all treatments. Bacterial strains were typically compatible with insecticides used to control white grubs. PGPR and nitrogen fertilization stimulate root growth resulting in tolerance of tall fescue and hybrid bermudagrass to white grub infestation. PGPR, acting as biostimulants to increase root biomass on grasses, may have utility for IPM of root herbivores. © 2019 Society of Chemical Industry.

Analysis of Tiphia parasitoids preovipositional behaviors and of their scarab host defensive responses

Tiphia vernalis Rohwer and Tiphia popilliavora Rohwer were introduced as biocontrol agents against Japanese beetles (Popillia japonica Newman) and oriental beetles (Anomala orientalis Waterhouse). Studies have shown that under field conditions, T. vernalis parasitize Japanese beetles more often than oriental beetles. This study was done to understand how tiphiid wasps handle the two different host species and the influence of host defensive behaviors on the oviposition process of tiphiid wasps. The preovipositional behaviors performed by Tiphia wasps included: stinging, examining, moving soil, kneading, host-feeding, and host scraping. The frequency, sequence, and total time spent on each behavior before oviposition were scored and compared between two host species. The sequence and frequency of preovipositional behaviors performed by both Tiphia wasps did not show a difference between the two host species. However, female T. vernalis spent significantly longer time trying to sting oriental beetles than Japanese beetles in order to paralyze them. The time T. popilliavora spent on prestinging behaviors did not show a difference between Japanese and oriental beetles. The defensive behaviors performed by Japanese and oriental beetle grubs included: vigorous movements, rubbing their abdomen or head against the wasp’s abdomen, and biting at the attacking wasp. The frequency and total time spent on each defensive behavior was scored and compared between two host species. Overwintered, third instar oriental beetle grubs spent significantly longer time on defensive behaviors when they were attacked by T. vernalis which likely cause wasps to spend longer time trying to sting oriental beetle grubs. The active host resistance gained through behavioral defenses could make oriental beetle grubs less susceptible to T. vernalis attack than Japanese beetle grubs, especially under field conditions. Younger grubs attacked by T. popilliavora did not exhibit these differences.

Comparison of Scarab Grub Populations and Associated Pathogens and Parasitoids in Warm- or Cool-Season Grasses Used on Transitional Zone Golf Courses

Seven different turfgrass species or mixes used on golf courses in the United States' transitional climatic zone were maintained as randomized and replicated plots in separate stands mowed at fairway (1.6 cm) or rough (6.4 cm) cutting heights and sampled in autumn to assess the density and species composition of scarab grubs; incidence of disease and parasitism thereof; and extent of turf damage from foraging insectivorous skunks, Mephitis mephitis. Influence of grass species on parasitism by spring or autumn-active tiphiid wasps was further assessed on implanted grubs in open enclosures. Masked chafers (Cyclocephala spp.) were three-fold more abundant than Japanese beetle, Popillia japonica Newman, grubs in plots of Zoysia and Cynodon sp. mowed at fairway height, and P. japonica were five-fold more abundant than masked chafer grubs in cool-season turf plots mowed at rough height. Phyllophaga spp. accounted for <1% of grubs in the samples. Milky disease bacteria (Paenibacillus sp.) were the predominant pathogens of Cyclocephala spp., followed by Serratia sp. bacteria and gregarines (Stictospora cf. villani). Cyclocephala grub densities, milky disease incidence (25%), and parasitism by the native tiphiid Tiphia pygidialis Alien (10-12%) were especially high in zoysiagrass. Japanese beetle grubs were infected by Paenibacillus, Serratia, Stictospora, and microsporidia (Ovavesicula sp.), but incidence of individual pathogens was relatively low (<6%) and similar among grasses within each stand. Few nematode-infected grubs were found. Skunk damage was mainly in the cool-season fairway-height grasses, probably reflecting difficulty in foraging in the much tougher stolons and rhizomes of the warm season turfgrasses. The degree of natural suppression of scarab grubs provided by endemic pathogens or parasitoids is unlikely to be compromised by the grass species used on a particular site.

Asiatic Garden BeetleMaladera castanea(Coleoptera: Scarabaeidae) Grubs Found in Damaged Turf in Alabama

Asiatic Garden Beetle<i>Maladera castanea</i>(Coleoptera: Scarabaeidae) Grubs Found in Damaged Turf in Alabama

Maximum likelihood estimation of regression parameters with spatially dependent discrete data

Generalized estimating equations (GEEs) have been successfully used to estimate regression parameters from discrete longitudinal data. GEEs have been adapted for spatially correlated count data with less success. It is convenient to model correlated counts as lognormal-Poisson, where a latent lognormal random process carries all correlation. This model limits correlation and can lead to negative bias of standard errors. Moreover, correlation is not the best dependence measure for highly nonnormal data. This article proposes a model which yields maximum likelihood (ML) estimates of regression parameters when the response is discrete and spatially dependent. This model employs a spatial Gaussian copula, bringing the discrete distribution into the Gaussian geostatistical framework, where correlation completely describes dependence. The model yields a log-likelihood for regression parameters that can be maximized using established numerical methods. The proposed procedure is used to estimate the relationship between Japanese beetle grub counts and soil organic matter. These data exhibit residual correlation well above the lognormal-Poisson correlation limit, so that model is not appropriate. The data and MATLAB code are available online. Simulations demonstrate that negative bias in GEE standard errors leads to nominal 95% confidence coverage less than 62% for moderate or strong spatial dependence, whereas ML coverage remains above 82%.

Pre-visible Detection of Grub Feeding in Turfgrass using Remote Sensing

Japanese beetle grubs (Popillia japonica Newman) are rootfeeding pests of turfgrass in the Midwest and eastern United States causing millions of dollars of damage annually. To reduce unnecessary pesticide output by applying only where needed, turfgrass managers need a practical, noninvasive method to locate patchy infestations before unsightly damage has occurred. Spectrometer data and multispectral aerial imagery were evaluated for detecting pre-visible symptoms of grub damage in turfgrass, to facilitate sitespecific grub management. Using spectrometer reflectance data, first derivatives of reflectance, narrow-band vegetation indices, and linear combinations of multiple bands/indices, infested turfgrass plots were distinguished from un-infested plots 10 to16 days before visual differences appeared in the year when visual ratings were conducted. Pre-visible symptoms of grub feeding were not detected using the position of the red edge or edge of the red edge. Results using multispectral imagery were mixed, with early symptoms detected in only one of two years.

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.

The generalized linear model for spatial data: assessing the effects of environmental covariates on population density in the field

AbstractWith interest in spatial ecology growing, correlational field studies are likely to become increasingly important. Unfortunately, ecological field data often do not follow the assumptions of classical statistics, so techniques like the popular and powerful multiple linear regression and its variants are often unreliable, and results can be misleading. The generalized linear model (GLM) is a flexible extension of linear regression that has proved especially useful for discrete data. In this paper, the technique is adapted to accommodate spatially correlated, discrete data. Specifically, to demonstrate the approach, Japanese beetle grub [Popillia japonica Newman (Coleoptera, Scarabaeidae)] population density in the field is modeled as a function of soil organic matter content. The response variable (grub counts in small soil samples) was a spatially autocorrelated, discrete random variable. Three classes of GLMs of the association between soil organic matter content and grub density were compared: (i) regression (assuming normally distributed response variable), (ii) GLM assuming negative binomial counts, and (iii) GLM based on the assumption that the counts conformed to Taylor's power law (TPL). Because the grubs were distributed in patches rather than at random, models that explicitly accounted for the spatial autocorrelation of grub counts were constructed, and compared with models that assumed independent observations. The fitted values for the discrete GLMs [viz., (ii) and (iii)] differed noticeably from the fitted values from multiple regression; but fitted values among the negative binomial and TPL GLMs were virtually identical, regardless of whether the spatial covariance was incorporated into a model, whether a spherical or exponential variogram model was used, or whether variance function parameters were estimated over a large or small scale. However, P‐values for the overall significance of the models depended heavily on whether the GLM assumed a discrete or continuous response variable, and whether or not spatial autocorrelation in the response variable was accounted for. On average, P‐values were 45‐fold higher in the spatial GLMs than in the non‐spatial and 23‐fold higher in the discrete GLMs than in the continuous.

Biology and management of the Japanese beetle.

The Japanese beetle, Popillia japonica Newman, an introduced scarab, has become the most widespread and destructive insect pest of turf, landscapes, and nursery crops in the eastern United States. It also damages many fruit, garden, and field crops. This review emphasizes recent research on the beetle's biology and management. Adults feed on leaves, flowers, or fruits of more than 300 plant species. Adaptations mediating their host finding, dietary range, mating, and oviposition are discussed. We also address abiotic and biotic factors affecting population dynamics of the root-feeding larvae. Japanese beetle grubs are widely controlled with preventive soil insecticides, but options for remedial control of adults and larvae presently are limited. Advances in understanding host plant resistance, entomopathogens, and other biorational approaches may provide more options for integrated management. Despite ongoing regulatory efforts, the Japanese beetle remains a threat as an invasive species.

Impact of four insecticides on Japanese beetle (Coleoptera: Scarabaeidae) egg predators and white grubs in turfgrass.

Field experiments were conducted to measure the effects of four commonly used turfgrass insecticides (isofenphos, diazinon, imidacloprid, halofenozide) on white grubs (Coleoptera: Scarabaeidae) and ant predators of white grub eggs. Ant populations were measured over time with canned tuna, whereas predation by the ants was measured with artificially placed Japanese beetle, Popillia japonica Newman, eggs. The effectiveness of each insecticide at controlling Japanese beetle grubs, when applied at different times during the growing season, also was measured. Isofenphos and diazinon significantly reduced both ant numbers and white grub egg predation, whereas imidacloprid and one halofenozide treatment did not significantly impact either measurement. A second halofenozide treatment significantly reduced white grub egg predation. Isofenphos and diazinon were ineffective at controlling Japanese beetle grubs when applied in June but were highly efficacious when applied in August. Evidence of enhanced biodegradation was found in plots that received both June and August applications of diazinon. Both June and August applications of imidacloprid and halofenozide provided good control of white grubs.

Absence of Interaction between Endophytic Perennial Ryegrass and Susceptibility of Japanese Beetle (Coleoptera: Scarabaeidae) Grubs to Paenibacillus popilliae Dutky1

Absence of Interaction between Endophytic Perennial Ryegrass and Susceptibility of Japanese Beetle (Coleoptera: Scarabaeidae) Grubs to Paenibacillus popilliae Dutky1

Spatial ecology of the Japanese beetle, Popillia japonica

AbstractA cornerstone of spatial ecology is the quantification of the patchy nature of animal and plant populations in space. By using spatial covariance, total covariance, and quantile variance, we found that patchiness of Japanese beetle grub populations varied more between years than between fairways at a central New York golf course. We also observed that populations tended to shrink and swell around patches with perennially low density, that locations with perennially low grub density were associated with high soil organic matter content, and that locations with frequently high grub density were associated with intense adult beetle activity in the vicinity.

Insecticide Dips for Control of Japanese Beetle and Other Soil-Infesting White Grubs in B&amp;B Nursery Stock

Abstract Studies conducted in 1996, 1998 and 1999 show that immersion of root balls in Dursban® (chlorpyrifos) significantly reduces the number of white grubs, particularly Japanese beetle, Popillia japonica Newman, in B&amp;B (ball and burlap) nursery stock. In 1996, the influence of root ball size, soil type, and dip time on the efficacy of Dursban® 50WP, Dursban® 4E, and Oftanol® 2F (isofenphos) for white grub control in dipped B&amp;B nursery stock was evaluated. The grubs found within the root balls were primarily oriental beetle, Exomala orientalis (Waterhouse), European chafer, Rhizotrogus majalis (Razoumowsky), Asiatic garden beetle, Maladera castanea (Arrow), northern masked chafer, Cyclocephala borealis Arrow and Japanese beetle. With one exception, all the insecticide treatments caused similar grub mortality (96–100%) in 61.0 and 81.3 cm (24 and 32 in) root balls, respectively, and in sand or clay soil. There were no significant differences in grub survival due to dip time (1, 2, and 5 min). However, there were consistently fewer live grubs recovered from the root balls dipped 2 or 5 min compared with the number of live grubs recovered from root balls dipped for 1 min. In 1998, trees with 30.5, 45.7 and 61.0 cm (12, 18 and 24 in) root balls were dipped in either 0.453 or 0.906 kg ai/378.5 liter (1 or 2 lbs ai/100 gal) of Dursban® 4E for 2 mins. Both rates of Dursban® provided 100% control of Japanese beetle grubs in all three root ball sizes. Five trees from each treatment were planted one week after dipping and were evaluated for phytotoxicity up to 12 months after dipping. Most of the trees with 30.5 cm (12 in) root balls dipped in Dursban® died. Three of five trees with 45.7 (18 in) root balls dipped in the low rate of Dursban® and all five root balls dipped in the high rate had small leaves. One tree dipped in the low rate and 2 trees dipped in the high rate died 12 months after dipping. All of the trees with 61.0 cm (24 in) root balls dipped in the low rate of Dursban® survived and showed no signs of phytotoxicity. Trees with the same root ball size dipped in the high rate of Dursban® exhibited smaller leaves in 3 of the 5 trees. In 1999, trees with 61.0 cm (24 in) root balls were dipped in either 0.453, 0.226 or 0.113 kg ai/378.5 liter (1, 0.5 or 0.25 lbs ai/100 gal) of Dursban® 4E for 2 mins. All rates of Dursban® provided 100% control of Japanese beetle grubs.

Estimation of Local Mean Population Densities of Japanese Beetle Grubs (Scarabaeidae: Coleoptera)

Insect populations tend to be patchy in distribution. Even when the mean population density is low, there may be local patches with high densities. As a result, estimates of mean populations may provide little information about the size or intensity of local patches within the sampled area. We compared the following 3 methods of estimating local population densities of insects: (1) with moving averages, a local mean population density is estimated as the mean of samples taken within a given radius of a central point, (2) with inverse distances, local means are estimated as weighted averages of samples; each sample is given a weight proportional to a power of the reciprocal of its distance from the center of the region for which the mean is to be estimated, (3) kriging is a geostatistical algorithm for estimating local means as weighted averages of samples. Weighting is based on the spatial covariance of the samples, or the degree to which samples that are near to each other are related. The first 2 methods are relatively easy to calculate but were unreliable when used with standard parameters to estimate local Japanese beetle grub densities. When an optimum radius was used with moving averages and an optimum exponent was used with inverse distances, the advantage of ease of calculation was lost, yet both methods were still inferior to kriging in providing accurate estimates of local means.

Curative Treatments of Grubex and Mach-2 2.5 G to Manage Japanese Beetle Grubs, 1997

Abstract The turfgrass area, located in Lancaster County, PA, consisted primarily of Kentucky bluegrass (20%), annual bluegrass (10%), and perennial ryegrass (60%). Treatment plots were 8 X 6 ft, arranged in a RCB design and replicated 3 times. Granular formulations were applied with a hand-held shaker and mixed with fine top dressing sand to facilitate product distribution. At treatment time (18 Aug) the following soil and environmental conditions existed: air temperature, 68° F; soil temperature at 1-inch depth, 72° F; soil temperature at 2 inch, 71° F; RH, 88%; amount of thatch, 0.375-0.5 inch; soil textural class, silt loam; soil particle size analysis: % sand, 15.1; silt, 66.0; % clay, 18.9; organic matter, 4.0%; soil percent water content (percent by weight), 18.8; water pH, 7.0; soil pH, 6.4; application time, mid-morning; and skies partly cloudy. Immediately after treatment select treatments were irrigated with 0.25 inch of water. The entire experimental area was irrigated in 24 hr later with 0.25 inch of water. Post-treatment counts were made on 29 Sep. Three ft2 sod samples were randomly taken from each replicate, and the total number of Japanese beetle grubs/ft2 was recorded.

Efficacy of Four B.T., Japonica BUI BUI, Formulations on Japanese Beetle Grubs, 1996

Abstract This trial was conducted at Amherst Country Club, Amherst, NH. The lawn was mowed at 1.5 inches and irrigated daily (0.1 inch). All treatments were applied on 19 Aug to 7 X 11 ft plots with 1-ft buffers, replicated 5 times in an RCB design. Liquid formulations were applied with a 2-wheel bicycle-type CO2 boom sprayer equipped with 4 spray heads fitted with a 50-mesh strainer and an 8004 fan-type nozzle. The volume of water and insecticide mix per plot was 2 gal/1000 ft2 delivered at 40 psi. Granular formulations were evenly dispersed using large plastic salt shakers. The surface of the turf was free of moisture (dew) at time of application. The plots were irrigated post-treatment with 0.4 in of water. Grubs were primarily 2nd instar. Weather conditions at time of application were as follows. Air, temp; 78°F; sky, clear; wind, moderate breeze. Soil conditions were as follows: surface temp, 80°F; at 1-inch depth, 76°F; at 2-inch depth, 75°F; soil pH, 5.6; texture, silt loam; sand, 50%; silt, 43%; clay, 7%; dry matter, 81%; moisture, 19%; organic matter, 5%. The trial was rated on 20 Sep using a Ryan 18-inch sod cutter to cut the plots to a depth of 3/4 inch. A 3 ft2 piece of sod was moved and live grubs counted.

Control of White Grubs with a Bt Biotoxin, 1996

Abstract Several formulations of the ‘Buibui’ strain of Bacillus thuringiensis japonensis were evaluated with chemical insecticide standards for control of Japanese beetle grubs at the Purdue University Nursery Grounds, West Lafayette. IN. Treatment plots were 10 X 10 ft, arranged in a RCB design, replicated 5 times. Treatments were applied on 16 Aug. Granular formulations were applied with a homemade salt shaker. Dispersable formulations were mixed in 2-Liter plastic bottles and dispensed through a hole poked in the cap of the bottle. Plots were moist prior to application and received 1 cm of sprinkler irrigation immediately after treatment. Conditions at the time of treatment were: air temp., 21°C and wind speed 1—5 mph. Efficacy was evaluated on 28 Sep by extracting cores from five random locations within each plot using a golf-hole cup cutter (0.90 square ft.) Soil to a depth of 4 inches, thatch and turfgrass from each core was examined for the presence of live grubs. The average number of live grubs from the five subsamples within each plot was used as the dependent variable in the statistical analysis of the data. There were two untreated plots in each replicate.

Efficacy of Entomophagous Nematodes Against Japanese Beetle Grubs in Large Plot Trials, Nh, 1994

Abstract The large plot study was conducted at the Amherst Country Club, Amherst; NH. Plot size was 20 X 80 ft, replicated 4 times. Treatments were applied in 1 gal water/1000 ft2 with a Chem Pro sprayer using MC5 nozzles. Each plot was sprayed for a total volume of 2 gal/1000 ft2. The first treatments were applied in the evening on 19 Aug to predominantly 2nd instar larvae and watered in. The second half of the split application of Vector WG was applied on 9 Sep (21 days later). Plots were irrigated as necessary 2-3 times per week with 0.2 inch water to keep soil moist. Three 1 ft2 samples were removed from each plot and the number of live larvae counted. Conditions at the time of treatment on 19 Aug were: air temperature, 68.3°F; wind, &amp;lt;3 mph; sky, clear; soil temperature 2 inch, 69.3°F; thatch depth, 0.5 inch soil pH, 6.5; soil texture, loam, 38% sand, 45% silt, 17% clay; soil organic matter, 5.2%; soil moisture, 23.4%; post treatment precipitation, 0.3 inch soils were moist due to recent rain. Conditions at the time of treatment on 9 Sep were: air temperature, 72.3°F; wind, 0 mph; sky, clear; soil temperature 2 inch, 63.5°F; soil moisture, 25.6%; post treatment precipitation, 0.3 inch soils were moist due to recent rain. Plots were rated on 7 Oct (42 days after initial treatment).

Management of Japanese Beetle Grubs With Rh0345 and Conventional Formulations on a Golf Fairway in Centre County, Pennsylvania, 1994

Abstract The turfgrass area consisted primarily of annual bluegrass (20%), Kentucky bluegrass (40%), and perennial ryegrass (40%). Treatment plots were 9 X 6 ft, arranged in a RCB design, replicated 3 times. Liquid formulations were applied with a CO2 compressed air sprayer with 4 8004VS TeeJet nozzles mounted on a 6 ft boom, operating at 28 psi, and applied in 1021 ml of water/54 ft2 or delivering 5 gal/1,000 ft2. Granular formulations were applied with a hand-held shaker and mixed with a fine grade top-dressing sand to facilitate product distribution. At treatment time (25 Aug) the following soil and environmental conditions existed: air temperature, 81°F; soil temperature at 1 inch depth, 74°F; soil temperature at 2 inch, 72°F; RH, 76%; amount of thatch, 0.125-0.25 inches; soil textural class, loam; soil particle size analysis: 43.6% sand, 36.4% silt, 20.0% clay; organic matter, 7.6%; soil moisture (oven baked), 31.3; water pH, 6-7; soil pH, 6.6; and clear skies. Immediately after treatment the experimental area was irrigated with 0.2 inches of water. Three hours prior to treatment the area received 0.3 inches of natural rainfall. Posttreatment counts were completed on 28 Sep. Three ft2 sod samples were taken from each replicate, and the total number of viable Japanese beetle grubs/ft2 was recorded.