R. E. Foster

Effect of Insecticides on the Diamondback Moth (Lepidoptera: Plutellidae) and Its Parasitoid Diadegma insulare (Hymenoptera: Ichneumonidae)

Abstract Studies were conducted to evaluate the toxicity of insecticides to adult Diadegma insulare (Cresson) and its host the diamondback moth, Plutella xylostella (L.). Leaf-dip and direct-dip bioassays for diamondback moth larvae and residual bioassays for adults of diamondback moth and D. insulare were used to assess mortalities. Larval mortalities at field rates were significantly higher with carbaryl, permethrin, spinosad, and tebufenozide when compared with Bacillus thuringiensis, or imidacloprid in the larval-dip bioassay 72 h after treatment. In the leaf-dip and residual bioassays, both permethrin and spinosad caused 100% mortalities to diamondback moth larvae and adults, respectively, 72 h after treatment. Of all the materials tested, only B. thuringiensis and tebufenozide were not toxic to D. insulare 24 h after treatment. Spinosad was not toxic to D. insulare 30 min after treatment. However, 100% mortality was observed 8 h after treatment.

Resistance to Pyrethroid Insecticides in Helicoverpa zea (Lepidoptera: Noctuidae) in Indiana and Illinois

ABSTRACT n The corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), can cause serious losses in many field and vegetable crops throughout the United States. Since their introduction, pyrethroid insecticides have become the primary insecticide class for managing H. zea. However, resistance has been reported in the southern United States and has recently became a concern in the Midwest after the observation of sporadic control failures and a decreased efficacy of pyrethroids in small-plot field trials. Larvae collected from Lafayette, IN, Vincennes, IN, and Collinsville, IL, were used to establish laboratory colonies in 2006 and 2007. Larvae from these colonies were tested for resistance to the pyrethroid insecticide bifenthrin by using topical assays. Adult males collected from pheromone traps in Lafayette were tested for resistance to Cypermethrin by using the adult vial test (AVT) method. Resistance ratios of ≥8 were observed for the larval bifenthrin assays in 2006 and 2007 in all colonies except for the 2007 Illinois colony. AVT assays conducted with Cypermethrin showed ≈15% survival in both 2006 and 2007 at the 5 µg per vial discriminating dose. These results suggest that low to moderate levels of pyrethroid resistance are present in these populations.

Influence of Selected Insecticides on the Population Dynamics of Diamondback Moth (Lepidoptera: Plutellidae) and Its Parasitoid, Diadegma insulare (Hymenoptera: Ichneumonidae), in Cabbage

The effects of insecticides on the diamondback moth, Plutella xylostella (L)., and its parasitoid, Diadegma insulare (Cresson), were evaluated in the field. Insecticides applied for control of the ...

Effects of insecticides applied to control cucumber beetles (Coleoptera: Chrysomelidae) on watermelon yields

Abstract Foliar insecticides applied to control the striped and spotted cucumber beetles, Acalymma vittatum (Fab.) and Diabrotica undecimpunctata howardi Barber, on watermelon, Citrullus lanatus, were of little or no value in three studies conducted in two locations over 2 years. However, an at-planting application of the systemic, soil insecticide carbofuran resulted in higher early yields, although the differences were not statistically significant in small plots. In 1991, large plots comparing carbofuran-treated watermelons with untreated watermelons in two commercial fields showed large and statistically significant increases in melon yield when carbofuran was applied, especially in early yield. Studies in 1992 and 1993 showed that the application of carbofuran at planting stimulated root and shoot growth after transplating and increased yields when compared with untreated plots, plots treated with methyl bromide, or another soil insecticide, terbufos. These studies suggest that carbofuran may be acting as a growth stimulant, as well as an insecticide.

Distribution and Dynamics of Japanese Beetles Along the Indianapolis Airport Perimeter and the Influence of Land Use on Trap Catch

Abstract As part of a program to minimize the accidental transportation of Japanese beetles (Popillia japonica) through cargo aircraft to areas where they are not established, a 4-yr trapping project was initiated to study the relative distribution and dynamics of the beetles along a trap line around the Indianapolis International Airport. Land use influence on beetle abundance (trap catch) was assessed using a geographic information system. Trap catch was consistently high in some locations and low in others. In general, high trap catches occurred near agronomic land planted with corn or soybeans, which are both preferred hosts of adult beetles. Low trap catches generally occurred in areas lacking preferred host plants. The amount of agronomic land within 500 m of the traps was always positively correlated with trap catch. Average trap catches were highly correlated by location from year to year, indicating stability of the relative distribution of the beetles along the trap line. Because high trap catches consistently occurred in the same locations, it can be inferred that trapping can be an effective method to monitor Japanese beetle populations. Taking airport-owned agronomic land out of corn and soybean production near the cargo terminals may reduce beetle activity in these areas.

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.