Homologous and heterologous nucleopolyhedroviruses (NPVs) were assayed to determine their effectiveness against beet armyworm larvae, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Included were three NPV isolates from S. exigua, one isolate each from S. littoralis Boisduval, S. litura (F.), and S. ornithogalli (Guenée), two isolates from other noctuids, Helicoverpa armigera (Hübner) and Rachiplusia ou (Guenée), and one isolate from Plutella xylostella (L.) (Lepidoptera: Plutellidae). Before bioassays, all of the NPVs were serially passed four times through S. exigua larvae to increase their concentrations. The narrow host-range homologous SeMNPVs from South Carolina (SeMNPV-SC), Maryland (SeMNPV-MD), and Florida (SeMNPV-FL  =  Spod-X®) were three of the most effective NPVs against the homologous host, S. exigua, based on median lethal concentration values (LC₅₀). Three heterologous isolates (HearNPV from H. armigera, SpliNPV from S. littoralis, and RoMNPV from R. ou) also had low LC₅₀ values. According to their LC₅₀ values, the least active NPVs were from P. xylostella (PlxyMNPV), S. ornithogalli (SoNPV), and S. litura (SpltNPV). Based on median time to kill (LT₅₀) at LC₉₀ concentrations, SeMNPV-SC and Spod-X® were the most effective isolates. The slowest acting NPVs were from S. litura, S. littoralis, and S. ornithogalli. The virulence of homologous and heterologous NPVs did not appear to be correlated with their genomic relatedness to SeMNPV or to the relatedness of the original NPV insect hosts to S. exigua.

Unexpected outbreaks of the aster leafhopper, Macrosteles quadrilineatus Forbes (Hemiptera: Cicadellidae), in wheat in the spring of 2012 across the Northern Plains of the U.S. prompted extensive applications of insecticides to suppress their populations. Aster leafhoppers are infrequent pests of wheat in the Northern Plains early in the spring, and data on insecticide efficacy for aster leafhoppers in wheat were unavailable at the time of the outbreak. Thus, our goal was to test several insecticides commonly used against key pests in wheat for their efficacy against aster leafhoppers. We examined the effects of chlorpyrifos and lambda- and gamma-cyhalothrin in greenhouse and field. These insecticides are not currently registered for suppression of aster leafhoppers in wheat, but they are used frequently to control potato leafhoppers in alfalfa. We found that all insecticides reduced numbers of aster leafhoppers four days after application (DAA) in the field, but not seven and 14 DAA, likely due to an influx of resident aster leafhoppers present in high numbers in the field surrounding the experimental plots. We also noted lack of effect of insecticides on total yield or the grain weight. We conclude that all insecticides effectively suppressed this pest immediately following applications, but the small-plot experiment obscured efficacy beyond the initial knockdown of the populations. These conclusions were supported by greenhouse experiments, which revealed that the insecticides killed 90% of the leafhoppers up to 14 days after application. This study will provide valuable efficacy data for new research-based chemical management recommendations for the aster leafhopper in wheat.

The greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae), is a major insect pest of tomato under field and greenhouse conditions, and its management is based primarily on foliar applications of insecticides. However, the continuous use of conventional insecticides leads to the development of insecticide resistance, which emphasizes the need for new pest management alternatives. The present study was conducted to investigate the efficacy of insecticides and bio-pesticides against the greenhouse whitefly on tomatoes grown in polyhouses (plastic-covered greenhouses) for two years at Palampur, Himachal Pradesh, India. Results showed that abamectin resulted in the highest mean percent reduction in immatures of T. vaporariorum, followed by acetamiprid and buprofezin. Spiromesifen and bifenthrin resulted in moderate levels of efficacy, followed by azadirachtin and mineral oil. Spinosad, Melia, and malathion (the insecticide-treated control) showed the least efficacy against immatures of T. vaporariorum. Similarly, abamectin and acetamiprid were the most highly effective materials against the adult stage. Bifenthrin, spinosad, azadirachtin, and buprofezin showed moderate reductions in adult whitefly populations. Spiromesifen, mineral oil, Melia, and malathion were the least effective against adult populations of T. vaporariorum. Overall, abamectin, acetamiprid, buprofezin, and bifenthrin were the most promising materials for managing T. vaporariorum in greenhouses. Azadirachtin and mineral oil also provided adequate control of greenhouse whitefly on greenhouse tomatoes.

Tetranychus urticae Koch (Acari: Tetranychidae) is one of the most important insect pests of tomatoes in greenhouses as well as open cultivation throughout the world. Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) is a polyphagous predatory bug, which is commonly found in tomato ecosystems. The present study was aimed at studying the predatory potential of N. tenuis against T. urticae. Results of this study indicate that all stages of the bug are highly predacious against T. urticae. Male nymphs consumed 11.8, 55.5, 66.3, 75.3, and 78.3 mites at the rate of 5.9, 18.5, 33.2, 37.6, and 39.1 mites per day for instars 1–5, respectively. The rate of consumption by female nymphs was 15.9, 61.8, 81.1, 88.8, and 90.1 mites at the rate of 7.9, 20.6, 40.6, 44.4, and 43.0 mites per day for instars 1–5, respectively. The overall consumption by female bugs (1137–1430 mites) was also higher than that of males (858–1092 mites). Augmentative releases of later instar nymphs of N. tenuis against T. urticae might therefore assure better mite control.

Corn rootworms, Diabrotica spp. (Coleoptera: Chrysomelidae), are the most economically important pest of maize in the United States. The larvae consume maize roots, contributing to poor nutrient uptake, lodging of the plants, and severe yield loss. Transgenic maize expressing toxins from the bacterium Bacillus thuringiensis (Bt) have been employed to combat the pest. However, corn rootworm resistance to Bt maize has recently been reported and spurred research on the effectiveness of Bt toxins against corn rootworm across the Corn Belt. Thus, our objectives were twofold. First, we quantified the efficacy of Bt maize hybrids against corn rootworm in South Dakota. Second, we surveyed populations of Diabrotica species in areas where Bt maize had been grown since its commercialization in 2003. Maize hybrids expressing Cry3Bb1, Cry34/35Ab1, and mCry3A were evaluated at two locations with previous corn rootworm infestations or in fields that were in continuous maize for three or more consecutive years. We reported damage to maize expressing Cry3Bb1 and mCry3A toxins. We also observed significantly higher numbers of western corn rootworm than northern corn rootworm in our Diabrotica species surveys, suggesting that western corn rootworm are the dominant species in the region. This research has implications for maize production and sustainable corn rootworm management in South Dakota and the Northern Plains, and will advance our knowledge of the incidence of resistance to Bt toxins and long-term impact of Bt hybrids on species diversity of Diabrotica.

Armored scale insects (Hemiptera: Diaspididae) are economically important pests of ornamental trees and shrubs in nurseries and landscapes. The cycad aulacaspis scale, Aulacaspis yasumatsui Takagi, and the tea scale, Fiorinia theae Green, are economically important armored scale pests of cycads, Cycas spp., and camellia, Camellia spp., respectively, in the southeastern United States. Our objective was to evaluate fungal, botanical, and chemical insecticides that were applied as foliar sprays or drenches when the motile crawler stages were active. In tests with A. yasumatsui over two years, products based on a mineral oil (SuffOil-X^®), azadirachtin (Molt-X^®), an entomopathogenic fungus (BotaniGard^®-ES), and an azadirachtin/fungus combination applied three times, significantly reduced the number of scales on cycads, Cycas revoluta Thunb., over 3–4 months, but were less effective overall compared with the insecticidal standard dinotefuran (Safari^®). In tests with F. theae, spinetoram sulfoxaflor (GF-2860), cyantraniliprole (Mainspring^®), pyriproxifen (Distance^®), buprofezin (Talus^®), horticultural oil (SuffOil-X), and dinotefuran (Safari) applied between one and three times, significantly reduced scale numbers (adults and large nymphs) on established foliage (older leaves) of Japanese camellia, Camellia japonica L., compared with controls within five months. The apparent slow activity (decline) in numbers of armored scales on old foliage was influenced by the difficulty of differentiating between live and dead insects that remained attached to leaf surfaces for some time after death. Monitoring infestations spreading to new foliage later in the season is a more reliable method to estimate the efficacy of insecticides against this group of pests.

Extracts from 37 fruits and vegetables were tested as ultraviolet (UV) protectants for the nucleopolyhedrovirus (SeMNPV) of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Only one extract (black currant) provided almost complete protection following UVB/UVA irradiation for 30 minutes under laboratory conditions. As a group, fruit and vegetable extracts were significantly less effective than published values for herb and spice extracts. Based on analyses of antioxidant capacity and total phenolic content of selected plants, it was determined that (1) herbs and spices contained much higher levels of antioxidants and phenolics than fruits and vegetables, (2) neither high levels of antioxidants nor high levels of phenolics alone could account for UV protection, and (3) selection of extracts with high levels of both antioxidants and total phenolics resulted in increased UV protection.