Rhodesgrass mealybug, Antonina graminis (Maskell) (Hemiptera: Pseudococcidae), has long been a pest of warm-season grass species used for turf and hay. This species is benefiting from a recent resurgence as a pest of golf course putting greens. No efficacy information is currently available to aid in selecting insecticides for the management of rhodesgrass mealybug. This three-year study evaluated the efficacy of seven active ingredients (acephate, alpha-cypermethrin, cyantraniliprole, dinotefuran, flupyradifurone, imidacloprid, and thiamethoxam) applied at several concentrations to golf course putting greens in Georgia and South Carolina, United States. The goal of this study was to identify the most effective insecticides for rhodesgrass mealybug management. Acephate, flupyradifurone, imidacloprid and thiamethoxam achieved greater and more consistent reduction in rhodesgrass mealybug abundance than other insecticides in multiple experiments. Based on our results, long-term suppression of mealybug populations could only be achieved through repeated applications of these insecticides targeting crawlers or an integrated pest management program that complement chemical control. There are needs to further improve management efficacy against rhodesgrass mealybugs by identifying additional effective insecticides of different modes of action to complement acephate, flupyradifurone, imidacloprid and thiamethoxam, and methods by which the efficacy of these insecticides could be further improved.

Pébrine is the most important disease of silkworm, Bombyx mori (L.) (Lepidoptera: Bombycidae), and is caused by Nosema bombycis (Nägeli) (Dissociodihaplophasida: Nosematidae). We investigated the effect of N. bombycis infection on the total hemocyte count (THC) and the differential hemocyte count (DHC) in hemolymph of a disease-resistant line (Line 104) and a susceptible line (Line 153) reared under optimum conditions. Fifth-instar silkworms were inoculated with a microsporidia spore suspension. Hemolymph was collected on the second, fourth and sixth days after inoculation, and THC and DHC of infected and uninfected silkworms were enumerated. Significantly higher THC was observed in the infected silkworms than the uninfected silkworms, but there was no significant difference in THC between lines. A significant difference in THC among days since inoculation in both lines was observed, with the average THC being higher on the second day since inoculation. DHC were significantly different among lines and days since inoculation. Granulocytes and plasmatocytes were the most numerous in Line 104, whereas granulocytes, plasmatocytes and prohemocytes were the most numerous in Line 153. Nosema infection decreased the percentage of all hemocytes, but increased the percentage of adipohemocytes and plasmatocytes. This study contributes to an improved understanding of the effects of microporidian infection that affects the sericulture industry.

The objective of this study was to evaluate different doses of butylated hydroxytoleuene (BHT) against the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleptera: Tenebrionidae). The effects on feeding behavior, growth, food consumption and total protein content of insects treated with different doses (1.48, 3.18, 6.36 and 9.54 mg g^–1) of BHT were evaluated. Antifeedant activity was observed only at 1.48 mg g^–1 in the choice assay, with a feeding deterrence index (FDI) of 0.41; this concentration also deterred feeding by 41.6%. All treatments showed feeding suppression index (FSI) and feeding inhibition index (FII) as <0, suggesting that the insects were dissuaded from eating and moved away even at the lowest doses. Repellency was observed at 1.48 mg g^–1. All insects were alive at the lowest dose, whereas mortality ranged from 40 to 86% between 3.10 and 9.50 mg g^–1. Food intake was reduced at the lowest dose. Adults exposed to a diet containing BHT showed significantly lower efficiency of conversion (ECI) than the untreated insects, indicating that more food was metabolized for energy and less was converted to body mass. The treated insects lost more than half of their initial weights. The protein content of insects exposed to 1.48 mg g^–1 of BHT was similar to that of untreated insects. This study contributes to understanding the feeding behavior of T. confusum and facilitates the management of this insect in stored products.

The twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the world's most damaging agricultural pests. Nanoparticles have become one of the most promising new tools for pest management in recent years, but their efficacies against T. urticae are poorly known. We conducted laboratory and greenhouse experiments to evaluate the efficacy of commercially available silicon oxide nanoparticle (SiO-NP) and zinc oxide nanoparticle (ZnO-NP), each applied at 5, 50 and 100 ppm, on the adult and egg stages of T. urticae on tomato, Solanum lycopersicum L. (Solanaceae). In the laboratory experiment, SiO-NP and ZnO-NP at 100 ppm caused 100% mortality among female adult mites at 72 h after treatment and among eggs at 7 d post-treatment. In the greenhouse experiment, SiO-NP and ZnO-NP at 50 and 100 ppm caused withered plants, whereas treatment at 5 ppm did not cause any phytotoxicity and decreased mite densities to 0.25 adult/leaf and 0.4 egg/leaf on SiO-NP-treated plants and 0 adult/leaf and 0.3 egg/leaf on ZnO-NP-treated at 7 d post-treatment. Mite densities at 7 d post-treatment were 1.8 adult/leaf and 1.7 egg/leaf on untreated plants. Average percentage of leaf area damaged was 25% on the untreated plants, and 0.7% and 0.9% on plants treated with SiO-NP and ZnO-NP at 5 ppm, respectively. These results suggest that application of SiO-NP and ZnO-NP at 5 ppm can be used as eco-friendly management strategy of T. urticae.