Soybean flour and wheat germ are the two most important protein components of wheat germ-based insect artificial diets. The effect of modifying the proportion of these two ingredients in a Noctuidae-specific diet was investigated utilizing the tobacco budworm Heliothis virescens (F.) (Lepidoptera: Noctuidae), with the goal of developing a suboptimal diet that, without drastically affecting this insect’s growth and reproductive rates, could manifest subtle negative effects in this insect. The original diet formula contained 2.51% protein. When the proportions of soybean flour and wheat germ were changed to 2.15% protein the net reproductive rate of the first generation was significantly lower. In the second generation, the net reproductive rate, development time, percent female survivorship, fertility, intrinsic rate of increase, finite rate of increase and female longevity were significantly lower in both the 2.15% and 2.26% protein diets. The survival rate of immatures to the adult stage was 1% in the 2.05% protein diet in the first generation. Interestingly, females exposed to these suboptimal diets produced a significantly higher number of eggs but the survival of their larvae was significantly reduced. It is evident from these results that modifications to the protein content and the nutrient composition profile of the original wheat germ-based insect artificial formula can be used to produce subtle negative effects on the growth of tobacco budworm.

Heliothis virescens F. is an important polyphagous pest that can develop on >100 plant species, including 20 economic crops. Populations of this i

The NI artificial diet is the only known successful diet for mass rearing the western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae). This diet has been used for more than a decade. However, because it contains cooked chicken egg, and thus requires laborious preparation (Cohen 2000), this diet is difficult to use. Three modifications (D1, D2, D3) of the NI diet were investigated in hopes of developing a more easily prepared diet that avoids the cooked egg and improves mass fitness parameters of L. hesperus. The modified D3 diet, containing autoclaved chicken egg yolk based component, had the highest egg/cage/day production (13120 ± 812 SE). This was significantly greater than diets D1, containing autoclaved dry chicken egg yolk based component (9027 ± 811 SE), D2, containing autoclaved chicken egg white based component (8311 ± 628 SE), and NI, which contained autoclaved chicken egg yolk + cooked egg diet (7890 ± 761 SE). Significant differences were observed in the weights of all developmental stages except for eggs and first instar nymphs. Higher rates of fertility, hatchability, and low mortality in nymphs during the first instar were also obtained in the modified D3 diet. The results clearly indicated that the D3 diet provided an opportunity to significantly reduce rearing cost by avoiding time-consuming issues with preparation of a cooked egg diet. This should result in an increase in production capacity and a reduction in production costs.

Bioassays were conducted to examine the pathogenicity of the fungus Beauveria bassiana (Balsamo) Vuillemin (Ascomycota: Hypocreales), strain NI8, against Lygus lineolaris (Palisot de Beauvois) and its impact on beneficial arthropods including Apis mellifera L., Crysoperla rufrilabris Burmeister, Orius insidiosus Say, Hippodamia convergens Guérin-Méneville, Harmonia axyridis (Pallas), Coleomegilla maculata De Geer, and field-collected Aranea spiders Salticidae and Thomisidae. Insects were treated with four concentrations of NI8 (3.9 × 104, 2.3 × 105, 4.2 × 106, and 1.5 × 107 spores/ml) directly via topical spray. Median lethal concentration (LC50), sporulation response, and resistance ratio were estimated for all species except for the two groups of spiders. No significant differences in mortality (10 d after application) were observed among L. lineolaris, A. mellifera, and C. rufilabris, and all three species were highly affected when exposed to the highest concentrations of B. bassiana with 99.0...

Redbanded stink bug, Piezodorus guildinii (Westwood), is a neotropical pest of soybean in the southern United States and the Neotropical Americas. Two strains of Beauveria bassiana (Bals.-Criv) Vuill. (Hypocreales: Cordycipitaceae) were evaluated for potential control of redbanded stink bug. Four concentrations (10⁴, 10⁵, 10⁶, and 10⁷ spores/mL) of both a Mississippi Delta native strain (NI8) and a commercially available formulation (GHA) were tested against field-collected redbanded stink bug adults in the laboratory and evaluated at four time points (3, 5, 10, and 15 days after application). Application methods simulated field sprays and were similar to those previously used to screen several other pests and beneficial insects. Both isolates of B. bassiana tested were pathogenic to redbanded stink bug adults. A significant overall difference between strains (regardless of the concentration) was observed at 3 days after treatment, while differences among concentrations were observed at 10, and 15 days after treatment. The lethal concentration (LC₅₀) and lethal sporulation (LS₅₀) were not significantly different between strains at either 10 or 15 days after treatment. However, higher mortality was observed in cohorts sprayed with GHA at lower concentrations than those sprayed with NI8. Unlike other control options, B. bassiana has a short re-entry interval and no harvest interval, making it a potentially attractive and environmentally benign alternative to conventional synthetic insecticides for control of redbanded stink bug in soybeans. Further testing on juvenile life stages and field testing is needed to evaluate the potential for in-field control.

Concentration-response assays were conducted from 2008 through 2015 to measure the susceptibility of field populations of Lygus lineolaris (Palisot de Beauvois) from the Delta regions of Arkansas, Louisiana, and Mississippi to acephate, imidacloprid, thiamethoxam, permethrin, and sulfoxaflor. A total of 229 field populations were examined for susceptibility to acephate, 145 for susceptibility to imidacloprid, and 208 for susceptibility to thiamethoxam. Permethrin assays were conducted in 2014 and 2015 to measure levels of pyrethroid resistance in 44 field populations, and sulfoxaflor assays were conducted against 24 field populations in 2015. Resistance to acephate and permethrin is as high or higher than that previously reported, although some populations, especially those exposed to permethrin, appear to be susceptible. Variable assay responses were measured for populations exposed to imidacloprid and thiamethoxam. Average response metrics suggest that populations are generally susceptible to the neonicotinoids, but a few populations from cotton fields experiencing control problems exhibited elevated LC₅₀s. Efforts to associate variability in LC₅₀s with recorded use of insecticides and estimated cotton insect losses and control costs suggest that intensive use of insecticides over several decades may have elevated general detoxifying enzymes in L. lineolaris and some field populations may be exhibiting resistance to multiple classes of insecticide. These results suggest that efforts should be made to manage these pests more efficiently with a reduced use of insecticides and alternative controls.