No abstract

Stink bugs are economically important pests of food and fiber production throughout the southeastern United States. In cotton, stink bugs feed on developing bolls thereby decreasing yield and fiber quality. The brown stink bug, Euschistus servus (Say) (Hemiptera: Pentatomidae), is a common species that is found throughout the southeast and feeds on a variety of wild and agronomic hosts. In this study, the population dynamics and reproductive biology of E. servus were assessed in 1.62–2.83-ha farmscapes planted with corn (Zea mays L.), cotton (Gossypium hirsutum L.), peanut (Arachis hypogaea L.), and soybean [Glycine max (L.) Merr.]. Farmscapes were sampled weekly using whole plant sampling for corn and sweep net sampling in cotton, peanut, and soybean. In 2010, but not 2009, nymphs were classified by instar, and adults were dissected to rate gonads as nonrepro-ductive, intermediate, or reproductive. Regardless of year, stink bugs observed in corn during the spring and early summer and were a mixture of all three reproductive stages. The number of E. servus nymphs and adults was low in all crops during the summer (July, August, and early September). In late September, the number of fifth instars rose sharply followed by an increase in the number of nonreproductive adults, which implies that these adults resulted from reproduction as opposed to immigration. Incidence of late instars and nonreproductive adults was extremely low for corn, cotton, and peanut, and these host plants did not seem to be highly suitable reproductive hosts. Results from this study are useful for pest management programs that focus on reducing stink bug populations on a landscape scale.

No abstract

No abstract

Long considered a failure, second-order symmetry-adapted perturbation theory (SAPT) based on Kohn-Sham orbitals, or SAPT(KS), can been resurrected for semiquantitative purposes using long-range corrected (LRC) density functionals whose asymptotic behavior is adjusted separately for each monomer. As in other contexts, correct asymptotic behavior can be enforced via "optimal tuning" of LRC functionals, based on the ionization energy theorem, but the tuning procedure is tedious, expensive for large systems, and comes with a troubling dependence on system size. Here, we show that essentially identical results are obtained using an automated tuning procedure based on the size of the exchange hole, making tuned "SAPT(wKS)" fast and convenient. In conjunction with SAPT-based methods that sidestep second-order dispersion, this procedure achieves benchmark-quality interaction energies, along with the usual SAPT energy decomposition, without the hassle of system-specific tuning.