C. A. Laub

Seasonality and Distribution Pattern of Brown Marmorated Stink Bug (Hemiptera: Pentatomidae) in Virginia Vineyards

ABSTRACT Brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a highly polyphagous invasive insect pest from eastern Asia that feeds on numerous fruit, vegetable, and field crops. Four commercial vineyards in Virginia were sampled in 2012 and 2013 to study the basic biology, seasonality, and distribution pattern of H. halys in vineyards. At each vineyard, two blocks were selected. Weekly 3-min timed count visual samplings were performed in border and interior sections from late May until mid-September. Overwintering adult bugs were first detected in vineyards in May; however, the timing of first detection differed among vineyards. Egg masses were found primarily in June and July, and were usually found on the lower surface of grape leaves, although they were occasionally on the upper leaf surface, on the berry, or on the rachis. All developmental stages of H. halys were found in vineyards, suggesting that grape can serve as a reproductive host for H. halys. Substantial variation in H. halys densities was found among vineyards and throughout the growing season. The first instars were found on egg masses and after molting, dispersed throughout the grape vines. The date on which the first egg mass was collected was considered as a biofix. Based on a degree—day model, there were sufficient degree—days for completion of a generation in Virginia vineyards. Significantly higher numbers of H. halys were collected in border sections compared with interior sections. These results are discussed in relation to the potential pest status of H. halys in vineyards and implications for possible control strategies.

Stink Bugs (Hemiptera: Pentatomidae) in Primocane-bearing Raspberries in Southwestern Virginia

Abstract Raspberries (Rubus species) are widely grown in Virginia, and stink bugs (Hemiptera: Pentatomidae) have become significant pests of this crop in recent years. To understand which species are attacking the crop, we sampled a well-established primocane-bearing raspberry planting near Blacksburg, VA in 2008 - 2009 and in 2011, 2012, and 2013. Altogether, 16 species of stink bugs were found on the raspberries. The brown stink bug, Euschistus servus (Say), was consistently a major species through 2012. The invasive species, Halyomorpha halys (Stål), was not found on the raspberries in 2008 or 2009, but was detected in 2011 and 2012, and became the most abundant stink bug species on these plantings in 2013. The Shannon-Weaver diversity index and Shannons equitability in 2012/2013 were higher than in 2008/2009. The increase in diversity and equitability revealed that H. halys may be displacing E. servus populations in Virginia raspberry plantings. Similar trends have occurred on other crops in the MidAtlantic USA where H. halys has become well established. Stink bugs were found on plants from midJuly to September, which corresponds to the presence of fruit. Both nymphal and adult stink bugs were feeding on the fruiting structures of raspberry. Most of the stink bugs found were adults, and no egg masses were collected from raspberry plants. Thus, there is no evidence that stink bugs commonly use raspberry as a reproductive host for nymphal development.

Risk of Western Corn Rootworm (Coleoptera: Chrysomelidae) Damage to Continuous Corn in Virginia

Information on the risk of western corn rootworm, Diabrotica virgifera virgifera LeConte, damage to continuously-grown corn previously was lacking in Virginia, as well as other mid-Atlantic states. A field study was conducted in 1993 and 1994 comparing root damage, whole-plant yields, and silage quality in insecticide-treated and untreated sections of 32 continuous corn fields in Virginia. Approximately 28% of the fields had serious root damage exceeding a rating of 3.5 (1–6 scale) in sections not treated with a soil insecticide. Also, 19% of the fields had an economic loss in whole-plant yield due to corn rootworm feeding damage. Silage quality, as evidenced by percent crude protein and acid detergent fiber, was not significantly affected by corn rootworm feeding. Because much of the continuous corn acreage in Virginia is treated preventively with soil insecticides for corn rootworms, the results of this study suggest that a large percentage of this insecticide use is unnecessary.

Ecology, Taxonomy, and Pest Management of Billbugs (Coleoptera: Curculionidae) in Orchardgrass of Virginia

Orchardgrass, Dactylis glomerata L. (Cyperales: Poaceae), is a cool season grass, cultivated throughout the United States as a high-value forage crop. Larval feeding by two weevil species (Coleoptera: Curculionidae), the bluegrass billbug, Sphenophorus parvulus Gyllenhal, and the hunting billbug, Sphenophorus venatus vestitus Chittenden, has caused widespread economic damage to orchardgrass stands in Virginia. The cryptic feeding habits of these species, combined with a lack of effective systemic insecticides, make billbug control extremely difficult in orchardgrass. Here, we present an overview of the biology of orchardgrass and its associated billbug pests, and review the control options for these pests.

Alfalfa Weevil (Coleoptera: Curculionidae) Phenology with its Host Crop and Parasitoids in Virginia

Alfalfa weevil, Hypera postica (Gyllenhal), phenology is influenced by winter climate. In 1997 we initiated a 2-yr study of alfalfa weevil phenology with respect to its host crop and parasitoids in three geographically distinct locations of Virginia: the central Piedmont, Shenandoah Valley, and southwestern region. Alfalfa weevil populations from nine fields were sampled regularly from November until first harvest in each season. Eggs laid in December and January resulted in alfalfa weevil larval infestations in March and April at all locations. Because of warmer winter temperatures, eggs developed faster in the Piedmont compared with the higher elevations, and resulted in larval populations attacking alfalfa earlier in the season, when the crop was at an earlier growth stage. The adult parasitoid, Microctonus aethiopoides Loan, was synchronized poorly with alfalfa weevil populations in Virginia. At all locations studied, adult emergence of first generation M. aethiopoides occurred in April and early May,...

Diurnal Abundance and Spatial Distribution of Armyworm, (Lepidoptera: Noctuidae) in No-till Corn

Armyworm, Pseudaletia unipuncta (Haworth), spatial and diurnal abundance in no-till corn was sampled at six-h intervals (at 0200,0800, 1400, and 2000) during three 24 h periods. During the early gr...