Publications by authors named "David W Held"

Background: Acanthacoccus lagerstroemiae (crape myrtle bark scale, CMBS) is an exotic scale insect that feeds on the sap of crape myrtle trees. Heavy infestations of CMBS reduce flowering and honeydew promotes sooty mold growth on the leaves and branches, reducing the aesthetic value of crape myrtle trees in urban landscapes. Lady beetles (Coleoptera: Coccinellidae) are generalist predators that feed on CMBS.

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Gene silencing by feeding double-stranded (dsRNA) holds promise as a novel pest management strategy. Nonetheless, degradation of dsRNA in the environment and within the insect gut, as well as inefficient systemic delivery are major limitations to applying this strategy. Branched amphiphilic peptide capsules (BAPCs) complexed with dsRNA have been used to successfully target genes outside and inside the gut epithelium upon ingestion.

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A two-year study was conducted in bermudagrass hay fields in central Alabama to estimate the potential of plant growth-promoting rhizobacteria (PGPR) as a tool for sustainable agriculture in forage management. This study compared the effects of two treatments of PGPR, applied with and without lowered rates of nitrogen, to a full rate of nitrogen fertilizer in a hay production system. The PGPR treatments included a single-strain treatment of (DH44), and a blend including two strains (AP7 and AP18) and a strain of (AP282).

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Background: Inoculation of bermudagrass with rhizobacterial biostimulants can increase plant growth and influence relationships with grass-feeding herbivores. Tunneling and root-feeding behaviors of tawny mole crickets cause severe damage to grass in pastures, golf courses, and lawns. The goal of this study was to determine if inoculation of bermudagrass by a rhizobacteria blend (plant growth-promoting rhizobacteria, PGPR) increases the tolerance of hybrid bermudagrass to tawny mole crickets in captivity and under field conditions.

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Background: Inoculation of hybrid bermudagrass with plant growth-promoting rhizobacteria (PGPR) can increase plant growth and influence relationships with above-ground herbivores like fall armyworms. However, few experiments have evaluated PGPR applications relative to root herbivory. Root-feeding white grubs cause severe damage to grasses, especially in tall fescue pastures, golf courses, and lawns.

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This project investigated associational interactions (associational resistance or susceptibility) between native and non-native trees commonly found in urban landscapes in the southeastern United States. Non-native plants offer limited ecological services because few native herbivore species are capable of feeding on them. In a 2-yr field study, abundance and species richness of caterpillars, plant damage, and herbivore natural enemies were evaluated in plots where a native red maple (Acer rubrum L.

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Popillia japonica is a generalist herbivore that feeds on >300 host plant species in at least 72 plant families. It is unknown why P. japonica, despite possessing active detoxification enzymes in its gut, is paralyzed when feeding on the petals of one of its preferred host plant, Pelargonium×hortorum, or on artificial diet containing quisqualic acid (QA), the active compound in zonal geranium.

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Nonpathogenic soil bacteria can colonize the rhizosphere and induce unique plant phenotypes that may influence plant-insect interactions. However, few studies have considered the influences of bacteria-plant interactions on insect feeding and oviposition. The objective of this study was to determine how rhizobacterial inoculation of bermudagrass affects larval development and ovipositional behaviors of the fall armyworm (Spodoptera frugiperda J.

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Induction of cytochrome P450, glutathione S transferase (GST), and carboxylesterase (CoE) activity was measured in guts of the scarab Popillia japonica Newman, after consumption of single or mixed plant diets of previously ranked preferred (rose, Virginia creeper, crape myrtle and sassafras) or non-preferred hosts (boxelder, riverbirch and red oak). The goal of this study was to quantify activities of P450, GST and CoE enzymes in the midgut of adult P. japonica using multiple substrates in response to host plant suitability (preferred host vs non-preferred hosts), and single and mixed diets.

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The black cutworm, Agrotis ipsilon Hufnagel, and fall armyworm, Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), are common turfgrass pests of golf courses in the southeastern United States. Heat-tolerant bentgrass (Agrostis stolonifera L.) cultivars are expanding the range of bentgrass further south, but these cultivars have not been studied for their potential host plant resistance to black cutworm or fall armyworm.

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Background: Larvae of the Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae), have a patchy distribution in soils, which complicates detection and management of this insect pest. Managed turf systems are frequently under pest pressure from fungal pathogens, necessitating frequent fungicide applications. It is possible that certain turfgrass fungicides may have lethal or sublethal adverse effects on eggs and larvae of P.

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Background: Cogongrass (Imperata cylindrica Beav.) is an aggressive, invasive weed with a global distribution. In North America, it threatens the integrity of southeastern pine agroecosystems, including longleaf pine (Pinus palustris Mill.

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The severity of damage to host plants by omnivorous pests can vary according to the availability of plant and animal prey. Two omnivorous mole crickets, Scapteriscus vicinus Scudder and S. borellii Giglio-Tos, were used to determine if the availability of prey influences damage to hybrid bermudagrass by adult mole crickets.

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Insecticides are widely used to manage turfgrass pest such as white grubs (Coleoptera: Scarabaeidae). Red imported fire ants, Solenopsis invicta (Buren) are important predators and pests in managed turfgrass. We tested the susceptibility of white grub life stages (adults, egg, and larvae) to predation by S.

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Turfgrass culture, a multibillion dollar industry in the United States, poses unique challenges for integrated pest management. Why insect control on lawns, golf courses, and sport fields remains insecticide-driven, and how entomological research and extension can best support nascent initiatives in environmental golf and sustainable lawn care are explored. High standards for aesthetics and playability, prevailing business models, risk management-driven control decisions, and difficulty in predicting pest outbreaks fuel present reliance on preventive insecticides.

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Background: Gynaikothrips uzeli Zimmerman was first detected in North America from galls on weeping fig (Ficus benjamina L.) in 2003. It has been reported from ten states in the continental United States, Hawaii, Trinidad and Costa Rica.

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The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified.

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An equine disease now known as mare reproductive loss syndrome (MRLS) struck the Ohio Valley in 2001-2002 causing thousands of foal abortions and enormous economic loss. Evidence that pregnant mares' exposure to Eastern tent caterpillars Malacosoma americanum (F) induces MRLS created an urgent call for control measures suitable for use on horse farms. We surveyed egg mass distribution and monitored emergence in wild cherry trees, and evaluated reduced-risk treatment strategies including foliage sprays, trunk injections, winter egg mass treatments and barrier sprays to intercept larvae entering pastures.

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The Japanese beetle, Popillia japonica Newman, feeds on the flowers and foliage of roses. Rosa x hybrida. Beetles attracted to roses land almost exclusively on the flowers.

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Many generalist herbivores, especially adult beetles, are facultative florivores, feeding on leaves but readily accepting floral tissues when available. We speculated that day-flying beetles with high energetic requirements would benefit from dietary mixing with nutrient-rich flower tissues and favor them during foraging. We tested that "Floral Affinity Hypothesis" with Popillia japonica, a day-active ruteline scarab that feeds intermittently throughout its adult life on multiple plant species.

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Insecticides used on turf are sometimes applied to areas with flowering weeds that attract honey bees and native pollinators. We tested residual effects of such treatments on colony vitality and behavior of the bumble bees Bombus impatiens Cresson foraging on turf containingwhite clover, Trifolium repens L. Imidacloprid, a syst emic chloronicotinyl used for preventive control of root-feeding grubs, was applied as granules, followed by irrigation, or sprayed as a wettable powder, with or without irrigation.

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The Japanese beetle, Popillia japonica Newman, an introduced scarab, has become the most widespread and destructive insect pest of turf, landscapes, and nursery crops in the eastern United States. It also damages many fruit, garden, and field crops. This review emphasizes recent research on the beetle's biology and management.

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