Thesis (M.S.)--Eastern Illinois University, 2009. / Includes bibliographical references.

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Thesis (M.S.)--Eastern Illinois University, 2009. / Includes bibliographical references (leaves 39-47).

Thesis (M.S.)--Eastern Illinois University, 2010. / Includes bibliographical references (leaves 24-29).

No description available.

No description available.

Leaves and fruit of nine apple (Malus x domestica Borkh.) genotypes were evaluated for insect injury in 1998 and 1999. Foliar and fruit injury from 12 insect species was inconsistently affected by genotype. Spraying trees with oil affected neither fruit insect injury nor fruit phytotoxicity. In choice feeding assays, incidence of Japanese beetle (JB) feeding and leaf area consumed was greater for 'Liberty' than for 'York.' Genotypes did not differ in no-choice feeding assays. Choice and no-choice feeding assays between apple and oak indicated that JB could distinguish host plants in an artificial environment. Trichome density appeared different among three genotypes. 'York', the non-preferred genotype, had highest specific leaf weight and concentration of phloridzin, a feeding repellent. 'Liberty' the preferred genotype, had the lowest specific leaf weight, and had the highest concentration of quercitrin, a feeding stimulant. Olfactory stimuli of JB was evaluated with a Y-tube olfactometer. Beetles preferred the side of the Y-tube containing leaf tissue of apple or Virginia creeper over the side with no leaf. Beetles did not choose one plant species over the other. Bias test of beetle orientation in the Y-tube olfactometer indicated that in the morning, but not the afternoon, beetles preferentially moved into the left side of the Y-tube. Humidity did not affect beetle orientation. In darkness JB preferred a leaf disc over a paper disc and beetles tended to remain on the leaf. / Ph. D.

The natural infestation level for 1985 of the Japanese beetle, Popillia japonica Newman, in the Shenandoah Valley of Virginia failed to reduce berry quality, yield or shoot growth in a commercial vineyard. Intensive postveraison foliage feeding by Japanese beetle resulted 1n fruit with lower soluble solids and higher total titratable acidity at harvest, but did not affect pH, sugar per berry, berry weight, yield, leaves per vine or shoot length. Intensive previraison feeding also resulted in fruit with higher total titratable acidity. All other parameters were unaffected. In a separate experiment with 0, 10, 20, and 33% leaf removal, no relationship was shown between leaf area loss and soluble solids, total titratable acidity or pH. Data from one season of damage by the beetle indicate that control measures may not be warranted in some years. In a third experiment, grape leaves on potted vines were artificially damaged by removing leaf disks with a paper punch. The leaves showed an increased loss of efficiency (measured in net photosynthesis, Pn) for the remaining tissue as leaf area loss (LAL) increased. This loss of efficiency in the remaining leaf area at low levels of damage was more pronounced after 12 days than after either 1 or 5 days. The additive effect on Pn of both LAL and lowered efficiency predicted the total shutdown of Pn at 60% damage at 1 and 5 days after treatment, but not at 12 days. / Master of Science

White grubs (Coleoptera: Scarabaeidae) are important turfgrass pests in Virginia. Insecticides such as the neonicotinoid imidacloprid are commonly applied to turfgrass in order to control these pests. As an alternative to synthetic insecticides, entomopathogenic fungi (EPF), including Metarhizium brunneum (Petch) and Beauveria bassiana (Balsamo) Vuillemin may also be used for white grub control. The interaction of combining these two control tactics for white grubs in Virginia merits further investigation as does their effects on other soil organisms such as earthworms, which cohabitate with white grubs in turfgrass soil ecosystems. Herein, I investigate the following: 1) the efficacy of combined applications of the EPF, M. brunneum and B. bassiana with lower rates of imidacloprid or the diamide insecticide, chlorantraniliprole against white grubs; 2) interactions of earthworms with white grubs and EPF; and 3) the effect of white grub control products on earthworms. In the laboratory, a combined application of one half the recommended rate of chlorantraniliprole plus the full recommended rate of B. bassiana caused significantly higher mortality of third instar Cyclocephala spp. grubs than the untreated control. In the field, imidacloprid applied at lower rates as a single treatment or as part of a combined treatment with EPF resulted in significantly fewer grubs when applications were made in June. In the greenhouse, Japanese beetle, Popillia japonica Newman females laid a significantly reduced number of eggs in turf treated with lower rate of imidacloprid either applied as a single treatment or as part of a combined treatment compared with untreated control. In an earthworm-white grub interaction study, the earthworms Eisenia fetida (Savingy) and E. hortenis (Michaelsen) were shown to transfer B. bassiana spores from fungus-infected soil to uninfected soil in the laboratory. However, the presence of earthworms in fungal infected soil did not enhance the mortality of Cyclocephala spp. grubs. In bioassays conducted in the laboratory, only two neonicotinoids, dinotefuran and imidacloprid, caused significantly higher mortality to adult Lumbricus terrestris L. earthworms than untreated control consistently. When applied as a drench to turfgrass in spring, summer, and fall, none of the insecticides significantly reduced the earthworm densities compared with a water control. / Ph. D. / White grubs cause serious damage to turfgrass in Virginia and as a part of turf management programs, insecticides such as the neonicotinoid imidacloprid are routinely applied to eliminate these pests. However, there are environmental concerns over the excessive use of neonicotinoids. In addition, these insecticides are typically only effective when they are applied in the summer to target small grubs. Herein, I investigated if combining reduced rates of imidacloprid or another insecticide, chlorantraniliprole, with commercially-available insect-killing fungi <i>Beauveria bassiana</i> or <i>Metarhizium brunneum</i>, could enhance white grub control. Neither the insecticides alone, nor the aforementioned fungal biopesticides provided effective control of larger white grubs in lab bioassays and field experiments. Additional research was aimed at understanding the interactions of insecticides and fungi on both white grubs and earthworms, which cohabitate frequently with white grubs in turfgrass soil ecosystems. In a greenhouse experiment, Japanese beetle females laid fewer eggs in turf treated with imidacloprid, but that chlorantraniliprole or the insect disease causing fungi did not affect beetle egg laying. In another experiment, earthworms were shown to transfer insect disease causing fungi in the soil in the laboratory. However, the presence of earthworms did not increase white grub fungal infection in fungi-infested soil in the lab. Additional experiments showed that two neonicotinoids, dinotefuran and imidacloprid, killed more earthworms than other insecticides when applied to soil in the lab. However, when applied as a drench to turfgrass in spring, summer, or fall, neither of these insecticides nor several others registered for use on turfgrass resulted in fewer earthworms compared with a water control. The complex interactions between turf-damaging white grubs, the insecticides used to control them, insect disease-causing fungi in the soil and non-target beneficial organisms such as earthworms warrant further investigation to help us move toward more sustainable pest management approaches in the future.