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Paul D. Curtis and Jason R. Boulanger

,000 and homeowners spent an average of almost $500 for plant replacement costs in 1988 alone ( Sayre and Decker, 1990 ). Several non-lethal alternatives exist for managing deer damage, including fences, repellents, and scare devices. Fences provide the

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Lusheng Zeng, Jiayang Liu, Robert N. Carrow, Paul L. Raymer, and Qingguo Huang

Soil water repellency (SWR) is a condition in which a soil does not spontaneously wet when a drop of water is applied to the surface, indicating that the soil is hydrophobic ( Müller and Deurer, 2011 ). In recent years there has been greater

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John C. Snyder, George Antonious, and Richard Thacker

Many accessions of Lycopersicon hirsutum are highly resistant to insects. Trichomes and their secretions have been extensively indicated as factors of resistance. One mechanism of resistance mediated by secretions is repellency, a mechanism that is consistent with the observation that few insects visit plants of L. hirsutum. Trichome secretions from certain accessions of L. hirsutum f. typicum are repellent to spider mites. However, the composition of secretions from different accessions of f. typicum are chemically diverse. Sesquiterpene hydrocarbons are prevalent in secretions, but are structurally diverse. How structure may relate to repellency is of interest but difficult to address because isolation of pure sesquiterpene hydrocarbons from hydrocarbon mixtures is difficult. To begin examining relationships between structure and activity we determined how chain length of n-alkanes related to repellency of spider mites. n-Alkanes having chain lengths from 8 to 22 carbon atoms were assayed for repellency. The C16-C18 alkanes were most repellent. Smaller and larger hydrocarbons were less repellent. The EC50 for n-hexadecane was equal to that of the most repellent natural products we have isolated from trichome secretions of L. hirsutum.

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Christine Harris, Eric Simonne, Lani Meritt, Peggy Codreanu, and John Owen

With an estimated white-tailed deer population of >25 million in the United States and 1.7 million in Alabama, deer feeding damage has become a serious problem for vegetable growers. Typically, deer feed on foliage during plant growth or dig roots near harvest time. Because there is currently no method available to control deer feeding damage to sweetpotatoes, studies were conducted with both confined and free-ranging white-tailed deer to determine the effectiveness of several commercial deer-repellent products on `Beauregard' sweetpotato. In 1998, testing was conducted at the Alabama Agricultural Piedmont Substation in Camp Hill, Ala., with free-ranging deer. Treatments included Deer Away (egg-based spray and powder), Tree Guard, Garlic Barrier, Thiram (a commercial fungicide), as well as a nontreated control. Damage was rated on a 0 to 4 scale (0 = no damage; 4 = 100% damage). In 1999, testing was continued with confined deer at the Auburn Univ. Deer Research Facility in Auburn, Ala. Havahart egg-based spray, Hinder, Grant's, XP-20 (Thiram), and Ro-Pel were applied to potted `Beauregard' plants. Nontreated plants were also included. Pots were placed in 2 one-acre pens, each containing six adult deer. Damage was rated on a 0 to 3 scale (0 = no damage; 3 = plant eaten to pot line or uprooted). Significant (P < 0.05) differences were found among products. The most effective products in 1998 were Deer Away powder, Garlic Barrier at 3× the manufacturer's recommended rate, and Deer Away spray. In 1999, Havahart egg spray provided the highest level of protection, followed by XP-20. Although no product provided complete protection to sweetpotato, egg- and Thiram-based products were most effective in 2 years of testing. None of these products are labeled for use on food crops at this time.

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John L. Cisar and Karen E. Williams

Soil-water repellency is often a problem for turfgrass grown on sand soils. Wetting agents used to alleviate repellency often provide mixed results. We evaluated AquagroL and an experimental material (ACA 864) at 0, 7, 14, and 21ml/m2 applied monthly to tifgreen bermuda grown on a soil-water repellent Margate fine sand over 6 months. Alleviation of repellency was based upon water drop penetration time (WDPT). Wetting agents did not effect turf quality, cover, or discoloration. Wetting agents did not reduce repellency 1 month after initial application. At 2 months, ACA 864 at 21ml/m2 significantly reduced WDPT. With repeat applications, lower rates of ACA 864 provided reductions in WDPT similar to the highest rate of ACA 864, suggesting an additive effect over time. There was a decline in WDPT for all wetting agent treatments, except the control, over time. Repellency decreased with soil depth, and repeat wetting agent application reduced WDPT at lesser depth.

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Larry D. Howery, Dale L. Nolte, Lawrence M. Sullivan, and Michael W. Kilby

The objective of our experiment was to determine if the application of two deer repellents to six grape cultivars (Vitis vinifera L.) caused significant phytotoxic effects, production losses, or altered the sensory characteristics of wine. We evaluated fifteen single vine plants from six different cultivars in a randomized block design that included the two repellent treatments and an untreated control. During spring 1997, we applied repellents biweekly from budbreak until flowering (2 Apr. to 14 May). Plantskyyd was applied more frequently than recommended by the product label (for trees) due to rapid emergence of unprotected shoot growth in vineyards. Hot Sauce and Plantskydd caused some initial minor phytotoxicity during 1997, however, the yield and phytotoxicity of treated plants were similar to controls by harvest. A panel detected a significant difference in the color, aroma, or taste of `Chardonnay' wine made from grapes treated with repellents compared to wine made from untreated control grapes (P = 0.001 for Hot Sauce; P = 0.05 for Plantskydd). We conclude that Hot Sauce and Plantskydd did not cause serious production losses or phytotoxic effects for the six cultivars treated. However, both Hot Sauce and Plantskydd significantly altered the sensory attributes of Chardonnay wine, which may preclude the use of chemical repellents in wine grape vineyards under the experimental conditions applied in our study.

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Hiram G. Larew and James C. Locke

The repellency and toxicity of a petroleum-based proprietary horticultural oil, Sunspray 6E Plus, was tested against the greenhouse whitefly, Trialeurodes vapor-ariorum (Westwood), on greenhouse-grown chrysanthemums [Dendranthema ×grandiflorum (Ramat.) Kitamura cv. Iceberg]. A 2% (v/v) aqueous spray repelled adult whiteflies for at least 11 days after spraying and it was toxic to newly hatched and third stage larval whiteflies. No phytotoxicity was observed when four weekly sprays of 1%, 2%, and 4% oil were applied.

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Keith J. Karnok and Kevin A. Tucker

Localized dry spot (LDS) caused by water repellent soil is a common problem on golf course putting greens having a predominately sand root zone. Fairy ring often causes LDS by developing hydrophobic soil. Although the fungicide flutolanil is labeled for the control of fairy ring, golf course superintendents often apply flutolanil to all LDS caused by hydrophobic soil and other conditions. The objective of this study was to determine the effect of flutolanil on an existing hydrophobic soil. The study was conducted on a creeping bentgrass [Agrostis palustris (synonym A. stolonifera)] experimental golf green in which the top 4 inches (10.2 cm) of the root zone was a moderately hydrophobic sand. Six treatments were used: uncored, cored, flutolanil (two applications.), flutolanil + Primer wetting agent (two applications.), Primer (two applications.) and Primer (three applications.). Plots receiving the fungicide and wetting agent treatments were cored before application. Each treatment containing the wetting agent significantly reduced soil water repellency. Flutolanil without wetting agent had no effect on soil hydrophobicity.

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Gary L. Wade, Jeff Jackson, and Kendra Henderson

Economic and aesthetic losses from deer browsing of ornamental plants in nurseries and landscapes has increased significantly during recent years. This, according to wildlife specialists, is primarily due to hunting restrictions in urban areas. There are numerous so-called “deer repellents” on the market, but most are foliar applied and can be washed off or diluted with rain or irrigation. This study evaluated the effect of a systemically absorbed deer repellent tablet, Repellex (trademarked product), on deer browsing of containerized ornamental plants. A foliar applied counterpart, Repellex liquid, was also evaluated. The 1.5-gm tablets are a 14–2–2 fertilizer containing denatonium benzoate, lactose, ammonium phosphate, hydrous magnesium, and potassium sulfide. Two to eight tablets, depending on the size of the container, are placed adjacent to the root ball of the plant and 2 inches below the media surface at time of transplant. Gumpo azalea, Indian hawthorne, daylily, and Manhattan Euonymus were used for the study. Plants treated with tablets were held 6 to 8 weeks, according to manufacturer recommendations, under nursery conditions, then transported to deer-holding pens at the Whitehall Forest Research Station at the Univ. of Georgia. The pens, 1/2- to 1 acre in size, contained seven to 12 deer, depending on the study. Growth measurements initially and at weekly intervals were used to assess the degree of deer browsing. Results varied by plant species. Generally, the tablets were ineffective in preventing deer browsing when compared to the control. The foliar applied liquid was effective in reducing deer for up to 6 weeks when compared to the control. Plants treated with a tablet at time of propagation and two additional tablets when transplanted were browsed to the container within 2 days of deer exposure.

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Karen E. Nix, Gregg Henderson, Betty C.R. Zhu, and Roger A. Laine

The growth rate of vetiver grass [Vetiveria zizanioides (L.) Nash (Graminales: Poaceae)], roots, and oil distribution were evaluated in an 8-month field study. The amount of vetiver oil present in the root system increased with each sampling date. In December, the final sampling period, mean root weight increased 520% from the previous sampling period (October). At the end of the study, root growth measured over 2 m long and 25 cm wide and weighed 0.48 kg (dry weight). In addition, a laboratory study was conducted to determine if the roots of vetiver grass when used as mulch, are effective against Formosan subterranean termites, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). In past studies, chemical components in the roots of this grass were shown to be effective repellents and toxicants to Formosan subterranean termites. In the present study, the 25% vetiver root mulch treatment proved to decrease tunneling activity and wood consumption and increase termite mortality. These results provide preliminary evidence that vetiver roots may have use as an additive to garden mulches against termites.