Browsing by Author "Chandran, Rakesh S."

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    2016 Spray Bulletin for Commercial Tree Fruit Growers
    Pfeiffer, Douglas G.; Bergh, J. Christopher; Frank, Daniel L.; Hooks, C. R. R.; Walsh, C. S.; Yoder, Keith S.; Rahan, Mahfaz; Kotcon, J. B.; Derr, Jeffrey F.; Chandran, Rakesh S.; Weaver, Michael W.; Brown, Amy; Parkhurst, James A. (2016-01-01)
    This is a multi-state guide, with orchard recommendations for Virginia, West Virginia and Maryland.
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    2017 Spray Bulletin for Commercial Tree Fruit Growers. Va. Coop. Ext. Serv. Publ. 456-419
    Pfeiffer, Douglas G.; Bergh, J. Christopher; Wilson, James M.; Frank, Daniel L.; Hooks, C. R. R.; Sherif, Sherif M.; Walsh, C. S.; Yoder, Keith S.; Rahman, M.; Kotcon, J. B.; Derr, Jeffrey F.; Chandran, Rakesh S.; Weaver, Michael J.; Brown, Amy; Parkhurst, James A. (2016)
    Integrated pest management (IPM) is the approach emphasized in this guide; some aspects of IPM are incorporated throughout, although this guide mainly deals with the chemical component of IPM. IPM combines biological control from predators with selective chemical application for maintaining pest populations below economic threshold levels. This approach requires that growers give careful consideration to the selection, application rate and timing of chemical sprays. The degree of integration achieved will vary according to the management ability, training and objectives of the orchardist. Inadequate monitoring or implementation of IPM practices will lead to unsatisfactory results. In order to encourage the biological control components of the program, growers must consider the toxicity of chemicals to predators (Table 9, page 59) in addition to their efficacy against fruit pests (Tables 7 and 8, pages 56-58).
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    2020 Spray Bulletin for Commercial Tree Fruit Growers: Virginia, West Virginia, and University of Maryland
    Pfeiffer, Douglas G.; Bergh, J. Christopher; Wilson, James; Hooks, C. R. R.; Sherif, Sherif M.; Walsh, C. S.; Yoder, Keith S.; Rahman, Mahfaz; Kotcon, J. B.; Derr, Jeffrey F.; Chandran, Rakesh S.; Frank, Daniel L.; Wycoff, Stephanie B.; Brown, Amy; Parkhurst, James A. (2020)
    Integrated pest management (IPM) is the approach emphasized in this guide; some aspects of IPM are incorporated throughout, although this guide mainly deals with the chemical component of IPM. IPM combines biological control from predators with selective chemical application for maintaining pest populations below economic threshold levels. This approach requires that growers give careful consideration to the selection, application rate and timing of chemical sprays. The degree of integration achieved will vary according to the management ability, training and objectives of the orchardist. Inadequate monitoring or implementation of IPM practices will lead to unsatisfactory results. In order to encourage the biological control components of the program, growers must consider the toxicity of chemicals to predators (Table 9, page 59) in addition to their efficacy against fruit pests (Tables 7 and 8, pages 56-58)...
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    Comparison of Mating Disruption and Insecticide Application for Control of Peachtree Borer and Lesser Peachtree Borer (Lepidoptera: Sesiidae) in Peach
    Frank, Daniel L.; Starcher, Stephen; Chandran, Rakesh S. (MDPI, 2020-09-25)
    The peachtree borer, Synanthedon exitiosa, and lesser peachtree borer, S. pictipes, are economically important indirect pests of peach in West Virginia. The purpose of this 3-year study was to compare the efficacy of mating disruption and post-harvest trunk sprays of chlorpyrifos insecticide for control of this pest complex in a commercial peach orchard. Overall, Isomate PTB-Dual disruption dispensers applied at a rate of 371/ha significantly disrupted the male mate-finding behavior of S. exitiosa and S. pictipes. In addition, the infestation of peach trees by S. exitiosa larvae did not vary significantly between mating disruption and insecticide treated plots. Hot-spot maps of S. exitiosa infestation showed significant spatial clusters of infestation predominately near the perimeter of all orchard plots, or where trees were missing within and/or between rows. The generation of standard deviational ellipses revelated that the location of S. exitiosa infestations in orchard plots remained relatively constant between years, and were generally oriented in a north and easterly direction, which coincided with the prevailing wind direction. Although our data indicated that mating disruption can provide growers with an effective non-chemical alternative to chlorpyrifos trunk sprays, several variables may affect its long-term success in West Virginia peach orchards; most notably the presence of high population densities, problems with maintaining adequate pheromone coverage, and the need for area-wide implementation.
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    Control of Common Pasture and Hayfield Weeds in Virginia and West Virginia
    King, Steve Russell; Chandran, Rakesh S.; Hagood, Edward S.; Bradley, Kevin Wayne; Love, Kenner; Heidel, Richard D. (Virginia Cooperative Extension, 2009-05-01)
    This publication will discuss control measures for many of the common weeds found in Virginia and West Virginia permanent fescue and mixed fescue, bluegrass, orchardgrass pastures and hayfields. In mixed grass, legume pastures and hayfields, selective removal of many problematic weed species is often not possible as most legumes will be killed after applications of broadleaf herbicides.
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    Influence of Isoxaben Application Timing on Dissipation and Broadleaf Weed Control in Turf
    Chandran, Rakesh S. (Virginia Tech, 1997-04-30)
    Isoxaben is a preemergence (PRE) broadleaf herbicide used in turf and ornamentals. Field, greenhouse, and laboratory research evaluated this herbicide for PRE control of selected broadleaves in turf, suspected postemergence (POST) herbicidal effects, and the influence of application timings and rates on soil residual. During seed germination in moist filter paper, isoxaben concentrations required for 50% inhibition of radicle growth (GR50) were 0.013, 0.010, 0.008, 0.008, and 0.007 ppm for dandelion, buckhorn plantain, white clover, black medic, and common lespedeza, respectively. In greenhouse experiments, isoxaben applied POST at 2.24 kg ai/ha suppressed the growth of Florida betony, black medic and white clover by 45, 65, and 66%, respectively, and reduced regrowth of Florida betony by 71%. In soil bioassays, yellow rocket control from isoxaben applied in fall was approximately 20 and 30% greater than spring-applied isoxaben at 3 and 6 MAT, respectively. Buckhorn plantain control from fall treatments at 3 MAT was approximately 15% higher than spring-applied isoxaben at 3 MAT. Application timings did not influence control of spotted spurge, a less sensitive weed. Isoxaben applied to turf in spring at 1.12 kg/ha provided > 90% control of buckhorn plantain, dandelion, and corn speedwell at 4 MAT. Fall applied isoxaben at the same rate provided total control of common chickweed, corn speedwell and henbit at 3 MAT and 80 to 90% control of white sweet clover and buckhorn plantain that germinated the following spring. Double (spring followed by fall) application of isoxaben to turf appeared to enhance broadleaf weed control in some instances. Dissipation of isoxaben in the top 3.8 cm of a Ross silt-loam soil as affected by spring, fall, and spring followed by fall applications was determined using high performance liquid chromatography (HPLC) analysis. Isoxaben residues in soil decreased by 55 and 92% by 3 and 6 MAT, respectively, for spring teatments, and decreased 29 and 52% by 3 and 6 MAT for fall treatments, respectively. A soil-bioassay study correlated well with chemical analysis of isoxaben residues, as the correlation coefficients were 0.85 and 0.89 for yellow rocket and buckhorn plantain, respectively.