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H. R. Sumner - One of the best experts on this subject based on the ideXlab platform.

  • application of agrichemicals by Chemigation pivot attached sprayer systems and conventional sprayers
    Applied Engineering in Agriculture, 2000
    Co-Authors: H. R. Sumner, C C Dowler, P M Garvey
    Abstract:

    The application method and the volume of water associated with the application method influences the effectiveness of agrichemicals. We evaluated the effectiveness of Chemigation, pivot-attached sprayer systems(PASS), and tractor-mounted sprayers for the applications of preemergence and postemergence herbicide and fungicide in peanut and for defoliant applications in cotton. Chemigation and PASS were effective methods for applying agrichemicals when high volumes of water are needed to provide penetration into the crop canopy or to activate preemergence herbicides. PASS applications demonstrated a potential for the commercial application of some materials that are not compatible with Chemigation systems, such as defoliants, postemergence herbicides, fungicides, and insecticides. Therefore, producers who install PASS may be able to increase the efficiency and versatility of their irrigation systems for applying selected agrichemicals.

  • a tractor mounted irrigation system simulator for Chemigation research
    Applied Engineering in Agriculture, 1997
    Co-Authors: H. R. Sumner
    Abstract:

    An improved system for the application of chemicals in irrigation water to small research plots was designed, constructed and evaluated. The system was tractor-mounted with a three-point hitch for easy removal from the tractor. It had application booms on both sides of the tractor with full jet nozzles spaced 51 cm (20 in.) apart for Chemigation and microsprinklers spaced 1.8 m (6 ft) apart for a pivot-attached sprayer system (PASS). The operator’s platform, located behind the tractor and in front of the spray booms, carried the injection system, injection pumps and chemical tanks. Water was supplied to the system from a 38-mm (1.5-in.) diameter drag hose or from a nurse tank towed behind the tractor. The injection pumps were powered by an auxiliary generator attached to the tractor. Research plots treated by the system were 5.5 m (18 ft) wide by the desired length. The system had the capacity to apply 2.5 to 6.3 mm (0.1-0.5 in.) of irrigation water or 1900 to 2800 L/ha (200-300 g/a) of chemical mixture for the PASS. The water application depth was controlled by varying the velocity of the tractor and/or the pressure of the irrigation or PASS nozzles. The system was calibrated for water application depth and coefficient of uniformity (CU) and subsequently evaluated for the application of insecticides on whorl-stage corn (Zea mays) during 1995. Chemigation water depth and CU increased linearly with system pressure but was not significantly influenced by nozzle height above catch cups.

  • Effect of Application Techniques on Performance of Propiconazole for Peanut Disease Control
    Peanut Science, 1994
    Co-Authors: T. B. Brenneman, H. R. Sumner, L. R. Chandler, J. M. Hammond, A. K. Culbreath
    Abstract:

    Abstract Propiconazole (Tilt®) was applied to Florunner peanut by injection into irrigation water (Chemigation) or as a foliar spray. At rates of 0.12-0.25 kg/ha of propiconazole control of both Rhizoctonia limb rot (Rhizoctonia solani AG-4) and stem rot (Sclerotium rolfsii) was inconsistent. Chemigation resulted in the lowest incidence of stem rot, but the incidence of stem rot was only 26% less than the control. Yields from plots receiving Chemigation were greater than expected based on disease ratings, indicating that some effects of the fungicide were not being evaluated. Where foliar sprays of chlorothalonil were applied for late leaf spot (Cercosporidium personatum), supplemental applications of propiconazole via Chemigation improved leaf spot control. However, substituting chemigated propiconazole for foliar sprays of chlorothalonil consistently resulted in more severe leaf spot and, in one year, decreased yields. Propiconazole is most effective against leaf spot when applied as a foliar spray, whe...

  • reduction of wireworm coleoptera elateridae damage in sweet potato with insecticides applied by Chemigation
    Journal of Economic Entomology, 1993
    Co-Authors: Richard B. Chalfant, H. R. Sumner, K Bondari, M R Hall
    Abstract:

    Chemigation of insecticides was compared with soil incorporation of granular insecticides to reduce feeding damage of wireworm, Conoderus spp., to sweet potatoes. In 1988, emulsifiable (EC) and oil (EC plus nonemulsifiable oil) formulations of chlorpyrifos chemigated at two water volumes were compared with soil-incorporated chlorpyrifos granules at planting. In 1989 and 1990 EC and oil formulations of chlorpyrifos, chemigated at planting, were followed at root enlargement by chemigated EC and oil formulations of chlorpyrifos, diazinon, ethoprop, or fonofos. These treatments were compared with soil-incorporated chlorpyrifos granules applied at planting followed at root enlargement by soil-incorporated ethoprop or diazinon granules. During all years, there were no significant differences among formulations in total wireworm feeding damage and all treatments resulted in significant reduction of feeding damage compared with the nontreated check. In 1988, chlorpyrifos chemigated in 63.5 kliter/ha of water resulted in significantly less wireworm damage than when applied in 25.4 kliter/ha of water and was as effective as the soil-incorporated granules. In 1989, plots chemigated both at planting and at root enlargement had Significantly less wireworm damage than plots chemigated only at planting. In 1990, when the wireworm population was high, granular chlorpyrifos applied only at planting was more effective than EC of oil formulations of chlorpyrifos chemigated only at planting but was not significantly different from either formulation of chlorpyrifos chemigated at planting followed by EC or oil formulations of ethoprop or diazinon chemigated at root enlargement. Chemigation of insecticides to the soil to control wireworm damage of sweet potato can be an effective, cost-saving alternative to mechanical incorporation of insecticide. Savings include reduction of application costs and less damage to the crop caused by mechanical incorporation of insecticide.

  • effective use of Chemigation technology for managing soybean insect pests with notes on geocoris punctipes say
    Journal of agricultural entomology, 1993
    Co-Authors: L. D. Chandler, H. R. Sumner
    Abstract:

    Field studies were conducted to evaluate the potential of Chemigation as a management tool for soybean insects. Applications of chlorpyrifos (Lorsban 4E). cypermethrin (Ammo 2.5), esfenvalerate (Asana .66 XL), and thiodicarb (Larvin 3.2) significantly reduced populations of velvetbean caterpillar, Anticarsia gemmatalis Hiibner, 48 h after treatment in all tests. All chemigated insecticides performed at least as well as chlorpyrifos applied with a high clearance sprayer. Esfenvalerate consistently reduced larval populations by >97%. Thiodicarb and esfenvalerate were the only chemigated insecticides that provided >90% velvetbean caterpillar reduction 7 d after treatment in all tests. Management of the threecornered alfalfa hopper, Spissistilus {eslinus (Say), using Chemigation was sporadic in each test, with no one insecticide treatment providing consistent population reduction. Plots chemigated with methomyl (Lannate 1.8L) and thiodicarb to manage velvetbean caterpillar populations appeared to offer favorable habitat for the lygaeid predator Geocoris punctipes (Say). Thiodicarb offers growers an effective management tool for the velvetbean caterpillar while not adversely impacting G. punctipes populations. Chemigation, the application of agricultural chemicals in irrigation water, has proven to be effective for controlling various insect pests in many crops (Chalfant and Young 1984, Young 1986). Recent studies conducted in Georgia have shown the advantages of Chemigation over conventional application systems for control of insect pests in cotton, Gossypium hirsut/1.nt L., and corn, Zea mays L. (Chandler and Sumner 1991, Chandler et al. 1991, 1992). In addition ro the improvement in insect control using reduced rates of insecticides, Chemigation offers several unique advantages for application of pesticides and crop management. Chemigation provides improved uniformity of agrichemical application, timely application of pesticides during

T. B. Brenneman - One of the best experts on this subject based on the ideXlab platform.

  • Effect of Application Techniques on Performance of Propiconazole for Peanut Disease Control
    Peanut Science, 1994
    Co-Authors: T. B. Brenneman, H. R. Sumner, L. R. Chandler, J. M. Hammond, A. K. Culbreath
    Abstract:

    Abstract Propiconazole (Tilt®) was applied to Florunner peanut by injection into irrigation water (Chemigation) or as a foliar spray. At rates of 0.12-0.25 kg/ha of propiconazole control of both Rhizoctonia limb rot (Rhizoctonia solani AG-4) and stem rot (Sclerotium rolfsii) was inconsistent. Chemigation resulted in the lowest incidence of stem rot, but the incidence of stem rot was only 26% less than the control. Yields from plots receiving Chemigation were greater than expected based on disease ratings, indicating that some effects of the fungicide were not being evaluated. Where foliar sprays of chlorothalonil were applied for late leaf spot (Cercosporidium personatum), supplemental applications of propiconazole via Chemigation improved leaf spot control. However, substituting chemigated propiconazole for foliar sprays of chlorothalonil consistently resulted in more severe leaf spot and, in one year, decreased yields. Propiconazole is most effective against leaf spot when applied as a foliar spray, whe...

  • Chemigation and ground spray applications of cyproconazole for control of late leaf spot of peanut
    Plant Disease, 1993
    Co-Authors: A. K. Culbreath, T. B. Brenneman, L. D. Chandler, H. R. Sumner
    Abstract:

    In field experiments conducted during 1990 and 1991, Chemigation applications of biosynthesis inhibiting fungicide cyproconazole (0.112 kg a.i./ha) were equal to or bether than ground-spray applications of cyproconazole or chlorothalonil (1.26 kg a.i./ha) late leaf spot, caused by Cercosporidium personatum, on peanut (Arachis hypogae) cultivars Florunner and Southern Runner. Late-season leaf spot epidemics and resulting defoliation were severe in nontreated plots in both years. All fungicide treatments provided similar levels of control in 1990 (.)

  • Combining center pivot irrigation applications of chlorothalonil with a moderately resistant cultivar for control of late leaf spit in peanut
    Plant Disease, 1992
    Co-Authors: A. K. Culbreath, T. B. Brenneman
    Abstract:

    The efficacy of center pivot irrigation applications (Chemigation) of chlorothalonil at recommended rates (1.25 kg a.i/ha) was less than with conventional, ground spray applications for control of late leaf spot (Cercosporidium personatum) in Florunner (susceptible) and Southern Runner (moderately resistant) peanut (Arachis hypogaea) cultivars in 1989 and 1990. Final leaf spot ratings in chemigated plots of Florunner were lower (P≤0.05) than those in untreated plots in both years and in 1989 were higher (P≤0.05) than ratings of unsprayed plots of Southern Runner (...)

  • populations of fungi in soil after Chemigation with chlorothalonil and tebuconazole via center pivot irrigation
    Plant Disease, 1991
    Co-Authors: D R Summer, T. B. Brenneman, G W Harrison
    Abstract:

    Chlorothalonil and tebuconazole were applied to peanut (Arachis hypogaea) through a centerpivot irrigation system (Chemigation), a pivot-mounted underslung boom, or ground sprays. Populations of Rhizoctonia solani AG-4, R. zeae, and Sclerotium rolfsii in soil at midseason and at digging were variable and were not influenced significantly by chemical treatment or application method. Chemigation with tebuconazole, but not with chlorothalonil, reduced populations of total fungi in soil at digging, and in one test all applications of tebuconazole reduced populations of binucleate Rhizoctonia CAG-3

  • Effects of tractor traffic and chlorothalonil applied via ground sprays or center pivot irrigation systems on peanut diseases and pod yields
    Plant Disease, 1990
    Co-Authors: T. B. Brenneman, D. R. Sumner
    Abstract:

    Chlorothalonil (as Bravo 720) was applied at 1255 g/ha 7 times to groundnut cv. Florunner in 0.12, 17.8 or 1.7 kl of water/ha via ground sprays, centre pivot irrigation (Chemigation) or pivot-mounted underslung boom, respectively. Some of the chemigated plots were subjected to tractor traffic. Rhizoctonia limb rot (caused by R. solani anastomosis group 4) was generally not controlled by chlorothalonil and tended to be more severe with tractor traffic. Plants in untreated plots had final defoliation of 96 and 68% because of late leaf spot (caused by Cercosporidium personatum [Mycosphaerella berkeleyi]) in 1987 and 1988, respectively. Ground sprays gave the best leaf spot control in both years, followed by the underslung boom and Chemigation applications. In 1987, yields were significantly lower in plots that received the underslung boom or Chemigation treatments than in ground-sprayed plots. With less disease in 1988, pod yields were equal in chemigated and ground-sprayed plots and were significantly higher in plots treated by means of the underslung boom.

Neil C Gudmestad - One of the best experts on this subject based on the ideXlab platform.

  • Influence of tillage and method of metam sodium application on distribution and survival ofVerticillium dahliae in the soil and the development of verticillium wilt of potato
    American Journal of Potato Research, 2005
    Co-Authors: Raymond J Taylor, Julie S Pasche, Neil C Gudmestad
    Abstract:

    The effect of plowing and deep-rip tillage, in combination with Chemigation or shank injection of metam sodium, on Verticillium dahliae populations and disease development was assessed in two fields with differing soil types and potato rotations. Soil samples were collected on a geo-referenced basis at depths of 0 to 10 cm and 10 to 20 cm before tillage, after tillage, after chemical application, and before planting and assayed for the presence of the pathogen. Propagules of V. dahliae were detected at 140 of 141 sites sampled prior to tillage. Most (74.4% in heavy, sandy loam; 63.1% in light, loamy sand) were concentrated in upper 10 cm of the soil profile. Plowing redistributed inoculum vertically while deep-rip tillage did not. In the non-chemical treated areas of both fields, the Verticillium population reached a maximum between 25 July and 8 August before declining to near pre-tillage levels. Overall, the population generally was lower in the field with heavy soil, higher organic matter content, and a 3-year crop rotation. Metam sodium appeared to be most effective when shank injected, as the levels of inoculum in both fields declined by 60% to 80% following this application method. Chemigation was ineffective in the lighter soil, but the inoculum density in the deep-rip tillage area of the field with the heavier soil declined by nearly 20% in the upper and 60% in the lower strata following this treatment. The number of V. dahliae propagules at the 10- to 20-cm depth in the plowed area of the same field was reduced by 25% following Chemigation, but remained unchanged in the upper strata. Wilt was reduced in both fields by as much as 50% with shank injection of metam sodium with concomitant increases in total yield, marketable yield and gross income. Increases in total yield were significant ( P

  • Influence of Tillage and Method of Metam Sodium Application on Distribution and Survival of Verticillium dahliae in the Soil and the Development of Verticillium Wilt of Potato
    American Journal of Potato Research, 2005
    Co-Authors: Raymond J Taylor, Julie S Pasche, Neil C Gudmestad
    Abstract:

    The effect of plowing and deep-rip tillage, in combination with Chemigation or shank injection of metam sodium, onVerticillium dahliae populations and disease development was assessed in two fields with differing soil types and potato rotations. Soil samples were collected on a geo-referenced basis at depths of 0 to 10 cm and 10 to 20 cm before tillage, after tillage, after chemical application, and before planting and assayed for the presence of the pathogen. Propagules ofV. dahliae were detected at 140 of 141 sites sampled prior to tillage. Most (74.4% in heavy, sandy loam; 63.1% in light, loamy sand) were concentrated in upper 10 cm of the soil profile. Plowing redistributed inoculum vertically while deep-rip tillage did not. In the non-chemical treated areas of both fields, theVerticillium population reached a maximum between 25 July and 8 August before declining to near pre-tillage levels. Overall, the population generally was lower in the field with heavy soil, higher organic matter content, and a 3-year crop rotation. Metam sodium appeared to be most effective when shank injected, as the levels of inoculum in both fields declined by 60% to 80% following this application method. Chemigation was ineffective in the lighter soil, but the inoculum density in the deep-rip tillage area of the field with the heavier soil declined by nearly 20% in the upper and 60% in the lower strata following this treatment. The number ofV. dahliae propagules at the 10- to 20-cm depth in the plowed area of the same field was reduced by 25% following Chemigation, but remained unchanged in the upper strata. Wilt was reduced in both fields by as much as 50% with shank injection of metam sodium with concomitant increases in total yield, marketable yield and gross income. Increases in total yield were significant (P

  • influence of tillage and method of metam sodium application on distribution and survival of verticillium dahliae in the soil and the development of verticillium wilt of potato
    American Journal of Potato Research, 2005
    Co-Authors: Raymond J Taylor, Julie S Pasche, Neil C Gudmestad
    Abstract:

    The effect of plowing and deep-rip tillage, in combination with Chemigation or shank injection of metam sodium, onVerticillium dahliae populations and disease development was assessed in two fields with differing soil types and potato rotations. Soil samples were collected on a geo-referenced basis at depths of 0 to 10 cm and 10 to 20 cm before tillage, after tillage, after chemical application, and before planting and assayed for the presence of the pathogen. Propagules ofV. dahliae were detected at 140 of 141 sites sampled prior to tillage. Most (74.4% in heavy, sandy loam; 63.1% in light, loamy sand) were concentrated in upper 10 cm of the soil profile. Plowing redistributed inoculum vertically while deep-rip tillage did not. In the non-chemical treated areas of both fields, theVerticillium population reached a maximum between 25 July and 8 August before declining to near pre-tillage levels. Overall, the population generally was lower in the field with heavy soil, higher organic matter content, and a 3-year crop rotation. Metam sodium appeared to be most effective when shank injected, as the levels of inoculum in both fields declined by 60% to 80% following this application method. Chemigation was ineffective in the lighter soil, but the inoculum density in the deep-rip tillage area of the field with the heavier soil declined by nearly 20% in the upper and 60% in the lower strata following this treatment. The number ofV. dahliae propagules at the 10- to 20-cm depth in the plowed area of the same field was reduced by 25% following Chemigation, but remained unchanged in the upper strata. Wilt was reduced in both fields by as much as 50% with shank injection of metam sodium with concomitant increases in total yield, marketable yield and gross income. Increases in total yield were significant (P<0.05) for the main effect of chemical, in the plowed area of the field with the heavier soil type following shank injection. These data suggest that growers might benefit from altering their tillage and chemical application practices as part of an integrated approach to managing Verticillium wilt.

C J Phene - One of the best experts on this subject based on the ideXlab platform.

  • comparison of drip and sprinkler irrigation systems for applying metam sodium and managing stem rot on potato
    Plant Disease, 2002
    Co-Authors: Greg T Browne, William R Detar, Blake M Sanden, C J Phene
    Abstract:

    Browne, G. T., DeTar, W. R., Sanden, B. L., and Phene, C. J. 2002. Comparison of drip and sprinkler irrigation systems for applying metam sodium and managing stem rot on potato. Plant Dis. 86:1211-1218. Drip and sprinkler systems were compared for effectiveness as preplant metam sodium Chemigation systems and conduciveness to late-season development of stem rot disease on potato. Sclerotia of Sclerotium rolfsii were used in a bioassay to test efficacy of metam sodium treatments. Drip application of metam sodium (532 liters/ha, 32.8% a.i.) through lines at 7 cm of depth in preformed beds (depths from bed top unless stated otherwise) killed all test sclerotia at 15-, 30-, or 46-cm depths. Drip application of the metam sodium through drip lines at 41 or 46 cm of depth resulted in 0 to 17 or 68 to 80% survival, respectively, of test sclerotia at 15 cm of depth; but all the sclerotia at 30 or 46 cm of depth were killed. Compared with the drip applications, sprinkler Chemigation with metam sodium generally treated beds less effectively (8 to 100% of sclerotia survived at 15 cm, 62 to 100% at 30 or 46 cm). On flat ground, drip and sprinkler Chemigation (metam sodium, 560 liters/ha) performed equally (4, 37, and 77% survival at 15-, 45-, and 75-cm depths, respectively). After potato planting and artificial soil infestation with S. rolfsii (5 to 6 weeks before harvest), subsurface drip-irrigated plots (line depth of 41 or 46 cm) had lower incidence of stem rot disease at harvest (13 to 23% on tubers) than that in sprinkler plots (56 to 62%). The low incidence of disease was associated with relatively dry surface soil. Subsurface drip Chemigation with metam sodium in preformed plant beds does not consistently eradicate S. rolfsii sclerotia near the upper bed surface but, in an arid climate, it is less conducive than sprinkler irrigation to development of stem rot disease of potato.

Pamela Wofford - One of the best experts on this subject based on the ideXlab platform.

  • modeling methyl isothiocyanate soil flux and emission ratio from a field following a Chemigation of metam sodium
    Journal of Environmental Quality, 2006
    Co-Authors: Lin Ying Li, Terrell Barry, Kevin Mongar, Pamela Wofford
    Abstract:

    : Metam-sodium had become the most heavily used soil fumigant in recent years as the deadline approached for methyl bromide to phase out in January 2005. After application, metam-sodium decomposes rapidly to methyl isothiocyanate (MITC), a highly toxic compound capable of killing a wide spectrum of soil-borne pests. Inhalation risk of MITC ranked high among airborne agricultural pesticides in California. Information about off-gassing intensity and percentage of emission is essential for exposure risk assessment and mitigation measures, but is limited, especially for new application methods such as drip Chemigation. Air concentrations of MITC were monitored around a field treated with metam-sodium through surface drip irrigation system. The field was tarped with plastic films before the Chemigation. The air concentrations at receptor locations were simulated for the period of air monitoring with the Industrial Source Complex (ISC3) Dispersion Model, and soil flux density of MITC at various periods after Chemigation was estimated through a back-calculation procedure. The estimated soil flux density of MITC showed a diurnal pattern, with the daytime flux stronger than nighttime. However, the average air concentration at nighttime was higher than that at daytime. Soil flux density peaked at 4.30 microg m-2 s-1 in the first 12-h period after Chemigation, then declined with time. The MITC emission percentage in the first 60-h was 2.65% of applied mass, of which 57% occurred in the first 24-h after Chemigation. The study indicated that the tarped bed drip application method of metam-sodium had a relatively good control of MITC emission from soil.

  • Modeling Methyl Isothiocyanate Soil Flux and Emission Ratio from a Field following a Chemigation of Metam‐Sodium
    Journal of Environmental Quality, 2006
    Co-Authors: Lin Ying Li, Terrell Barry, Kevin Mongar, Pamela Wofford
    Abstract:

    : Metam-sodium had become the most heavily used soil fumigant in recent years as the deadline approached for methyl bromide to phase out in January 2005. After application, metam-sodium decomposes rapidly to methyl isothiocyanate (MITC), a highly toxic compound capable of killing a wide spectrum of soil-borne pests. Inhalation risk of MITC ranked high among airborne agricultural pesticides in California. Information about off-gassing intensity and percentage of emission is essential for exposure risk assessment and mitigation measures, but is limited, especially for new application methods such as drip Chemigation. Air concentrations of MITC were monitored around a field treated with metam-sodium through surface drip irrigation system. The field was tarped with plastic films before the Chemigation. The air concentrations at receptor locations were simulated for the period of air monitoring with the Industrial Source Complex (ISC3) Dispersion Model, and soil flux density of MITC at various periods after Chemigation was estimated through a back-calculation procedure. The estimated soil flux density of MITC showed a diurnal pattern, with the daytime flux stronger than nighttime. However, the average air concentration at nighttime was higher than that at daytime. Soil flux density peaked at 4.30 microg m-2 s-1 in the first 12-h period after Chemigation, then declined with time. The MITC emission percentage in the first 60-h was 2.65% of applied mass, of which 57% occurred in the first 24-h after Chemigation. The study indicated that the tarped bed drip application method of metam-sodium had a relatively good control of MITC emission from soil.