H. D. Niemczyk

Overseeding Endophytic Perennial Ryegrass into Stands of Kentucky Bluegrass to Manage Bluegrass Billbug (Coleoptera: Curculionidae)

Abstract Studies were conducted to determine the utility of overseedingendophyte enhanced varieties of perennial ryegrass, Loliumperenne L., into existing stands of Kentucky bluegrass, Poapratensis L., to manage bluegrass billbug, Sphenophorusparvulus Gyllenhal, larval populations and their damage. Twocommercial varieties of endophyte enhanced perennial ryegrass (RepellII and Triple Play) were overseeded at two different rates in thefield. S. parvulus larval populations, their damage, andturfgrass composition were monitored over the course of 3 yr.Significantly fewer larvae were found in plots overseeded with RepellII, whereas Triple Play had no significant effect on larval populationdensity. Endophyte infection was confirmed in ≈58% of all Repell IIshoots, whereas only ≈31% of Triple Play shoots were infected.Regression analysis, using a segmented model, demonstrated that larvalpopulations declined as the proportion of endophyte-infected perennialryegrass increased. However, no additional reductions in larvalpopulation density were achieved in stands containing >40%endophyte-infected perennial ryegrass. Visual damage varied withcultivar, seeding rate, and year, but generally decreased as theproportion of endophyte-infected perennial ryegrass increased. Althoughseeding rate had an initial effect on turfgrass composition, thesedifferences were not detected after the first year of the study.Results indicate overseeding existing stands of Kentucky bluegrass withendophytic varieties of perennial ryegrass can reduce S.parvulus larval populations and their damage. However, plantgenetic characteristics (i.e., different cultivars) may be overridingdeterminants of many aspects of plant performance includingestablishment, tolerance to insect feeding, and expression ofendophyte-mediated resistance.

Sorption of chlorpyrifos and fonofos on four soils and turfgrass thatch using membrane filters

Abstract Chemical transport in soil is a major factor influencing soil and water contamination. Four soils and turfgrass thatch, representing a wide range of organic carbon OC content were studied to determine sorption Kd and Kf parameters for the insecticides chlorpyrifos and fonofos. The batch equilibrium method was used. The concentration of insecticide was measured in the solution as well as in the solid phase to determine the most accurate sorption data. Four soils and thatch were equilibrated for 24 h at 22 ± 1OC with aqueous insecticide solutions. Four concentrations of the insecticides, each <50% of their respective water solubilities, were selected for the experiments. After extraction with an organic solvent, the concentration of insecticides in the aqueous solution was determined by gas liquid chromatography using electron capture detection for chlorpyrifos, and nitrogen/phosphorus detection for fonofos. Data obtained were fitted to the log and simple linear form of the Freundlich equation. Mas...

Behaviour and mobility of preemergent herbicides in turfgrass: A field study

Abstract The quality of many golf courses and other turfgrass areas often requires high levels of cultural management. The fact that this level of maintenance usually includes the use of preemergent herbicides has caused concern about their potential for ground water contamination. Much of this concern is based on extrapolation from agricultural situations rather than data developed from studies conducted in field turfgrass situations. To address this data gap, a two‐year field project evaluating the behaviour and mobility of the commonly used preemergent herbicides, benfluralin, trifluralin, bensulide, oxadiazon. pendimethalin, and DCPA with its two metabolites was conducted at OARDC/The Ohio State University, Wooster, Ohio, in 1988–89. Plots were located on a site with thatch (WT) and one with no thatch (NT)to further clarify the impact of thatch on herbicide behavior. Treatments were applied in April and samples of thatch and four zones of soil (0–2.5, 2.5–5, 7.5–10 and 22.5–25cm) were collected throug...

Gas-liquid chromatographic analysis of chlorthal-dimethyl herbicide and its degradates in turfgrass thatch and soil using a solid-phase extraction technique

Abstract An analytical technique for analysis of dimethyl tetrachloroterephthalate herbicide and two degradates (monomethyl tetrachloroterephthalate and tetrachloroterephthalic acid) residues in turfgrass thatch and soil has been developed. It involves solid‐phase extraction/purification and final gas‐liquid chromatographic determination with electron capture detection. The degradates are determined as ethyl esters. The method is sensitive for dimethyl tetrachloroterephthalate to 0.01 and 0.02 ppm for thatch and soil, 0.01 and 0.01 ppm for monomethyl tetrachloroterephthalate, and 0.02 and 0.01 ppm for tetrachloroterephthalic acid, for thatch and soil, respectively.

Simultaneous gas‐liquid chromatographic analysis of trifluralin and benfluralin residues in turfgrass thatch and soil by solid‐phase extraction technique

Abstract A method is presented for either simultaneous or separate residue analysis of 2,6‐dinitro‐N,N‐dipropyl‐4‐trifluoromethylaniline (trifluralin) and N‐butyl‐N‐ethyl‐2, 6‐dinitro‐4‐trifluoromethylaniline (benfluralin) in turfgrass thatch and soil. Trifluralin and/or benfluralin residues are extracted from thatch and soil with acetohitrile‐water mixture, reextracted and purified with C18 solid‐phase extraction (SPE) tubes, and quantified by megabore column gas chromatography with a nitrogen specific detector. Method sensitivity for both compounds is 0.05 mg/kg for thatch and 0.02 mg/kg for soil.

Improved gas chromatographic method for analysis of trichlorfon insecticide in soil and turfgrass thatch

Abstract An improved Gas Chromatographic method utilizing simple extraction and one‐step purification on solid phase extraction tubes was developed for analysis of trichlorfon as an intact insecticide compound in turfgrass thatch and soil. A Gas Chromatograph/Mass Spectrum (GC/MS) was used for confirmation of trichlorfon structure. The method readily determines trichlorfon in the presence of dichlorvos. Using an electron capture (EC) detector, the detection limits were 0.02 ppm in soil, 0.04 ppm in turfgrass thatch, and 0.09 ppm in soil, and 0.2 ppm in turfgrass thatch using an nitrogen phosphorus (NP) detector.

Gas-liquid chromatographic analysis of oxadiazon residues in turfgrass thatch and soil using a solid-phase extraction technique.

Abstract A simple and inexpensive technique for analysis of oxadiazon (5‐tert‐butyl‐3‐(2,4‐dichloro‐5‐isopropoxyphenyl)‐1,3,4,‐oxadiazol‐2(3H)‐=one) residues in thatch and soil involving solid‐phase extraction/purification and final gas‐liquid chromatographic determination with nitrogen‐phosphorus specific detection has been developed. The method, sensitive to 0.08ppm for thatch and 0.04ppm for soil, significantly reduces the use of organic solvents and labor, and allows simultaneous analysis of multiple samples.