| Abstract/Contents: | "This study was undertaken to determine product effectiveness when applied in May, Jun, and Aug to control a predominant Northern masked chafer (NMC) white grub population on a turfgrass area maintained on a golf course driving range in Mingoville, PA. The turfgrass area consisted of fine fescue (40%), Kentucky bluegrass (30%), and crabgrass (30%). Treatment plots were 6 ^D#x 8 ft, arranged in a randomized split block design and replicated three times with a 1 ft barrier around all replicates. Liquid formulations were applied by using a CO2 sprayer with four 8002VS TeeJet nozzles mounted on a 6 ft boom, operating at 28 psi, and applied in 363 ml of water/48 ft2 or delivering 2.0 gal/1000 ft2. Conditions during the mid morning on 12 May (treatment time one) were cloudy with air temp = 57°F and RH = 64%. Soil was dry with temp at 1 and 2 inch depth = 55 and 54°F respectively. Thatch, 0.125 inch thick, was dry and water pH was 7.0. General soil conditions were: soil textural class, loam; soil particle size analysis: sand, 35.4%; silt, 47.5%; clay, 17.1%; soil percent water content (percent by wt), 18.4; organic matter, 4.9%; CEC, 10.4; and soil pH, 5.4. The experimental area was irrigated post treatment with 0.25 inch of water. Conditions during the late morning on 7 Jul (treatment time two) were cloudy with air temp = 81°F and RH = 63%. Soil was moist with temp at 1 and 2 inch depth = 72 and 70 °F, respectively. Thatch, 0.125 inch thick, was moist and water pH = 7.0. At that time, particle size analysis showed soils to be 30.7% sand, 54.8% silt, 14.5% clay, with 20.8% soil percent water content (percent by wt), 6.2% organic matter, CEC = 9.7, and pH = 5.4. The experimental area was irrigated post treatment with 0.25 inch of water. Conditions during early morning on 12 Aug (treatment time three) were cloudy with air temp = 75°F and RH = 45%. Soil was dry with soil temp at 1 and 2 inch depth = 72 and 71°F, respectively. At that time, soil textural class was silt loam; particle size analysis: sand, 28.5%; silt, 57.0%; clay, 14.5%; soil percent water content (percent by wt), 13.3; organic matter, 56.2%; CEC, 10.0; and soil pH = 5.4. Thatch, 0.25 inch thick, was dry and water pH was 7.0. The experimental area was irrigated post treatment with 0.25 inch of water. Conditions during the early morning on 9 Sep (treatment time four) were cloudy with air temp = 74°F and RH = 73.5%. At that time, soils were dry with temp at 1 and 2 inch depth = 64°F, and percent water content (percent by wt) = 21.4. General soil conditions were as follows: soil textural class, silt loam; soil particle size analysis: sand, 31.8%; silt, 54.7%; clay, 13.6%; organic matter, 6.7%; CEC, 11.2; and soil pH, 5.4. Thatch, 0.5 inch thick, was dry and water pH was 7.0. The experimental area was irrigated post treatment with 0.25 inch of water. Throughout the summer and early fall the area was placed on a regular fairway irrigation schedule. Three 1 ft2 soil samples were removed from each replicate on 30 Sep and the total no. of Northern masked chafer (NMC) and JB grubs was recorded. Data was analyzed using Waller-Duncan k ratio (WD; P ≤ 0.05). The area selected for the experiment had been infested with a natural population of NMC and JB during the spring of 2005. An avg of 12.2/ft2 grubs were present on 16 May. Adult NMC flight was monitored in 2005 with a black light trap maintained at the Valentine Turfgrass Research Center, Centre Co., PA. The first adult NMC was collected on 24 Jun. Adult NMC flight peaked between 2 and 8 Jul, and the last NMC adult was collected on 28 Jul. Japanese beetle adults were observing flying late this season. Second instar, as well as third instar, grubs were present. Drought conditions delayed development of scarab grubs in 2005. All treatments provided significant suppression of NMC and JB grubs disregarding date applied. All treatments significantly reduced combined JB and NMC grub populations. However, AGB grub populations were present in low no. and were not significantly suppressed. No phytotoxicity was noted." |
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