(F37) COTTON: Gossypium hurtsutum L., 'Fibermax 989 B/RR' J. S. Bacheler Dept. of Entomology North Carolina State Univ. Raleigh, NC 27695-7613 Tel: (919) 515- 8877 D. W. Mott Thrips primarily: Frankliniella fusca (Hinds) Cotton was planted on 6 May on Nahunta sandy loam soil at the Upper Coastal Plain Research Station near Rocky Mount, NC. Plots were four rows by 40 ft with the middle two rows treated with either Temik 15 G or a seed treatment, as indicated in the tables. The at-planting granular insecticides (various rates of Temik 15 G), were dispensed via a tractor-mounted plywood box with holes to fit inverted Mason jars. The jar lids were calibrated to deliver a precise amount of insecticide when the jars were inverted over the holes at a constant, known tractor speed. The holes in the plywood platform led directly into the open furrow via funnels under which flexible tubes had been placed. All foliar insecticides were applied on 20 May with a CO -powered backpack sprayer calibrated to deliver 8.0 gpa at 50 psi with a single TX-8 Spraying Systems nozzle/row. A second Orthene application was made to one of the three Cruiser seed treatments on 28 May. Five cotton seedlings/plot (20/treatment) were carefully cut off with a razor blade, put into Mason jars filled with soapy water, transported back to NCSU, and processed using the washing/screening technique. Thrips were later counted under a dissecting stereo microscope and separated into immatures (larvae) and adults. Thrips collections were made on 27 May and on 1 Jun, or at approximately 3-3.7 wk after planting. Plant heights were taken on 20 Jun by measuring 10 plants/plot (40 total/treatment), and stand counts were made on 7 Jul by counting the number of living plants/plot in 7.5 row ft in the middle two rows (60 row ft/treatment). The center two rows of each plot were harvested with two row John Deere mechanical harvester on 4 Nov. All of the insecticides resulted in significant height increases over the untreated check, except for the Gaucho seed treatment alone. At the initial May 27 thrips evaluation, all treatments showed significantly lower levels of both immature and total thrips than the untreated control, except the Gaucho alone, the Gaucho plus Temik, and the Cruiser alone treatments. At the 1 Jun evaluation, the check again showed significantly higher total thrips levels than the above treatments, as well as Temik at the low rate. No significant differences were noted between treatments in stand establishment. Due to extremely poor fall harvest conditions and excessive regrowth, no significant yield differences were found.
Arthropod Management Tests – Oxford University Press
Published: Jan 1, 2003