EVALUATION OF EARLY SEASON APPLICATION OF TRIMAX, CENTRIC, VYDATE AND BAYTHROID FOR COTTON INSECT CONTROL AND YIELD ENHANCEMENT, 2004

Abstract

Cotton was planted on 11 May on an Acock very fine sandy loam at the Upper Coastal Plain Research Station near Rocky Mount, NC. Plots were 6 rows by 50 ft with 4 replications and the treatments arranged in a RCB design. Insecticides were applied with a CO2-powered backpack sprayer calibrated to deliver 10.0 gpa at 60 psi with a single TX-8 Spraying Systems nozzle per row at square initiation on Jun 15. The Trimax, Centric and Baythroid plots were treated additionally on 22 and 29 Jun. Late season oversprays for stinks bugs and bollworms were made weekly with a Hi-Boy by research station personnel. On 15 July: 1) Fifty-sweep net samples were taken per plot (200/treatment) for all beneficial and pest insects , such as TPB, 2) Two small squares (one terminal and one lateral square) of approx. 1/8 inch length were checked for presence or a missing position in each of 25 randomly-selected cotton plants per plot (200 per treatment) as an indication of plant bug feeding, 3) Yellowed or blackened squares were counted as a missing position, and 4) Twenty-five blooms/plot (100/treatment) were scored as either normal or “dirty” (the presence of blackened or brownish pollen anthers in white blooms). On 3 Sep, number of opened bolls/50 ft was counted, and on 21 Sep when on average approx. half of the bolls had opened across the plots opened, closed and total bolls were counted in 7.5 ft of each plot (30 ft/treatment). The center 2 rows of each plot were harvested on 11Oct with a 2-row John Deere mechanical harvester. Data were analyzed with ANOVA and means were separated using an F-protected LSD (P ≤ 0.05).