Control of Whitefly in Cotton with Capture and Various Additives, 1992

Abstract

Abstract Two-month old cotton plants grown in Sunshine Mix® potting mixture in 15 cm diam. pots and exposed to heavy whitefly infestations were transferred on 26 Jun into spray booths (60 cm X 60 cm × 90 cm frames covered with polyethylene on three sides) arranged in a randomized complete block design with eight treatments and six replicates. Plants were irrigated daily using drip tubes to avoid wetting of foliage. Adult SW were counted on the third expanded leaf node from the growing point and nymphs were counted on a 2.1 cm diameter leaf disk from the central portion of the leaf on the fifth or sixth node. A pre-treatment count of whiteflies was made before the first spray on 29 Jun 1992 and then SPWF adults were counted at 24 and 72 hours after treatment and immatures were counted at 72 and 144 hours after each of three weekly treatments. Plants were treated by spraying to runoff (approximately 3 seconds/15 ml/plant, ca. 473 liters/ha) using a CO2 backpack sprayer with two TX-2 hollow cone spray tips (Spraying Systems Co.) positioned 5 to 10 cm from the plant canopy (one above and one below) at 4.2 kg/cm2. Bartlett’s test for homogeneity of variance indicated that a log transformation was needed for analysis of variance of immature whitefly data and a square-root transformation was needed for adult data. Analysis of variance and LSD tests for separation of treatment means were calculated on means averaged over six sample dates. ValOil® (a cottonseed oil spray adjuvant), jojoba oil, and Butacide® 8EC (piperonyl butoxcide) were tested alone and in combination with Capture® 2EC (bifenthrin) to assess their potential as adjuvants to enhance whitefly control.