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Arthropod Management Tests 2013, Vol. 38 doi: 10.4182/amt.2013.E9 (E9) BROCCOLI: Brassica oleracea L. var. italica Plenck, ‘Emerald Crown’ EVALUATION OF FOLIAR INSECTICIDES FOR CONTROL OF BAGRADA HILARIS AND SWEETPOTATO WHITEFLY IN BROCCOLI, 2012 John C. Palumbo University of Arizona Department of Entomology Yuma Agricultural Center Yuma, Arizona 85364 Phone: (928) 782-3836 E-mail: jpalumbo@cals.arizona.edu Ta-I Huang E-mail: huang@cals.arizona.edu Thomas M. Perring E-mail: thomas.perring@ucr.edu Darcy A. Reed E-mail: darcy@ucr.edu Nilima Prabhaker E-mail: nilima.castle@ucr.edu Bagrada bug: Bagrada hilaris (Burmeister) Sweetpotato whitefly (SWF): Bemisia tabaci (Gennadius) – biotype B The objective of this study was to evaluate the efficacy of several conventional insecticides against a new invasive pest, Bagrada hilaris, and SWF in broccoli under desert growing conditions. Broccoli ‘Emerald Crown’ was direct seeded into double row beds on 42 inch centers on 18 Sep 2012 at the Yuma Agricultural Center. Plots were two beds wide by 35 ft long and bordered by two untreated beds. Stand establishment was achieved using overhead sprinkler irrigation, and irrigated with furrow irrigation thereafter. Four replications of each treatment were arranged in a RCB design. Formulations and rates for each compound are provided in the tables. Two foliar sprays were applied on 16 and 23 Oct as broadcast applications delivered through 2 TXVS-18 ConeJet nozzles at 25 gpa and 40 psi. An adjuvant, Dyne-Amic (Helena Chemical Co.), was applied at 0.25% vol/vol to all treatments. Evaluations of B. hilaris control was estimated by carefully examining whole plants (20 per replicate) for the presence of live adults on leaves, petioles and stems, as well as on the soil st surface beneath each plant at 1, 3 and 5 days (DAT; 1 application only). In addition, the number of plants in each sampled replicate that showed signs of recent feeding was recorded by inspecting the terminal growth and young leaves on each plant for fresh feeding signs that appeared as pale, starburst-shaped lesions on foliage where B. hilaris adults prefer to feed. Adult SWF were evaluated at 1, 3 and 7 DAT following both applications. Populations were estimated using a modified vacuum method that employed a 2- gallon portable vacuum (DeWALT, Baltimore, MD) which was fitted with cloth- screened 40 Dram containers to capture and retain vacuumed adults. On each sample date, 5 separate plants from each replicate were sampled by vacuuming the terminal area of the plants for 3 s. Containers with adults were taken into the laboratory, placed in a freezer for 24 h after which the number of adults/ plant was recorded. Because of heterogeneity of mean variances, data were log transform (mean+1) and subjected to ANOVA; means were separated using a F-protected LSD (P ≤ 0.05). Actual non-transformed means are presented in the tables. Plants were at the 4-leaf node stage when the first application was made. The B. hilaris population was moderate during the trial, and SWF adult numbers were moderate-heavy. At 1-DAT1, all spray treatments except Assail at the 4.0 oz/acre rate significantly reduced B. hilaris adult numbers compared to the untreated check (Table 1). At 3-DAT1, differences in adult numbers varied among the spray treatments where numbers in the Assail (4.0 oz/ac) and Exirel treatments did not differ from the untreated check. By 5-DAT1, adult numbers had increased in the spray treatments and did not differ from the untreated check except for the Venom, Endigo and Leverage treatments. Furthermore, evaluation of feeding signs at each sampling interval suggested that these same treatments provided the most consistent plant protection. SWF control was most consistent in the Venom, Assail (both rates) and Exirel treatments (Table 2).When considering control for both insect 1 Arthropod Management Tests 2013, Vol. 38 doi: 10.4182/amt.2013.E9 pests, Venom was clearly the most efficacious insecticide. No phytotoxicity symptoms were observed following any of the insecticide treatments. This research was supported by grants from the USDA-NIFA, Western Region IPM, 2011-34103- 30851, and AZ Dept. of Agric., SCRBP, 10-09. Table 1. B. hilaris Adults / 20 plants Plants with fresh feeding signs Treatment/ Rate amt formulation product/acre 1-DAT1 3-DAT1 5-DAT1 1-DAT1 3-DAT1 5-DAT1 Venom 70WG 4 oz 0.3cd 0.8cde 0.5b 0.0d 0.5de 1.3b Endigo ZC 4.5 oz 0.5de 0.0e 0.8b 0.0d 0.0e 1.5b Assail 30SG 4 oz 2.8ab 2.0ab 3.0a 2.5ab 2.5ab 5.8a Assail 30SG 5.3 oz 1.0d 1.5bc 3.3a 0.8c 1.5bc 4.5a Closer 2SC 5.7 oz 2.5bc 0.3de 2.8a 2.5ab 0.8cd 3.5a Exirel 10SC 20.5 oz 1.8de 1.8ab 4.3a 1.8b 1.5bc 5.8a Leverage 360 3 oz 0.0e 1.0bcd 0.5b 0.0d 0.5de 1.0b Untreated control --- 5.3a 3.8a 3.3a 3.8a 3.3a 6.0a F value 10.5 5.76 5.86 19.69 8.28 10.67 Pr > F <.0001 0.0008 0.0007 <.0001 <.0001 <.0001 Means in a column followed by the same letter are not significantly different (P > 0.05, F-protected LSD). Table 2. Mean SWF Adults / Vacuum Sample Treatment/ Rate amt formulation product/acre 1-DAT1 3-DAT1 7-DAT1 1-DAT2 3-DAT2 7-DAT2 Avg Venom 70WG 4 oz 26.2d 10.4e 9.5c 5.5c 0.8cd 5.3bc 5.5e Endigo ZC 4.5 oz 63.7ab 68.9a 20.6ab 15.8b 6.0a 15.1a 15.8b Assail 30SG 4 oz 41.4c 17.9c 10.1c 4.8cd 1.6bc 6.6bc 4.8d Assail 30SG 5.3 oz 29.6d 10.9de 8.1cd 4.6cd 0.9cd 5.2c 4.6e Closer 2SC 5.7 oz 44.2bc 42.8b 20.8b 10. b 3.9a 9.9ab 10.3c Exirel 10SC 20.5 oz 61.7ab 15.1cd 6.0d 2.6d 0.5d 2.4d 2.6e Leverage 360 3 oz 63.3ab 62.2ab 23.8ab 11.8b 2.4ab 14.8a 11.8bc Untreated control --- 87.0a 90.8a 31.4a 27.5a 5.2a 16.7a 27.5a F value 9.6 37.6 18.1 16.3 9.0 10.3 85.1 Pr > F <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 Means in a column followed by the same letter are not significantly different (P > 0.05, F-protected LSD).
Arthropod Management Tests – Oxford University Press
Published: Jan 1, 2013
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