Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

SWEETPOTATO WHITEFLY CONTROL WITH FOLIAR INSECTICIDES ON FALL CANTALOUPES, 2011

SWEETPOTATO WHITEFLY CONTROL WITH FOLIAR INSECTICIDES ON FALL CANTALOUPES, 2011 Arthropod Management Tests 2012, Vol. 37 doi: 10.4182/amt.2012.E19 (E19) CANTALOUPE: Cucumis melo L. var. cantalupensis Naudin, ‘Gold Express’ John C. Palumbo University of Arizona, Yuma Agricultural Center th 6425 W. 8 St., Yuma, Arizona 85364 Phone: (928) 782-3836 Fax: (928) 782-1940 E-mail: jpalumbo@ag.arizona.edu Sweetpotato whitefly: Bemisia tabaci (Gennadius) – biotype B With the impending loss of the endosulfan registration on melons, this trial was designed to evaluate the efficacy of several foliar insecticide alternatives against adult SWF and the associated incidence of Cucurbit Yellows Stunting Disorder Virus (CYSDV) in fall melons. Cantaloupe plots planted with ‘Gold Express’ were established at the Yuma Agricultural Center on 10 Aug, 2011 and managed similarly to local growing practices. Plots consisted of one 84-inch bed, 45 ft long with a 7 ft buffer between each plot. The study was designed as a RCB design with 4 replicates / treatment. The treatments and rates are shown in the table below. Foliar spray treatments were applied on 22 Aug and 1 and 12 Sep as a broadcast spray at 25 gpa and 40 psi using 4 -TX18 Conejet nozzles per bed. All spray treatments included an adjuvant DyneAmic at 0.25% vol/vol. Populations of whitefly adults were evaluated at intervals following each application (DAT). Adult populations were estimated using a modified vacuum method that employed a 2- gal 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. Incidence of CYSDV was recorded by estimating the number of leaves in each 45 ft plot that expressed symptoms of the severe yellowing of leaf tissue and obvious yellow interveinal chlorosis (YIVC) consistent with CYSDV infection. Representative samples of symptomatic leaves were positively identified for CYSDV by Judy Brown, University of Arizona. Insect and virus data were subjected to ANOVA and means were separated using F-protected LSD (P ≤ 0.05). In this fall trial, the efficacy of NNI-0101 (pyrifluquinazon) and Sivanto (flupyradifurone) compounds with translaminar activity against sucking insects was evaluated along with Venom as foliar standards. Courier (an IGR with weak adult activity) was included to determine whether it had any significant activity on CYSDV suppression. Whitefly pressure was heavy and provided a realistic st look at what growers can expect in whitefly/CYSDV pressure on fall melons. Following the 1 spray treatment, the experimental compounds NNI-0101 and Sivanto provided 3-day knockdown comparable to the Venom standard (Table 1). By 7 days, whitefly adults had re-infested all plots. Following the 2nd and 3rd sprays, the experimental compounds provided significant knockdown of adults for 7-8 days relative to the untreated check. By 8 days following the 3rd spray, whitefly adult number in the NNI-0101, Sivanto and Venom plots had been reduced by 90% or more. Furthermore, both NNI-0101 and Sivanto provided virus suppression comparable to the Venom standard and significantly lower than the untreated check (Table 2). Addition of Courier with NNI-0101 as a tank-mixture did not significantly enhance efficacy or virus suppression. Courier provided only marginal control of adults (primarily through nymph management) and did not provide a significant reduction in CYSDV incidence. All treatments provided significant control of nymphs relative to the untreated check (data not shown) following each application. No phytotoxicity symptoms were observed following any of the insecticide treatments. This research was supported by industry gift(s) of pesticide and/or research funding. 1 Arthropod Management Tests 2012, Vol. 37 doi: 10.4182/amt.2012.E19 Table 1. SWF Adults/ Sample Treatment/ Rate amt 1-DAT1 3-DAT1 7-DAT1 1-DAT2 3-DAT2 8-DAT2 formulation product/acre 23-Aug 25-Aug 29-Aug 2-Sep 5-Sep 9-Sep NNI-0101 20SC 3.2 oz 4.4c 15.6c 38.7a 4.7b 3.2b 6.5c Courier 40SC 12 oz 18.0c 34.9ab 52.1a 28.4ab 21.5ab 16.6b NNI-0101 1.6 oz 4.9c 17.8c 36.9a 4.4 2.4b 4.6c + Courier + 12 oz Venom 70WG 3 oz 3.2c 25.4bc 48.3a 3.7b 7.3b 10.4bc Sivanto 200SL 10 oz 3.8c 24.5bc 55.3a 3.5b 4.9b 8.3c Untreated check 35.0a 49.1a 70.6a 56.5a 44.2a 30.4a F value 15.94 5.88 2.21 5.51 4.84 15.66 Pr > F <.0001 0.007 0.13 0.009 0.01 0.0001 SWF Adults/ Sample Treatment/ Rate amt 1-DAT3 3-DAT3 8-DAT3 Trial formulation product/acre 13-Sep 15-Sep 20-Sep Avg. NNI-0101 20SC 3.2 oz 0.6c 1.4b 7.9b 9.2c Courier 40SC 12 oz 14.0b 18.6b 56.0b 28.9b NNI-0101 1.6 oz 1.2c 1.9c 11.2b 9.4c + Courier + 12oz Venom 70WG 3 oz 2.1c 1.6b 21.7b 13.7c Sivanto 200SL 10 oz 3.9c 2.1b 23.1b 14.4c Untreated check 29.2a 63.0b 347.5a 80.6a F value 11.31 14.69 13.95 47.71 Pr > F 0.0005 0.0001 0.0002 <.0001 Means in a column followed by the same letter are not significantly different (P > 0.05, F-protected LSD). Table 2. No. leaves with CYSDV symptoms (YIVC) / 45 row ft Treatment/ Rate amt formulation product/acre 27-Sep 4-Oct NNI-0101 20SC 3.2 oz 34.5a 87.3b Courier 40SC 12 oz 39.0a 95.8ab NNI-0101 1.6 oz 26.8a 77.9b + Courier + 12 oz Venom 70WG 3 oz 28.5a 82.5b Sivanto 200SL 10 oz 28.3a 74.3b Untreated check 56.5a 126.8a F value 1.62 3.44 Pr > F 0.23 0.04 Means in a column followed by the same letter are not significantly different (P > 0.05, F-protected LSD). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Arthropod Management Tests Oxford University Press

SWEETPOTATO WHITEFLY CONTROL WITH FOLIAR INSECTICIDES ON FALL CANTALOUPES, 2011

Arthropod Management Tests , Volume 37 (1) – Jan 1, 2012

Loading next page...
 
/lp/oxford-university-press/sweetpotato-whitefly-control-with-foliar-insecticides-on-fall-mtpxnr9WRd
Publisher
Oxford University Press
Copyright
© Published by Oxford University Press.
eISSN
2155-9856
DOI
10.4182/amt.2012.E19
Publisher site
See Article on Publisher Site

Abstract

Arthropod Management Tests 2012, Vol. 37 doi: 10.4182/amt.2012.E19 (E19) CANTALOUPE: Cucumis melo L. var. cantalupensis Naudin, ‘Gold Express’ John C. Palumbo University of Arizona, Yuma Agricultural Center th 6425 W. 8 St., Yuma, Arizona 85364 Phone: (928) 782-3836 Fax: (928) 782-1940 E-mail: jpalumbo@ag.arizona.edu Sweetpotato whitefly: Bemisia tabaci (Gennadius) – biotype B With the impending loss of the endosulfan registration on melons, this trial was designed to evaluate the efficacy of several foliar insecticide alternatives against adult SWF and the associated incidence of Cucurbit Yellows Stunting Disorder Virus (CYSDV) in fall melons. Cantaloupe plots planted with ‘Gold Express’ were established at the Yuma Agricultural Center on 10 Aug, 2011 and managed similarly to local growing practices. Plots consisted of one 84-inch bed, 45 ft long with a 7 ft buffer between each plot. The study was designed as a RCB design with 4 replicates / treatment. The treatments and rates are shown in the table below. Foliar spray treatments were applied on 22 Aug and 1 and 12 Sep as a broadcast spray at 25 gpa and 40 psi using 4 -TX18 Conejet nozzles per bed. All spray treatments included an adjuvant DyneAmic at 0.25% vol/vol. Populations of whitefly adults were evaluated at intervals following each application (DAT). Adult populations were estimated using a modified vacuum method that employed a 2- gal 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. Incidence of CYSDV was recorded by estimating the number of leaves in each 45 ft plot that expressed symptoms of the severe yellowing of leaf tissue and obvious yellow interveinal chlorosis (YIVC) consistent with CYSDV infection. Representative samples of symptomatic leaves were positively identified for CYSDV by Judy Brown, University of Arizona. Insect and virus data were subjected to ANOVA and means were separated using F-protected LSD (P ≤ 0.05). In this fall trial, the efficacy of NNI-0101 (pyrifluquinazon) and Sivanto (flupyradifurone) compounds with translaminar activity against sucking insects was evaluated along with Venom as foliar standards. Courier (an IGR with weak adult activity) was included to determine whether it had any significant activity on CYSDV suppression. Whitefly pressure was heavy and provided a realistic st look at what growers can expect in whitefly/CYSDV pressure on fall melons. Following the 1 spray treatment, the experimental compounds NNI-0101 and Sivanto provided 3-day knockdown comparable to the Venom standard (Table 1). By 7 days, whitefly adults had re-infested all plots. Following the 2nd and 3rd sprays, the experimental compounds provided significant knockdown of adults for 7-8 days relative to the untreated check. By 8 days following the 3rd spray, whitefly adult number in the NNI-0101, Sivanto and Venom plots had been reduced by 90% or more. Furthermore, both NNI-0101 and Sivanto provided virus suppression comparable to the Venom standard and significantly lower than the untreated check (Table 2). Addition of Courier with NNI-0101 as a tank-mixture did not significantly enhance efficacy or virus suppression. Courier provided only marginal control of adults (primarily through nymph management) and did not provide a significant reduction in CYSDV incidence. All treatments provided significant control of nymphs relative to the untreated check (data not shown) following each application. No phytotoxicity symptoms were observed following any of the insecticide treatments. This research was supported by industry gift(s) of pesticide and/or research funding. 1 Arthropod Management Tests 2012, Vol. 37 doi: 10.4182/amt.2012.E19 Table 1. SWF Adults/ Sample Treatment/ Rate amt 1-DAT1 3-DAT1 7-DAT1 1-DAT2 3-DAT2 8-DAT2 formulation product/acre 23-Aug 25-Aug 29-Aug 2-Sep 5-Sep 9-Sep NNI-0101 20SC 3.2 oz 4.4c 15.6c 38.7a 4.7b 3.2b 6.5c Courier 40SC 12 oz 18.0c 34.9ab 52.1a 28.4ab 21.5ab 16.6b NNI-0101 1.6 oz 4.9c 17.8c 36.9a 4.4 2.4b 4.6c + Courier + 12 oz Venom 70WG 3 oz 3.2c 25.4bc 48.3a 3.7b 7.3b 10.4bc Sivanto 200SL 10 oz 3.8c 24.5bc 55.3a 3.5b 4.9b 8.3c Untreated check 35.0a 49.1a 70.6a 56.5a 44.2a 30.4a F value 15.94 5.88 2.21 5.51 4.84 15.66 Pr > F <.0001 0.007 0.13 0.009 0.01 0.0001 SWF Adults/ Sample Treatment/ Rate amt 1-DAT3 3-DAT3 8-DAT3 Trial formulation product/acre 13-Sep 15-Sep 20-Sep Avg. NNI-0101 20SC 3.2 oz 0.6c 1.4b 7.9b 9.2c Courier 40SC 12 oz 14.0b 18.6b 56.0b 28.9b NNI-0101 1.6 oz 1.2c 1.9c 11.2b 9.4c + Courier + 12oz Venom 70WG 3 oz 2.1c 1.6b 21.7b 13.7c Sivanto 200SL 10 oz 3.9c 2.1b 23.1b 14.4c Untreated check 29.2a 63.0b 347.5a 80.6a F value 11.31 14.69 13.95 47.71 Pr > F 0.0005 0.0001 0.0002 <.0001 Means in a column followed by the same letter are not significantly different (P > 0.05, F-protected LSD). Table 2. No. leaves with CYSDV symptoms (YIVC) / 45 row ft Treatment/ Rate amt formulation product/acre 27-Sep 4-Oct NNI-0101 20SC 3.2 oz 34.5a 87.3b Courier 40SC 12 oz 39.0a 95.8ab NNI-0101 1.6 oz 26.8a 77.9b + Courier + 12 oz Venom 70WG 3 oz 28.5a 82.5b Sivanto 200SL 10 oz 28.3a 74.3b Untreated check 56.5a 126.8a F value 1.62 3.44 Pr > F 0.23 0.04 Means in a column followed by the same letter are not significantly different (P > 0.05, F-protected LSD).

Journal

Arthropod Management TestsOxford University Press

Published: Jan 1, 2012

There are no references for this article.