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Soil and Foliar Applications of Systemic Insecticides for Control of Sweetpotato Whitefly on Zucchini Squash, 2015

Soil and Foliar Applications of Systemic Insecticides for Control of Sweetpotato Whitefly on... Arthropod Management Tests, 2016, 1–2 doi: 10.1093/amt/tsw062 Section E: Vegetable Crops ZUCCHINI SQUASH: Cucurbita pepo L., ‘Obsidian’ Soil and Foliar Applications of Systemic Insecticides for Control of Sweetpotato Whitefly on Zucchini Squash, 2015 Philip A. Stansly, and Barry C. Kostyk University of Florida/IFAS, Southwest Florida Res. and Ed. Center, 2686 State Road 29 North, Immokalee, FL 34142- 9515, Phone: (239) 658-3427, Fax: (239) 658-3469 (pstansly@ufl.edu; bkostyk@ufl.edu) and Corresponding author, e-mail: pstansly@ufl.edu) Section Editor: Jonathan Babcock Yellow squash fruit j Cucurbita pepo Sweetpotato whitefly (SWF): Bemisia tabaci (Gennadius) Sweetpotato whitefly, also known as silverleaf whitefly is a serious of vertical booms, each equipped with 3 yellow Albuz hollow cone nozzles pest of curcubit vegetables in southwest Florida. Feeding can result in and applying at a total rate of 40 GPA on 23 and 30 Mar. In addition, loss of yield and fruit quality due to silverleaf disorder but watermelon arotationofQuadris Opti andPrevicurFlexwithManzate ProStick growers can experience catastrophic losses from watermelon vine de- was applied weekly for control of powdery and downy mildew. cline caused by squash vein yellowing virus transmitted by B. tabaci. Adult whitefly were counted weekly by carefully turning over We prepared three raised beds 32 inches wide on 6-ft centers and two lower leaves on each of 5 plants per plot. Whitefly nymphs were 430 ft long for this trial on 22 Jan at the Southwest Florida Research sampled weekly from one lower leaf from each of 5 plants per plot and Education Center in Immokalee FL. Two drip tapes with 8-inch (Table 1). On 19 March, the entire leaf surface was assessed but on emitter spacing and flow rate of 0.67 gpm/100ft were laid on each the later sample dates ten 0.5 in discs were removed from each leaf bed which was then covered with whiteface polyethylene film and fu- in order to count pre-imaginal stages under a stereoscopic micro- migated with 300 lbs/acre Pic-Clor 60 EC (chloropicrin 56.7% þ 1-3 scope (Table 1). On 26 Mar, silverleaf was evaluated by giving each dichloropropene 37.1%) injected through the drip. Dry fertilizer of 5 centrally located plant in each plot a rating based on the follow- (10-2-10 NPK) had been incorporated to cover half anticipated crop ing scale : 0 ¼ no symptoms, 1 ¼ less than 10 % of leaf surface af- nutrient requirements, and the rest was fertigated with 7-2-7 daily fected, 2 ¼ 11–33%, 3 ¼ 34–67% and 4 68% of leaf surface throughout the course of the trial. Greenhouse raised seedlings were exhibiting silvering. Fruit was removed, counted and weighed from transplanted 12 Sep spaced at 24-inches in plots of 14 plants each sep- all 15 plants in each plot on 8, 13 and 17 Apr. Data were subjected arated by 5 buffer plants. Plots were assigned in an RCB design to to ANOVA and means separated using LSD (P ¼ 0.05). four replications and five treatments plus an untreated check. All treatments significantly reduced the number of whitefly Soil drenches of Venom and Sivanto were made 9 Mar by delivering adults observed compared to the untreated on 20 Mar and 17 Apr a 120-ml suspension per plant using an EZ-Dose sprayer operating at a whereas only the two treatments of Sivanto sprays @ 10.5 oa/ac did pressure of 45 psi. Foliar treatments were applied with a high clearance on 2 Apr. However, the sprays did not control adults any better sprayer operating at 180 psi and 2.3 mph with delivery through two than the 21 oz drench on any date whereas as both were better than Table 1 Adults/leaf Nymphs/Leaf Silver leaf damage rating (0–4) 20 Mar 26 Mar 2 Apr 9 Apr 17 Apr 19 Mar 26 Mar 2 Apr 9 Apr 17 Apr 26 Mar Product/ Rate/ac Method 5 sq in 5 sq in 5 sq in 5 sq in Formulation Untreated check 2.35 a 6.20 a 2.95 a 3.73 ab 8.58 a 18.45 a 15.00 a 13.11 a 27.50 a 21.72 a 3.25 a Venom 70 SG 6 oz drench 1.10 bc 4.07 bc 2.38 ab 4.00 a 4.63 b 1.00 b 0.70 b 0.95 b 3.80 c 12.85 b 1.35 c Sivanto 200 SL 14 oz drench 1.35 b 5.03 ab 2.10 ab 3.03 bc 4.38 b 0.85 b 0.20 b 3.25 b 15.15 b 24.40 a 1.85 c Sivanto 200 SL 21 oz drench 0.38 c 3.05 c 2.13 ab 2.52 c 4.88 b 0.45 b 0.35 b 1.25 b 6.10 bc 10.75 b 1.35 c Sivanto 200 SL 10.5 oz foliar na 2.68 c 1.58 b 2.40 c 4.38 b na 3.20 b 3.50 b 5.70 bc 12.75 b 2.55 b Means followed by same letter are not statistically different (LSD> 0.05). V C The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com 1 2 Arthropod Management Tests, 2016, Vol. 41, No. 1 the 15 oz/ac drench on 26 Apr. Venom was not different than the soil drenches and were significantly less symptomatic than Sivanto untreated check on 2 and 9 Apr while the 14.0 oz drench of Sivanto @ 5 oz as a foliar spray, possibly due to damage done before the did not decrease adults observed on 26 Mar, 2 and 9 Apr. All treat- spray was applied. However, no yield differences were observed ments significantly reduced nymphs on all sample dates except for with each plant producing an average of 2.86 0.35 fruit per plant. the 14.0 oz rate of Sivanto on 17 Apr (Table 1). Silverleaf caused by No Phytotoxicity was observed. This research was supported by in- nymphal feeding was reduced in all treatments with plants receiving dustry gifts of pesticide and funds. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Arthropod Management Tests Oxford University Press

Soil and Foliar Applications of Systemic Insecticides for Control of Sweetpotato Whitefly on Zucchini Squash, 2015

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© The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com
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Abstract

Arthropod Management Tests, 2016, 1–2 doi: 10.1093/amt/tsw062 Section E: Vegetable Crops ZUCCHINI SQUASH: Cucurbita pepo L., ‘Obsidian’ Soil and Foliar Applications of Systemic Insecticides for Control of Sweetpotato Whitefly on Zucchini Squash, 2015 Philip A. Stansly, and Barry C. Kostyk University of Florida/IFAS, Southwest Florida Res. and Ed. Center, 2686 State Road 29 North, Immokalee, FL 34142- 9515, Phone: (239) 658-3427, Fax: (239) 658-3469 (pstansly@ufl.edu; bkostyk@ufl.edu) and Corresponding author, e-mail: pstansly@ufl.edu) Section Editor: Jonathan Babcock Yellow squash fruit j Cucurbita pepo Sweetpotato whitefly (SWF): Bemisia tabaci (Gennadius) Sweetpotato whitefly, also known as silverleaf whitefly is a serious of vertical booms, each equipped with 3 yellow Albuz hollow cone nozzles pest of curcubit vegetables in southwest Florida. Feeding can result in and applying at a total rate of 40 GPA on 23 and 30 Mar. In addition, loss of yield and fruit quality due to silverleaf disorder but watermelon arotationofQuadris Opti andPrevicurFlexwithManzate ProStick growers can experience catastrophic losses from watermelon vine de- was applied weekly for control of powdery and downy mildew. cline caused by squash vein yellowing virus transmitted by B. tabaci. Adult whitefly were counted weekly by carefully turning over We prepared three raised beds 32 inches wide on 6-ft centers and two lower leaves on each of 5 plants per plot. Whitefly nymphs were 430 ft long for this trial on 22 Jan at the Southwest Florida Research sampled weekly from one lower leaf from each of 5 plants per plot and Education Center in Immokalee FL. Two drip tapes with 8-inch (Table 1). On 19 March, the entire leaf surface was assessed but on emitter spacing and flow rate of 0.67 gpm/100ft were laid on each the later sample dates ten 0.5 in discs were removed from each leaf bed which was then covered with whiteface polyethylene film and fu- in order to count pre-imaginal stages under a stereoscopic micro- migated with 300 lbs/acre Pic-Clor 60 EC (chloropicrin 56.7% þ 1-3 scope (Table 1). On 26 Mar, silverleaf was evaluated by giving each dichloropropene 37.1%) injected through the drip. Dry fertilizer of 5 centrally located plant in each plot a rating based on the follow- (10-2-10 NPK) had been incorporated to cover half anticipated crop ing scale : 0 ¼ no symptoms, 1 ¼ less than 10 % of leaf surface af- nutrient requirements, and the rest was fertigated with 7-2-7 daily fected, 2 ¼ 11–33%, 3 ¼ 34–67% and 4 68% of leaf surface throughout the course of the trial. Greenhouse raised seedlings were exhibiting silvering. Fruit was removed, counted and weighed from transplanted 12 Sep spaced at 24-inches in plots of 14 plants each sep- all 15 plants in each plot on 8, 13 and 17 Apr. Data were subjected arated by 5 buffer plants. Plots were assigned in an RCB design to to ANOVA and means separated using LSD (P ¼ 0.05). four replications and five treatments plus an untreated check. All treatments significantly reduced the number of whitefly Soil drenches of Venom and Sivanto were made 9 Mar by delivering adults observed compared to the untreated on 20 Mar and 17 Apr a 120-ml suspension per plant using an EZ-Dose sprayer operating at a whereas only the two treatments of Sivanto sprays @ 10.5 oa/ac did pressure of 45 psi. Foliar treatments were applied with a high clearance on 2 Apr. However, the sprays did not control adults any better sprayer operating at 180 psi and 2.3 mph with delivery through two than the 21 oz drench on any date whereas as both were better than Table 1 Adults/leaf Nymphs/Leaf Silver leaf damage rating (0–4) 20 Mar 26 Mar 2 Apr 9 Apr 17 Apr 19 Mar 26 Mar 2 Apr 9 Apr 17 Apr 26 Mar Product/ Rate/ac Method 5 sq in 5 sq in 5 sq in 5 sq in Formulation Untreated check 2.35 a 6.20 a 2.95 a 3.73 ab 8.58 a 18.45 a 15.00 a 13.11 a 27.50 a 21.72 a 3.25 a Venom 70 SG 6 oz drench 1.10 bc 4.07 bc 2.38 ab 4.00 a 4.63 b 1.00 b 0.70 b 0.95 b 3.80 c 12.85 b 1.35 c Sivanto 200 SL 14 oz drench 1.35 b 5.03 ab 2.10 ab 3.03 bc 4.38 b 0.85 b 0.20 b 3.25 b 15.15 b 24.40 a 1.85 c Sivanto 200 SL 21 oz drench 0.38 c 3.05 c 2.13 ab 2.52 c 4.88 b 0.45 b 0.35 b 1.25 b 6.10 bc 10.75 b 1.35 c Sivanto 200 SL 10.5 oz foliar na 2.68 c 1.58 b 2.40 c 4.38 b na 3.20 b 3.50 b 5.70 bc 12.75 b 2.55 b Means followed by same letter are not statistically different (LSD> 0.05). V C The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com 1 2 Arthropod Management Tests, 2016, Vol. 41, No. 1 the 15 oz/ac drench on 26 Apr. Venom was not different than the soil drenches and were significantly less symptomatic than Sivanto untreated check on 2 and 9 Apr while the 14.0 oz drench of Sivanto @ 5 oz as a foliar spray, possibly due to damage done before the did not decrease adults observed on 26 Mar, 2 and 9 Apr. All treat- spray was applied. However, no yield differences were observed ments significantly reduced nymphs on all sample dates except for with each plant producing an average of 2.86 0.35 fruit per plant. the 14.0 oz rate of Sivanto on 17 Apr (Table 1). Silverleaf caused by No Phytotoxicity was observed. This research was supported by in- nymphal feeding was reduced in all treatments with plants receiving dustry gifts of pesticide and funds.

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Arthropod Management TestsOxford University Press

Published: Jan 1, 2016

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