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WESTERN FLOWER THRIPS CONTROL IN ROMAINE LETTUCE, SPRING 2006

WESTERN FLOWER THRIPS CONTROL IN ROMAINE LETTUCE, SPRING 2006 (E23) LETTUCE (ROMAINE): Lactuca sativa var. longifloria, Lam. ‘Fresh Heart’ John C. Palumbo University of Arizona Department of Entomology 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 Western Flower Thrips (WFT): Frankliniella occidentalis (Pergande) The objective of the study was to evaluate the efficacy of several insecticide treatments against WFT on romaine lettuce under desert growing conditions. Lettuce was direct seeded on 18 Jan 2006 at the Yuma Valley Agricultural Center, Yuma, AZ into double row beds on 42 inch centers. Stand establishment was achieved using overhead sprinkler irrigation, and irrigated with furrow irrigation thereafter. Plots were two beds wide by 40 ft long and bordered by two untreated beds. Four replications of each treatment were arranged in a RCB design. Formulations and rates for each compound are provided in the tables. Foliar sprays were applied on 6 Mar, 13 Mar and 20 Mar with a CO operated boom sprayer at 60 psi and 21.5 gpa. A broadcast application was delivered through 2 TX-18 ConeJet nozzles per bed. An adjuvant, Dyne-Amic (Helena Chemical Co.), was applied at 0.125% to all treatments. Numbers of WFT from 5 plants per replicate were recorded on each sample date. Relative WFT numbers were measured by removing plants and beating them vigorously against a screened pan (12 x 7 x 2 inch) for a predetermined time (15 s). A 6 inch by 6 inch sticky cards was placed inside of the pan to catch the dislodged WFT. Sticky cards were then taken to the laboratory where numbers of adults and larvae were counted. Data were analyzed as a 1-way ANOVA with means compared where appropriate using a protected LSD F test (P < 0.05) WFT populations were moderately heavy during this spring trial. Adult numbers varied among treatments following each application, but the Orthene treatments and the Lannate and pyrerthroid combinations provided the most consistent control of adult WFT throughout the trial (Table 1). The Success and Tesoro combination provided significantly greater adult WFT reductions than the Success alone or Radiant treatments. In contrast, all spray treatments significantly reduced WFT larvae numbers compared to the untreated following each application. However, the Radiant treatment and the Success combinations (with Tesoro or Lannate) provided the most consistent reductions in larvae numbers (Table 2). These results further showed that reduced rates of Success (3.5 fl oz) can be used in combination with Tesoro and Lannate to provide control WFT comparable to Success (6.0 fl oz) or Radiant applied alone. Furthermore, Assail used in combination with Lannate provided significantly less control than the other combinations. No phytotoxicty was observed. Table 1 Mean WFT adults/plant 3-DAT1 7- DAT1 4-DAT2 7-DAT2 4-DAT3 9-DAT3 Treatment Rate/acre 9-Mar 13-Mar 17-Mar 20-Mar 24-Mar 29-Mar Orthene 97 0.5 lb 2.4bc 5.5de 4.5e 7.1de 15.0d 39.6bc Orthene 97 0.75 lb 1.7c 4.0e 3.7e 5.5e 14.8d 36.6c Assail 30SG + Lannate SP 4 oz + 0.5 lb 2.2bc 9.5b 9.7abc 14.3a 26.4b 70.0a Lannate SP + Renounce 20WP 0.5 lb + 3.5 oz 2.0c 6.2cde 5.1de 8.5cde 12.7d 60.0ab Success 2SC + Renounce 20WP 5 fl oz + 3.5 oz 2.0c 8.2bc 6.0de 12.0ab 15.5d 51.9abc Success 2SC + Lannate SP 3.5 fl oz + 0.5 lb 2.3bc 6.8cd 6.6cde 11.8abc 14.9d 59.4ab Success 2SC + Tesoro 4EC 3.5 fl oz + 6 fl oz 1.9c 4.2e 8.1bcd 9.4bdc 21.5c 59.1ab Success 2SC 6 fl oz 3.3bc 7.3bcd 10.0ab 14.8a 23.4bc 63.0a Radiant 1SC 5 fl oz 3.8b 5.6de 12.3a 14.2a 25.2bc 56.7abc Untreated --- 9.1a 14.6a 11.8a 10.2bcd 31.6a 40.9bc Renounce was replaced with Mustang Max (4.0 oz), and Lannate rate increased to 0.75 lb/acre on the 3rd application (20 Mar); Means followed by the same letter are not significantly different, ANOVA; protected LSD (P < 0.05) Table 2 Mean WFT larvae/plant 3-DAT1 7- DAT1 4-DAT2 7-DAT2 4-DAT3 9-DAT3 Treatment Rate/acre 9-Mar 13-Mar 17-Mar 20-Mar 24-Mar 29-Mar Orthene 97 0.5 lb 11.6b 20.7bc 28.0b 26.8b 19.0b 33.9bc Orthene 97 0.75 lb 5.5cd 21.3b 27.5b 18.7bc 17.8b 34.8bc Assail 30SG + Lannate SP 4 oz + 0.5 lb 5.0d 18.4bc 24.4b 20.7bc 13.1bc 57.3ab Lannate SP + Renounce 20WP 0.5 lb + 3.5 oz 4.2d 16.0cd 18.6bc 15.8cd 11.1cd 25.2bc Success 2SC + Renounce 20WP 5 fl oz + 3.5 oz 9.6bc 22.5b 24.0b 16.4cd 8.7cd 33.6bc Success 2SC + Lannate SP 3.5 fl oz + 0.5 lb 4.5d 10.4ef 8.0d 7.7de 4.7de 30.9bc Success+Tesoro 4EC 3.5 fl oz + 6 fl oz 7.2cd 11.8de 10.6cd 7.7de 7.4cde 34.2bc Success 2SC 6 fl oz 7.4bcd 12.1de 6.6d 8.7de 5.9de 43.8bc Radiant 1SC 5 fl oz 4.3d 5.9f 3.5d 2.8e 1.4e 15.3c Untreated --- 16.8a 35.7a 60.7a 63.5a 77.3a 92.7a Renounce was replaced with Mustang Max (4.0 oz), and Lannate rate increased to 0.75 lb/ac on the 3rd application (20 Mar); Means followed by the same letter are not significantly different, ANOVA; protected LSD (P < 0.05) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Arthropod Management Tests Oxford University Press

WESTERN FLOWER THRIPS CONTROL IN ROMAINE LETTUCE, SPRING 2006

Arthropod Management Tests , Volume 32 (1) – Jan 1, 2007

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2155-9856
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10.1093/amt/32.1.E23
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Abstract

(E23) LETTUCE (ROMAINE): Lactuca sativa var. longifloria, Lam. ‘Fresh Heart’ John C. Palumbo University of Arizona Department of Entomology 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 Western Flower Thrips (WFT): Frankliniella occidentalis (Pergande) The objective of the study was to evaluate the efficacy of several insecticide treatments against WFT on romaine lettuce under desert growing conditions. Lettuce was direct seeded on 18 Jan 2006 at the Yuma Valley Agricultural Center, Yuma, AZ into double row beds on 42 inch centers. Stand establishment was achieved using overhead sprinkler irrigation, and irrigated with furrow irrigation thereafter. Plots were two beds wide by 40 ft long and bordered by two untreated beds. Four replications of each treatment were arranged in a RCB design. Formulations and rates for each compound are provided in the tables. Foliar sprays were applied on 6 Mar, 13 Mar and 20 Mar with a CO operated boom sprayer at 60 psi and 21.5 gpa. A broadcast application was delivered through 2 TX-18 ConeJet nozzles per bed. An adjuvant, Dyne-Amic (Helena Chemical Co.), was applied at 0.125% to all treatments. Numbers of WFT from 5 plants per replicate were recorded on each sample date. Relative WFT numbers were measured by removing plants and beating them vigorously against a screened pan (12 x 7 x 2 inch) for a predetermined time (15 s). A 6 inch by 6 inch sticky cards was placed inside of the pan to catch the dislodged WFT. Sticky cards were then taken to the laboratory where numbers of adults and larvae were counted. Data were analyzed as a 1-way ANOVA with means compared where appropriate using a protected LSD F test (P < 0.05) WFT populations were moderately heavy during this spring trial. Adult numbers varied among treatments following each application, but the Orthene treatments and the Lannate and pyrerthroid combinations provided the most consistent control of adult WFT throughout the trial (Table 1). The Success and Tesoro combination provided significantly greater adult WFT reductions than the Success alone or Radiant treatments. In contrast, all spray treatments significantly reduced WFT larvae numbers compared to the untreated following each application. However, the Radiant treatment and the Success combinations (with Tesoro or Lannate) provided the most consistent reductions in larvae numbers (Table 2). These results further showed that reduced rates of Success (3.5 fl oz) can be used in combination with Tesoro and Lannate to provide control WFT comparable to Success (6.0 fl oz) or Radiant applied alone. Furthermore, Assail used in combination with Lannate provided significantly less control than the other combinations. No phytotoxicty was observed. Table 1 Mean WFT adults/plant 3-DAT1 7- DAT1 4-DAT2 7-DAT2 4-DAT3 9-DAT3 Treatment Rate/acre 9-Mar 13-Mar 17-Mar 20-Mar 24-Mar 29-Mar Orthene 97 0.5 lb 2.4bc 5.5de 4.5e 7.1de 15.0d 39.6bc Orthene 97 0.75 lb 1.7c 4.0e 3.7e 5.5e 14.8d 36.6c Assail 30SG + Lannate SP 4 oz + 0.5 lb 2.2bc 9.5b 9.7abc 14.3a 26.4b 70.0a Lannate SP + Renounce 20WP 0.5 lb + 3.5 oz 2.0c 6.2cde 5.1de 8.5cde 12.7d 60.0ab Success 2SC + Renounce 20WP 5 fl oz + 3.5 oz 2.0c 8.2bc 6.0de 12.0ab 15.5d 51.9abc Success 2SC + Lannate SP 3.5 fl oz + 0.5 lb 2.3bc 6.8cd 6.6cde 11.8abc 14.9d 59.4ab Success 2SC + Tesoro 4EC 3.5 fl oz + 6 fl oz 1.9c 4.2e 8.1bcd 9.4bdc 21.5c 59.1ab Success 2SC 6 fl oz 3.3bc 7.3bcd 10.0ab 14.8a 23.4bc 63.0a Radiant 1SC 5 fl oz 3.8b 5.6de 12.3a 14.2a 25.2bc 56.7abc Untreated --- 9.1a 14.6a 11.8a 10.2bcd 31.6a 40.9bc Renounce was replaced with Mustang Max (4.0 oz), and Lannate rate increased to 0.75 lb/acre on the 3rd application (20 Mar); Means followed by the same letter are not significantly different, ANOVA; protected LSD (P < 0.05) Table 2 Mean WFT larvae/plant 3-DAT1 7- DAT1 4-DAT2 7-DAT2 4-DAT3 9-DAT3 Treatment Rate/acre 9-Mar 13-Mar 17-Mar 20-Mar 24-Mar 29-Mar Orthene 97 0.5 lb 11.6b 20.7bc 28.0b 26.8b 19.0b 33.9bc Orthene 97 0.75 lb 5.5cd 21.3b 27.5b 18.7bc 17.8b 34.8bc Assail 30SG + Lannate SP 4 oz + 0.5 lb 5.0d 18.4bc 24.4b 20.7bc 13.1bc 57.3ab Lannate SP + Renounce 20WP 0.5 lb + 3.5 oz 4.2d 16.0cd 18.6bc 15.8cd 11.1cd 25.2bc Success 2SC + Renounce 20WP 5 fl oz + 3.5 oz 9.6bc 22.5b 24.0b 16.4cd 8.7cd 33.6bc Success 2SC + Lannate SP 3.5 fl oz + 0.5 lb 4.5d 10.4ef 8.0d 7.7de 4.7de 30.9bc Success+Tesoro 4EC 3.5 fl oz + 6 fl oz 7.2cd 11.8de 10.6cd 7.7de 7.4cde 34.2bc Success 2SC 6 fl oz 7.4bcd 12.1de 6.6d 8.7de 5.9de 43.8bc Radiant 1SC 5 fl oz 4.3d 5.9f 3.5d 2.8e 1.4e 15.3c Untreated --- 16.8a 35.7a 60.7a 63.5a 77.3a 92.7a Renounce was replaced with Mustang Max (4.0 oz), and Lannate rate increased to 0.75 lb/ac on the 3rd application (20 Mar); Means followed by the same letter are not significantly different, ANOVA; protected LSD (P < 0.05)

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Arthropod Management TestsOxford University Press

Published: Jan 1, 2007

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