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United States Department of Agriculture

Agricultural Research Service

Research Project: MINOR USE PESTICIDE-FOOD/ORNAMENTALS

Location: Application Technology Research Unit

Title: Evaluation of acibenzolar for the control of bacterial spot on bell pepper, 2012

Authors
item Krause, Charles
item Horst, Leona

Submitted to: Plant Disease Management Reports
Publication Type: Abstract Only
Publication Acceptance Date: June 30, 2013
Publication Date: August 14, 2013
Citation: Krause, C.R., Horst, L. 2013. Evaluation of acibenzolar for the control of bacterial spot on bell pepper, 2012. Plant Disease Management Reports. 7:V162.

Technical Abstract: The experiment was conducted at the Ohio Agricultural Research and Development Center’s North Central Agricultural Research Station located in Fremont, OH located on Rimer loamy fine sand soil, pH 6.1. On 29 Mar, the field was cultivated. On 5 Apr 2012, 7 lbs/A 14.3% granular boron, 300 lbs/A 0-0-60 (N-P-K), 150 lbs/A10-52-0 (N-P-K) and 200 lbs/A 46-0-0-(N-P-K) were incorporated into the test field that was chisel plowed on 18 Oct 2011. On 5 Apr raised beds on 5 ft centers were prepared. On 11 May, herbicides Roundup powermax (22 oz/A) and Request (12.8 oz/A) were applied. Additional herbicides Dual magnum (1 pt/A) and Graamoxone (2 pt/A) plus crop oil (31 oz/A) were applied 17 and 23 May, respectively. On 30 May, pepper transplants 1 ft apart into single rows 20 ft long on the beds. Starter fertilizer (N-P-K 10-34-0; 0.7 qt/50 gal water) was applied in the transplant water. Treatments were arranged in a randomized complete block design with four replications. Each treatment consisted of 20 plants spaced 1 foot apart with 5 feet between rows. Treatment rows were alternated with untreated border rows. The field was cultivated on 12, 21 Jun, 11 and 26 Jul for weed control. Insecticides Spintor (10 oz/A), Asana (8 oz/A), Mustang Max (4 oz/A), Lanate LV (2 pt/A), Warrior (3.8 oz/A), Spintor (8 oz/A), Asana (9 oz/A), Coragen (5 oz/A), and Dipel (1 lb/A) were applied on 8, 20, 28 Jun, 5, 18, 24 Jul, 2 and 9 Aug, respectively. Nine broadcast applications were applied beginning on 30 May and ending on 31 Jul. Treatment 1 was applied using a CO2-pressurized backpack sprayer (30psi, 37.3 gal/A, 3.0 mph). Treatments 2, 3, 4, 5, 6, 7, 8, and 9 were broadcast applications using a tractor pulled pump sprayer (30psi, 44.6 gal/A, 2.8 mph). Treatment 1 and 2 were actigard alone; treatments 3,5,7, and 9 were Dithane and Kocide 3000. Treatments 4,6, and 8 were actigard, dithane and kocide 3000. Treatments Plants were inoculated with approximately 108 CFU/fl oz (3x108 CFU/ml) of Xanthomonas campestris pv. Vesicatoria strains 110C and 767 in the evening of 27 Jun using a CO2-pressurized backpack sprayer (30 psi, 56.2 gal/A). Phytotoxicity and disease incidence of bacterial spot were evaluated on 27 Jun, 3, 12, 17, 25, and 31 Jul, 7 and 14 Aug using a scale of 0-100% foliage affected. Fruits were harvested from 5 plants chosen at random from each treatment row on 7 and 14 Aug. The number and weight of marketable fruit, the number of marketable fruit with bacterial spot, number and weight of healthy culls, plant height, number of blossoms and immature fruit were determined. Average minimum and maximum temperatures were 54.1 and 83.90F for 14-31 May, 57.7 and 82.90F for1-30 Jun, 69.2 and 87.10F for 1-31 Jul, and 62.8 and 79.40F for 1-22 Aug; rainfall amounts were 1.43, 1.95, 0.95, and 2.88 in., respectively. Plots were irrigated on with 0.9 inches of water on 12 and 29 Jun and 13 Jul and 1.1 inches of water on 27 Jul. Analysis of variance was performed using the general linear model procedure with SAS statistical software and means were separated using Fisher’s least significant difference test. On 12 Jul, 15% of the North Star plants appeared to be stunted. This had disappeared by 17 Jul. At harvest, no phytotoxicity was observed on the plants for any of the Actigard treatments when compared to the plots with standard treatment. Bacterial spot disease pressure was high for this trial from surrounding fields. The variety was significant in the amount of disease based on the Area Under the Disease Progress Curve (AUDPC), but did not effect the total yield (ton/A). For variety Aristotle, Actigard did not significantly reduced bacterial spot severity, number of blossoms, number of immature fruit(data not shown), total yield by the end of the season when compared to the untreated control. It did increase the marketable yield. For variety North Star, Actigard at the lowest rate significantly reduce bacterial spot severity, but had no affect on the number of blossoms or number of immature fruit(data not shown) when compared to the standard treatment. Actigard at the higher rates had a significant effect on the amount of disease based on AUDPC when compared to the standard treatment.

Last Modified: 11/27/2014
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