Evaluation of fungicides and bactericides for the control of bacterial leaf spot of processing tomatoes, 2016

摘要

The experiment was conducted at the Ohio Agricultural Research and Development Center's North Central Agricultural Research Station in Fremont, OH on Colwood fine sandy loam soil. On 18 Apr, the test field was plowed and potassium (240 lb/A K2O), phosphorous (52 lb/A P2O5), nitrogen (126 lb/A NH4NO3), and boron (10 lb/A) were incorporated. The field was disked on 19 Apr, and raised beds were prepared on 5-ft centers on 25 Apr. Tomato 'Peto 696' seeds were hot water-treated (10 min pre-soak at 100 F,soak for 25 min at 122 F) and sown on 15 Apr into 288-cell plug trays containing Baccto Professional Grower Mix. Raised beds were reshaped on 19 May. The herbicides Dual II Magnum (20 fl oz/A) plus Sencor (0.33 lb/A) were applied and incorporated into the test field on 23 May. An additional application of Sencor (0.33 lb/A) was made on 30 Jun. In the greenhouse, the experimental products Innovotech A (0.1% w/v) and Innovotech B (0.14% w/v) were applied beginning at the two-leaf stage on 9 May and continuing weekly until 31 May for a total of four applications. Three applications of Manzate Flowable (2.4 qt/A) + Kocide 3000 (1 lb/A), Mycoshield (3.9 oz/25 gal water), Mycoshield (3.9 oz/25 gal water) alt Kocide 3000 (1 lb/A), and Agri-Mycin 17 (3.9 oz/25gal water) were made beginning 16 May and ending on 31 May. USF2018A 200SC (Bayer Corp, Kansas City, MO) (3.4 fl oz/A) was applied once on 31 May, 7 days prior to transplanting. One Actigard 50WG (0.25 oz/100 gal) treatment was drenched twice on 23 and31 May, and the second only on 31 May. Drenches were applied by using a watering can. All foliar applications in the greenhouse were applied using a hand-held sprayer. All treatments were inoculated in the greenhouse using a hand-held sprayer 5 days after their first treatment application except for the Innovotech treatments, which were inoculated one day after the first application. Inoculum concentration was approximately 106 CFU/ml copper-sensitive X. euvesicatoria strains 110c and 767 in a 1:1 mixture. The inoculated tomato seedlings described above were transplanted on 7 Jun. Plots were arranged in a randomized complete block design with four replications. Each plot consisted of 25 plants spaced 1 ft apart with 5 ft between rows. Treated rows werealternated with non-treated border rows. Warrior II (1.9 fl oz/A), Hero EW (5 fl oz/A) and Coragen Insect Control (5.0 fl oz/A) were applied on 21 Jun and 11 Aug; 7 Jul; and 21 Aug, respectively. Field foliar applications were applied using a tractor-mounted CO2-pressurized sprayer (55 psi, 43.2 gal/A, 3 mph) beginning 8 Jun and ending 1 Sep for a total of ten applications. The field was cultivated on 16 Jun and hand weeded and hoed on 21 Jun. Plants were overhead irrigated with 1.0 in. of water on 23Jun, 15 and 28 Jul and 8 Aug. Incidence and severity of bacterial leaf spot on foliage were evaluated on 6 Jun and 12 Sep in the greenhouse and field respectively by randomly selecting 12 plants per treatment per rep and randomly picking ten leaflets perplant. Leaflets were assessed visually by using a scale of 0-100% foliage affected. Incidence and severity of bacterial leaf spot on fruit were also evaluated by randomly picking 24 fruits per treatment per rep on 12 Sep. In the field, the severity of bacterial leaf spot on foliage was evaluated in full plots on 3, 12, 19 and 29 Aug and 7 Sep using a scale of 0-100% foliage affected, and Area Under the Disease Progress Curve (AUDPC) was calculated. Average maximum temperatures for 7-30 Jun, Jul, Aug and 1-12 Sep were 82.8, 85.9, 85.7 and 82.5°F; average minimum temperatures were 59.8, 64.9, 64.9 and 59.1 °F; and rainfall amounts were 0.69, 1.45, 2.45 and 0.78 in., respectively. Analysis of variance was performed using the GLIMMIX procedure and meanswere separated by Fisher's least significant difference (FLSD) test with SAS software.