Evaluation of bactericides and a plant activator for the control of bacterial leaf spot of processing tomatoes, 2014

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 loamy fine sandy soil. On 21 Apr the test field was cultivated and disked. Tomato ('Heinz 3402') seeds were hot water-treated (10 min pre-soak at 100 F followed by 25 min at 122 F, then 5 min in cold tap water) and sown on 14 Apr into 288-cell plug trays containing Metro-Mix 360 seedling mix. On 8 May potassium (240 lb/A K2O), phosphorous (104 lb/A P2O5), nitrogen (114 lb/A NH4NO3), and borate (7 lb/A) were incorporated and on 9 May raised beds were prepared on 5 ft centers. The herbicides Dual II Magnum (1.3 pt/A) and Dimetric 75DF (0.3 lb/A) were applied and incorporated into the test field on 14 May; on 29 Jun Sencor 75DF (0.3 lb/A) was applied by broadcast. On 22 May tomato seedlings were transplanted. Starter fertilizer (N-P-K 10-34-0; 0.7 qt/50 gal water) was applied in the transplant water. 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 were alternated with non-treated border rows. The insecticides Warrior II with Zeon Technology (1.9 fl oz/A), Capture LFR (5 fl oz/A), Coragen~R Insect Control (5 fl oz/A) and Assail 30SG (4 fl oz/A) were applied on 12 Jun; 5 Jul; 18 Jul and 1 Aug; and 14 Aug, respectively. Treatments were applied using a tractor-mounted CO2-pressurized sprayer (55 psi, 44.9 gal/A, 3 mph) beginningon 30 May and ending on 17 Jul. The field was cultivated on 16 Jun and hand weeded and hoed on 9 Jun and 15 Jul. Plants in treated and non-treated control rows were inoculated with approximately 108 CFU/ml copper sensitiveX. euvesicatoria strains 767 and 110c, on 4 and 27 Jun using a backpack CO2-pressurized sprayer. Plant vigor was evaluated on 2 and 16 Jul on a scale of 0-100%, assigning 100% to the treatment with the fullest canopy development within each rep. The severity of bacterial leaf spot wasevaluated on 9, 16, 24 and 30 Jul, 7, 13, and 20 Aug, using a scale of 0-100% foliage affected, and the Area Under the Disease Progress Curve (AUDPC) was calculated. Fruits were harvested from five plants in the center of each treated or non-treated control row on 4 Sep; weights of healthy fruit and fruit with bacterial spot, anthracnose, blossom end rot, and minor fungal fruit rots were measured. Average maximum temperatures for 22-31 May, Jun, Jul, Aug and 1-4 Sep were 77.9, 81.5, 79.2, 81.1 and 85.3°F; average minimum temperatures were 56.0, 61.5, 58.6, 60.5 and 63.1 °F; and rainfall amounts were 0.68, 4.0, 2.4, 1.1 and 0.1 in., respectively. Analysis of variance was performed using the GLIMMIX procedure and means were separated by Fisher's leastsignificant difference test with SAS software.