Evaluation of fungicides and production methods for the control of downy mildew and Phytophthora fruit rot of cucumber, 2014

摘要

The experiment was conducted at the Ohio Agricultural Research and Development Center's Muck Crops Agricultural Research Station in Celeryville, OH on Linwood muck soil. The field was plowed and 175 lb/A 46-0-0 (N-P-K), 110 lb/A 18-46-0 (N-P-K) and 215 lb/A 0-0-61 (N-P-K) were incorporated on 18 Apr. 'Dasher II' slicing cucumber seeds were sown on 12 May into 72-cell plug trays containing Metromix 360. The field was disked on 21 May, leveled, and raised beds were prepared on 5 Jun. The herbicides Makaze (22 fl oz/A) plus ammonium sulfate (10 lb/100 gal) were applied on 18 Apr and on 9 May; Curbit EC (3 pt/A) and Command ME (1 pt/A) were applied on 5 Jun. The field was hand weeded on 3, 7, 16, 22 and 23 Jul. The insecticide Sevin XLR Plus (1 qt/A) was applied on 10, 17, 24 and 31 Jul; Assail 70WP (1.7 oz/A) was applied on 12 Jun; Assail 30SG (5 oz/A) was applied on 20 Aug; Beleaf 50 SG (2 oz/a) was applied on 27 Aug; Fulfill (2.7 oz/A) plus Advance 90 (0.25%) was applied on 3 Sep. Cucumber seedlingswere transplanted on 10 Jun. Treatments were arranged in a randomized split plot design with four replications. Each treatment consisted of one row of 10 plants spaced 2 ft apart on 6 ft centers. Treatment rows were alternated with non-treated ground production guard rows. Six ft. wooden stakes and trellis string were placed in the trellised plots on 23 Jun. Treatments were applied using a tractor mounted 3.0 hitch (hydraulic attached) motor driven sprayer (40 psi, 29.1 gal/A, 3 mph) beginning 2 Jul and ending 12 Sep for a total of 11 applications for products applied on a 7-day schedule and eight applications for those applied on a 10-day schedule. Downy mildew was first observed on 2 Sep (disease severity average 8% in the non-treated control). Theseverity of downy mildew on foliage was evaluated on 2, 10 and 17 Sep using a scale of 0-100% foliage affected. Cucumber fruits from all plants of each treatment were harvested, separated by healthy, culls or Phytophthora-infected, counted and weighed on21 and 28 Jul, 4, 11, 18 and 25 Aug, and 3 and 10 Sep. Average maximum temperatures for 10-30 Jun, Jul, Aug and 1-17 Sep were 81.1, 78.9, 80.5 and 75.3°F; average minimum temperatures were 62.8, 57.8, 59.2 and 53.0°F; and total rainfall amounts were 4.9, 2.0, 1.7 and 2.2 in., respectively. Analysis of variance was performed using the general linear models procedure with SAS statistical software and means were separated using Fisher's least significant difference test.