Oakes Irrigation Research
Site
Carrington Research Extension Center * North Dakota State University
P.O. Box 531, Oakes, ND 58474-0531, Voice: (701) 742-2189, FAX: (701)
742-2700, email: rgreenla@ndsuext.nodak.edu
COMPARISON OF FUNGICIDES AND TIMING OF SPRAYS FOR CONTROL OF WHITE MOLD ON IRRIGATED DRY BEANS
Pat L. Gross and Jim R. Venette
Department of Plant Pathology, NDSU
Table 53. Fungicide effects on white mold and edible bean yields.
Pinto beans were planted at the Oakes Irrigation Research Station on May 15. The soil was an Embden loam. The plot was naturally infested with sclerotia of Sclerotinia scleroliorum. Beans were planted in four-row plots with rows 30 in. apart. Each row was 20 ft. long with a 2 ft. buffer area at each end of the row. At planting, soil moisture was good and soil temperature was 53 F. Pre-emergence herbicide Dual was applied at 1.5 pt/acre on May 15. Basagran (1 pt/acre) + Blazer (2 pt/acre) were applied post emergence on June 13 to control weeds. Beginning May 17, plots were sprinkler irrigated as needed to keep plants growing. Between bud formation and pod fill, plots were irrigated frequently to keep the soil wet to promote white mold growth. Temperatures averaged 3.2 F cooler than the 30 year average for May and were above average for June (+2.8 F). July and August temperatures were near average. Rainfall was below the 30 year average for May (-1.3 in.) and June (-1.6 in.), and above average on July (+1.3 in.) and below average for August (-1.1 in.). The first fungicide spray was applied at 10 % bloom on June 30. Fungicides were suspended in deionized water adjusted to pH 7.0 and applied with a CO2- powered sprayer at 35 psi at a rate of 37.5 gal/acre through Teejet 8001 nozzles. The sprayer was equipped with four drop nozzles configured to apply fungicide on each side and over the top of each of the rows. Topsin M 70WP was applied at 10% bloom and 9 days later. Water-sprayed plots were included for comparisons. The experimental design was a randomized complete block with four replicates. White mold incidence was evaluated on July 23 and 30. Incidence was evaluated as disease presence or absence at 22 sites within randomly selected 10 ft. segments of the center two rows of each plot. Severity was estimated on July 30 at the same time and site as white mold incidence. At each location, the plant material in a 1 ft segment of row was rated on a 0-5 scale: 0=0%, 1=1-10%, 2=11-25%,3=26-50%,4=51-85%, and 5=86-100% infection. Plants were harvested August 12 from 10 ft. sections of the center two rows of each plot. Plants were clipped from their roots, collected in burlap bags, dried at 120° F for 5 days and threshed with a belt thresher. Seed samples were cleaned by aspiration and hand-picking. Seed moisture was uniformly near 8%, and yields were calculated from nonadjusted weights.
Bean growth was good in June and early July. Plants began to flower June 28. White mold was observed in the plots on July 21. Common blight (Xanthomonas campestris pv. phaseoli) was found in the field July 23. Defoliation from common blight reduced the foliage and rows did not close. White mold may have been reduced throughout the field because of common blight. No phytotoxicity was observed in the plots. All treatments except BWC01101F 2.09 EC significantly reduced severity, but none affected yield.
Return to top of edible bean white mold study
Table 53. Fungicide effects on white mold and edible bean yields.
| Treatment | Rate | Disease rating | Yield† | ||
|---|---|---|---|---|---|
| Incidence | Severity | ||||
| July 23 | July 30 | July 30 | |||
| per acre | ------------------------%----------------- | cwt/acre | |||
| Untreated control | 15.9 | 34.5 | 15.7 | 16.5 | |
| Topsin M 70WP | 1.5 lb‡ | 4.5 | 16.7 | 4.2 | 15.3 |
| Topsin M 70WP | 1.5 lb§ | 12.5 | 11.9 | 2.4 | 14.7 |
| Topsin M 70WP + Phase | 1.5 lb + 0.56%v/v‡ | 11.4 | 15.5 | 8.9 | 15.9 |
| Topsin M 70WP + Phase | 1.5 lb + 0.56%v/v§ | 6.8 | 16.7 | 4.8 | 15.6 |
| Topsin M 70WP + Phase | 1.5 lb + 0.56%v/v¶ | 1.1 | 4.8 | 0.3 | 17.3 |
| Topsin M 70WP + Phase | 1.5 lb + 0.56%v/v†† | 4.6 | 9.5 | 2.4 | 16.4 |
| BWC 011 01F 2.09 EC | 0.76 pt‡ | 27.3 | 44.0 | 20.1 | 15.9 |
| BWC 012 01F 4.17 SC | 0.29 pt‡ | 9.1 | 25.0 | 9.3 | 17.0 |
| BWC 012 01F 4.17 SC | 0.38 pt‡ | 6.8 | 20.2 | 8.5 | 17.1 |
| BWC 012 01F 4.17 SC | 0.48 pt‡ | 12.5 | 16.7 | 7.0 | 16.4 |
| Ronilan 50 DF | 1.0 lb‡ | 5.7 | 21.5 | 6.0 | 15.8 |
| LSD(P=0.05) | 8.8 | 11.6 | 6.1 | 5.1 | |
†Yield is calculated from cleaned beans taken from 0.001
acre and weighed at 8.0% moisture.
‡ Sprayed two applications, the first at 10% bloom and a
second 9 days later.
§ Sprayed one application at 10% bloom.
¶ One application four days after 10% bloom.
†† Two applications, the first four days after 10% bloom
and the second 9 days later.
Return to top of edible bean white mold study
Go to Oakes Irrigation Research Site 1997 annual report
Go to Oakes Irrigation Research Site disease studies