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
EVALUATION
OF CALCIUM COMPOUNDS FOR
WHITE MOLD CONTROL IN DRY BEAN
Patrick Gross
NDSU, Department of Plant Pathology
Table 70. Incidence and severity of white mold and yield of edible dry beans.
A field trial was conducted at the NDSU Oakes Irrigation Research Site in Oakes, ND. Certified 'Hatton' pinto bean was planted on 13 May in a field with soil type Emben loam. Bean seeds were planted in four-row plots with rows 30 in. apart. Each row was 20 ft long and a 3 ft buffer area was included at each end of each row. Seeds were planted to a depth of 1.5 in. and were spaced approximately 2.5 in. apart using John Deere flexiplanters fitted with standard hoppers. At planting, soil moisture was high and soil temperature was 52 F. Sonalan, Dual, Basagran, cultivation and hand weeding provided good weed control. The plots were sprinkler irrigated when needed. Calcium compound applications were made on June 30 at 20% bloom and July 9 at 100% bloom. Row closure was at 50% on June 30 and at 80% on July 9. Calcium treatments were mixed in Fargo tap water (previously adjusted to pH 7.0 with HCl and/or NaOH) and applied within 2 hr of mixing. Sprays were applied using a CO2 powered sprayer set to deliver 37 gal/A at 30 psi. White mold incidence was evaluated on 22 and 29 Jul. Percent incidence was measured by placing a 10-ft rod arbitrarily between the center two rows of each plot. The rod was marked in 1 ft increments and the presence of disease was recorded if the imaginary visual plane at each mark passing through each row transected diseased material. Thus, 20 evaluations (ten per row) were made on each plot on each date. Percentage of infected sites was calculated. White mold severity was evaluated at the same site and time as incidence. Severity ratings were 0-5: 0 =0%; 1 = 5%; 2 = 15%; 3 = 40%; 4 = 65%; and 5 = 85% infection. This rating scale is a modification of Horsfall-Barrat 11-point scale that recognizes exponential differences in severity evaluations. Means for severity were calculated only from plants with white mold. Plots were harvested on 18 Aug. All of the plants in 5 ft of the two center rows (=10 linear ft) of each plot were clipped from their roots and collected in burlap bags. Plants in bags were dried in forced air driers at 120 F for approximately 5 days. Beans were threshed using a belt thrasher (Seedburo) set for beans. Final cleaning was with a blower fan and hand picking. Beans were weighed to the nearest 0.1-gram and moisture was determined on a Dickey-John moisture tester. Since the moisture on all samples was uniformly near 8%, the yields are reported as nonadjusted weights. Statistical analysis was done using the SAS ANOVA or GLM. Alpha levels of 0.05 were used for all evaluations. LSD values were calculated and used for mean comparisons.
RESULTS AND DISCUSSION
Soil conditions and temperatures were favorable for normal plant growth early in the season. Timely rains and irrigation helped continue normal plant growth in June. Plants began to flower around June 25. The canopy was well filled at the time of the first spray application on June 30.
Plants continued to flower uniformly for most of the summer. White mold from natural infection was not observed in the field after the second spray application on July 9. A suspension of white mold spores was sprayed on the middle two rows of each plot on July 10 to insure white mold infection. White mold was observed in the field five days later. White mold was quite uniform across the field.
No treatments improved white mold control or increased yields above the check treatment.
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Table 70. Incidence and severity of white mold and yield of edible dry beans.
| Treatment | Rate | Incidence† | Severity‡ | Yield¶ | ||
| July 22 | July 29 | July 22 | July 29 | |||
| Calcium EDTA 3% | 2 qt | 68.0 | 86.0 | 25.6 | 28.2 | 1798 |
| Calcium EDTA 3% | 1 qt | 49.0 | 79.0 | 19.8 | 27.5 | 1590 |
| Crop Booster 8% | 1 qt | 66.0 | 86.0 | 26.5 | 30.9 | 1748 |
| Crop Booster 8% | 1 pt | 70.0 | 86.0 | 22.2 | 32.9 | 1903 |
| Super-Cal 34% | 5 lbs | 67.0 | 76.0 | 17.8 | 31.3 | 1520 |
| Super-Cal 34% | 2.5 lbs | 55.0 | 81.0 | 13.6 | 27.3 | 1688 |
| Calcium 6% | 1.6 gal§ | 53.0 | 83.8 | 16.7 | 22.7 | 1965 |
| Calcium 6% + Boron 0.5% | 1.6 gal§ | 59.0 | 72.0 | 19.9 | 26.8 | 1739 |
| Calcium carbonate | 0.66 gal§ | 61.0 | 80.0 | 23.4 | 24.2 | 1785 |
| Ronilan†† | 1.5 lb | 60.0 | 81.0 | 15.0 | 24.0 | 1663 |
| Check | ---- | 66.0 | 84.0 | 21.0 | 26.0 | 1695 |
| LSD (0.05) | 14.0 | 13.0 | NS | NS | 405 | |
†Incidence based on number of infected plants divided by
total number of observations.
‡Severity is based on average percentage disease of four
replications.
¶Yield based on harvested area of 0.00057 acre (25 sq ft.).
§Adjusted to 1500 ppm of total calcium.
††Had only one spray application on June 30 when dry
beans were at 20% bloom.
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Go to Oakes Irrigation Research Site 1999 annual report
Go to Oakes Irrigation Research Site disease studies