Wisconsin continues to rank first in the production of snap beans and the acreage planted to green peas comes in third in the nation. Yields, however, continue to be variable and depend, in large measure, on paying close attention to rotations, following crops where fumigation is used, close observation of root health and careful irrigation to avoid the ravages of white mold. The five year (1998-2002) yield average for snap beans was 3.79 ton/acre while peas averaged 1.86 tons/acre. We can all look at exceptional snap bean fields yielding close to 5 tons/acre and pea fields running 3 tons or more, but we can also recall fields where the grower is lucky to recover the cost of the seed. Root rot is one of the key limiting factors determining the yield of both crops.

Years ago I heard the story about a snap bean producer who was warned by the world famous plant pathologist, Dr. J.C. Walker, that he needed to follow a minimum of a three-year rotation to avoid root rot and that the grower would have no future if he grew snap beans as a monoculture in the central sands area of Wisconsin. The grower promptly responded that he already followed a three year rotation, growing for Company A the first year, Company B during the second year and completing the rotation with Company C during the third year. I can only imagine Dr. Walker’s response and wish that I’d been there in person. The story still gets a chuckle at grower meetings, but the message is still just as pertinent. Without careful attention to rotation and the root rot that accompanies a lack of rotation, disease losses can be costly.

Root rot is still prevalent today, especially in seasons with wet soils during the early portion of the growing season and particularly in fields with too short a rotation between susceptible crops. The early portion of the past growing season provided the cool wet conditions that favor root rot on peas and the excessive rainfall of May and June provided just the right conditions favoring bean root rot on the early planted fields. Subsequent stands of both crops were often spotty and plant roots were commonly decayed. As we moved into July, pea fields turned yellow before harvest, maturity was spotty within fields and yields were highly variable. The saving grace for many growers was the cooler than normal temperatures that helped to reduce potential losses and the number of passed fields.