N O V E M B E R / D E C E M B E R 2 0 1 7 POTATO GROWER 13 chemical practices are the current options. Cultural Practices Ideal conditions for common scab infection are low soil moisture (less than 65-70% soil moisture) during tuber initiation, soil pH between 5.2 and 8.0 and daytime temperatures above 70o F, so increasing soil mois- ture to 80-85% during tuber initia- tion until tubers are 1 to 1.5 inches in size is reported to reduce com- mon scab incidence. Utilizing a dis- ease suppressive rotation with green manures, such as buckwheat, canola, oat, rye or millet can inhibit Streptomyces scabies. Animal manure has been reported to increase and decrease common scab. It may increase common scab when soil pH increases. Current research by Dr. Linda Kinkel in Minnesota has found local soil microbial popula- tions have reduced common scab. Planting scab-resistant potatoes can be one of the best options, if the cultivar fits the potato operation. Breeding programs have focused on developing cultivars that are resist- ant to common scab and continue to evaluates clones for their resist- ance to common scab. Chemical Practices Chemical management for com- mon scab would likely include a good seed treatment to help main- tain good plant health. A recent study reported that fludioxonil (Maxium) reduced common scab by 58% and a biopesticide containing Bacillus subtilis reduced common scab by 56%. Common scab has been suppressed by pentachloroni- trobenzene (Blocker) as an in-fur- row soil treatment. Chloropicrin (Strike) is a soil fumigant that pro- vides control of a number of soil borne diseases and has been report- ed to work well to reduce common scab. Common scab continues to be a problem for potato growers. This seed and soil borne disease can be managed somewhat through cultur- al and chemical practices, but there are no known methods that provide complete and consistent control. Researchers are continuing to study this disease and look for best man- agement practices to control com- mon scab. It is going to take an ongoing effort of research, breeding and better management practices to decrease common scab severity. For more information visit strikefumigants.com If you have scab problems, we have the solution. Healthy Fields. Healthy Yields. Fumigation with promotes early root development, targets common scab, and suppresses verticillium wilt. By improving Quality and Yield, increases your profit. www.TriEstAg.com TM