Pathogens such as Fusarium, Pythium, Phytophthora, Thielaviopsis and Rhizoctonia that cause pre- and post-emergent damping-off can cause serious problems in organic transplant production.
Remember, Phytophthora and Pythium are more likely to cause damping-off in cool, wet soils. Conversely, Rhizoctonia and Fusarium are more likely to cause damping-off under warmer, drier conditions. In general, Pythium tends to kill seedlings before they emerge whereas Rhizoctonia and Fusarium tend to kill seedlings after emergence. There are exceptions to the rules, but none the less, all damping-off pathogens can cause serious losses if not identified and controlled properly. Remember seeds or transplants that sit in cold, wet soils for prolonged periods of time are more prone to damping-off. Outside weather conditions also play an important role in potential disease development in spring transplant production. Most importantly, daily watering schedules need to be monitored and/or adjusted so as not to overwater during cool, cloudy periods or underwater during bright, warm, sunny days. Always do your watering early enough in the day so leaves are dry going into the overnight. [Read more…]
