It is extremely important to know which pathogen is causing damping-off problems and which fungicide to properly apply. The key to controlling damping-off is being proactive instead of reactive. Always refer to the fungicide label for crop use, pathogens controlled, and application rates.

Damping-off is caused by a number of important vegetable pathogens and is very common during the spring. Damping-off can kill seedlings before they break the soil line (pre-emergent damping-off) or kill seedlings soon after they emerge (post-emergent damping-off). Common pathogens that cause damping-off include Pythium, Phytophthora, Rhizoctonia and Fusarium spp.

Control of damping-off depends on a number of factors. First, is recognizing the conditions which may be leading to the problem (i.e., weather/greenhouse growing conditions) and second, identifying the pathogen causing the problem.

Conditions Favoring Damping-off

Although all four pathogens are associated with damping-off, the conditions which favor their development are very different. In general, Phytophthora and Pythium are more likely to cause damping-off in cool, wet or overwatered soils that aren’t allowed to dry out due to cloudy weather or cooler temperatures. Conversely, Rhizoctonia and Fusarium are more likely to cause damping-off under warmer, drier conditions especially if plug trays are kept on the dry side to help reduce transplant growth. [Read more…]

Seed corn maggot larvae and adult flies have been detected in early seeded zucchini squash fields in Gloucester County this week. They are most likely in other areas of Southern New Jersey. Seed corn maggots can also attack other vegetable crops like beans, peas, cucumbers, melons and sweet corn. Cool and wet weather increase activity and survivability of this early season pest. When adult maggots lay eggs near the planting hole, eggs can hatch in just a few days after being laid. Maggots then can burrow into seeds or seedlings, feed for a period of 2 to 3 weeks and then develop into egg-laying adults. There can be many generations per year, but activity is heightened during periods of cool and wet weather.

Adult flies are most abundant in fields with cover crops, fields that have just been tilled, or in fields that have had manure applied. When a seed or seedling is attacked, it may continue to grow, but will be weak and not produce a crop. Preventative control methods are most effective, since once larvae are found causing damage in the field, they are difficult to control underground. Some commercial insecticide seed treatments are available. See page 112 of the Mid-Atlantic Commercial Vegetable Production Recommendations, 2018 guide. This information can be downloaded at http://njaes.rutgers.edu/pubs/publication.php?pid=E001

Other preventative methods include row covers to create a barrier between the insect pest and the seeds or seedlings, waiting to plant in the field until soils and air temperatures are warm enough to quicken germination and plant growth, and selecting fields for early plantings with low organic matter and that do not remain wet for long periods.