We generally compare our current situation with the most recent past. I believe this is the case with the winter we have just experienced. Those of us who have seen enough growing seasons can think back to similar winters in the past. We already know there has been damage to fruit crops, but fortunately most vegetable crops have the advantage of being planted on an annual basis. However, this does not mean they escape the effects, positive or negative, of a harsh winter.
Asparagus is the only perennial vegetable crop of any consequence in Michigan. Asparagus can be winter-damaged if the ground gets cold enough. For this to happen, the ground needs to be mostly clear of snow and the air really cold to lower the ground temperature enough to cause damage. Fortunately, the snow cover was sufficient to protect against those deep, cold temperatures, so I would not expect to see any winter problems with our asparagus plantings.
I would expect the winter to have little to no effect on 2014 disease pressure. Many diseases overwinter in the soil, in plant debris or carried from other areas on wind currents. The snow cover again would keep temperatures within the suitable survival range for those diseases overwintering in soil and plant debris. The only effect it might have on wind-blown diseases would be a slight delay on inoculum arrival and, therefore, symptom expression.
The cold winter could have an impact on overwintering insect populations. Insects overwinter in the ground, in cracks and crevasses of trees and other plants and in plant litter in the hedgerows around production fields. If temperatures get cold enough, it can kill some but not all of that population. Insect mortality is most often seen if there is a warm up that causes insects to become active and then a return to cold. We did not get those conditions and the heavy snow cover would again protect those insects living on the ground. Since insect development is directly dependent on temperature, emergence of local, overwintering populations is expected to be delayed. This may not be true for insects such as certain leafhoppers and corn earworm that migrate in from southern states.
There will always be exceptions and two of them could be the corn flea beetle/Stewart’s wilt and the cucumber beetle/bacterial wilt relationship. Spread of Stewart’s wilt and bacterial wilt are dependent on their beetle carriers and if cold temperatures reduce the overwintering survival of the beetles, then disease incidence will be less or delayed until the beetle population increases. Our temperatures were well below the minimum temperatures needed to affect flea beetle survival, so Michigan State University Extension experts do not expect Stewart’s wilt to be significant in 2014.
The biggest problem I see facing the Michigan vegetable industry is the winter just doesn’t seem to want to go away. This has kept growers out of their fields and delayed field preparation for planting. In recent years, many southern Michigan growers have been able to work their earliest fields in late March or early April. So far, little field work has been done. If the weather does not break soon and the soil dries enough for preparation, we could have later planting dates and, therefore, later harvest dates. This could be a greater problem for the cool season vegetables like peas, broccoli, cauliflower, spinach and others. What could happen with these crops is that the later planting date moves their maturity dates to a later time when it could be quite warm, potentially reducing yield and quality.
The weather for the week of April 14, 2014, is not forecasted to be that conducive for field work. The current forecast is calling for potential rain and temperatures 15 to 20 degrees Fahrenheit below normal, so it looks even more likely that we will have a late start to the 2014 growing season.