What is in this article?:
- Itâ€™s time to make soybean fungicide decisions
- Doubt mild winter increased disease potential
• I am sure some parts of the country probably do have an increased disease risk as a result of the mild winter, but I do not believe Kentucky is among them.
• I do not believe the mild winter of 2011-12 has resulted in greater than normal potential for FPS fungal diseases to occur in Kentucky soybeans.
Recently I was reading an article on the Plant Management Network (http://www.plantmanagementnetwork.org/pub/php/news/2012/TimelyFungicideApplication/) regarding the timely use of foliar fungicides to achieve maximum effect on soybeans.
The article stated that the recent mild winter has resulted in an increased disease risk that growers should take into consideration when making fungicide use decisions. I am sure some parts of the country probably do have an increased disease risk as a result of the mild winter, but I do not believe Kentucky is among them.
In most years, foliar, pod and stem (FPS) fungal diseases of soybeans are held in check by planting adapted varieties (mostly Maturity Group IV varieties), avoiding extremely early planting dates (full-season crops) or planting late (double-crop soybeans), crop rotation, limited-sporadic rainfall and high temperatures during the summer months, and timely harvest.
Typically, measurable yield losses caused FPS diseases — the targets of foliar fungicides — are limited to certain environments like river-bottoms, fields prone to extended periods of dew or fog, and continuous soybean fields.
Early maturing varieties (mainly Group III) are often impacted by damaging levels of FPS diseases, especially when planted early. The same is true for crops that are not harvested on time. However, FPS diseases are usually not that destructive in Kentucky.
True enough, the winter of 2011-12 was very mild, even by Kentucky’s standards. However, if anything, the mild conditions probably enhanced residue breakdown, thereby reducing fungal survival in weed and crop residue, due to increased microbial activity.
Moreover, early planting may have been somewhat more common this year, but the higher than normal temperatures and limited rainfall in April to early-May likely negated the increased risk to FPS diseases normally associated with early planting.