Numbered Publications: PPFS-AG-S
PPFS-AG-S-24: Soybean Cyst Nematode Management Recommendations for Kentucky, 2015
Don Hershman | Nov. 1, 2014 (Reviewed)
SCN-resistant soybean varieties are an essential tool in the management of SCN. Although some of the early resistant varieties lagged behind susceptible varieties in yield, newer resistant varieties adapted for use in Kentucky do not suffer the same yield penalty. In fact, in the absence of SCN, it is common for modern SCN-resistant varieties to out-yield the best susceptible varieties in university research trials.
PPFS-AG-S-9: Sampling Soybean Fields for Soybean Cyst Nematode Analysis
Don Hershman | Jan. 1, 2014 (Minor Revision)
The soybean cyst nematode (Heterodera glycines, SCN) causes many millions of dollars worth of damage to Kentucky soybean fields each year. This occurs even though damage is mostly preventable and controls are inexpensive. This situation exists because a large number of soybean producers are unaware that cyst nematode is damaging their crops. In most cases soybean cyst nematode will cause significant yield reductions without producing any detectable symptoms in soybeans. When symptoms do occur, they are frequently thought to be associated with some other factor, such as soil compaction or low soil fertility.
PPFS-AG-S-19: Soybean Foliar Spots and Blights
Don Hershman | May. 1, 2013 (Minor Revision)
Soybean foliage is susceptible to a number of fungal and bacterial pathogens. These pathogens cause leaf spots and blights and are generally common in Kentucky; however, few fields in any given year are seriously damaged by foliar diseases. Crop rotation and weather that is unfavorable to disease typically keeps foliar diseases at low levels. Occasionally an extended period of wet and humid weather in July to early August will result in significant amounts of foliar disease and yields may be seriously affected. However, this scenario is relatively uncommon in Kentucky.
PPFS-AG-S-3: Downy Mildew of Soybean
Don Hershman | Sep. 1, 2012 (Minor Revision)
Small, irregular spots on upper leaf surfaces are initially pale yellow in appearance, later becoming gray-brown with a yellowish margin. On the underside of the leaves, the spots have a gray, fuzzy appearance due to the presence of the pathogen. These fungal-like tufts are reproductive structures of the organism and their appearance is diagnostic for this disease. Symptoms frequently occur at low levels throughout the crop canopy. Early leaf spots are non-descript and are commonly confused with leaf spots and pustules caused by soybean rust.
PPFS-AG-S-4: Phytophthora Root and Stem Rot of Soybean
Don Hershman | Jul. 1, 2012 (Minor Revision)
Phytophthora root and stem rot (PRSR), caused by Phythophthora sojae, is infrequently encountered in Kentucky. However, where it does occur, the disease can be quite destructive. Soon after planting, P. sojae can cause damping-off of germinating seeds and/or young seedlings. Severe stand loss often necessitates replanting. Alternately, this pathogen can infect and kill established plants of susceptible soybean varieties any time during the season. Varieties that have some resistance to P. sojae may be stunted, but rarely die. PRSR is primarily a problem in poorly drained fields (due to high clay content, "hard pan," and/or soil compaction) or areas of fields that are prone to flooding.
PPFS-AG-S-1: Brown Spot of Soybean
Don Hershman | Jun. 1, 2012 (Minor Revision)
Brown spot, caused by the fungus Septoria glycines, is present in all soybean fields in Kentucky. In most years the disease causes little to no yield impact; however, up to 15% yield losses can occur in select environments. For example, brown sport tends to be worse where soybeans follow no-till soybeans, where early-maturing varieties are planted, and/or when fields are planted in late April. River bottom fields or fields subject to fog or morning shade are frequently impacted.
PPFS-AG-S-12: Seed Treatment Fungicides for Soybeans: Issues to Consider
Don Hershman | Apr. 1, 2011 (Minor Revision)
Kentucky soybean producers frequently ask the question "Is it advisable to treat soybean seed with fungicides?" There is no pat answer to this question because of the many variables involved. Historically, soybean has not been treated to the same extent that corn and wheat have in the U.S. There are many good reasons for this, and some of them are discussed below. However, the trend is toward greater use of fungicide seed treatment on soybean, both in Kentucky and nationally.
PPFS-AG-S-23: Soybean Rust Fungicide Use Guidelines
Don Hershman | Jun. 1, 2010 (Minor Revision)
Effective use of fungicides to control soybean rust is not very complicated. The whole idea is to wait to spray until the soybean rust risk is at least moderate, and make a fungicide application before significant infection has occurred. This means applying fungicides when plant pathologists in and around Kentucky are "sounding the alarm," but before symptoms are evident. Many soybean producers in the deep South have been using fungicides to control soybean rust since 2005 with considerable success. I believe we will have the same experience if it ever becomes necessary to apply fungicides for soybean rust in Kentucky.
PPFS-AG-S-13: Soybean Diseases Control Series: Soybean Cyst Nematode
Don Hershman | Jan. 1, 2010 (Minor Revision)
Soybean cyst nematode (SCN) exists virtually everywhere soybean is grown in Kentucky. The pest is insidious in that significant yield damage often occurs without the appearance of visible disease symptoms. This is an extremely important point because it suggests that farmers are frequently unaware that SCN is active and doing damage in a field.
PPFS-AG-S-20: Cercospora Leaf Blight in Kentucky
Don Hershman | Oct. 1, 2009 (New)
In most years, Cercospora leaf blight (CLB) is a minor disease problem in Kentucky soybeans. It is one of the more common "late-season" diseases, but usually comes in too little, too late to cause damage. However, in wet, late seasons like the one we experienced in 2009, significant yield and grain/seed quality losses can occur in fields that develop severe CLB before pod fill has completed.
