Fusarium Head Blight Update – June 11
/0 Comments/in Uncategorized /by earthlingCurrently, wheat is still ranging from early heading to well past flowering growth stages around the state. We are still receiving questions regarding disease management decisions, especially if we should be concerned for Fusarium head blight. Recall the critical period for infection by the pathogen that causes FHB (Fusarium graminearum) is during flowering and requires warm and humid conditions (i.e., moisture). This period lasts approximately 7 days.
Short Wheat Does Not Necessarily Mean Reduced Straw Yield
/0 Comments/in Uncategorized /by shawn conley spconley@wisc.eduAs most wheat across Wisconsin has headed, county agents as well as crop scouts alike are commenting on the overall “shortness” of the 2009 winter wheat crop. It has been well documented that plant height alone is a poor predictor of straw yield. However, Morrison et al. (2007) found a strong relationship among plant height, grain yield, and straw yield in high yielding wheat varieties in Northern Illinois (Predicting Wheat Straw Yields in Northern Illinois). A more critical factor for Wisconsin growers in 2009 would be their planting date. Donalson et al. (2001) found that planting date proved to be a strong driver in increasing straw yield (earlier planting date increased straw yield). In Wisconsin many acres of wheat were planted later than normal due to delayed corn and soybean harvest. Wisconsin growers also experienced significant winter-kill that thinned wheat stands. Though these thin wheat fields did compensate somewhat through increased tillering, straw yields may be reduced.
Edwin Donaldson, William F. Schillinger and Stephen M. Dofing. 2001. S traw Production and Grain Yield Relationships in Winter Wheat. Crop Science. 41:100-106
Pay Attention to Wheat Growth Stages
/0 Comments/in Uncategorized /by earthlingThe winter wheat is rapidly advancing around the state, based both on our observations in the field as well as from reports around the state. It is very important that you closely examine the growth stage if considering the application of a foliar fungicide. For example, when we examined the winter wheat variety trial at Lancaster today, wheat ranged from Feekes 10.4 (heads approximately 3/4 emerged) to Feekes 10.5.1 (anthesis) (Figure 1). Many fungicides that are used for control of foliar diseases, including Headline, Quilt, Quadris, and Stratego, for example, are only labeled until Feekes 10.5 (full head emergence). Applications made after this growth stage are considered off-label.
Cool Temperatures Causing Crooked and Broken Wheat Heads
/0 Comments/in Uncategorized /by shawn conley spconley@wisc.eduTemperatures at our winter wheat variety testing sites (Janesville, Arlington, Lancaster, and Chilton) ranged from the mid 30’s to the high 40’s in the early morning hours of June 1st. Though these temperatures are generally not low enough to cause yield loss we are hearing initial reports of wheat heads being caught in the boot or in the extreme being tangled in the flag leaf (Images 1 and 2). This symptomology is most prone in awnletted wheat varieties (varieties with very short awns), but can also occur to awned wheat. If wheat heads are merely bent then yield loss is unlikely however if wheat heads are completely snapped off then yield loss has occured and growers should contact their crop insurance agent.
If entire fields are showing uniform injury or patterns appear check spray records and timings to ensure that head damage is environmetnal and not herbicidal as growth regulator herbicides such as dicamba and 2,4-D can cause epinasty (twisting) and head malformation.