Growers: Watch for wheat disease

It is so nice to have the sun shin­ning for more than one day at a time! Fol­low­ing Ohio’s worst wet spring con­di­tions in more than 100 years farm­ers across Delaware County are able to get into the fields and con­tinue plant­ing. Hay is being cut for the first time, and farm­ers will have the hay bail­ers rolling soon. Even bet­ter news is that mainly dry con­di­tions will con­tinue into next week, despite the chance of rain and thun­der­storms, accord­ing to the National Weather Ser­vice in Wilm­ing­ton. So, hope­fully we will get the rest of the corn crop into the ground this com­ing week. This has been the busiest farm activ­ity we’ve seen all year.

Watch for Wheat Disease

The scab fore­cast­ing sys­tem is indi­cat­ing moderate-to-high risk for scab in North­ern and North­west­ern Ohio for wheat flow­er­ing at this time. Accord­ing to Pierce Paul, OSU Exten­sion Spe­cial­ist, Plant Pathol­ogy, this risk pre­dic­tion has essen­tially been the same since last Sat­ur­day, sug­gest­ing that con­di­tions have been favor­able for scab dur­ing the last week or so. Although it has not rained since last Fri­day or Sat­ur­day, we have had enough wet and humid days over the last week to keep the risk for scab moderate-to-high. This was the case in sev­eral fields last year where high rel­a­tive humid­ity resulted in rel­a­tively high scab and vom­i­toxin lev­els, even in the absence of fre­quent rain­fall dur­ing flowering.

Pro­duc­ers with fields flow­er­ing at this time should con­sider apply­ing either Prosaro, Caramba or Foli­cur to sup­press scab and vom­i­toxin, Paul said. Such an appli­ca­tion will also pro­vide pro­tec­tion against late devel­op­ment of Stagonospora. Foli­cur is less effec­tive against scab than Prosaro and Caramba, how­ever, none of the three prod­ucts will pro­vide 100 per­cent scab or vom­i­toxin reduc­tion. Paul says that at best you can expect about 50 to 60 per­cent sup­pres­sion. With drier con­di­tions in the fore­cast, the risk for scab may be reduced for wheat fields flow­er­ing late this week or early next week, how­ever, we will keep you posted for more updates and keep your eyes on your local weather con­di­tions and the scab risk tool to see how things develop.

As the wheat enters the grain fill stage of devel­op­ment, tem­per­a­tures, espe­cially dur­ing the nights, will deter­mine the length of the grain fill period, and con­se­quently, how well the crop yields. Above-average tem­per­a­tures are fore­casted for the next two weeks and this will likely shorten the grain fill period con­sid­er­ably, accord­ing to Paul. At tem­per­a­tures above 85 F, pho­to­syn­the­sis slows down and even­tu­ally stops, mean­ing that the pro­duc­tion of mate­ri­als to fill grain stops. At these same high tem­per­a­tures, res­pi­ra­tion increases, burn­ing up sug­ars and result­ing in lower yield and grain qual­ity. The process of burn­ing up food through res­pi­ra­tion at high tem­per­a­tures with­out replac­ing it via pho­to­syn­the­sis is com­monly referred to as the wheat crop “shut­ting down.” So, if the fore­cast is cor­rect and we do indeed get sev­eral hot days over the next few weeks, we can expect a shorter grain fill period and lower yields than in cooler seasons.

Rob Leeds is an OSU Exten­sion Edu­ca­tor for Agriculture/NR.

Posted by Rob Leeds on Jun 4 2011. You can follow any responses to this entry through the RSS Feed. Comments can be made below.