When it comes to crop disease possibilities, predicting a field’s fortune is not all luck. By making observations and following a few steps, crop consultants and retail sales agronomists can help growers to forecast disease outbreaks that face their operations.
Problematic diseases can change by the year. The trusted advisors to growers should be on the lookout for which diseases are affecting their region in order to help farmers plan accordingly. Last year, many corn growers saw cases of northern corn leaf blight. Earlier this season, seedling diseases were reported as well as early anthracnose leaf blight in corn. More recently, mature lesions of northern corn leaf blight and gray leaf spot have been reported in corn. Growers also need to be aware of possible Septoria brown spot in soybeans.
Caren Schmidt, technical market manager, BASF, says there are new threats in addition to these familiar diseases to consider.
“While traditionally found in cooler, higher elevation climates, cases of tar spot broke out in parts of the Corn Belt last year,” said Schmidt. “Although new to the United States, tar spot should be on every corn grower’s radar this season.”
Understand disease pressures
After knowing which diseases are occurring in their region, the likelihood of an outbreak can be determined by evaluating certain risk factors. Weather conditions are the easiest first consideration. Cold, wet weather – especially early in the season – can commonly cause spikes in disease troubles like anthracnose leaf blight and early onset of northern corn leaf blight.
Diseases from previous seasons have a higher chance of causing repeat challenges for growers thanks to inoculum overwintering in the soil. If a pathogen persists in an environment, then future crops will face immediate exposure and greater risk.
Individual cultural practices can also drive disease, notes the BASF technical specialist. Tillage and crop rotation practices influence the ability of a disease to exist as harmful inoculum. Disrupting or burying inoculum in the soil through field tillage can break the disease cycle by destroying or isolating the pest. Increased crop rotation reduces inoculum in soil even further by depriving any lingering spores of a viable host.
Look to other regions
Southern regions often forecast disease issues for Midwestern states, and can sometimes even cause outbreaks. Rust species, for example, will overwinter in the south and then move north with prevailing winds.
“This year is shaping up to be a high year for rust diseases,” said Schmidt. “Many southern states have reports of soybean rust, and growers have seen southern corn rust earlier than normal, especially in the coastal plain of Georgia.”
With knowledge of nationwide disease activity, growers can better prepared for a particular disease and avoid a potential surprise outbreak.
Protect acres early
By knowing disease threats and pressures both regionally and nationally, growers can take a vital first step in protecting against disease before a problem is at hand. Next comes taking action. Proactive applications of fungicides can get fields ahead of a disease cycle, promoting higher yields along the way, BASF suggests.
More is available about fungicides and other tools for fighting crop disease is at www.agproducts.basf.com.