Throughout the course of the year we had many wet spells with days or even weeks of precipitation and warmer weather. Although the weather was great for growth this left a challenge for some growers to get their planting in and created a great environment for disease and slugs.
Those of you who saw early damage to corn and soybeans may have wondered what pest was destroying your crops. If you scouted early morning or late evening you may have noticed a reflection pattern on the ground from the slime of slugs. Slugs are becoming a more popular pest due to the increase in no til acres and warmer winters in the past. While an insecticide leaves slugs unaffected due to being a mollusk slugs have limited treatments. One popular molluskicide is a metaldehyde based product a common product used last year was deadline bullet. Slugs are becoming a popular threat to no till growers in the website below you can learn more information on slugs’ life cycle and other options on controlling slugs in the future.
Slugs: http://ento.psu.edu/extension/factsheets/slugs-as-pests-of-field-crops
If you saw premature defoliation in your soybeans you may have spotted an area that got infected by a disease. Two common diseases that I had seen in soybeans that lead to early defoliation of the plant was sudden death syndrome and anthracnose.
Sudden death syndrome (SDS) was most common in wet lying areas in the field after large rainstorms. Areas that had puddles formed were noted to have a increased chance at forming SDS. SDS is commonly confused for other diseases such as brown stem rot. While the disease appears to be similar and untreatable by fungicide SDS is rated on your seed guides. If you are going into a field that is known to have a history of SDS picking a more tolerable variety may be of benefit to your operation. Below is a link with more information on SDS in soybeans.
Sudden Death Syndrome:
https://www.extension.umn.edu/agriculture/crop-diseases/soybean/suddendeathsyndrome.html
Anthracnose’s environment is warm humid weather for prolonged time periods. This is especially seen around the beginning bloom to early pod development stage. Common symptoms of this disease are reddish veins, leaf rolling, twisting in the upper canopy creating a shepherd’s crook and black blotches on the pods and stem of the plant. This disease can be prevented with a fungicide and can affect yield with premature defoliation and pods that are not properly developed. It is important to note that fungicides are used to prevent disease not always to treat disease after infection. Below is a link with more information on the listed disease.
Anthracnose:
https://cropwatch.unl.edu/plantdisease/soybean/anthracnose
Disease in corn maybe not have always been as noticeable as the soybeans when driving on the highway. Although not as noticeable as seeing premature defoliation in fields from R1 on disease was very prevalent in fields this year. The most common foliar disease seen in corn was gray leaf spot and the most common stalk rot was anthracnose.
Gray leaf spot was one of the most common diseases seen this year and this was primarily due to the fact of its greatly favored environment. With warm humid weather throughout the growing season this disease had a favorable environment most of the year. Infection happens around the later vegetative stages going into the early reproductive stages. This is a disease that should be watched closely this foliar disease can affect yield if unmanaged and let to and above the ear leave. Below is a great link on gray leaf spot. This website gives yield effect data and options on controlling this disease.
Gray Leaf Spot:
https://www.extension.purdue.edu/extmedia/bp/BP-56-W.pdf
Anthracnose stalk rot is one of the most prevalent stalk rot diseases in Pennsylvania. This disease thrives in warm weather following silking in corn. The fungi can over winter in corn residue during the winter months and be carried by insects. Anthracnose is typically scouted during the R5 stage. Often the disease can be seen by turning brown or black blotches on the stalk. Scouting can be done by walking into a corn field and giving the pinch and pull test. Pinch the lower nodes to see if they crack or break following this push and pull the plant to a degree to test how much strength is left in the stalk. If more than 15 percent of the stalks appear to be weak due to disease an early harvest may need to be scheduled. By cutting the lower part of the plant the nodes can show a watery or brown appearance to show rotting is present. Prevention can be done through fungicide application before symptoms begin to show. Another tactic for fighting this disease is picking varieties that are highly rated against this disease. Below is a link to learn more information on Anthracnose Stalk rot.
Anthracnose Stalk Rot:
https://crops.extension.iastate.edu/cropnews/2015/09/why-all-corn-dying-anthracnose-blame