Cool nights, full new backpacks, smiling parents, fall is nearly here and the growing season is winding down. Disease in either the corn or soybean crop has not been a monumental issue this season. A few fungi though are still likely to become more active.

In the soybeans, sudden death syndrome (SDS) has shown up in some area fields. Symptom presentation was fairly late this year so yield losses are not expected to be serious. Nevertheless, for future management you do need to know if that's what's causing the telltale brown and dying patches. You can't diagnose SDS unless you go out to the field and split stems of affected plants. Other soybean diseases that have similar leaf symptoms such as brown stem rot or late cyst nematode are endemic to our area and each is managed differently. Split stems from the soil line and up to look for diagnostic symptoms. Low on the stem, the tissue just outside the pith will appear to have grayish streaks, as if you had dirt on your knife before splitting the stem, and this is diagnostic for SDS. The pith should appear normal. The root system will also appear to have a reddish brown rot, after all, this is a root rot despite the dramatic leaf and subtle stem symptoms it causes.

Now for something completely different, Charcoal rot. You may be surprised that I am bringing up a disease that is considered a drought pathogen given the timeliness of the rains this season. I have a reason though and it's soybean aphids. Soybean aphids having been not very active the past couple of seasons are making up for it in many areas of the state this year. The aphids get busy sucking sap out of the plants and this presents a situation for the plant not so different from drought. When we last had a large population of soybean aphid in our area, charcoal rot was also present and not noticed in many of those fields because of the overriding aphid problems. Have you had a soybean aphid infestation this season? If you have, then take a look for charcoal rot in those fields.

Leaves may first appear lighter and fairly speckled with lesions. Or more typically, you will see plants out and out wilting and dying. When you split the stems it will look like someone took a fine point black pen and scribbled inside the stem, this is diagnostic.

This pathogen can survive for years in soil and has a wide host range that includes corn and grain sorghum. Charcoal rot is difficult to manage. There are some differences in varietal susceptibility however, most varieties are susceptible. However, some good news! The USDA has developed a new breeding line, DT97-4290. This is a potentially valuable source of resistance to charcoal rot for soybean breeders and producers in areas experiencing yield losses due to the disease.

Now a very brief word about the corn crop and ear rots. Weather has been conducive for development of one of our more common ear rots, Diplodia. Diplodia ear rot is first noticed by the bleached appearance of the husk. When you peel back the husk, you will see a white, fluffy fungus. Diplodia will not produce toxins in the grain, but the kernels will be very lightweight and shriveled in appearance. Scouting for Diplodia or other ear rots can be done by making observations of five ears in ten random areas of the field.