Warm, wet conditions across Nebraska the past two weeks created optimal conditions for crop diseases. This update looks at identification and management of three diseases in corn: southern rust, which is expanding in the state, bacterial leaf streak, and diplodia, which is new to Nebraska.
As conditions heated up the last two weeks, the fungus causing phytophthora root and stem rot became active in irrigated fields and those fields that received significant rain over the past couple weeks. Growers are encouraged to scout for this disease and, if found, manage through seed selection and treatment for the next crop.
Figure 1. Southern rust has been confirmed in corn in eight eastern Nebraska counties and growers are urged to scout from now through August, as weather conditions are quite favorable for its development.
Southern rust has been confirmed in corn in 8 eastern Nebraska counties and growers are urged to scout vigilantly to schedule optimal timing of treatment, if needed. Most systemic fungicides can provide protection of leaves from future infections for 21-28 days.
Several diseases, as well as other problems that look like diseases, have been confirmed in corn samples from around the state. These diseases can be difficult to differentiate from each other and from abiotic causes. This story offers photos and brief descriptions to aid your diagnosis before making treatment decisions.
Holcus spot in corn was among the diseases diagnosed by the UNL Plant and Pest Diagnostic Lab in samples submitted June 15-27. See what diseases were confirmed in corn, soybean, wheat, and hops.
Bacterial leaf streak disease has been confirmed on a sample submitted to the UNL Plant and Pest Diagnostic Clinic from Adams County. The corn was at the V4 growth stage and represents the earliest that the disease has been confirmed in a field.
