Plants or Crops
All Plants or Crops Content
Is a Fungicide Needed for Developing Corn Diseases?
Corn is starting to tassel in several locations across the state. This is also the growth stage when a fungicide may be applied to control fungal leaf diseases. Diseases currently starting to develop are: anthracnose leaf blight, common rust and eyespot.
Fusarium Root and Crown Rot Developing in Corn
A few corn fields scouted in Brookings County were found with Fusarium root rot at low levels. Infected plants were wilting and upon splitting of the lower nodes revealed brown discoloration of the pith. Root and crown rots developing in corn after the seedling stage are usually caused by Fusarium spp. and can be enhanced by injury to the roots or crown, mainly by insect feeding.
Bacterial Blight Common in Soybean Fields
Several soybean fields scouted the week of July 15, 2019 were found with bacterial blight developing. The frequent rains experienced in most soybean growing counties have led to the development of this disease. Bacterial blight affected leaves are most evident on younger leaves in the upper canopy.
Current Weather Conditions Are Conducive White Mold Development in Soybeans
Frequent rains and overcast conditions continue to occur in South Dakota’s main soybean growing counties. These conditions favor white mold development. In some of these counties, soybean is already at R1, which is also the best timing for fungicide application targeting white mold control.
Diseases in Winter Wheat Imply High Inoculum for Spring Wheat
Winter wheat is past the need for an in-season fungicide application. However, many spring wheat fields are yet to flower, making them prone to disease development. A few diseases, including leaf rust, stripe rust, and Fusarium head blight have developed in winter wheat. This implies that there is enough inoculum available for these diseases to develop in spring wheat; especially East River, where rainfall has been frequent.
Bacterial Blight Developing in Oats
Oats scouted in a few fields in the Eastern and South Central parts of the state were found with bacterial blight developing on the lower leaves. Plants infected have leaves with water-soaked brown longitudinal lesions in the top-half of the leaf. Severe symptoms can lead to premature leaf death.
Stripe Rust and Leaf Rust Developing in Winter Wheat
Stripe rust and leaf rust were found in winter wheat plots at the SDSU research farm in Aurora. Observation of these two rusts indicates that we have inoculum in our area, therefore winter wheat fields should be scouted until wheat is done flowering.
Use the Scab and Leaf Disease Forecasting Tools to Decide on Fungicide Application in Wheat
Fungicide application in winter wheat has consistently shown to prevent yield loss caused by fungal diseases. However, in some cases, a fungicide application may not always result in a profitable yield when disease pressure is low. Disease forecasting tools can aid fungicide application decisions and hence improve on the profitability of fungicide application.
Frogeye Leaf Spot of Soybean
This fact sheet is about a soybean disease that is increasingly becoming more severe in South Dakota. Moreover, fungicide resistance for this pathogen has been detected in South Dakota.
Winter Wheat Disease Update: Wheat Streak Mosaic and Tan Spot Developing at Low Level
Winter wheat fields scouted the week of May 27, 2019 in South Central South Dakota were found with wheat streak mosaic virus and tan spot developing at very low levels. Both diseases were found in non-rotated wheat fields.