Kingfisher County’s small grain crops are subject to a variety of fungal diseases due to damp, cool conditions, County Extension Director-Agricultural Agent Bryan Kennedy said Thursday.

He advised producers to keep a close watch on their fields for signs of the problems.

The county’s grain crops are in a wide range of development this year due in part to rain-forced delays in seeding operations during the fall and a mild winter when plants failed to enter dormancy.

Some fields are entering the boot stage while others are much later.

Kennedy said Oklahoma State agronomists reported numerous fungal diseases in small grain fields – stripe rust, tan spot, septoria – in a video conference Wednesday.

He said tan spot has been noticed locally particularly in no-till and lo-till fields.

(Note: The state has ordered extension offices closed due to the coronavirus pandemic. Kennedy is visiting the office but limiting personal contacts due to medical advisories to maintain social distancing to avoid spread of the disease.)

Kennedy said monitoring fields for fungal infections is recommended to avoid grain losses although most treatment for fungus problems occurs after the flag leaf appears on plants.

Because of the close margin on the crop and the expense of treatments, producers must always balance costs of treatment against potential yield increases, he said.

Appearance of fungi indicates the plants are unhealthy and that can reduce yields, Kennedy said.

Oklahoma State University Extension advises disease prevention by growing resistant varieties as the most economical method of control.

However, a new variety may remain resistant for a few years but become susceptible later as the fungi adjust to the genetic resistance.

“To keep ahead of genetic changes in the pathogen, breeding for resistance must be a never-ending task,” OSU Extension advises.

“Crop rotation, plowing under crop debris, and destruction of volunteer wheat lessens the chances of severe infections by reducing the overwintering sources of the causal fungi. Particularly, with the Septoria diseases and tan spot, removal or plowing under of old wheat straw is helpful in reducing the initial source of infection, OSU Extension related.

“Leaf rust can be reduced by livestock grazing, especially if infected wheat is grazed in the fall. By grazing the infected and exposed wheat leaves, additional disease development is retarded. With the exception of some respiratory problems under extremely severe infections, leaf rust is not harmful to livestock.”

Extension Specialists Ervin Williams Jr. and Larry J. Littlefield reported:

“These fungal diseases can be serious alone or as components of a complex of leaf and stem diseases. Estimates of yield losses caused by these disease are not precise. However, in recent OSU wheat field tests where adequate disease suppression was obtained with fungicides, average grain yield increases ranged from 14 to 16 percent over a period of 11 years starting in 1984. Fungi that infect plants are parasitic, and production losses are mainly caused by the depletion of host nutrients.”