WHEAT DISEASE SURVEY AND FORECASTING    

 

The Extension Service small grain disease survey for south central and southeast ND has been in progress since early June. Twenty-two fields were checked in Wells, Sheridan, LaMoure, Dickey, and Barnes Counties during June 30-July 3. Tan spot was found in 18 of the 22 wheat fields, leaf rust in 21 fields, barley yellow dwarf virus in 11 fields, and Septoria leaf blotch in 7 fields. Also, scab (Fusarium head blight) was found in one winter wheat field in Dickey County on July 3.

 

With daily wet conditions we are currently experiencing, growers continue to contemplate the use of a fungicide to control scab and leaf spot diseases in wheat. An aid in forecasting or confirming favorable conditions for leaf spot disease (tan spot, septoria, and leaf rust) and scab infection is available from NDSU at the following website:

 

As examples, at Carrington during July 2 to 6 conditions have been favorable for tan spot and leaf rust infection in wheat. At Baker (Benson County), scab spore counts were high on July 3.

 

WHEAT MIDGE UPDATE

Orange wheat blossom midge are being found in our area, but currently no reports have been received of midge reaching economic thresholds (average of 1 midge/4-5 wheat heads). The following is a listing degree day (DD) units accumulated on July 6, based on the ND Ag Weather Network, for selected south-central and southeast ND locations: Oakes = 1782; McLeod = 1746; Linton = 1651; Edgeley = 1586; Carrington, Dazey, Jamestown, McHenry, Robinson, and Streeter = 1509 to1539; and Harvey = 1445.  The following table lists predicted % emergence of midge based on DD units:

 

DD units

Wheat midge event

1300

10% of the females will have emerged

1475

about 50% of the females will have emerged

1600

about 90% of the females will have emerged

1800

emergence completed and scouting can be terminated

 

Continue scouting wheat fields that are at risk until 1800 DD have been reached.

Details on wheat midge scouting and management may be obtained from NDSU Extension Service offices.

 

 

DRY BEAN HERBICIDE APPLICATION TIMING LIMITS AND CULTIVATION TIMING

Delays in herbicide application in dry edible bean likely have occurred due to frequent and heavy rainfall, windy conditions, etc. The following are application timing limits for post-emergence herbicides based on dry bean stage: Pursuit and Raptor = Prior to flowering. Assure II, Poast, Select and Reflex = 30 days or more before harvest. Basagran = No crop stage restrictions. Refer to the herbicide label for other herbicide application timing considerations including weed size.

Also, consider the following label recommendations regarding the timing of between-row cultivation following post-emergence herbicide application in dry bean: Basagran = Do not cultivate within 5 days of application. Timely cultivation 2-3 weeks after application may assist weed control. Pursuit and Raptor = For maximum weed control, cultivate 7-10 days following application. Reflex = Timely cultivation 1-3 weeks after application may assist weed control. Assure II = Do not cultivate within 7 days after application as damage to the grass roots may result in unsatisfactory control. Optimum timing for cultivation is 7-14 days after application. Poast = Do not cultivate within 7 days after application. Cultivating 7-14 days after treatment may help provide season-long control. Select = Cultivation of treated grasses within 7 days after application may reduce weed control.