Diagnosing Plant Problems

The following plant labs can help diagnose plant pests and problems. Contact the lab for instructions before submitting plant samples.

NDSU — Waldron Hall, Room 206, PO Box 5012, Fargo, ND, 58105, ph (701) 231-7854, email: diaglab@ndsuext.nodak.edu , web site: www.ag.ndsu.nodak.edu/diaglab .  Services include insect and plant identification, plant disease diagnosis, herbicide injury diagnosis, and soybean cyst nematode screening.

UM — Plant Plant Disease Clinic, 495 Borlaug Hall, 1991 Upper Buford Circle. St. Paul, MN 55108-6030, (612) 625-1275. Web site: www.plpa.agri.umn.edu/extension/plantdiseaseclinic.htm .  Services include insect, plant, disease, virus ID, as well as seed quality testing.

SDSU — Oscar E. Olson Biochemistry Labs, SH 059, Box 2170. Brookings, SD 57007-1217, ph (605) 688-6172, email Nancy_Thiex@ sdstate.edu, web site: anserv.sdstate.edu.  SDSU Plant Disease Clinic: plantsci.sdstate.edu/planthealth/PDClinic.htm l, ph (605) 688-5157

More labs can be found on the online link: www.ag.ndsu.nodak.edu/diaglab/diaglab_chemlabs.htm

These labs (as well as certified crop advisers) can help determine key factors that affect crop productivity, such as:

Soil organic matter tests — Knowledge of the organic matter level will serve as a guide in selecting an effective herbicide and rate of application, as well as helping to assure crop safety. Testing once every five years should be adequate.

Herbicide spray water analysis — High salt levels in spray water can reduce weed control in nearly all situations.  Calcium, and to a lesser degree, magnesium, are antagonistic to 2,4-D and MCPA amine, dicamba, and glyphosate. 

Plant tissue analysis — This indicates the nutrient status of plants at the time of sampling, serving as a monitoring tool for determining the adequacy of current fertilization practices.  Plant tissue analysis will also detect unseen nutrient deficiencies and may confirm visual symptoms of deficiencies. Toxic levels also may be detected. Combined with soil test information, a plant analysis report can help a producer tailor fertilization practices to specific soil-plant needs.

Reducing Spray Drift

NDSU research has demonstrated weed control from Roundup Ultra, Raptor, Pursuit, Distinct, Assure II, and Poast to be comparable between drift-reducing nozzles and standard flat-fan nozzles. The same results were observed with fast acting contact herbicides of Gramoxone Extra and Aim. Reflex applied with drift-reducing nozzles was the only herbicide examined in which weed control was found to be slightly less as compared to a standard nozzle. All other herbicides gave similar control regardless of nozzle.  For more information on managing spray and vapor drift, refer to NDSU Extension Circular A-657, “Herbicide Spray Drift” and Circular WC-751 “Documentation for Suspected Herbicide Drift Damage,” both of which can be found on the Internet under NDSU online weed control publications: www.ext.nodak.edu/extpubs/weeds.htm .