Zinc Deficient Corn Observed in MS Delta

Over the last several weeks corn has either passed or approached the V2-V5 stage of corn growth. During this time we have received numerous calls about corn having a yellow, streaky appearance. Many of the fields we received calls on have been positively identified as zinc deficient through tissue testing.

Classical zinc deficient symptom. Note the bleached area along the midrib

Zinc deficiency in corn generally occurs early in the season (V2-V5) and manifests itself by producing a distinct interveinal chlorosis and/or white mid-leaf streaking in newly developed corn growth.  However, keep in mind that application of some herbicides (e.g. bleachers) can produce a similar symptomology.  Favorable conditions for inadequate plant uptake of zinc include, low soil test levels of zinc, cool wet soils, high pH, and sandy soils low in organic matter.  Many soils in the Mississippi delta contain one if not most of these conditions at some point during the period of early season corn growth.

Zinc deficient corn near Inverness, MS. (credit Wes McPherson)

Numerous methods of zinc delivery to the corn plant are available such as seed treatments, foliar sprays, or zinc granules for either soil incorporation or application in-furrow.  The best method to ensure that soil test zinc levels are adequate on fields with a history of zinc deficiency is to apply 10 lbs Zn/acre as Zinc sulfate (30-33 lbs product/acre) blended in with the preplant P & K fertilizer application.  In-season corrections to zinc deficient corn will probably be most likely conducted with a foliar spray.  At the V2-V5 growth stage, foliar sprays are perhaps the easiest method to remedy a zinc deficiency, because zinc is only needed in small amounts by the corn plant.  Research has shown that supplying 1 lb actual Zn/acre can correct most deficiencies observed between the V2-V5 stage of corn growth.

Many liquid formulations that contain chelated zinc are on the market in Mississippi.  The available liquid formulations generally range between 9 and 10% zinc and weigh approximately 10 lbs per gallon.  In many instances a gallon of product/acre will supply approximately 1 lb of actual zinc in the above scenario.  However, check the manufacturers label to ensure the proper amount of product is used to supply the rate necessary to correct the deficiency.  Foliar sprays to supply rates greater than 1 lb Zn/acre, can have the propensity to cause leaf burn depending upon spray conditions.

Marginal Zn Deficient syptom. Note the slight yellowing along the Midrib

Zinc deficient corn near Lynn, MS.