Effective management practices that reduce the impact of NCLB include selecting resistant hybrids, reducing corn residue, timely planting, and applying foliar fungicides.
1. Choose Resistant Hybrids
An important first step in managing NCLB is selecting resistant hybrids based on disease reaction characterization scores. The Pioneer NCLB rating reflects the hybrids’ expected performance against the major NCLB races predominant in your area. As race shifts inevitably occur, continued testing by Pioneer researchers may result in a rating adjustment for some hybrids. Use of multigenic resistance by breeders increases hybrid stability as NCLB races shift over time.
Hybrids should be selected based on all important traits needed for a field. In addition to NCLB resistance, select hybrids with high yield potential, appropriate insect resistance traits, suitable (usually full-season) maturity for the area, and consistent performance demonstrated in data from multiple locations and years. Strong emergence, stalk strength, and drought tolerance are other agronomic characteristics to consider in helping to optimize stands and harvestable grain yields.
2. Reduce Previous Corn Residue
Reducing corn residue decreases the amount of NCLB inoculum available to infect the subsequent crop. Crop rotation is one effective method of reducing residue. In addition, any form of tillage that places soil in contact with corn residue promotes decomposition and decreases the amount of residue that survives to the subsequent cropping season. Stover harvest for cellulosic ethanol production or animal feed is another means to reduce corn residue and disease inoculum. However, reducing corn residue does not protect against spore showers carried into a field on wind currents.
3. Plant Timely
Timely planting can often help hybrids escape the most severe damage from NCLB if crop development outpaces normal disease progression. The latest-planted corn in an area may be infected when plants are smaller, resulting in the disease progressing more rapidly relative to the crop. However, in cases of high disease incidence, both early- and late-planted corn may be severely damaged.
4. Consider a Fungicide Application
Various foliar fungicides are available to help control or suppress NCLB development (Table 3).