Harvest season is officially underway, with great progress being made in our soybean fields and the grain corn harvest approaching very quickly. Your NK Agronomy team has been out scouting and watching for potential concerns in both corn and soybean crops.

Here are some key takeaways from our time in field:

Soybean Disease Pressure – Pod and Stem Blight

Pod and stem blight is a disease that often occurs early in the season, however its visual damages unfortunately only reveal themselves later in the season when management is no longer an option. Pod and stem blight has been identified at many locations throughout Ontario and Quebec. Outlined below are some disease details and some management considerations for the future.

Infection

• The fungus overwinters in pod and stem blight infected seeds and crop residue
• The fungus infects early in the season when water splashes from infected residue onto the soybean plants
• Wet, warm, and humid environment during pod development stages favours disease establishment
• As the soybean crop reaches maturity, the visual symptoms begin to appear

Symptoms

• Small black dots / specks positioned in rows on stems, petioles, and pods
• Infected pods can produce infected seeds that are often wrinkled, cracked, and mouldy resulting in poor seed quality

Management

• Tillage and infected soybean residue management can help reduce the risk of infection
• Crop rotation
• Selection of varieties with good pod and stem blight tolerance ratings
• Fungicide application at R3 to R6 stages
• Harvest pod and stem blight infected fields in a timely manner to prevent worsening infection

Potential Corn Standability Issues

Some areas across Ontario and Quebec have been subject to an excess amount of rain and moisture throughout the growing season. These wet and humid environments favour a variety of issues in a corn crop including foliar diseases, root rots, and stalk rots which can all increase the probability of corn standability issues. Plant stresses often reduce the photosynthesis rate which forces the plant to use carbohydrates that are stored in the stalks and roots. Unfortunately, the utilization of these reserves weakens the overall stalk and root health. Severe weather such as heavy rains or high winds can cause stalk breakage and lodging in fields where stalk and root health is not optimal.

Foliar Diseases

This year, many areas have been significantly affected by diseases like northern corn leaf blight and tar spot, as well as various other foliar infections. A significant infection of any one of these diseases can cause plant stresses that can eventually result in poor stalk health. Foliar diseases like tar spot and northern corn leaf blight reduce the leaf area available for photosynthesis requiring the plant to cannibalize the stalks to find additional sugar required for grain fill. This reallocation of sugars from the stalk can cause reduced standability and increased lodging risk. Management of foliar diseases through a fungicide application can help minimize chances of late season cannibalization which can then reduce the potential of lodging issues.  

Stalk and Root Rots

Most stalk and root rot infections are caused by pathogens who take advantage of stressed or injured corn plants. Some of the common stalk and root rots that can affect a corn crop include Anthracnose, Diplodia, Fusarium, and Giberella stalk rots. All of these diseases can cause lodging issues leading to potential yield losses and unfavorable harvest conditions. Choosing hybrids that have strong root and stalk strength can be a great steppingstone in reducing standability issues.

Use the NK Corn Seed Finder to see how our portfolio could perform on your farm.

Pre-Harvest Considerations

Scouting to determine whether stalk rots are present in a field is an important practice that can allow one to make appropriate harvest management decisions. Methods such as the “pinch test” and the “push test” can help identify if potential stalk issues are present. The “pinch test” is done by pinching the stalks at the bottom nodes of the plant on multiple plants away from headlands and observing if the stalk is hollow and fragile which would signal rot damages. The “push test” is done by pushing corn plants at a 30–45 degree angle to see if it lodges or returns to its initial position. If these two tests show negative results such as hollow and fragile stalks and plants that did not return to their upright positions, a timely harvest prior to lodging will reduce the struggles of harvesting a lodged corn field. 

On behalf of the entire NK Seeds team, we wish you all a safe and successful harvest season. Be sure to watch out for our upcoming Field Evaluation Trial Results emails to see how some of our favourite varieties and hybrids are performing this season. 

If you have any questions or concerns, please reach out and we will be happy to help!

Cheers,
The NK Agronomy Team

These are general considerations. Always consider the specific situation on your field and exercise good agronomic practices. 

Performance evaluations are based on internal trials, field observations and/or public information. Data from multiple locations and years should be consulted whenever possible. Individual results may vary depending on local growing, soil and weather conditions. Always read and follow label directions.

Syngenta hereby disclaims any liability for third party websites referenced herein.