2017
Can Plant Population Play a Role in Reducing Lodging Losses in Soybeans from Dectes Stem Borer?
Contributor/Checkoff:
Category:
Sustainable Production
Keywords:
Biotic stressCrop protectionField management Pest
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Bill Cissel, University of Delaware
Co-Principal Investigators:
Phillip Sylvester, University of Delaware
Cory Whaley, University of Delaware
+1 More
Project Code:
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:

Can plant population play a role in reducing lodging losses from Dectes stem borer in soybeans? This project evaluates the role plant populations can play in reducing lodging losses from Dectes stem borers. It also identifies the ideal plant populations for maximizing stem diameter while maintaining yield potential under irrigated and non-irrigated soybean production. Seeding rate did not have a significant effect on plant height, yield, percent infested stems, percent lodged plants, or lodging loss. However, stem diameter was significantly greater at the lower seeding rates compared to the higher plant populations regardless of irrigation treatment.

Key Benefactors:
farmers, agronomists, Extension agents

Information And Results
Project Deliverables

Report detailing the role plant populations play in reducing losses from Dectes stem borers and recommendations for ideal planting densities under both irrigated and nonirrigated soybean production so that stem diameter and yield potential are maintained.

Final Project Results

Updated November 6, 2019:
Seeding rate did not have a significant effect on plant height, yield, percent infested stems, percent lodged plants, or lodging loss. However, stem diameter was significantly greater at the lower seeding rates compared to the higher plant populations regardless of irrigation treatment. The irrigated plots were significantly taller, had fewer infested stems, fewer lodged plants, and less lodging loss compared to the non-irrigated plots. There were no significant differences between the irrigated and non-irrigated treatments for yield.

Stem diameter was significantly greater at lower plant populations compared to higher seeding rates but this did not reduce the percentage of lodged plants or lodging losses based on the populations evaluated (final stand: 73,000, 96,000, 123,000, and 146,000 plants per acre). However, there is a trend that suggests that as plant populations increase, the percentage of lodged plants also increases. The irrigated plots had fewer infested plants, less lodging, and less lodging losses compared to the non-irrigated plots. One possible explanation for this may be that the non-irrigated plants were more stressed, weakening the plant’s natural defenses and as a result, they may have been more attractive to females for depositing eggs.

There were no significant differences for yield, regardless of seeding rate. This suggests that final plant populations, as low as 73,000 plants per acre have similar yield potential compared to higher plant populations. However, it should be noted that plant spacing was even for all the plant populations evaluated. Results may be different if plant spacing is uneven and there are large skips within rows, especially at lower plant populations. Irrigation did not have a significant effect on yield. Additional research is needed to evaluate the yield potential of lower seeding rates under different growing conditions such as a dry year.

View uploaded report PDF file

Stem diameter was significantly greater at lower plant populations compared to higher seeding rates but this did not reduce the percentage of lodged plants or lodging losses. However, there is a trend that suggests that as plant populations increase, the percentage of lodged plants also increases. The irrigated plots had fewer infested plants, less lodging, and less lodging losses compared to the non-irrigated plots. One possible explanation for this may be that the non-irrigated plants were more stressed, weakening the plant’s natural defenses and as a result, they may have been more attractive to females for depositing eggs.

There were no significant differences for yield, regardless of seeding rate. This suggests that final plant populations, as low as 73,000 plants per acre have similar yield potential compared to higher plant populations. However, it should be noted that plant spacing was even for all the plant populations evaluated. Results may be different if plant spacing is uneven and there are large skips within rows, especially at lower plant populations. Irrigation did not have a significant effect on yield. Additional research is needed to evaluate the yield potential of lower seeding rates under different growing conditions such as a dry year.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.