This proposed 3-year project would continue to evaluate planting date relative to adult
emergence and expand this effort to include the use of an insecticide seed treatment. In
addition, growers would be identified to evaluate and compare the results of planting
dates on their farm relative to soybean gall midge emergence. Results from this study
would provide farmers with an understanding of risk for overwintering soybean gall
midge infestation with different planting dates as well as the potential for seed treatments
to mitigate early season infestations.

The first objective will be to evaluate soybean gall midge infestation and injury of soybean planted
at four different planting dates with and without an insecticide seed treatment.
For the second portion of the project, farmer fields will be monitored for adult emergence data as
part of an ongoing NCSRP and NSB project. To add to this project, adjacent farmer field’s will be
evaluated for the planting date and the use of seed treatments relative to adult emergence at
these sites.

For the planting date and insecticide study, a research site will be located in fields
adjacent to areas with significant soybean gall midge pressure the previous year. The first
objective will be to evaluate soybean gall midge infestation and injury of soybean
planted at four different planting dates with and without an insecticide seed treatment.
Soybean will be planted in 10 x 30 ft plots at a population of 140,000 plants per acre in a
split-plot randomized complete block design with a minimum of 4 replications. Split-plot
treatments would consist of soybean seed with and without an insecticide seed treatment
at a labelled rate. Insecticide seed treatment will be chosen based on the most effective
product identified from industry-funded university trials over two years of data. Planting
dates will start on April 15th with plantings occurring every two-weeks until June 1st for a
total of four planting dates. Overwintering adults will be tracked using emergence cages
in an adjacent source field. In addition, 1st and 2nd generation adult emergence will be
monitored from the non-yield rows of the planting date study. Plots will be evaluated 2-3
weeks after adult emergence to determine the percentage of infested plants and assigned
an injury score based on the number of dead or dying plants. Additional evaluations
would be made 2-3 weeks after each adult flight. Plant development stage will be
recorded every week following emergence and yields will be taken on plots at the end of
the growing season.
For the second portion of the project, farmer fields will be monitored for adult
emergence data as part of an ongoing NCSRP and NSB project. To add to this project,
adjacent farmer field’s will be evaluated for the planting date and the use of seed
treatments relative to adult emergence at these sites. These adjacent fields will be
evaluated using the same methods described in the first experiment. Hand harvests will
be made on these adjacent fields at the end of the season.

Planting date has always been an important consideration for soybean farmers. Knowledge of the
impact on this tactic with significant soybean gall midge pressure would allow farmers to potentially
prioritize fields to reduce risk of soybean gall midge injury. Studies of its interaction with seed
treatments would provide an evaluation of the value of this tactic in combination with planting date
to mitigate losses and maintain production of soybean.