D3201: Effect of pre-plant calcium silicate on soybean gall midge (Diptera: Cecidomyiidae) abundance and plant injury

Since 2018, Soybean Gall Midge Ressiliella maxima Gagné (Diptera: Cecidomyiidae) has become an important pest of soybean with the potential to cause up to 100% yield losses for the first 30 m of field edge. Adult females lay eggs in the fissures located in the base of soybean stem, and after eggs hatch, the larvae feed on plant tissue. Nutrient studies with other pests have shown that silicate provides structure and rigidity to aboveground plant parts and can potentially protect plants from biotic stressors. A field research study was conducted to evaluate if different rates of calcium silicate have an impact on soybean gall midge abundance and plant injury. Calcium silicate was applied at three different rates (0 ton/ha, 3 ton/ha, 6 ton/ha) one day before planting soybean. The number of larvae, plant injury score, and yield were collected during the season to evaluate if silicate could mitigate soybean gall midge injury. The results of this study can provide a better understanding of the potential of silicon as a management tactic for this new pest in soybean.