Weed Science General Conclusions: Soybean stand was not affected by PRE herbicide use, but rather by planting date, with early planting dates resulting in reduced stand. Even under non-optimal environmental conditions for soybean development and metabolism during early planting, PRE herbicide use at planting did not compromise soybean stand. At all three sites, the earliest planting date (PD1) resulted in higher weed density exposed to POST herbicide applications, with common lambsquarters at PPAC, giant ragweed at TPAC, and waterhemp at SEPAC. For common lambsquarters and giant ragweed, the increased number of plants exposed to POST herbicide in the earliest planting dates (22 March at PPAC and 2 May at TPAC) can be attributed to anticipating competition between the crop and weeds, and matching the planting date with the peak emergence period for those weeds. While early planting can lead to increased yield, it may also increase herbicide resistance selection pressure, as more weeds are exposed to POST herbicide applications.
Entomology General Conclusions: ACRE. Only bean leaf beetles were recorded as no other pest were observed. No significant main effects and interactions between planting dates and seed treatments were detected for pest count and defoliation. Bean Leaf Beetle count and defoliation percentage remain below economic threshold. Soybean yield was significantly higher for planting dates on 14 Apr and 27 Apr compared to 11 May and 31 May. PPAC: Only bean leaf beetles and white grubs were recorded as no other pest were observed. There was a significant interaction between planting date and seed treatment for pest count. Pest count was significantly lower in nontreated control compared to CruiserMaxx APX soybean seeds with thiamethoxam and four fungicides thiamethoxam seed treatments in the 27th April planting date. There was a significant interaction between planting date and seed treatment for defoliation. Defoliation was significantly lower in nontreated control compared to CruiserMaxx APX soybean seeds with thiamethoxam on 11th April planting date. Defoliation was significantly lower in nontreated control compared to CruiserMaxx APX soybean seeds with four fungicides thiamethoxam. Bean Leaf Beetle and white grub count and defoliation percentage remain below economic threshold. Soybean yield was significantly lower on the last planting date, 31 May, as compared to earlier planting dates. No significant differences were detected between seed treatments for stand count, and soybean yield. SEPAC: No significant interaction between planting dates and seed treatments were detected for pest count. There was a significant difference between plantings for pest count. The pest count was significantly higher in planting at 26 April, 10 May, and 25 May compared to planting at 12th April. Slugs are the key pest. Slugs count were significantly higher in Planting on 12th April compared to planting on 25th May at SEPAC.
Plant Plathology Summary: Very little disease developed in plots in 2023. No significant differences were detected between the seed treatments on soybean yield.