Evaluating flowering cover crops as an IPPM tactic on commercial watermelon farms

In watermelon systems, growers extensively use cover crop grasses, such as rye or wheat, to protect seedlings against sand-blasting damage, but these cover crops do not provide many resources to support beneficial arthropods (i.e., pollinators and natural enemies). In contrast, flowering cover crops, such as vetch, can provide more pollen and nectar throughout the season to help boost beneficial arthropods, which can then deliver ecosystem services to the crop. In 2023, we investigated the effects of multiple flowering cover crops (mustard, buckwheat, crimson clover, vetch, crimson clover + rye and vetch + rye compared to rye) on beneficial arthropods and yields, while in 2024, we further tested the use of vetch, being the most promising flowering cover crop, compared to rye. Following results from these two trials, in 2025, we investigated the use of vetch + rye in a commercial setting using a 95-acre field, compared to an 88-acre field that had only rye. Both fields were located in Southwestern Indiana and were managed conventionally, including the use of honey bees. Managed bumble bees were also added to investigate whether the presence of vetch can improve bee health (i.e., colony weight). We conducted weekly surveys from May to August, recording density and
diversity of beneficial arthropods and pests and measuring pollination services through pollination experiments and biological control through bait cards. Fruit set (number of watermelons) was recorded at harvest across multiple 100-m transects to estimate yields. Results from the 2025 trial with a focus on pollination will be presented.