Arkansas

They found that cover crops that flowered before termination in the spring, such as mustard, crimson clover and Austrian winter pea, attracted more beneficial insects (lady beetles and parasitoids) compared to the control with no cover crops. In addition, the insects were present after cover crops were terminated, likely bridging the cover crops into the subsequent watermelon crop and, thereby, aiding in keeping pest pressures low.

Pollinator sampling revealed that native bees played more of an important role in watermelon pollination than honey bees, but the researchers found that only those cover crops that flowered before termination served as good resources for pollinators.

Based on the results, researchers offered these tips for growers:

• Growers who seek to promote pollinators should plant a flowering winter cover crop like mustard or canola that blooms before termination in the spring.
• If growers would like to keep general agricultural pests low, they should use a grass cover crop like black oats, cereal rye, or wheat.
• If melon aphids are an issue, growers should plant mustard or a legume to increase natural enemies of aphids.
• If growers are growing a legume nearby they should avoid using legume cover crops because they could increase problematic pests like pea aphids.
• If growers are going to produce cereals, then they should avoid grass cover crops that were shown to support rice stink bug.

Ultimately, growers should choose cover crops not only based on their potential impact on beneficial insects, but also based on other benefits like nutrient contribution and their impact on soil health and yield.

GS18-189 Exploring Cover Crops in an Integrated Approach to Reduce Disease Pressure and Increase Beneficial Insects in Watermelon Production