The use of a winter-wheat dry bean relay crop with the goal of enhancing natural biological control

                One of the most valuable ecosystem services is biological control. Natural biological control has been estimated to be worth billions of dollars per year. Conservation biological control seeks to enhance this by providing natural enemies with food or shelter.
                Relay cropping systems may be a good way to practice conservation biological control while reaping other benefits; such as, improved weed control and production of an extra crop. To quantify these benefits, we conducted trials with a winter wheat-dry bean relay cropping system in 2019 and 2020 near Scottsbluff, NE. The relay cropping system was compared with conventional dry bean, dry bean planted into a terminated winter wheat cover crop, and conventional winter wheat. Vacuum samples were collected at key times to quantify predator abundance. Western bean cutworm (Striacosta albicosta) egg masses and artificial caterpillars made of plasticine were placed in the plots to quantify predation.
                In 2019, we found no statistically significant differences in the number of aphids, chrysopids, or coccinellids among the treatments in samples collected prior to wheat harvest. Although, the number of aphids were slightly higher in the winter wheat and the relay plots compared with the conventional dry bean and cover crop plots. These aphids may serve as a food source for arthropod predators which will allow for enhanced predation later in the season.