Response of Armadillidium vulgare to immersion in water

In order to increase agricultural production and decrease costs, it is important to continue developing efficient farming practices.  One way to maximize profits is to reduce costs associated with pest control, largely accrued in the form of pesticides, and more recently, by introduction of natural predators.  Another, less expensive, option is to employ intermittent flooding to fields to control pest populations.  Armadillidium vulgare is a terrestrial isopod that is an emerging pest in soybean fields in Kansas and Nebraska.  In order to determine how well it will survive under flooding conditions, we used a video camera to record the movement of A. vulgare both under normal conditions in air and during immersion in water.  A t-test was used to determine if there was a significant difference for both conditions in time spent in motion and survival time.  For total time in motion, there was no difference between the control (7.4 ± 3.6 min.; mean ± SD) and the experimental (4.3 ± 3.2 min.; t = -2.02, df = 18, P = 0.059) trials. There was, however, a significant decrease in survival time of A. vulgare during immersion (3.71 ± 1.73 hours; mean ± SD) compared to normal conditions (10.96 ± 3.29 hours; t = 6.17, df = 14, P << 0.05). Since A. vulgare was found to exhibit no difference in behavior under both conditions, but survived a significantly shorter amount of time, we conclude that further study is needed to determine if flooding is a viable way to get rid of it as a pest in crop fields.  Since small mammals are the primary predators of A. vulgare, introduction of natural predators is not feasible, and the use of pesticides can have negative effects on the health of humans and other organisms, coupled with a high cost.  Flooding may be a safe and economically sound way to get rid of A. vulgare as pests in soybean crops.