You can trap beneficial insects in your garden and release them when and where you need them to get pests. Spined soldier bugs are valuable beneficial insects in home gardens because they prey on a multitude of pests, including Mexican bean beetles, cabbage loopers, diamondback moth, armyworm and other caterpillars, flea beetles, and Colorado potato beetles. And when prey is not available, the soldier bugs survive by feeding on plant sap, which does not significantly harm the plant. How beneficial are spined soldier bugs? Research has shown that just five to 10 young soldier bugs per plant can control even such a formidable pest as the Colorado potato beetle. Spined soldier bugs (Podisus maculiventris) occur throughout the United States and Canada. They are more common in the East, especially around deciduous forests and meadows, which provide natural prey and cover for the adults to survive the winter. So how do you get the little soldier bugs where they are needed at the right time to combat garden pests? We've been developing a "Soldier Bug Nursery" technique, which has shown promising results for home gardeners. The technique utilizes the natural chemical attractant (pheromone) produced by male soldier bugs. In our research at the USDA-ARS Insect Behavior Lab, we identified and patented this pheromone and it is available commercially as the Soldier Bug Attractor. You can use the Attractor to draw spined soldier bugs to your garden at any time. And with my nursery technique (which I explain below), you can trap the soldier bugs when they first emerge in spring (before they lay their eggs), store them in a nursery cage or the refrigerator and then move them into your garden, where they will lay eggs and produce hundreds of hungry nymphs. Soldier Bug Pheromone System To use the soldier bug nursery technique, you will need to purchase the solder bug lure in time to use it in early spring. In nature, males use their pheromone to attract a mate, but other males also go to the vicinity of a calling male in an effort to intercept females. Spined soldier bug adults are strong fliers and, during responsive phases of their life cycle, will fly toward the pheromone from considerable distances. Trapping Wild Soldier Bugs We have tested several trap designs and found that the soldier bugs are generally easy to capture. The bugs walk to the source of the pheromone; therefore, traps for capturing spined soldier bugs alive must allow the bugs to easily walk inside but not out of the trap. The bugs tend to crawl upward, but not downward. The trap described below takes advantage of these soldier bug habits. 1. Cut off the top one third of a 2 liter soda bottle, and then cut off the screw cap tip. This is your "funnel." 2. Cut off the top two thirds of a second soda bottle, leaving the cap on; this is the trap body. Punch a few small slits around the top so the pheromone scent will be released. Cut a wooden stake, about 3 feet long, that will fit through the hole in your funnel and leave spaces about a half-inch wide so the bugs can crawl in. Hammer the stake into the ground where you want to place the trap (best sites are along the edges of wooded areas with plenty of brush and leaf litter). 3. Slide the funnel over the stake, then lay a soldier bug lure in the funnel. 4. Finally, slide the trap body onto the stake and push the funnel section up securely into it. Tape or staple the bottom edges of the trap. When to trap spined soldier bugs Soldier bug adults overwinter under fallen leaves, duff, bark of dead trees and the like. Just prior to the bud burst of deciduous trees (when red maple trees shed their pollen is a good indicator) the adult bugs come out of diapause (the insect equivalent of hibernation), in a synchronized, massive emergence. You need to have your traps out before this emergence. The bugs soon mate, if they had not already done so the previous fall, and the females lay eggs on tree bark and vegetation (about 20 eggs / mass; on the order of 300 eggs per female). Eggs hatch in a week or less depending on temperature. There are 5 nymphal stages, each lasting a week or so if the nymphs are well-fed, followed by the final molt to the adult stage. Storing and using the soldier bugs After you've trapped the bugs, you have several choices. You can move them directly into a nursery area in your garden in either a porous or non-porous nursery cage. The simplest nursery might be a cylinder of aluminum window screen, set over an area where prey (other insects) may be present, such as a patch of an overwintered cover crop or kale, etc. Fold the top of the cylinder over and pin it closed with clothespins, and bank soil around the bottom edges so the adult bugs can't crawl away. To assure the bugs have enough food if insect prey is scarce, place some apple slices in the nursery. The non-porous window screen will hold both adults and nymphs. If you want to move the nursery every few days, disturb the plants inside the nursery and most of the adult soldier bugs will fly up and land on the screen, then you can move it, and them, to a new location. You can make an even more effective nursery using a porous wire mesh material known as "hardware cloth" instead of the window screen. I recommend the one-eighth inch mesh. This material would be strong enough to stand up on its own but will allow the soldier bug nymphs to escape after they hatch and move out into the garden, while the adults stay confined and continue to lay eggs. You can also hold the trapped soldier bugs in the refrigerator for a few weeks, to delay their egg-laying until more garden crops are up and growing. To preserve the bugs in the fridge, bring them out for a few hours every few days, so they can warm up and drink and feed. Spray them lightly with water, and give them some apple slices. This way, later in the spring you can place the nursery screen right over some plants in the middle of your potato patch, etc., add the bugs from the fridge, and they will lay their eggs right on whatever crops you want to protect.
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