“Friendly” Bug Control

July 23rd, 2019

   Bugs.

   We like it when those pretty little skippers and monarchs flit around the flowers.

We like this bug, but not so much when it comes to Japanese beetles and stinkbugs.

   And more people are coming around to the idea that bees are a good sign in the garden and that spiders do more good than not.

   But pretty much everyone is aghast when Japanese beetles swarm all over the roses or when stinkbugs decide to head inside for the winter.

   It’s a gardener’s dilemma.

   Can’t we have it both ways… welcome the “good” while keeping a lid on the “bad?”

   Yes. Or at least maybe. Here’s a 10-point game plan to a “friendlier” way to deal with yard-bug problems:

   1.) Plant bug-resistant plants. This is by far your best bet.

   Relatively few landscape plants run into serious insect problems, so if you steer clear of those (spider mites on dwarf Alberta spruce, scale on euonymus, adelgids on hemlock, for example), you can virtually plant-select your way out of spraying.

   Penn State Extension has an excellent booklet on what bugs attack which landscape plants.

   Pittsburgh’s Phipps Conservatory has a helpful list of dozens of the best “sustainable” plants for Pennsylvania.

   I’ve posted lists of both my Bottom 10 and Top 10 plants and have an 18-page “Survivor Plant List for Pennsylvania” online ($5.95 download) that steers you toward the least problematic choices.

   2.) Let nature work for you. The bug world is surprisingly well equipped to police itself. Given time, beneficial and predatory insects keep most pests in check.

   Tip the scale in your favor by planting enough diversity to attract beneficials. Especially pay attention to picking plants that bloom throughout the season. Dr. Douglas Tallamy’s book “Bringing Nature Home” (Timber Press, 2009) is one good resource.

   Then knock off spraying as much as possible. Spraying kills the predators along with the pests and puts you in the control seat since pests typically return first. (Without that pest-bug food supply there first, predators would starve.)

   3.) Let you work for you. Follow pest-discouraging practices in your yard care.

   Don’t whack into bark with your string trimmer and leak sap that attracts pest bugs.

   Pick up bug-infested fallen leaves at the end of the season to get rid of overwintering eggs.

   And above all, keep your plants as healthy as possible. It’s typically stressed plants that pests go after first. That means improve your lousy soil before planting, get plants in the site where they’re ideally suited, keep them watered in dry weather, and test every now and then to be sure the soil nutrition is optimal.

   4.) Separate the cosmetic from the real trouble. A majority of bug issues are temporary and cosmetic. The plants grow through the damage, and go on to bloom another day.

Aphids look like trouble, but they seldom kill plants.

   Relative few bugs threaten to kill plants if you don’t act. Identify your problem, and decide whether it’s merely a passing leaf-chewing matter that you can ignore or something more harmful in need of action.

   I’ve posted numerous resources to help with this in the Bugs/Diseases/Plant Problems of my Links and Resources page.

   Also check out Penn State’s Integrated Pest Management website and the University of Maryland’s Landscape Problem Solver.

   5.) Keep them out with barriers. Some bug problems are solvable by physically blocking the pest bugs.

   Floating row covers are light-weight blankets that are draped over edibles to stop egg-laying bugs, such as cabbageworms and carrot rust flies.

   Diatomaceous earth is a scratchy granular product that keeps soft-bodied slugs from crawling into your hosta patch.

   Sand over the soil surface discourages fungus gnats from laying eggs in your indoor pots.

   6.) Invite them in. If you can’t keep bugs out, use traps with bug-attractants to lure and capture them.

   Japanese beetle traps are the best known, although there’s debate over whether they cause more plant damage despite all of the dead bodies in the bag.

   Several light traps are designed to lure stink bugs to their death inside.

   Yellow-colored sticky cards (both commercially available and homemade) are effective at luring and trapping aphids and whiteflies.

   And Rescue has a new line of hanging sticky traps that flies and stinging bugs apparently find curious visually.

   7.) Mechanical controls. These work best on bigger bugs and involve, as the police would say, “physical assault on your person.”

   There’s no more effective or “organic” way to eliminate Japanese beetles than to squish them one by one or to hand-pick them and drop them in a jar of soapy water.

Bagworms can be snipped off plants or crushed.

   Bagworms – those wormy things inside the cone-shaped sacs on many an evergreen – can be controlled by picking them and stomping them.

   June beetles can be swatted with a tennis racket (good exercise also).

   An early borer attack of a tree can be stopped by unfurling a paper clip and poking the larvae to death before he/she gets too far inside.

   And vacuum cleaners can be employed to suck smaller bugs off of plants.

   8.) Use nature against itself. Also called “biocontrol,” this approach employs bacteria, fungi, nematodes and similar “friendly” organisms that naturally prey on or kill pests.

   Best known is Bt (Bacillus thuringiensis), the bacterium that’s used to control blackflies, gypsy moths and other caterpillars. It’s fairly targeted against caterpillars, but keep in mind, butterflies and moths are caterpillars before they become butterflies and moths.

   Milky spore is another fairly well known biopesticide (a bacterium) that’s marketed as a control for grubs in the lawn.

   Microscopic nematodes are microorganisms that also prey on beetle grubs as well as bagworms.

   And spinosyn (Spinosad) is one of several recent bacteria products that can control a variety of pest insects (caterpillars, spider mites and sawflies, for example).

   9.) “Soft” pesticides. These are bug-killers that generally kill by smothering, repelling or eroding exoskeletons as opposed to poisoning bugs.

   Horticultural oil, insecticidal soap, neem oil and hot-pepper sprays are examples.

   The good side is that these do little to no collateral damage. You pretty much have to hit the bug with them or have one come along before the spray dries.

   The down side is that you have to time the sprays more efficiently and apply them more often, both of which tend to frustrate gardeners.

   10.) Judicious use of the “big guns.” If all else fails, numerous conventional insecticides are available to clean up unacceptable outbreaks.

   If you must use these, avoid the spray-everything-just-in-case approach. Limit sprays to what’s being mercilessly attacked despite softer approaches. And use them as little as possible to achieve acceptable control.

   Check the labels for toxicity (“Caution” means less acutely toxic than “Warning” or “Danger”), and always follow label directions. More is not better.

   Also, “organic” or “natural” doesn’t mean safe. Some natural products test out more toxic than some synthetic chemicals. The Extension Toxicology Network is one source to gauge toxicity of gardening products.