Diggin' In: Ridding gardens of pests without using pesticides

September 8, 2014

Pesticides are generally just not good. They kill beneficial bugs as well as bad bugs, and adversely impact our environment, especially bee and butterfly populations, according to experts.

Most of the United States, including here in Virginia, is experiencing dramatic losses in honey bees, according to a news release from the Virginia Department of Agriculture and Consumer Services. Nationally, over last winter (between October 2013 and April 2014), 23.2 percent of managed honey bee colonies died, according to the 8th annual national survey of honey bee colony losses conducted by the Bee Informed Partnership.

"Scientists believe that those losses are likely caused by a combination of multiple stressors, including poor bee nutrition, loss of forage lands, parasites, pathogens and exposure to pesticides," says Jeffrey Rogers, environmental program planner with the Virginia Department of Agriculture & Consumer Services.

In farming parts of the country, weed-controlling chemicals are eradicating much of the native milkweed that monarch butterfly caterpillars rely on. Homeowners, with the help of Monarch Watch at , are doing their best to help monarchs by planting milkweed in backyard habitats. This year’s milkweed efforts look promising, according to recent reports about increased numbers of monarchs showing up in late summer gardens.

Since 1990, Virginia has taken steps to reduce the use and abuse of pesticides — the generic term for insecticides, herbicides, fungicides and rodenticides — by sponsoring state collections and dispensing educational information on the prudent use of garden chemicals. Since its inception, Virginia’s Pesticide Disposal Program has collected and destroyed more than 1.2 million pounds of outdated and unwanted pesticides, according to a news release.

If you feel compelled to use a pesticide, follow the instructions for use, cautions Rogers. The pesticide label is the law, he stresses. Failure to follow the directions could constitute violations of the Federal Insecticide, Fungicide and Rodenticide Act, which is the federal pesticide law, as well as the Virginia Pesticide Control Act. Both the federal and Virginia pesticide laws provide for civil or criminal penalties for violations.

What are the risks of not reading and following the label? Using the wrong formula can cause personal injury or environmental contamination, but also possibly result in restrictions on the use of a chemical, cautions Rogers. For example, he says, in 2013, an estimated 50,000 bumblebees were killed in Wilsonville, Ore., after a commercial pesticide applicator treated blooming linden trees with an insecticide in an effort to control aphids. That incident prompted Oregon officials to prohibit the use of certain insecticides. 

Two more recent incidents of large bee deaths also in Oregon prompted officials in that state to prohibit the application of certain products to linden, basswood and other trees of Tilia species, he adds.

"By using pesticides according to the label, pest control professionals and homeowners can reduce the potential for a similar incident occurring," he says.

Pesticide alternatives

In the home and yard, pests can include anything and everything from aphids and squash bugs to flies and mosquitoes — spiders and stink bugs, too. Before you grab a container of powerful pesticide, consider alternative ways of dealing with them.

Horticultural oils work well on soft-bodied pests, and do not pose problems to bees unless they are sprayed directly on them, according to local beekeepers. Weeds can easily be hand pulled in the yard and garden, or vinegar- and salt-mixed-with water sprays used on them.

Indoors, bothersome stink bugs and beneficial ladybugs can be vacuumed up and deposited outdoors.

In Virginia’s King and Queen County, Karen Hinson Mumaw uses a diluted spray mixture of Dawn dish liquid on squash.

"This is the first year my harvest wasn’t ruined by squash beetles," she writes through my Facebook page.

"It must be used as a preventative, though. Once you see the little buggers, it’s usually too late. You must keep up with it — spray about once a week as soon as the plants get large leaves."

In Yorktown, Va., the mosquito control division promotes mosquito-repellent gardening, targeting small areas, such as patios.

"We’re encouraging people to add plants — lavender, basil, bee balm — that have been shown to repel mosquitoes," says Leah Aguilar, operations superintendent. A full list with descriptions and tips is found at .

"This winter, we are going to try to make some sample mosquito repellents from these plants so that we can teach the citizens how to do this if they want.," she said. "Additionally, we are studying Native American ethno botany to see how plants were used historically and how we may be able to incorporate that into our efforts today."


Integrated Pest Management tips

IPM is a holistic approach to pest management, with chemical controls being one of the many tools available, says Dan Nortman, Virginia Cooperative Extension agent in Yorktown.

"With an IPM approach, you monitor your yard for pests, ID them, and make sure that they are truly a pest of concern," he says. "If they are a pest of concern, then you should find alternative controls, using pesticides as a last resort."

Controls and tips for pesticides, he says, include:

More is not always better. When using concentrates, do not add more to the dilution to "get a better kill." There’s a reason for the recommended rates, and disobeying them is not only a violation of federal law, but can have unintended consequences for you, your family, plants in your yard and the environment.

Follow label directions for timing. Some pest biology is very complex, and when and where to spray is very important. The label often gives timing for some pests, but if you have additional questions, call your local extension office.

Make sure you ID your pests.

Practice good sanitation. Pick bad bugs off plants when you see them, use proper pruning techniques, clean up diseased leaves, and control weeds before they go to seed

For insect pests in particular, look for bio control. Many pests are controlled by naturally occurring predators, so look for good guys before you spray.

Pay attention to the active ingredients in the pesticides you use. Many products from different companies have the same or similar active ingredients; if a pesticide doesn’t work for you, instead of buying another product, look for another active ingredient.

When you buy pesticides, buy only what you need. It’s easier to go to the store and get more than it is to properly store or dispose of old pesticides.

Diversity is key! Having different plants makes the impact less if one plant species is killed by insect or disease. An example would be when building a screen. Relying on one plant for a screen between yards sets yourself up for disappointment when that plant fails and you lose your entire screen in a few seasons. Plant diversity also brings in good insects, and reduces the ability of certain pests to build up over time.


McClatchy-Tribune Information Services