Photo by KATHY CLEVELAND After her “Insects in Your Landscape” presentation, Rachel Maccini, who’s wearing a nametag, and some of her audience look over books and insect specimens. Maccini is a master gardener and pesticide safety education coordinator with the University of New Hampshire Cooperative Extension.

LYNDEBOROUGH – Out of the 23,000 species of insects found in New Hampshire, only a small percentage are considered pests.

But we do hate them, especially if we’re gardeners.

They go after our carefully tended vegetables, flowers and trees, chewing on leaves and roots, damaging buds and fruit, boring tunnels in bark and stems.

And then, as if to be as obnoxious as possible, some of them bite us.

Rachel Maccini, from the University of New Hampshire Cooperative Extension, was at the J.A. Tarbell Library earlier this month to show how to identify the insects in our gardens and what to do with those we don’t want there.

Like most of nature, it’s complicated. Maccini told her audience at “Insects in Your Landscape” that most “bad” insects do some good, one way or another.

They help pollinate plants, or they kill other insect pests, or they help decompose leaf litter, or they’re a food source for animals, birds or other insects.

“They are doing jobs they were created to do. There is a lovely balance out there,” she said, and we interfere with that balance by putting plants where they don’t belong and creating monocultures, such as lawns or cornfields.

Maccini teaches integrated pest management, defined as responding to pest problems with the most effective, least-risk options. She used a slide presentation

to show the major pests and how to deal with them.

Often, they can be controlled without pesticides, using floating row covers, by lightly tilling the soil or by planting at the right time. And learn to tolerate predators such as wolf spiders and ground beetles that eat plant-eating pests.

“People kill them,” Maccini said. “You don’t want to do that.”

Likewise, lacewings and ladybugs, even at the larva stage, eat destructive bugs.

The immature stage of the ladybug can eat 50 aphids at a time, she said, and aphids can also be dispatched with a forceful stream of water. Other bugs become discouraged when weeds are kept to a minimum.

Maccini warned against putting out Japanese beetle traps, which will attract beetles from far and wide to the garden. She was happy to report that Utah recently eradicated the invasive pest, which had been damaging more that 350 plant species in the state.

She also talked about biological controls such as milky spore disease and nematodes.

“There is a catch-22 for everything you use,” Maccini said.

Some products are expensive, some could be the cause of colony collapse disorder in bees and some kill earthworms, which are beneficial to the soil.

Handpicking can be an effective way to control pests, but you might not want to do it with the larval stage of the highly destructive lily leaf beetles. They are easy to spot, but particularly repulsive because they cover themselves in their own excrement.

“I paid my son to pick them off plants,” and he gave up after picking two, she said.

Gypsy moth caterpillars on trees should be removed with a broom handle, not insecticides, which can’t penetrate the web.

Lawns, the ultimate monoculture, are subject to predation by ants, sod webworms, grubs and hairy chinch bugs.

“I tell everyone to put in Astroturf,” Maccini joked.

Seriously, she said, make sure the soil is healthy, and the grass will withstand the stress caused by pests.

Maccini is a master gardener and pesticide safety education coordinator with the extension service. Along with insect specimens, she brought samples of insect-fortified chocolate to share, but there were few takers.

The program was part of the library’s Third Monday Series. The next one is a special date of July 31, with an ice cream social and activities for all ages.

Kathy Cleveland can be reached at 673-3100 or kcleveland@cabinet.com.