Published in the Wyoming Tribune Eagle June 19, 2016, “How to keep pests out of your garden.”
By Barb Gorges
Summer in the garden looks so idyllic from afar—especially back last winter when you were dreaming about it. And then a couple weeks after the last frost, the annoying summer visitors show up, the garden pests.
I asked Catherine Wissner, University of Wyoming Extension horticulturist for Laramie County, what pests people call about most. Her top three are ants, yellowjacket wasps and weeds.
I dealt with weeds in a previous column, but I would like to address those pests and a few more with an eye to integrated pest management. By that I mean the minimum impact on human health, the environment and non-target organisms.
That includes growing the right plant in the right place, checking plants regularly, identifying pests correctly and trying physical and biological control methods before reaching for chemicals.
For more information, see the UW Extension publications at www.wyoextension.org/publications.
When it comes to garden pests, we humans, the big-brained species, should be able to outsmart even a hungry critter.
Last summer we had little brown ants making themselves at home along the cracks in our patio. We followed Wissner’s suggestion to put a sugar substitute, aspartame (one brand is NutraSweet), on top of every mound. Between that and caulking the cracks, we cut down on the numbers. But will aspartame work on bigger ants?
“Aspartame only works for the tiny sugar ants,” Wissner said. “For the bigger ants you can buy ant traps at the grocery store. They seem to work and there are no poisons for pets to get into.”
Yellowjackets like the meat and sugary foods served at picnics and they can be aggressive in late summer. But Wissner notes their ill effects on the beneficial garden insects as well.
“All wasps are predacious and go after caterpillars, grasshoppers and sometimes spiders as a food source for their larvae. If you are trying to develop a butterfly garden, then they are a problem,” she said.
Wissner recommends yellowjacket traps sold at hardware stores, “The best one I found is a hexagonal green sticky trap that hangs. It also catches flies. Late April is the best time to put out traps (to catch the queens), but it’s not too late to put them out now.”
To picnic safely in our yard, we have used the yellow plastic traps with the refillable attractant (which is toxic to pets). We hang them out of reach and 20 feet away from pets, food and people. The brand we use has a wasp identification chart and so far we’ve caught prairie and western yellowjackets.
Keep Benadryl or similar antihistamine on hand if someone gets stung and starts to swell.
It’s hard to see tiny green (or other color) aphids, but easy to see the damage they cause sucking on plant leaves, making them curl or grow misshapen.
Prevention is the best cure for aphid and many other insect infestations. Wissner said, “They are a good indicator of plants and the soil system being off balance. Too much fertilizer and not enough water typically invites bugs.”
In other words, a stressed plant is a target for hungry insects, who, like wolves, go for the sick and weak, stressing them further.
Besides adjusting fertilizer and water amounts, you can knock aphids off with a stream of water. If the leaves are sticky with aphid “honeydew” you might want to prune them away before the stickiness attracts other insects and fungus. And you can try treating the leaves with neem oil.
Some beneficial insects leave behind a bit of cosmetic damage. The leafcutter bee cuts little circles out of the edges of leaves for building its nest. It doesn’t usually hurt the plant and as Wissner said, “They are important in the garden and pollinate a wide variety of vegetables, fruits and flowers.”
It’s surprising to find slugs in Cheyenne, with average precipitation of only 15 inches a year. I didn’t have any until a few years ago.
I asked Wissner her favorite remedy for slugs. “Chickens,” she said.
If that isn’t an option, beer traps have worked well for me, especially in the vegetable garden. I’ve sunk a 6-ounce yogurt container in the ground and filled it half way with cheap beer (though I hear better beer works better). The slugs are attracted to the yeast, dive in and drown. The next morning, I remove the slugs by pouring out the traps into an old kitchen strainer held over a bowl and then pouring the beer back in the traps. I can reuse the beer several days.
For slugs in the flower garden it is easier to change the habitat—thinning out the vegetation and removing the leaf mulch for a while, giving the birds a chance to find any slugs I didn’t already pick off. “More air, less moisture,” said Wissner.
Fencing is the best option, chicken wire about 2 to 3 feet high and buried about 6 inches deep to keep rabbits from digging under. Our backyard is completely walled in and our dog Sally is on patrol, so no problems there.
In the unfenced front yard, I apparently don’t grow any flowers that are lush and delicious, except for pansies and so I don’t grow those there anymore. Instead, the rabbits nibble our grass. One garden blogger suggested growing clover in your lawn, a rabbit favorite, as a distraction. It also provides nitrogen for lawns, a key nutrient.
My friend Florence Brown has particular plants she guards with the prunings from her rosebushes. The thorny mulch can keep rabbits away as well as dogs and cats.
While many plant catalogs will mark certain plants as deer resistant, they don’t mention whether they are also antelope resistant. Photo by Barb Gorges.
Deer and antelope
You might think deer and antelope are only a problem for the folks living on acreage outside of town, but it seems the antelope from F.E. Warren Air Force Base walk into the west side neighborhoods in late winter looking for snacks.
Both deer and antelope are browsers, fond of shrubbery, but they will occasionally pick off less woody plants. While many plant catalogs will mark certain plants as deer resistant, that isn’t a guarantee they won’t get eaten.
Various substances are recommended as repellents, but need to be reapplied frequently and after rain. Or you can build a cage to protect an important plant.
There’s only one solution for growing vegetables in deer-filled neighborhoods, Wissner said, “Tall double fencing.” The idea behind a fence inside a fence is that deer are hesitant to jump a fence into a space if there isn’t enough room to take a running jump back out. For particulars, talk to Wissner, 307-633-4383.
While Mark and I invite birds to our yard for the many benefits they provide, if we wanted to harvest our chokecherries, or grow other fruit, we would need to put up netting at the right time—before the fruit begins ripening (birds like it greener than we do). But also, Wissner said, “It needs to be monitored several times a day as birds have a tendency to get tangled up in the netting.”
Addendum: Ground squirrels, pocket gophers and prairie dogs are a menace to rural gardens. Try protecting trees and other plants with chicken wire and repellents. For information about traps and poisons, consult your Extension office or your county conservation district. For the Laramie County Conservation District, call Rex Lockman, 307-772-2600.