Garden Plot: Pests never take a vacation

Don\'t let squirrels terrorize your tomatoes. Scare them away with water or rubber snakes. (Thinkstock)
How to get ready for the fall planting season

Mike McGrath | November 14, 2014 8:34 pm

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Stink bug revenge

Not every email I get is a question. Greg in Paeonian Springs (just north of Leesburg in Loudoun County) writes: “You may already know this, but stink bugs seem to love hosta flowers. We have a sea of hostas that recently started blooming, and nearly every bloom cluster has a corresponding cluster of stink bugs. I have developed an intense dislike of stink bugs, and see this as an opportunity to get rid of as many as I can. I fill a bucket with a few inches of soapy water and hold it under the plants while gently tapping the blooms with a trowel. The bugs panic and let go, falling into the soapy water and drowning. Works every time.”

All I can say is great work, Greg! Keep soaping them stinkers. Get a few for me while you’re at it. Oh – and maybe taunt them on the way down. That’s Philly style!

Don’t let evil squirrels eat your tomatoes

Shelia in Sumerduck, Va., writes: “My tomatoes are being eaten and not by deer (or I would see hoof prints). No, I’m thinking it’s squirrels, as I have plenty of those little critters! Do I have any options? It’s been an awesome summer and I would hate to pull the plants out so early!”

You should immediately think of evil squirrels as the guilty culprits whenever evil things occur, because – well, because evil squirrels are evil!

I keep a motion-activated sprinkler aimed at my garden to keep the terrible tree rats (and deer, and cats, etc. …) at bay. Works great. All you need is a hose and a 9-volt battery. The best-known brand name is “The Scarecrow.” It’s available online and at bigger independent garden centers.

I just had a long conversation with a gardener who swears he’s had great success with rubber snakes. He buys them at the dollar store and hangs them on his tomato cages. He says they even stopped the terrible tree rats from nibbling on his cedar siding. (Here’s a money-saving tip: I bet that a lot of rubber snakes and big spiders and similar scary things will be on heavy markdown the day after Halloween. Hmmm … I wonder how Evil Squirrels would react to one of those motion-activated, grabby, skeleton-hand thingies?)

Several other gardeners have told me they decided to get even with squirrels by covering red Christmas tree balls with a sticky substance (such as Tanglefoot or a non-temporary sticky spray adhesive) and hanging them next to the ripe tomatoes. (OK, maybe that’s a little mean. Make it hard red plastic balls instead of glass ones. Try red ping-pong balls!)

Next season, grow your tomatoes inside cages of sturdy fencing like rabbit wire and be ready to cover the tops with more fencing (held on with twist ties) when and if evil squirrels strike again.

And finally, don’t feed evil squirrels – either directly or with birdseed. If you want to attract lots of birds, set out birdbaths filled with clean water.

Don’t let caterpillars eat your oaks

Bob, who lives on Sherwood Forest Drive in Mount Airy writes: “For the past three years, the oak trees in our neighborhood have become ‘infested,’ completely covered, with inch-and-a-half-long caterpillars and been completely defoliated. Have you heard of such recurrence of evil-doers? And are there any organic based methods of eradicating them and saving our woodland neighborhood?”

Yes, Bob. When pest caterpillars aren’t controlled, they’ll breed like – well, like caterpillars. And the next generation will naturally return to do the same damage to the same kinds of plants in subsequent seasons.

And yes, there is a great organic answer, Bt, an organic pesticide derived from a naturally-occurring soil organism that only affects caterpillar. And it only affects caterpillars that chew on the sprayed leaves. There’s nothing more direct or safer for the environment and it’s tremendously effective. It’s also known as BTK for Bacillus thuringensis Kurstaki. Now you know why we just call it Bt. Sold under brand names, including Dipel, Thuracide and Green Step, it’s available online and at virtually all garden centers.

Organize your neighbors and/or enlist your local municipality and be ready to start spraying the trees as soon as the first caterpillars appear next season and you’ll break the cycle and save your oaks. Bt is effective against any caterpillar pest, but only when the caterpillars are actually eating the sprayed leaves.

Oh, and there’s a reason I included the name of your street. I spent a good amount of time in Nottingham when I visited England years ago and was broken-hearted to discover that what used to be Sherwood Forest was now an industrial park – so please protect its namesake!

Damp air good for pests; bad for people

Alice in D.C. writes: “Last year, you solved our ant infestation problem. Your boric acid traps worked like a charm! But now I’m in a new place, a basement apartment, and I have flies, crickets that jump, and something that resembles a centipede. My landlord offered to get an exterminator in here, but I’d rather try something gentler first, gentler to ME, that is!”

Good thinking Alice. Spraying pesticides indoors is never the answer.

Flies are a common problem. Hang some old-fashioned flypaper next to a light source, turn off all the other lights in the room and the flies will all be trapped within a day. Use sheets of newspaper to take it down and throw it/them in the trash.

The crickets and millipedes (not centipedes – they’re much bigger and less common), however, are signs of excessive dampness, which is a common problem in basements, especially in D.C. in the summer, when we challenge St. Louis for the swampiest air. You need to run a dehumidifier to dry out the air, which will drive the pests away and be much better for you as well. Keeping the basement air dry will keep mold and mildew problems to a minimum.

You may not need to run the dehumidifier in the winter when the air is naturally drier. Get a thermometer that also has a humidity indicator (called a hydrometer) and shoot for 55 percent humidity or below.

Big wasps that dig big holes are only a threat to big bugs

We’ve gotten a lot of emails about this creature. I’ll pick two examples.

Clara in Rockville writes: “I have many holes in my yard created by bees that are approximately an inch and a half long with striped yellow and black tails.”

Donald in Shadyside has the same “bees.” He writes: “Can you help? What are they? They’re scary looking, seem aggressive, and spend a lot of time sitting on the Azaleas in front of our porch.”

You two, and all the other panicked listeners with similar fears, can relax. The amazing cicada-killing wasp is a wonder of nature that never harms humans. These large, female wasps lurk in areas rich with cicadas, paralyze them with a sting then fly and/or drag the doomed bug to a hole they dig in the ground. Then the female wasp lays her eggs inside and seals it up. Bad day to be a cicada, but no threat whatsoever to people. In fact, they’re a great lesson that scary-looking doesn’t always mean a threat.

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