Anchorage Daily News

Let's talk about some pests you are experiencing this week.

Last week I urged readers to check their delphiniums for the "delphinium defoliators," small, green caterpillars with black legs and which sometimes have a black streak on their heads. These are, I think, the larval form of looper moths, Autographa biloba. I noted the remedy is to hand-pick them and then apply products containing a bacterium, Bacillus thuringiensis, to the plants, but I got a number of questions. Here is the scoop.

There are several strains of Bacillus thuringiensis. So (as with everything) read the label carefully. B. thuringiensis var. kurstaki is the main variety for moth and butterfly caterpillars. B. thuringiensis var. aizawai is sometimes found and also works. Dipel, Thuricide and Caterpillar Attack all contain one or both of these bacteria. Do not delay. It may already be too late. These moth larvae are ferocious eaters.

By the way, B.t var. israelensis is effective against mosquito larvae if you have a pond or water feature. Israelensis is also effective against fungus gnats and some flies. It is worth trying on the sawfly invasions that will hit your gooseberries and currants in the next few weeks.

On to the next invasion, this one the explosion of dandelions. I know the first response to dandelions that many have is an application of a weed-and-feed product or a spray herbicide for broadleaf weeds. Don't. Just don't. These are serious poisons that I no longer believe should be used, and you will agree. Just Google "dogs, dandelions, cancer." These are bad chemicals.

So what to do? First, mow or pick flowers as they appear so they won't go to seed. Take a weed eater or golf club to your dandelions. Put in 20 minutes a day hand-pulling dandelions with a Fiskars UpRoot tool or another kind of dandelion fork. Use BurnOut or other vinegar-based formulas to spot-hit weeds.

And finally, learn to live with a few weeds in your lawn. It is difficult, sure. Incidentally, more and more, people are associating green, weed-free lawns with selfish, boorish and inconsiderate homeowners who don't care about the environment, their health or the health of their neighbors -- strong words from a former user.

Next, Equisetum arvense, aka horsetail, has made its annual appearance and is causing all sorts of concerns. Left over from Devonian times, this prehistoric plant throws off spores, not seed, and can also spread underground. Dig it up, leave a few pieces and you'll end up with more than you started with.

Please, do not think you can clear your beds of horsetail using Round-Up, the first thing frustrated gardeners turn to, thinking it will kill anything so why not horsetail. It won't help with your equisetum.

First, realize that horsetail really only lasts about six weeks. Around the middle of July, it goes away without help, and as it decays, it adds all sorts of good stuff to the soil. Still, I know people don't want to wait. When it appears in the lawn, just mow it. After one or two mowings, it won't be back this year. Similarly, in the garden, hand-pick it to ground level without disturbing the roots and remove it so the spores don't "germinate." Toss it on your compost pile.

Mulch garden beds (brown mulches for perennials, green for annuals) to smother as much as you can that might sprout later. Yes, some equisetum will grow though the mulch; pick off it to ground level. Incidentally, the stuff is supposed to have great medicinal value, getting rid of scars, acne and all sorts of other things. Again, a bit of googling might help you put this bad weed to good use.

Finally, if you pay attention you will find the beginnings of this year's invasion of butter-and-eggs -- scientifically, Linaria vulgari. Anywhere it grew last year, it will be growing this year unless you picked off the seed heads. This is a great time to pull it, weed eat it, burn it or whatever it takes to kill it. If you don't remember what the leaves look like (the flower is yellow and white, like a miniature snapdragon) browse to www.invasive speciesinfo.gov/plants/yellowtoadflax.shtml and enlarge the picture.

There are other pests, for sure. Let me know what is bothering your yard.

Jeff Lowenfels is a member of the Garden Writers Hall of Fame. You can reach him at gardenerjeff.googlepages.com or by joining the "Garden Party" radio show from 10 a.m. to noon Saturdays on KBYR 700 AM.

Alaska garden calendar

• KENAI TALK: If you live on the Kenai and want to learn about the soil food web, organic gardening and how to "team with microbes," come to the Kenai Visitors & Cultural Center at 7 p.m. Friday. You won't be disappointed. $5 for members, $8 for nonmembers. Open to the public. Refreshments and door prizes. Phone: Marion Nelson, 283-4632.

• BARE ROOT SALES: Unpotted trees and shrubs won't last much longer at the greenhouses. Take advantage of great savings now, especially if there is a hedge in your future.

• ALASKA BOTANICAL GARDEN FAIR, bigger and better than ever, is June 21-22. The Summer Gala is June 19. Learn about these and other Alaska Botanical Garden events at www.alaskabg.org. You are a member, aren't you?

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