Show from May 28, 2006

Cankerworms

Good morning gardeners. What a beautiful day in Manitoba. It's supposed to be a warm day, perfect for being in the garden and I have a lot to finish planting, not to mention the weeding that seems to be getting out of hand with all the rain and nice weather.

Gardening won't be so easy for some gardeners today, though, thanks to those nasty cankerworms and their honeydew secretions – yes, the honeydew is from the canker worms right now, not from aphids.

Did you know that cankerworms are also known as inchworms? When the larvae are fully grown, they are about one long but they also have a its hump-backed way of "inching along".

When they are finished feeding on the leaves of your trees, they drop from the braches by means of a long silken thread.

Now you have heard that there are both spring and fall cankerworms, but did you know that they both hatch as larvae at the same time in spring and often on the same tree?

You can tell the difference (if you care) by the number of legs and their colour – spring worms are yellowish-green to brownish to blackish, fall worms are light green to dark green to black.

The fall cankerworms leave their summer home in the soil where they have rested wrapped snugly in a tight cocoon just after the first hard frost in fall. The wingless female fall cankerworms climb into tree branches to mate with the winged males who visit them there. They then they lay their eggs around small twigs in the tree. Spraying with dormant oil in late winter can get rid of the eggs.

The spring female cankerworms emerge from the earth to climb into the trees in late March or early April, depending on the weather, after overwintering as naked brown pupae about four inches under the ground. They deposit their eggs in bark cracks and crannies.

The wingless females of both species look more like fat brown or gray, oval-shaped bugs with spidery legs than moths. The males are typical beige- or gray- coloured moths.

But to the homeowner who wants to prevent these nasty invasions of his ornamental fruit trees, Manitoba maples, oaks, and lindens, there are only a couple of important things to remember. One: band your trees in fall on or just after the labour Day weekend and keep the bands up, renewing the Tanglefoot in March, until on or just after the May long weekend. This way, you'll catch both populations as they climb heavenward to mate. Be sure to remove the bands in after Victoria Day to avoid damaging the bark of the tree.

If you didn't band and are now infested with cankerworms, you can spray the trees with BT (Bacillus Thuringiensis), a naturally occurring bacteria that attacks and paralyses the digestive system of the larvae, causing death in anywhere from 12 hours to five days. To be effective this must be done when the trees are fully leafed out and the larvae are only about half grown. You may have to spray more than once as the larvae hatch at different times starting in April of May and lasting until late June. If you're too late for this, then forbearance is about the only remedy. The worms, and their nasty brown droppings that are fouling everything beneath the trees they infest, will be gone in two to three weeks.

Healthy, mature trees will refoliate, but young trees or trees under a lot of stress may be at risk, so preventative banding of trees is doubly important to protect what can be a considerable investment thee days and to avoid all the nasty experience fo these fellows dropping first their honeydew on you and then their fat bodies when they are finished dining.

ANNOUNCEMENTS

By the way folks. If you're at home during the day, tune into CTV at noon on Thursdays to get the latest gardening tips. Again this year, Karen Mitchell and I will be talking about gardening and showing you what you can do to make your garden grow better. That's Thursdays at noon on CTV.

GARDEN SPACE

Do you want to start your own vegetable garden but don't have enough room? Well I have the answer for you. Contact Wallace Steiner at 489-9726 or Al Siis at 489-9305 to enquire about garden space at Corydon and Lindsay. Now I'm going to give you those numbers again: it Wallace Steiner at 489-9726 or Al Siis at 489-9305 for garden space at Corydon and Lindsay.