Sunday 20 May 2007

Fighting Defoliators One Worm at a Time

Fighting Defoliators One Worm at a Time

May 25, 2007

The new leaves are a welcome harbinger of spring. Green cankerworms eating the leaves are just as seasonal but not nearly as welcome. The process of controlling cankerworms starts in the spring and will result in decreased activity next year. You are not alone in your efforts. A number of parasitic insects feed on the eggs, larvae and pupas of these insects. Spiders, birds and small rodents also feast on the cankerworms at various times of the year. While all this eating is beneficial it does little to curb an epidemic population of worms. That is usually controlled by weather and soil conditions. Favorable weather conditions, like cold winters and late season frosts may control populations naturally. All of these factors combine to create a cyclical population boom and bust. Rather than waiting for the weather, or just talking about the weather, there are steps that you can take on your property to reduce the extent of the infestation next year. The first step is to arm your self with information on the life cycle of the two cankerworm species. The primary culprit that turns your elm, ash, or maple into a communal salad bar is the fall cankerworm, (Alsophila pometaria).

The life cycle of the fall cankerworm begins with the eggs over wintering in the upper branches of the host tree. The eggs hatch in late May as the new leaves unfold. Warm weather in spring will speed up the emergence of the leaves and the larvae. It takes approximately three weeks for them to mature and then the larvae spin a thread and drop to the ground like super heroes. When they reach the ground they spin a protective cocoon and change into pupae. Pupas are a stage in the development of insects where they change into moths. They emerge in September or October, as male and female moths. The males have wings and the females do not. At this point they have only to mate and lay eggs to start the process again. While the males are off being distracted by lights and flames, the females begin the long crawl to the top of the host tree to prepare to mate and lay eggs.

The spring cankerworm (Paleacrita vernata) has a similar life cycle with the larvae over wintering in the soil and pupating in spring. Both forms have wingless females. The female moth’s wingless crawl presents an opportunity to control both spring and fall forms of this insect. The application of sticky bands around the trunk of the tree will trap the females and prevent the deposition of eggs in the upper crown.

Start in mid summer, before the September long weekend, by lightly brushing off loose bark in a 6 inch band at 5 to six feet up the trunk of the tree. Do not girdle the tree by removing all the bark. You can then wrap glass wool, backed with stiff paper or foil in a four inch band around the tree. It can be secured with natural fiber like jute twine at the top and bottom of the strip. It is important to secure the band tightly to avoid the moths crawling under and not to tight as to injure the tree. Once you have the band in place paste sticky tangle foot, available from nurseries, evenly on the band. This will trap the females, so be sure to check it often to make sure there is no bridging over the trapped females. This would allow late arriving females to pass over the band. Reapply the tangle foot as necessary in the early spring to catch the spring cankerworm. Remove the bands in summer and reinstall in late summer. This will allow the tree to grow, and not damage the bark during the growing season. With single isolated trees this can significantly reduce the population of worms the following year. In a group, all trees will have to be banded.

When out breaks are severe, spraying with various products, as directed on the label, will give additional control. Btk, a bacterial insecticide works well when the insects are actively feeding.

Sunday 13 May 2007

Fruits of the Forest: High Bush Cranberry

May 13, 2007

You won’t likely find this cranberry next to your turkey this fall! That is unless you take the time to collect the berries yourself and make a delicious jelly with them.

The High Bush cranberry is some what underrated compared to other sweet berries of the woods.

High Bush cranberry, Viburnum trilobum, is a shrub with a large natural range. It is found in river valleys and open moist woods from the aspen parkland and the southern boreal forest. It is found in abundance along the Souris River, the Turtle River, and Assiniboine just to name a few areas. This shrub will attain a height of up to 12 feet in moist fertile soils, typically they are closer to 6 feet. This assumes that they haven’t been browsed by the local moose. The leaves are opposite, simple with three long pointed lobes typically 3 to four inches long. The Latin name, trilobum means “three lobed”.

The flowers are typical of most of the Viburnum family, flat topped white clusters of small flowers with larger sterile flowers, around the outer edge of the cluster. These sterile flowers may make the flower clusters more attractive to pollinators. You will see these flowers most often in June or early July.

The clusters of flowers once pollinated produce bunches of bright orange to red fruit.

These berry like drupes have a fleshy outer layer and a single large seed. The raw fruit is bitterly tannic and acidic. These are quite refreshing if you have a taste for them but should not be eaten in large quantities as they may cause cramps and vomiting. It is a favorite of bears and birds alike. Take care when gathering them in the wild not to startle the former. The Cree are reported to use the stems leaves and roots for a variety of medicinal propose. These range from pain relief to sore throat treatment. The bark is still boiled as a tea to relive menstrual cramps.

My personal favorite use for this fruit is in flavorful jellies. They have a unique odor, described by many as, sock like, but the taste is very good. I have included an untested recipe that seems to have the necessary amount of sugar. If anyone has good recipes feel free to email it to me.

This may be the plant to fill the gap in your diet as well as your wooded landscape.

For more information on native trees and shrubs contact an ISA Certified Arborist.

High Bush Cranberry Jelly

4 cups high bush cranberries

6 cups water

Additional water (as needed)

7 cups sugar

1/2 tsp. margarine or butter

1 pouch liquid pectin (Certo)

Bring the berries and water to a boil and simmer for 10 minutes. Crush the

berries or put through a food mill. Strain the juice in a cheesecloth-lined

sieve. Add any additional water if need to bring the juice up to 5 cups.

Bring the juice and sugar up to a boil. Add the margarine, then the liquid

pectin. Bring back to a boil, stirring constantly boil hard for 1 minute.

Remove from heat. Skim foam from surface and pour into sterile pint jars and

seal. Process in boiling water bath for 5 minutes.

Yield: 8 cups