Saturday, September 17, 2011

Crane Flies

Crane Fly

There back! Those long, gangly looking insects that look like giant mosquitos have resurfaced for fall mating season.  Although they are completely harmless (they neither bite nor sting) their off spring can cause some serious damage (if in sufficient numbers) to the roots of lawns and other garden plants. 

A Few Facts:

About Crane Flies:
Crane Flies (sometimes called daddy-long-legs or mosquito hawks) begin emerging from the soil in late summer. Within 24 hours after their emergence they begin mating. The impregnated females then deposit approximately 300 eggs into the upper soil level and die shortly after. The eggs which are oval and black in colour require moisture and a temperature of at least 14 degrees Celsius in order to hatch. Under these ideal conditions they  will hatch within 2 weeks.

Crane Fly Larvae:
The larvae of crane flies are called Leatherjackets. They have a tough outer skin which is light grey to brown in colour, thus their name.  Leatherjackets look like short fat and slightly darker earthworms. However when stretched out from their usual contracted state they measure approximately 1 1/2 inches long.

Leatherjackets begin feeding in the fall soon after hatching. They over winter in the soil then continue their feeding frenzy in the spring. (Note: Although leatherjackets over winter many do not survive the winter especially if they are exposed to cold, dry conditions.) This feeding frenzy lasts until early summer when they enter the pupil stage. This stage involves a resting period where the adults develop and emerge approximately two weeks later.

Beneficial nematodes (Steinernema feltiae) are a safe, natural and effective way to control leatherjacket populations. These microscopic, parasitic, non-segmented worms, (which occur naturally in soil all over the world), seek out the leatherjackets and attack the pest by entering natural body openings or by penetration of the body wall. Once inside, they release a bacterium that kills the host within 48 hours.  The nematodes then continue to reproduce inside the dead pest and release a new generation of hungry nematodes, which set off in search of further prey. Nematodes are not harmful to birds, animals, people or plant life.

The best time to apply these specific nematodes is in spring when the soil temperature is above 12ºC (54ºF) and in the fall as soon as the eggs begin to hatch. Apply to moist lawns and keep continuously moist for about 2 weeks. You can find nematodes at larger garden nurseries in the refrigerated section or by mail order. Read the label carefully for storage, application and specific hosts it is effective against.

1 comment:

  1. Quite an informative post. One of the things we should remember in landscaping is pest control and which method will be effective without collateral damage to plant or animals. Or even harmful side effects on humans.