Issue 5, May 21, 2010

Spider Webs

The high winds in the last couple of weeks have resulting in masses of webbing on turf and trees. When spiders hatch, each disperses by spinning out a long strand of silk, which catches in the wind and allows them to float for long distances to new locations. This is how spiders disperse and is called ballooning. If a common spider species with many individuals are ballooning on windy days, frequently these webs blow into each other and merge into large masses. This commonly occurs in the fall because the eggs of many spider species hatch in the fall and disperse at the same time.

Although many species of spiders hatch in the spring and balloon at that time, it is unusual to see this at this time of year.

The webbing disperses over a few days, excess spiders will eat each other, and the phenomenon will pass. Webbing can be washed off of trees and shrubs or into turf with forceful streams of water. There are no pesticides that are very effective against spiders, although pyrethroids, such as cythruthrin (Tempo) would have some contact toxicity.--Phil Nixon

Phil Nixon

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