Central Virginia Organic Gardener

"And 'tis my faith that every flower enjoys the air it breathes." - William Wordsworth, 1798

Sunday, March 17, 2013

What Evil Lurks in YOUR Shrubbery?

"Nice looking evergreen shrubbery.  Bet ya would hate to lose it"  is what I imagine little bag worms saying to home owners. These caterpillars are a nemesis of evergreens...

This shrub, at first blush, looks OK...

...until you zero in on this thing.

This is  bag worm in its "home."

People sometimes mistake bagworms for some natural part of their evergreen, like a pine cone (they have an upside-down pine cone sort of appearance).  But they contain a destructive caterpillar, one that secretes a gooey substance and builds a "house" of sorts for itself.  Bagworms prefer juniper, arborvitae, spruce, pine, and cedar, but may also attack deciduous trees. A serious infestation can kill a tree, smaller infestations can cause death of portions of the plant,
The best organic remedy is to catch the infestation early, and cut each bag off the plant.  This may be impossible if the plant in question is a large tree.  On this case,  Bt, spinosads and pyrethrins are organic controls, but must be applied in May or June, when larvae are small and susceptible.  After they build their "home" they are less susceptible to pesticides and other controls.  In any case, cut off the bags you can reach before you spray.

Happy gardening!
And Happy St. Pat's Day, the traditional day to plant your peas!

1 comment:

Anita said...

I keep staring at it and thinking of your explanation and asking myself is it as gross and heebie-jeebish as it makes me feel. :)