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Got gardening questions? Contact the Hortline at (515) 294-3108 (Monday-Friday; 10 a.m.-12 Noon and 1-4:30 p.m.) or send an e-mail to hortline@iastate.edu. For more gardening information visit us at Yard and Garden Online at www.yardandgarden.extension.iastate.edu.

 

8/15/2007

I have a walnut tree that is infested with big, furry worms. They are eating all the leaves and building a large, tent-like structure.  What are they and how do I get rid of them?
The “worms” may be fall webworms. Fall webworms are hairy, tan to yellow caterpillars. As they feed, fall webworms construct tents or webs at the ends of branches. Tents are initially small, but the caterpillars enlarge the tents as they grow and consume the leaves within the tents.  By the end of summer, tents may be 2 to 3 feet long and enclose entire ends of branches. Fall webworms feed on more than 200 species of deciduous trees. However, walnuts are their favorite host.  In Iowa, the first sightings of fall webworms usually occur in early to mid-August.     
Fall webworms do not cause serious damage to healthy, well-established trees.  As a result, controls are not necessary. Damage to trees can be minimized by taking control measures as soon as the tents are discovered. Tents on branches that can be safely reached from the ground or with a ladder can be pruned out and the caterpillars destroyed.  Insecticides also can be used for control, but must be applied with sufficient pressure to penetrate the tent and reach the caterpillars inside. 

When can I transplant jack-in-the-pulpit? 
Jack-in-the-pulpit (Arisaema triphyllum) can be transplanted after the foliage dies back to the ground in late summer/early fall. Jack-in-the-pulpit performs best in moist, organic-rich soils in partial to heavy shade. The corm-like tubers should be planted 2 to 4 inches deep. 

What is the best way to dry herbs? 
Herbs should be harvested in the early morning, after the dew has evaporated and before the sun becomes too hot. After harvesting, rinse the herbs in cool water. Shake off excess water and place them on paper toweling to dry for a few minutes.

Air drying is the most popular method used to dry herbs. To dry whole branches or stems, gather 8 to 12 stems in a bunch. Tie the ends of the stems together and hang each bunch upside down in a warm (70-80 F) dry area. Don't dry the herbs in direct sunlight. The herbs should be dry in 2 to 4 weeks. When thoroughly dry, strip the leaves from the plants. Crush or crumble the leaves and store in airtight jars in a cool, dry place.

Another way to air dry herbs is to place them on a drying tray. A simple drying tray consists of fine mesh screen or cheesecloth attached to a wooden frame. A window screen also works well. Place blocks under the corners of the drying tray to ensure good air circulation. Place a single layer of leaves or branches on the drying surface and keep the herbs in a warm, dry area until they are thoroughly dry.

A gas or electric oven also can be used to dry herbs. To oven dry, spread a layer of leaves or stems on a cookie sheet or shallow baking pan. Place the herbs in a warm (up to 180 F) oven for 3 to 4 hours. Leave the door open and stir the herbs periodically until they are thoroughly dry.

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Contacts :

Richard Jauron, Horticulture, (515) 294-1871, rjauron@iastate.edu

Jean McGuire, Extension Communications and Marketing, (515) 294-7033, jmcguire@iastate.edu