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Wasps - Trichogramma


Moth eggs that contain trichogramma eggs are glued to the black strips or small cards. On the strips there are holes punched at each end of the strip and perforations in the middle of the strips so that it may easily be torn into two pieces.  There will also be loose black or gray eggs inside the bag but they will not move. There are enough trichogramma eggs on one strip to treat 25 pecan trees. This will vary from brand to brand.

Under good lighting, watch to see if there is movement in the bag. When the Trichogramma start to hatch you will see tiny insects moving inside the bag. Remember the loose eggs will not move. A magnifying glass is  needed to be sure you are seeing movement.

A wire or paper clip or needle and heavy thread are needed to attach the strip (or a 1-inch piece of the strip) to the tree. 

At dusk or at night, take the unopened bag outside to the trees on which you wish to place the Trichogramma. If you have more than five pecan (or other) trees in your yard, cut the strip into five one-inch pieces. Hang these pieces in the trees on the south side of the tree (so the wind will blow the trichogramma into the tree). Pierce the strip with one end of the paper clip.  Do not slide it over the paper because you will knock off trichogramma eggs. The strips can be cut into five one-inch pieces if you desire. The strips or small cards can also be put  in containers with holes punched in the lids. Place in shady locations to prevent excessive heat. The tiny wasps normally hatch in 24-48 hours.


Trichogramma wasps can be released from small containers or cards attached to plants that are having problems with pecan casebearers, cabbage worms, tomato hornworms, corn earworms, armyworms, and many orchard pests. These beneficial insects are tiny gnatlike parasitic wasps. They should be released in a succession of releases, starting in the spring when affected plants first leaf out. Repeat the release every two weeks. Once established, these beneficials don't necessarily need to be released every year. In an organic program the gnatlike wasps will establish natural populations and be around every year to help control pest insects.

Trichogramma Wasps

Trees have been having some caterpillar problems.  The preventative treatment for this pest is the release of the beneficial insect called trichogramma wasp.  If the worms are already feeding, killing sprays need to be used. 

Various worms, the larvae of moths and butterflies, eat the buds, leaves and flowers of many different species of food crops and ornamental plants.  They can be sprayed and killed with Bt (Bacillus thuringiensis) products, spinosad products or orange oil-based products.  For better effect from the killing sprays, add one ounce of molasses per gallon of spray.  Although  Bt is an acceptable biological product, it will kill butterflies as well as the larvae of moths and should only be used as a last resort and on plants where caterpillar feeding is in progress.  When used, it should be sprayed at dusk.


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The better approach is to release trichogramma wasps as a preventative. They can be purchased at organic garden centers, feed stores and ordered by mail.  The 1” cards contain about 3000 moth eggs.  Larger strips have more wasps.  Simply pin the cards or strips on tree trunks or on fences.  The almost microscopic wasps emerge from the sandpaper looking moth eggs and fly off to parasitize and destroy other pest eggs.  Nothing works better for the control of canker worms, greenworms, loopers, armyworms, pecan casebearers, tent caterpillars, webworms and other vegetarian worms. Trichogramma wasps must be put out before the pests hatch and start eating.



If the wasps are dead or have been eaten by fire ants, they won’t work.  Buy from reputable dealers and control the fire ants with organic techniques.  Vaseline put on the nail or pin used to mount the cards or strips will prevent any existing fire ants from getting to the eggs.  They will eat them like jelly beans if present and have access.

Mail Order Sources:

Arbico - Arizona Biological Control   
P.O. Box 4247CRB
  Tucson, AZ  85738-1247  (800) 827-2847

BioLogic Company   
P.O. Box 177  Willow Hill, PA  17271  (717) 349-2789

BioPac Crop Care, Inc.  
P.O. Box 87
  Mathis, TX  78368  (361) 547-3259

Garden's Alive 
5100 Schenley Place
  Lawrenceburg, IN  47025  (812) 537-5108      

Gardener's Supply Catalog  
I -128 Intervale Road  Burlington, VT  05401-2804  (800) 863-1700

Green Methods Catalog - The Green Spot, Ltd.,
93 Priest Rd., Nottingham, NH  03290-6240  (603) 912-8925

Harmony Farm Supply & Nursery 
3244 Hwy. 116  Sebastopol, CA  
(707) 823-9125

M&R Durango  

P.O. Box 886  Bayfield, CO  81122  (800) 526-4075

Rt. 1, Box 39  Quemado, TX  78877  (800) 832-1113

Natural Insect Control 
RR #2  Stevensville, ON  LOS 1SO  Canada  (905) 382-2904

Nature's Control 
P.O. Box 35
  Medford, OR  96501  (541) 245-6033

Nitron Industries
P.O. Box 1447  Fayetteville, AR  72702  (800) 835-0123

Peaceful Valley Farm Supply
P.O. Box 2209
  Grass Valley, CA  95945  (916) 272-4769

Planet Natural 
1612 Gold Avenue  Bozeman, MT  59715  (800) 289-6656

Rincon-Vitova Insectaries 
P.O. Box 1555  Ventura, CA  93001  (805) 643-5407


Question:  I hung the trichogramma wasps on my pecan tree and within hours ants were eating the eggs. How do I keep the ants away?

Answer:  Apply Vaseline to the pin or nail. The ants won't be able to crawl across to the eggs. One of the most important parts of a successful trichogramma release is to control the fire ants. Most organic gardeners don't usually have a problem with them, but outbreaks can be handled with orange oil drenches, beneficial nematodes, spinosad and/or dry molasses

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