Trap Crops fit into the realm of companion planting. Though the process may go against a traditional gardeners nature you must place your faith in The Bug Lady and understand the logic.
The concept is to plant a species of plant susceptible to a specific pest to act as a lure for beneficial insects, such as Lupines. The Lupine aphid (macrosiphum albifrons) is specific to Lupines and will not transfer onto your peppers or cabbage. The sacrificial plant is allowed to have a colony of aphids establish. Once the host plant achieves a pest colony the parasitic wasps and predators will also move onto the Lupine as well. Voila, a pocket insectary. The Lupine provides a source of predators without threatening the intentional crop. By situating the trap plants around gardens which typically suffer from aphids, you are actually protecting your gardens by providing an established security force.
It is important that when you attempt to apply this method using other plants as the trap crop that you confirm the pest species is host specific. Obtain this information through a reliable source. A search through our links is a good place to start.
The Following list has been gathered from; Common Sense Pest Control by William and Helga Olkowski and Shiela Daar, Rodales Encyclopedia of Organic Gardening, Cornell University and Appropriate Technology Transfer for Rural Areas.
|Predator||Host pests||Associated Companion plants|
|Aphidoletes||Aphids||Dill, Mustard, Thyme, Sweet clover|
|Nectar plants with small flowers.
Caraway, Parsley, Fennel, Mustard,
Clover, Tansy, Yarrow.
|Damsel Bugs||Aphid, Thrips
|Sunflower, Goldenrod, Yarrow, Alfalfa|
Some small caterpillars
|Aamaranth, sweet clover, mulches,
|Angelica, Caraway, Dill, Coreopsis
Cosmos, Sunflowers, Dandelion
|Minute Pirate Bug
|Bishops weed, Chevril, Tansy,
Queen Annes Lace, Strawberries,
Carrots, Corn, Hairy Vetch, Daisies,
|Rove Beetles||Aphids, flies, Springtails||Rye, Ornamental grasses, mulches|
|Stethorus||Spidermites||Carrots, Dill, Fennel, Sweet
|Syrphid Fly||Aphids||Dill, Fennel, Queen Annes Lace
Coriander, Bishops weed, Tansy
Lupines, Scabiosa, California
|Tachinid Fly||Cutworms, Tent
|Caraway, Bishops weed, Goldenrod
Sweet Alyssum, Parsley, Buckwheat
Trap Crops for Aphids:
Trap crops for Thrips: