Table 6: Intercropping for Pest Reduction—Successful Scientific Trials

The results of many recent pest management studies, which demonstrate the positive impacts of plant diversification on populations of beneficial insects in agricultural systems, are included in the table below. Use this table to determine the intercrops and related management mechanisms that will mitigate specific pests plaguing your crops. See Key References for literature reviews and additional citations to these studies.

Crop	Intercrop	Pest(s) Reduced	Mechanisms
Apple	Phacelia sp., Eryngium sp.	San Jose scale, aphid	Parasitic wasps, weedy ground cover, tent caterpillar, codling moth
Barley	Alfalfa, red clover	Aphid	Predators
Bean	Goosegrass, red strangletop	Leafhopper	Chemical repellent, Brassicas, candytuft, shepherd's purse, wormseed mustard, flea beetle, chemical repellent
	Similar-sized crops	Rootfly, cabbage butterfly and moth	Chemical repellent, predators
Brussels Sprout	Weedy ground cover	Imported cabbage butterfly	Predators
	French beans, grasses	Aphid	Physical interference
	White clover	Cabbage root fly, aphid, white cabbage butterfly	Visual masking
	Clover	Aphid	Physical interference
Cabbage	Tomato	Diamondback moth	Uncertain
	Hawthorn	Diamondback moth	Attract pest to alternative plant
	Red and white clover	Cabbage aphid, imported cabbage butterfly	Physical interference, predators
	Clover	Cabbage root fly	Predators
	Green ground cover	Imported cabbage butterfly	Visual masking
Carrots	Onion	Carrot fly	Chemical repellent
Califlower	Corn spurry	Cabbage looper, flea beetle, aphid	Predators
	Lambsquarters	Imported cabbage butterfly	Predators
	White or red clover	Cabbage aphid, imported butterfly	Physical interference, predators
Collards	Tomato, ragweed	Flea beetle	Chemical repellent
	Pigweed, lambsquarters	Green peach aphid	Predators
	Weedy ground cover	Cabbage aphid	Parasitic wasps
	Weedy ground cover with wild mustards	Flea beetle	Predators
	Tomato, tobacco	Flea beetle	Chemical repellent
	Weedy ground cover	Flea beetle, cabbage butterfly	Uncertain
	Weedy ground cover	Flea beetle	Visual masking
Corn	Wild parsnip, wild mustard, chickweed, shepherd's purse, and lady's thumb smartweed	Black cutworm	Parasitic wasps
	Pigweed	Fall armyworm	Uncertain
	Giant ragweed	European corn borer	Parasitic wasps
	Sweet potato	Leaf beetle	Attract pest to alternative plant
	Beans	Leafhoppers, leaf beetle, fall armyworm	Physical interference, predators
	Beans, weeds	Fall armyworm	Predators
	Pigweed, Mexican tea, goldenrod, beggertick	Fall armyworm	Predators
	Peanut	Corn borer	Physical interference
	Clover	Corn borer	Physical interference
Cow pea	Sorghum	Leaf beatle	Chemical repellent
Cucumber	Corn, broccoli	Striped cucumber beetle	Physical interference
Crucifers	Wild mustard	Cabbageworm	Parasitic wasps
Fruit trees	Rye, wheat, sorghum used as mulch	European red mite	Predators
	Alder, bramble	Red spider mite	Predators
Grapes	Wild blackberry	Grape leafhopper	Parasitic wasps
	Johnsongrass	Pacific mite	Predators
	Sudangrass, johnsongrass	Willamette mite	Predators
	Kale, closely planted	Aphid	Visual masking
Kale	Weedy ground cover	Beanfly	Physical interference
Mung beans	New Zealand white clover	Fruit fly	Physical interference
Oats	Carrots	Thrips	Visual masking
Onions	Ragweed	Oriental fruit moth	Parasitic wasps
Peach	Strawberry	Oriental fruit moth	Predators
	Ragweed, smartweed, lambsquarters, goldenrod	Oriental fruit moth	Uncertain
Radish	Broccoli	Golden peach aphid	Parasitic wasps
Soybean	Corn, weed cover	Corn earworm	Parasitic wasps
	Siklepod	Velvet bean caterpillar, green stink bug	Uncertain
	Desmodium sp., Croton sp., Cassia sp.	Corn earworm	Parasitic wasps
	Barley, wheat	Monitored only predators of soybean pests	Predators
	Rye	Seedcorn maggot	Physical interference
Squash	Corn	Cucumber beetle	Physical interference
	Corn, cow pea	Western flower thrips	Predators
Sugar beet	Manure	Pests preyed upon by predatory ground beetles	Predators
	Broccoli	Green peach aphid	Parasitic wasps
Sweet potato	Morning glory	Argus tortoise beetle	Parasitic wasps
Tamarack trees	White spruce and shrubs	Sawfly	Chemical repellent
Tomato	Cabbage	Flea beetle	Chemical repellent
Turnip	Dutch white clover	Cabbage root maggot	Chemical repellent
Vegetables	Wild carrot	Japanese beetle	Parasitic wasps
Walnut	Weedy ground cover	Walnut aphid	Parasitic wasps