The European Corn Borer. 5 
The economic plants (other than corn) attacked by the insect in 
New England may be roughly divided into two groups, according to 
their susceptibility as recorded at this writing. Only the more im- 
portant economic plants are listed. 
Group I.—EHconomic plants frequently attacked by the European corn borer. 
Aster. | Chrysanthemum. Hemp. Sunflower. 
Barley.® Cotton.* Hops. Swiss chard. 
Beans. Cowpea.’ Millet. Sweet sorghum * 
Beets. Dahlia. Peppers. 
Broom corn.® Gladiolus. Potato. 
Celery. 3rain sorghums.® Rhubarb. 
Group II.—Hconomic plants occasionally attacked ~ y the European corn borer. 
Artichoke. Golden glow. Okra.® Sweet clover. 
Buckwheat.® Hollyhock. Parsnip. Timothy. 
Calendula. Johnson grass.’ Salvia. Tobacco.® 
Canna. Marigold. Soy bean.’ Tomato. 
Cosmos. Mignonette. Spinach. Zinnia. 
Geranium. Oats. Sudan grass.* 
The infestation of these crops, other than corn, is especially likely 
to occur (1) when corn is growing near by; (2) when the infested 
crop remnants and weeds from previous crops on the same, or ad- 
jacent, areas have not been destroyed; and (3) when susceptible 
weeds are growing in the same field or in its immediate vicinity. 
Many of the thick-stemmed weeds and grasses serve as hosts of 
the borer in the New England area of infestation, and aid in its 
multiplication as well as complicating its effective control. Among 
these plants are included barnyard grass,‘ cocklebur,®> smartweed,°® 
pigweed,’ ragweed,® beggarticks,® dock,!° panic grass, burdock,” 
horseweed,!* tansy,!* wormwood,' and other similar plants, These 
susceptible weeds are often very heavily infested in some of the cul- 
tivated fields and waste places. Occasionally the borers appear to 
prefer these plants as hosts rather than corn. ; 
In New York, Pennsylvania, Chio, and Michigan the infestation 
to date has been confined mostly to corn, with a light infestation in 
the more susceptible weeds. In western New York a very few borers 
have also been found in some of the cultivated crops and flowering 
plants (soy beans, sorghum, millet, dahlia, and cosmos). It is prob- 
able that the degree and variety of infestation in susceptible weeds, 
vegetable crops, field crops, and flowering plants will increase if the 
insect becomes more numerous in these areas. 
To date (January 1, 1922) the European corn borer has been found 
in 185 species and varieties of plants in the United States. Some of 
these plants undoubtedly serve primarily as shelter for the borers 
_ rather than as food. 
8’ Plants occurring rarely in the infested portion of New England or which were grown 
only in the experimental fields. 
4 Echinochloa crus-galli. 8 Ambrosia spp. 2 Arctium spp. 
6 Xanthium spp. ® Bidens spp. 13 Brigeron canadensis. 
6 Polygonum spp. 10 Rumex spp. 14 Tanacetum vulgare. 
7 Amaranthus retrofiexus. “4 Panicum spp. % Artemisia spp. 
