Cabbage crop environments were modified by either use of a hay mulch or intercrop- ping with "companionate" plants (nasturtium, thyme, and rosemary). A temporary reduction in egg and larval numbers of imported cabbageworm (Artogeia rapae L.) occurred on mulched plots. This effect disappeared later in the season as the plants grew large and coyered the mulch. On some interplanted plots, temporary increases in cabbage looper (Trichoplusia ni Hubner) larvae and decreases in imported cabbageworm eggs were noted. Hov.'Cver. on most dates, there was no effect of interplanting on pest populations. The general lack of effects on cabbage insect pests due to these cultural changes indicates that use of a mulch or interplanting cannot provide effective pest suppression under Minnesota conditions.
Cranshaw, W. S.
"Effect of a Hay Mulch and of a Companionate Planting on Cabbage Pest Populations,"
The Great Lakes Entomologist, vol 17
Available at: https://scholar.valpo.edu/tgle/vol17/iss1/2