They account for nearly 70 percent of the pesticide load. Onion thrips is also a serious threat. If growers of processing cabbage are not using resistant varieties, they devote substantial insecticide to the control of this pest. Every field receives multiple applications of insecticides throughout the season for thrips control. Insecticides are also applied to some fields for the management of flea beetle and cabbage maggot control, depending upon insect pressure.
Fungicides are next in terms of use.
It should be noted, however, that usage data were collected when EBDC fungicides were legal on crucifers. Since these materials are no longer legal, patterns of fungicide use may have changed. Many processing cabbage fields now receive no fungicide applications at all. Copper sprays for black rot are included in this category of fungicide even though the copper is technically being used as a bactericide. When symptoms of black rot are observed in a field, it is not unusual for multiple copper applications to be made.