Agricultural pest management
Special Weed Problems
(Reviewed 1/07, updated 1/07)
BUTTERCUP OXALIS. Buttercup oxalis, a perennial weed, is propagated from nutlets that germinate in fall. This weed is easily spread with planting stock and cultivation. Buttercup oxalis is a contributor to rodent problems in artichoke as the nutlets are a desirable rodent food. Oxyfluorfen (Goal) is helpful in the control of seedlings.
BERMUDAGRASS. Bermudagrass is a vigorous spring- and summer-growing perennial that grows from seed but can also be spread during cultivation from its extensive system of rhizomes and stolons. It is very competitive with artichoke, competing for moisture, nutrients, and light. Sethoxydim (Poast) is useful in controlling bermudagrass, however, repeated applications are necessary.
BLACK MUSTARD. Black mustard is an annual weed that is very competitive with artichoke in the winter months. It is also attractive to bees and must be controlled before it blooms and attract bees in order to allow insecticides that are toxic to bees to be used for the control of plume moth. Oxyfluorfen (Goal, GoalTender) and diuron (Karmex, etc.) will control black mustard before germination or in the seedling stage.
FIELD BINDWEED. Field bindweed is a vigorous perennial weed that grows either from seed, stolons, rhizomes, or extensive roots. Because seeds can survive up to thirty years in the soil, destroy plants before they can produce seed. The plants may be spread vegetatively through stem or root sections during cultivation. Prevention is the best control. Monitor fields and destroy spot infestations before they increase. Avoid bringing in propagules with planting material and cultivation equipment.
NUTSEDGE (YELLOW OR PURPLE). Yellow and purple nutsedge are perennial weeds that reproduce from underground tubers. These tubers survive for several years in the soil and contain several buds that are capable of producing plants. Only one bud at a time germinates to form a new plant. However, if that bud is destroyed by cultivation or an herbicide, then a new bud is activated. Be sure to monitor the site for the nutsedge emergence every few weeks during the warm season. Control is best accomplished by continuous cultivation during a summer fallow period before planting and by spot treatment to prevent new infestations from becoming established in the field. The tubers are easily spread by cultivation equipment.
WILD OAT. Wild oat is a winter annual grass that is a prolific seed producer. Wild oat germinates and grows vigorously during the winter rainy period and competes directly with artichoke for nutrients and light. It also reduces harvesting efficiency. Wild oat can be controlled with preemergent treatments of napropamide (Devrinol) or pronamide (Kerb), and by postemergent treatment with sethoxydim (Poast).
UC IPM Pest Management Guidelines: Artichoke
R. F. Smith, UC Cooperative Extension, Monterey County
Acknowledgment for contributions to Weeds:D. W. Cudney, Botany, UC Riverside
W. L. Schrader, UC Cooperative Extension, San Diego County
B. J. Mullen, UC Cooperative Extension, San Joaquin County