Preemergence Control before Conifers Germinate

glyphosate (numerous products)

Rate Consult labels

Time Apply to emerged weeds just before conifer seedlings emerge using similar techniques described on the label under "cropping systems" for various cereal and vegetable crops.

Remarks Consult the Vegetable Crops section of this handbook for information about the stale seedbed technique. Use lower rates on vigorous annual weeds. Inhibits production of three amino acids and protein synthesis.

Caution Do not exceed 10.6 lb ai/a (10.6 quarts/a) per season.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

lactofen (Cobra)

Rate 0.125 to 0.25 lb ai/a (8 to 16 fl oz/a)

Time Preemergence to weeds and after conifers are seeded, or after transplanting.

Remarks Irrigate with 0.25 to 0.5 inch water or rain for preemergence control of annual grass and broadleaf weeds. Cobra is a contact herbicide with some soil residual activity. May be sprayed over recently transplanted conifers if budbreak has not occurred. Do not disturb soil surface after application or weed control will suffer.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Diphenylether

oxyfluorfen (Goaltender)

Rate 0.25 to 1 lb ai/a (0.5 to 2 pints/a)

Time Preemergence to weeds and conifers

Remarks Irrigate with 0.5 to 0.75 inch water or rain for preemergence control of annual grass and broadleaf weeds. Goaltender is a contact herbicide with some soil residual activity.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Diphenylether

oxyfluorfen (Goal 2XL)

Rate 0.25 to 1 lb ai/a (1 to 4 pints/a Goal 2XL)

Time Apply after seeding but before conifers emerge; sprinkler-irrigate with 0.5 to 0.75 inch water.

Remarks Use 0.5-lb rate when grass weeds are present, and highest rate when extreme weed infestations are expected. Acts as a contact herbicide when weeds are emerging, with soil residual activity.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Diphenylether