Not all registered pesticides are listed. The following are ranked alphabetically. When choosing a pesticide, consider information relating to environmental impact, resistance management, the pesticide's properties, and application timing, Always read the label of the product being used.
PREPLANT
A.
AMMONIUM NONANOATE
(Axxe)#
6–15% spray solution
4
0
WSSA MODE-OF-ACTION GROUP NUMBER1: Unknown
COMMENTS: An organic contact, nonselective foliar herbicide without residual activity. Check with organic certifier to determine which products are organically acceptable. The degree of control is greater when weeds are actively growing, small, and immature; larger weeds are less affected. Use in a band application over the crop row or as a broadcast application at or before planting, or prior to the emergence of the crop. Provides control of annuals and some suppression of perennials. For best results, target weeds should be thoroughly wetted with spray solution but not to the point of runoff. Use up to 80–125 gal spray solution per broadcast acre to ensure thorough weed coverage. Use 6–8% solution for annual weeds less than 1 inch tall; 8–10% solution for annual weeds between 1 and 4 inches tall; use 10–13% solution for weeds over 4 inches tall; and use 15% for perennial weeds or severe infestations.
B.
CAPRYLIC AND CAPRIC ACIDS
(Suppress EC)#
3–9% spray solution
24
0
WSSA MODE-OF-ACTION GROUP NUMBER1: Unknown
COMMENTS: An organic contact, nonselective foliar herbicide without residual activity. Check with organic certifier to determine which products are organically acceptable. The degree of control is greater when weeds are actively growing, small, and immature; larger weeds are less affected. Use in a band application over the crop row or as a broadcast application at or before planting, or prior to the emergence of the crop. Provides control of annuals and some suppression of perennials. For best results, target weeds should be thoroughly wetted with spray solution but not to the point of runoff. Use up to 100 gal spray solution per broadcast acre to ensure thorough weed coverage. Use 3% solution for most annual weeds while perennial or large annual weeds require a 6–9% solution.
C.
METAM SODIUM*
(Vapam HL)
37.5–75 gal
See label
NA
COMMENTS: Fumigants such as metam sodium are a source of volatile organic compounds (VOCs) but are minimally reactive with other air contaminants that form ozone. Fumigate only as a last resort when other management strategies have not been successful or are not available.
STAND ESTABLISHMENT
A.
AMMONIUM NONANOATE
(Axxe)#
6–15% spray solution
4
0
WSSA MODE-OF-ACTION GROUP NUMBER1: Unknown
COMMENTS: An organic contact, nonselective foliar herbicide without residual activity. The degree of control is greater when weeds are actively growing, small, and immature; larger weeds are less affected. Use in a band application over the crop row or as a broadcast application at or before planting, or prior to the emergence of the crop. Provides control of annuals and some suppression of perennials. For best results, target weeds should be thoroughly wetted with spray solution but not to the point of runoff. Use up to 80–125 gal spray solution per broadcast acre to ensure thorough weed coverage. Use 6–8% solution for annual weeds less than 1 inch tall; 8–10% solution for annual weeds between 1 and 4 inches tall; use 10–13% solution for weeds over 4 inches tall; and use 15% for perennial weeds or severe infestations.
B.
CAPRYLIC AND CAPRIC ACIDS
(Suppress EC)#
3–9% spray solution
24
0
WSSA MODE-OF-ACTION GROUP NUMBER1: Unknown
COMMENTS: An organic contact, nonselective foliar herbicide without residual activity. Controls most annual weeds. The degree of control is greater when weeds are actively growing, small, and immature; larger weeds are less affected. Use in a band application over the crop row or as a broadcast application at or before planting, or prior to the emergence of the crop. Provides control of annuals and some suppression of perennials. For best results, target weeds should be thoroughly wetted with spray solution but not to the point of runoff. Use up to 100 gal spray solution per broadcast acre to ensure thorough weed coverage. For most annual weeds, use a minimum 3% solution and a maximum 6% solution. For perennial or large annual weeds, use a 6–9% solution.
C.
GLYPHOSATE
0.38–3.71 lb a.e.
(Roundup Powermax)
0.34–3.3 qt
4
See label
WSSA MODE-OF-ACTION GROUP NUMBER1: 9
COMMENTS: A nonselective foliar herbicide used to control small annual weeds in finished beds before the asparagus emerges. Asparagus emerged at the time of treatment will be killed.
D.
PARAQUAT*
0.63–1 lb a.i.
(Gramoxone SL 2.0)
2.5–4 pt
24
See label
WSSA MODE-OF-ACTION GROUP NUMBER1: 22
COMMENTS: A nonselective foliar herbicide without soil activity applied as a band or broadcast treatment before or after planting, but before the asparagus emerges. Asparagus that has emerged at the time of application will be killed. Apply when weeds are succulent and less than 16 inches high; larger weeds are less affected. Surfactant is needed. Late afternoon applications increase activity.
E.
PELARGONIC ACID
2.34–20 gal/broadcast acre
(Scythe)
3%–10% spray solution
12
0
WSSA MODE-OF-ACTION GROUP NUMBER1: Unknown
COMMENTS: A contact, nonselective foliar herbicide without residual activity. The degree of control is greater when weeds are actively growing, small, and immature; larger weeds are less affected. Apply as a band treatment over the crop row or as a broadcast treatment at or before planting. Provides control of annuals and some suppression of perennials. For best results, target weeds should be thoroughly wetted with spray solution but not to the point of runoff. Use 75 to 200 gal spray solution/broadcast acre, with higher volume used when weed density is high. A 3 to 5% solution is sufficient for most annual weeds while perennial or large annual weeds require a 7% solution.
F.
LINURON
(Lorox)
Label rates
24
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 7
COMMENTS: Can be applied over the top to direct-seeded, transplanted, or crown plantings when ferns have 6–18 inches of growth. Has excellent activity on small emerged annual weeds. Do not apply with an adjuvant or in a fertilizer mix.
G.
SETHOXYDIM
0.281–0.468 lb a.i.
(Poast)
1.5–2.5 pt
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 1
COMMENTS: For use on direct-seeded or transplanted plantings. Apply to actively growing grasses that are not under moisture stress; best applied 2–4 days after a rain or irrigation. Apply in 10–20 gal water plus an oil concentrate at the rate of 1 qt/acre. Rates dependent on grass size and species. Follow label instructions regarding the use of adjuvants.
H.
DIURON
(Karmex DF)
See comments
12
0
WSSA MODE-OF-ACTION GROUP NUMBER1: 7
COMMENTS: On light soils and other soils low in clay and organic matter, use a rate of 1–2 lb (0.8–1.6 lb a.i.) per acre. For newly planted crowns in the San Joaquin Delta and soils with high clay or organic matter, use a rate of 2–4 lb (1.6–3.2 lb a.i.) per acre. Considered to be a groundwater contaminant and requires a use permit within Groundwater Protection Areas. Soils should have greater than 2% organic matter; crowns must be buried at least 2 inches deep. Use lower rates on coarse-textured soils.
I.
FLUAZIFOP-P-BUTYL
0.09375–0.1875 lb a.i.
(Fusilade DX)
6–12 fl oz
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 1
COMMENTS: For use on asparagus that is either direct-seeded, transplanted, or crown planted. Apply in 20–40 gal water/acre along with a 1% crop oil concentrate. Rates depend on grass size and species. Follow label instructions regarding the use of adjuvants.
ESTABLISHED CUTTING BEDS
Preemergence (When spears are not present)
A.
AMMONIUM NONANOATE
(Axxe)#
6%–15% spray solution
4
0
WSSA MODE-OF-ACTION GROUP NUMBER1: Unknown
COMMENTS: An organic contact, nonselective foliar herbicide without residual activity. Check with organic certifier to determine which products are organically acceptable. The degree of control is greater when weeds are actively growing, small, and immature; larger weeds are less affected. Use in a band application over the crop row or as a broadcast application at or before planting, or prior to the emergence of the crop. Provides control of annuals and some suppression of perennials. For best results, target weeds should be thoroughly wetted with spray solution but not to the point of runoff. Use up to 80–125 gal spray solution per broadcast acre to ensure thorough weed coverage. Use 6–8% solution for annual weeds less than 1 inch tall; 8–10% solution for annual weeds between 1 and 4 inches tall; use 10–13% solution for weeds over 4 inches tall; and use 15% for perennial weeds or severe infestations.
B.
CAPRYLIC AND CAPRIC ACIDS
(Suppress EC)#
3%–9% spray solution
24
0
WSSA MODE-OF-ACTION GROUP NUMBER1: Unknown
COMMENTS: An organic contact, nonselective foliar herbicide without residual activity. Check with organic certifier to determine which products are organically acceptable. Controls most annual weeds. The degree of control is greater when weeds are actively growing, small, and immature; larger weeds are less affected. Use in a band application over the crop row or as a broadcast application at or before planting or prior to the emergence of the crop. Provides control of annuals and some suppression of perennials. For best results, target weeds should be thoroughly wetted with spray solution but not to the point of runoff. Use up to 100 gal spray solution per broadcast acre to ensure thorough weed coverage. For most annual weeds, use a minimum 3% solution and a maximum 6% solution. For perennial or large annual weeds, use a 6–9% solution.
C.
GLYPHOSATE
0.38–3.7125 lb a.e.
(Roundup Powermax)
0.34–3.3 qt
4
See label
WSSA MODE-OF-ACTION GROUP NUMBER1: 9
COMMENTS: A nonselective foliar herbicide used to control small annual weeds in finished beds before spears emerge. Asparagus spears emerged at the time of treatment will be damaged and should be discarded. Use the higher rate to control perennial weeds.
D.
PARAQUAT*
0.63–1 lb a.i.
(Gramoxone SL 2.0)
2.5–4 pt
24
See label
WSSA MODE-OF-ACTION GROUP NUMBER1: 22
COMMENTS: A nonselective foliar herbicide without soil activity applied as a band or broadcast treatment before spears emerge. Asparagus that has emerged at the time of application will be damaged. Apply when weeds are succulent and 16 inches high; larger weeds are less affected. Surfactant is needed. Late afternoon applications increase activity.
E.
PELARGONIC ACID
2.34–20 gal/broadcast acre
(Scythe)
3%–10% spray solution
12
0
WSSA MODE-OF-ACTION GROUP NUMBER1: Unknown
COMMENTS: A contact, nonselective foliar herbicide without residual activity. The degree of control is greater when weeds are actively growing, small, and immature; larger weeds are less affected. Apply as a band treatment over the crop row or as a broadcast treatment at or before planting. Provides control of annuals and some suppression of perennials. For best results, target weeds should be thoroughly wetted with spray solution but not to the point of runoff. Use 75 to 200 gal spray solution per broadcast acre, with higher volume used when weed density is high. A 3 to 5% solution is sufficient for most annual weeds, while perennial or large annual weeds require a 7% solution.
F.
METRIBUZIN
(Metribuzin 75)
Label rates
12
14
WSSA MODE-OF-ACTION GROUP NUMBER1: 5
COMMENTS: Apply to soil; metribuzin has both soil and foliar activity on newly emerged annual weeds. Soil should not be moved after application. Rainfall or irrigation is necessary for activation of this herbicide.
G.
DIURON
(Karmex DF)
See comments
12
0
WSSA MODE-OF-ACTION GROUP NUMBER1: 7
COMMENTS: On light soils and other soils low in clay and organic matter, use a rate of 1–2 lb (0.8–1.6 lb a.i.) per acre. For newly planted crowns in the San Joaquin Delta and soils with high clay or organic matter, use a rate of 2–4 lb (1.6–3.2 lb a.i.) per acre. Apply as a band or broadcast treatment to weed-free beds no earlier than 4 weeks before spears emerge; a second application may be made following harvest. Incorporate mechanically or with irrigation if rainfall does not occur. Considered to be a groundwater contaminant and requires a use permit within Groundwater Protection Areas. Do not use on soils with less than 2% organic matter; use lower rates on coarse-textured soils.
F.
NAPROPAMIDE
4 lb a.i.
(Devrinol 50 DF)
8 lb
24
0
WSSA MODE-OF-ACTION GROUP NUMBER1: 15
COMMENTS: Apply to weed-free soil in established beds. Requires shallow (1–2 inch) mechanical incorporation, and if rainfall does not occur, it must be irrigated.
G.
PENDIMETHALIN
1.1–3.8 lb a.i.
(Prowl H2O)
2.4–8.2 pt
24
14
WSSA MODE-OF-ACTION GROUP NUMBER1: 3
COMMENTS: With a single application apply up to 8.2 pints/acre to the soil surface at least 14 days before harvest. On sandy soils, do not apply more than 2.4 pints/acre. Application must be made prior to spear emergence and prior to weed emergence. This material will not control emerged weeds.
H.
TRIFLURALIN
(Treflan HFP)
Label rates
12
0
WSSA MODE-OF-ACTION GROUP NUMBER1: 3
COMMENTS: Apply to established asparagus after bed preparation but before spears emerge. Trifluralin has no postemergence activity on weeds and must be mechanically incorporated immediately after application with disks or rolling cultivators in two directions or with a power-driven incorporator in one direction. Higher rates necessary for the suppression of field bindweed.
I.
LINURON
(Lorox)
Label rates
24
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 7
COMMENTS: A soil-applied herbicide noted for its foliar activity on small seedling, broadleaf weeds and for its relatively short soil residual activity. Can be applied immediately after cutting, but do not harvest within one day after application. Do not apply more than 4 lb/acre/season with a maximum of 3 applications per year.
J.
FLUAZIFOP-P-BUTYL
0.09375–0.1875 lb a.i.
(Fusilade DX)
6–12 fl oz
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 1
COMMENTS: Do not apply more than 24 fl oz/acre/season. Do not make sequential applications at less than a 3-week interval.
K.
SETHOXYDIM
0.281–0.468 lb a.i.
(Poast)
1.5–2.5 pt
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 1
COMMENTS: Apply to actively growing grasses that are not under moisture stress; best applied 1 to 2 days after a rain or irrigation. Rate depends on grass size and species. Follow label instructions regarding the use of adjuvants.
L.
FLUMIOXAZIN
0.19 lb a.i.
(Chateau)
6 oz
12
14
WSSA MODE-OF-ACTION GROUP NUMBER1: 14
COMMENTS: Apply no less than 14 days before spears emerge and before weeds emerge, or burn weeds back with a tank-mix material. Requires 0.25 inch of rainfall or irrigation to activate the material.
M.
HALOSULFURON
0.023–0.046 lb a.i.
(Sandea)
0.5–1.5 oz
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 2
COMMENTS: May be applied before harvest season. Works best on nutsedge when it is actively growing (i.e. following an irrigation). Do not use adjuvant with any applications made before or during harvest. Check label for regional constraints.
ESTABLISHED CUTTING BEDS
Postemergence (After spears emerge)
A.
DICAMBA*
0.25–0.5 lb a.i.
(Banvel)
0.5–1 pt
24
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 4
COMMENTS: Apply immediately after cutting but at least 24 hours before the next harvest. Postharvest applications should be done as directed sprays to avoid fern contact. Do not use in Coachella Valley. Do not exceed 1 pt/acre/season.
B.
LINURON
(Lorox)
Label rates
24
1
COMMENTS: A soil-applied herbicide noted for its foliar activity on small seedling, broadleaf weeds and for its relatively short soil residual activity. Can be applied immediately after cutting, but do not harvest within one day after application. Do not apply more than 4 lb a.i./acre/season with a maximum of 3 applications per year.
C.
HALOSULFURON
0.0234–0.0703 lb a.i.
(Sandea)
0.5–1.5 oz
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 2
COMMENTS: May be applied before or during harvest season. Works best on nutsedge when it is actively growing (i.e. following an irrigation). Do not use adjuvant with any applications made before or during harvest. Check label for regional constraints.
D.
FLUAZIFOP-P-BUTYL
0.09375–0.1875 lb a.i.
(Fusilade DX)
6–12 fl oz
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 1
COMMENTS: Do not apply more than 24 fl oz/acre/season. Do not make sequential applications at less than a 3-week interval.
E.
SETHOXYDIM
0.281–0.468 lb a.i.
(Poast)
1.5–2.5 pt
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 1
COMMENTS: Apply to actively growing grasses that are not under moisture stress; best applied 1 to 2 days after a rain or irrigation. Rate depends on grass size and species. Follow label instructions regarding the use of adjuvants.
ESTABLISHED CUTTING BEDS
Postharvest and fern stage
A.
GLYPHOSATE
0.38–3.71 lb a.e.
(Roundup)
0.34–3.3 qt
4
See label
WSSA MODE-OF-ACTION GROUP NUMBER1: 9
COMMENTS: A nonselective foliar herbicide used to control both annual and perennial weeds. Use on clean-cut beds after all remaining spears have been removed. Higher rates of application are necessary for the control of perennial weeds. Direct contact of the spray to asparagus can cause serious injury. Useful as a spot treatment for the control of perennial weeds at field edges. Do not apply within a week before the first asparagus spears emerge.
B.
HALOSULFURON
0.0234–0.0703 lb a.i.
(Sandea)
0.5–1.5 oz
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 2
COMMENTS: May be applied at end of harvest season. Under heavy nutsedge pressure, split applications are recommended. Works best on nutsedge when it is actively growing (i.e. following an irrigation). Use drop nozzles to improve coverage on weeds and reduce contact with fern.
C.
DIURON
(Karmex DF)
See comments
12
0
WSSA MODE-OF-ACTION GROUP NUMBER1: 7
COMMENTS: On light soils and other soils low in clay and organic matter, use a rate of 1–2 lb (0.8–1.6 lb a.i.) per acre. For newly planted crowns in the San Joaquin Delta and soils with high clay or organic matter, use a rate of 2–4 lb (1.6–3.2 lb a.i.) per acre. Can be applied following the harvest period. Do not exceed seasonal application limits.
D.
TRIFLURALIN
(Treflan HFP)
Label rates
12
0
WSSA MODE-OF-ACTION GROUP NUMBER1: 3
COMMENTS: Can be mechanically incorporated to suppress bermudagrass and other grasses following the harvest period but before fern growth.
E.
LINURON
(Lorox)
Label rates
24
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 7
COMMENTS: Can be used as a directed spray to the base of the fern.
F.
FLUAZIFOP-P-BUTYL
0.09375–0.1875 lb a.i.
(Fusilade DX)
6–12 fl oz
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 1
COMMENTS: Can be used before the fern stage to suppress bermudagrass and other grasses.
G.
SETHOXYDIM
0.281–0.468 lb a.i.
(Poast)
1.5–2.5 pt
12
1
WSSA MODE-OF-ACTION GROUP NUMBER1: 1
COMMENTS: Apply to actively growing grasses that are not under moisture stress; best applied 1 to 2 days after a rain or irrigation. Rate depends on grass size and species. Follow label instructions regarding the use of adjuvants.
H.
METRIBUZIN
0.9975–1.995 lb a.i.
(Metribuzin 75)
1.3–2.0 lb
12
14
WSSA MODE-OF-ACTION GROUP NUMBER1: 5
COMMENTS: Apply after last harvest of the season but before fern growth begins.
‡
Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
*
Permit required from county agricultural commissioner for purchase or use.
NA
Not applicable.
1
Group numbers are assigned by the Weed Science Society of America (WSSA) according to different modes of action. Although weeds may exhibit multiple resistance across many groups, mode-of-action numbers are useful in planning mixtures or rotations of herbicides with different modes of action.
Text Updated: 08/19
Treatment Table Updated: 08/19