UC IPM Online UC ANR home page UC IPM home page

UC IPM Home

SKIP navigation

 

How to Manage Pests

UC Pest Management Guidelines


Plum

Herbicide Treatment Table

(Reviewed 5/06, updated 4/09)

In this Guideline: More about weeds in plum:

Common name Amount/Acre R.E.I.+ P.H.I.+
(trade name)   (hours) (days)

  Calculate impact of pesticide on air quality
When choosing a pesticide, consider information relating to environmental quality.
 
PREPLANT
Preemergent (before weeds germinate)
A. TRIFLURALIN 0.5–1 lb a.i. 12 0
  (Treflan, Trilin)
  WSSA MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: Broadcast preplant in 5 to 40 gallons of water per acre. Trifluralin must be incorporated immediately after application to avoid loss of activity. Plant tree roots below treated soil. Do not place treated soil near roots during planting. Controls many annuals and is helpful in suppressing perennial weeds. Residual period: 2–12 months.
 
Postemergent (after weeds emerge)
A. GLYPHOSATE 1–4 lb a.i. 4 17
  (Roundup UltraMax, Touchdown etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 9
  COMMENTS: Apply with a controlled applicator or with low-pressure flat fan nozzles. For annual weed control use 1 lb/acre in 3–10 gal water. Ammonium sulfate can also be added (1 to 2% by weight or 8.5 to 17 lbs per 100 gallon of water) to the spray solution, and significantly improves control in areas with hard water. It is important to add the ammonium sulfate to the water prior to adding the herbicide. Apply to young annuals or vigorously growing perennials in flowering stage. Some perennials require the 4 lb/acre rate for control. May be used on young weeds in the planting row followed by planting into the dead weeds. New weeds usually do not establish for a month or more, as a result of the no-till effect. Do not use more than 10.6 lb/year.
 
NEWLY PLANTED ORCHARDS (nonbearing trees)
Preemergent (before weeds germinate)
A. FLUMIOXAZIN 0.19–0.38 lb a.i 12 365
  (Chateau)
  WSSA MODE OF ACTION GROUP NUMBER1: 14
  COMMENTS: Apply as a uniform broadcast application to the orchard floor or as a uniform band at the base of the trunk. Should not be applied through any type of irrigation system or on frozen soil. Mechanical incorporation is not encouraged as it will reduce residual weed control. Should not be applied to trees established less than one year, unless protected from spray by a tree collar. Do not apply within 1 year of the first harvest. Flumioxazin also has postemergent activity. When applied postemergence, always add crop oil concentrate or methylated seed oil. Ammonium sulfate can also be added to enhance weed control, at the rate of 2 to 2.5 lbs of ammonium sulfate per treated acre. Ammonium sulfate does not replace crop oil or methylated seed oil in the mixture. Use allowed under a supplemental label.
 
B. ISOXABEN 0.5–1 lb a.i. 12 365
  (Gallery T&V)
  WSSA MODE OF ACTION GROUP NUMBER1: 21
  COMMENTS: Wait until soil has settled around newly planted trees before applying. Controls broad-leaf weeds only before they have germinated; will not control emerged weeds. If weeds are emerged, lightly cultivate or add a postemergent herbicide. Requires incorporation for activation, either by light cultivation (1 to 2 inches) or rainfall (minimum of 0.5 inches) within 21 days after application. Sprinkler or flood irrigation can also be used for incorporation. Apply in at least 10 gal/acre of water.
 
C. TRIFLURALIN 1–2 lb a.i. 12 0
  (Treflan, Trilin etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: Preemergent selective herbicide for annual grasses. Apply prebloom by ground as a directed spray and mechanically incorporate, taking care not to injure the trees with the incorporation. Trifluralin must be incorporated immediately after application to avoid loss of activity. Used on new plantings or established orchards as a strip treatment. Suppresses bermudagrass, johnsongrass, and dallisgrass rhizomes. Only one application per year. Residual period: 2–12 months.
 
D. ORYZALIN 2–6 lb a.i. 24 0
  (Surflan, Farmsaver Oryzalin etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: Preemergent selective herbicide for annual grasses. Apply to the soil surface in 20–40 gal water/acre. If rain does not occur within 21 days, sprinkle irrigate with 0.5–2 inches of water. May be combined with a postemergent herbicide if weeds are present. Most effect on annual grasses and numerous broadleaf annuals. Very safe for young or newly planted trees and on sandy or sandy loam soils. Used to maintain control in strips down the row. The higher rates give the longest soil residual. Usually used at 4 lb a.i./acre. Residual period: 4–10 months.
 
E. NAPROPAMIDE 4 lb a.i. 12 35
  (Devrinol 50DF)
  WSSA MODE OF ACTION GROUP NUMBER1: 15
  COMMENTS: Use is being dropped from label. Read label carefully to be sure crop is listed on label of product used. Apply to the soil surface in 20–60 gal water/acre. Use only once per season. Must be incorporated within either mechanically or with sprinkler irrigation or rainfall, within 21 days of application between November and February, or within 24 hours the remainder of the year. Effective on annual grasses and several annual broadleaves. Effective in maintaining weed-free strips down the row. Needs to be combined with a postemergent herbicide if weeds have emerged. Residual period: 4–10 months.
 
F. PENDIMETHALIN 2–4 lb a.i. 24 365
  (Prowl H20)
  WSSA MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: For use on dormant nonbearing trees only. Apply in 10 or more gal water/acre to soil under trees. Do not apply on newly planted trees unless soil is firm and there are no cracks in soil around base of trees. Best control is achieved when irrigation or rainfall occurs within 7 days. Will not control emerged weeds. Residual period: 4–10 months.
 
G. THIAZOPYR
  (Visor) 2E 0.5–1 lb a.i. 12 1 year
  WSSA MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: For use on nonbearing trees only. Apply in 20 or more gal water/acre. Provides nutsedge and marestail suppression on coarse textured soils with low organic matter. Best control is achieved when irrigation or rainfall occurs within 7 days of application. Will not control emerged weeds. Residual period: 4-10 months. Use allowed under a SLN registration.
 
Postemergent (after weeds emerge)
A. CLETHODIM
  (Select Max) 0.095-0.125 lb a.i. 24 1 year
  WSSA MODE OF ACTION GROUP NUMBER1: 1
  COMMENTS: For use on nonbearing trees only. Apply to young perennial grasses. Repeat applications will be required for the control of perennial grasses. Apply in 5 to 40 gal water/acre. Add 0.25% v/v nonionic surfactant to the spray solution. Spray pressure should be between 30 and 60 PSI, with higher pressures used when weed density is high. Do not apply a broadleaf herbicide within one day following a clethodim application or reduced grass control may occur. Residual period: less than one month.
 
B. SETHOXYDIM 0.19–0.47 lb a.i. 12 1 year
  (Poast)
  WSSA MODE OF ACTION GROUP NUMBER1: 1
  COMMENTS: For use on nonbearing trees only. Apply to young perennial grasses. Repeat applications will be required for the control of perennial grasses. Add 2 pt/acre of a non-phytotoxic crop oil concentrate to the spray solution. Residual period: less than one month.
 
C. MSMA 2-4 lb a.i. 12 1 year
  (MSMA 6 Plus etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 17
  COMMENTS: For use in nonbearing trees only. Apply in 50 gallons of water per acre to insure adequate coverage. Can be applied up to three times per year. Apply as a directed spray or in such a way as to avoid contact with the foliage of prunes.
 
ESTABLISHED ORCHARDS
Preemergent (before weeds germinate)
A. TRIFLURALIN 1–2 lb a.i. 12 0
  (Treflan, etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: Preemergent selective herbicide for annual grasses. Apply prebloom by ground as a directed spray and mechanically incorporate, taking care not to injure the tree. Trifluralin must be incorporated immediately after application to avoid loss of activity. Frequently used as a strip treatment. Suppresses bermudagrass, johnsongrass, and dallisgrass rhizomes. Only one application per year. Residual period: 2–12 months.
 
B. ORYZALIN 2–6 lb a.i. 24 0
  (Surflan, Farmsaver Oryzalin etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: Apply to the soil surface in 20–40 gal water/acre. If rain does not occur within 21 days, sprinkle irrigate with 0.5–2 inches of water. Most effect on annual grasses and numerous broadleaf annuals. Very safe for sandy or sandy loam soils. Used to maintain control in strips down the row. May be combined with a postemergent herbicide if weeds are present. The higher rates give the longest soil residual. Usually used at 4 lb a.i./acre. Residual period: 4–10 months.
 
C. NAPROPAMIDE 4 lb a.i. 12 35
  (Devrinol) 50DF
  WSSA MODE OF ACTION GROUP NUMBER1: 15
  COMMENTS: Use is being dropped from label. Read label carefully to be sure crop is listed on label of product used. Apply to the soil surface in 20–60 gal water/acre. Use only once per season. Must be incorporated within either mechanically or with sprinkler irrigation or rainfall, within 21 days of application between November and February, or within 24 hours the remainder of the year. Effective on annual grasses and several annual broadleaves. Effective in maintaining weed-free strips down the row. Needs to be combined with a postemergent herbicide if weeds have emerged. Residual period: 4–10 months.
 
D. NORFLURAZON 1.97–3.93 lb a.i. 12 60
  (Solicam DF)
  WSSA MODE OF ACTION GROUP NUMBER1: 12
  COMMENTS: Similar to oryzalin, but is effective on more annual broadleaf and grass species. Can suppress yellow nutsedge or bermudagrass when used year after year. Apply to soil as a directed spray from fall to early spring under trees established for at least 2 years. If no rainfall occurs within four weeks, incorporate with sprinkler or flood irrigation. Existing weeds must be removed with cultivation or a postemergent herbicide, as norflurazon has no postemergent activity. Considered to be a ground water contaminant and requires a use permit within Ground Water Protection Areas. Do not use in the Coachella Valley. Apply in 20–100 gal water/acre. Residual period: 6–12 months.
 
E. OXYFLUORFEN 0.5 – 2 lb a.i. 24 0
  (GoalTender)
  WSSA MODE OF ACTION GROUP NUMBER1: 14
  COMMENTS: For use on dormant trees only. Apply following harvest up to February 15 (February 1 in the Coachella Valley). Apply by ground one time per season in 40–100 gal water/acre on firm soil. Must not be mechanically disturbed or poor weed control will result. Effective as a pre-and postemergent herbicide. Effective on little mallow (cheeseweed). Useful combined with other postemergent herbicides, such as glyphosate or in combination with preemergent herbicides, such as oryzalin, simazine, or thiazopyr. Check label for use period. Residual period: 4–10 months.
 
F. PRONAMIDE
  (Kerb) 50W 1-4 lb a.i. 24 0
  WSSA MODE OF ACTION GROUP NUMBER1: 3
  COMMENTS: Do not apply to trees less than 1 year old. Selective herbicide for control of winter annual and perennial grasses. Apply in Fall after fruit harvest. Apply in 40-50 gal water/acre to the soil at the base of the trees. Pronamide must be applied before weed emergence as it will not control emerged weeds. Rainfall or irrigation is essential after application for effective weed control. Residual period: 4-8 months.
 
Postemergent (after weeds emerge)
A. GLYPHOSATE 1–4 lb a.i. 4 17
  (Roundup Ultra Max, Touchdown etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 9
  COMMENTS: Apply with controlled droplet application or with low-pressure, flat-fan nozzles. For annual weed control, use 1 lb a.i./acre in 3–10 gal water. Ammonium sulfate can also be added (1 to 2% by weight or 8.5 to 17 lbs per 100 gallon of water) to the spray solution, and significantly improves control in areas with hard water. It is important to add the ammonium sulfate to the water prior to adding the herbicide. For chemical mowing, consult label for exact timing and rates, depending on weed size and species. Apply to young annuals or vigorously growing perennials. Some perennials require the 4 lb a.i./acre rate for control. A good herbicide for perennial weeds, but doesn't eradicate field bindweed or nutsedge. Not effective on some broadleaf weeds at older stages of growth (little mallow and filaree). Avoid drift onto green bark or foliage of tree or injury will result. It is important to monitor treated areas for escaped weeds, as glyphosate resistant weeds have been observed in orchards where glyphosate has been used repeatedly for several years.
 
B. PARAQUAT* 0.625–1 lb a.i. 12 28
  (Gramoxone Inteon)
  WSSA MODE OF ACTION GROUP NUMBER1: 22
  COMMENTS: Nonselective postemergent, contact herbicide used for quick top kill of most weed species. Less effective against perennials that will regrow (bermudagrass, dallisgrass, johnsongrass and field bindweed). Most effective when used in late winter or early spring on small annual grass species in combination with preemergent herbicides. Apply in 10–60 gal water/acre to young weeds. Use 0.25% v/v nonionic surfactant or 1.0% v/v of a crop oil concentrate. Repeat treatment as new growth occurs. Residual period: less than one month. A restricted use pesticide.
 
C. OXYFLUORFEN 0.5–2 lb a.i. 24 0
  (Goal 2 XL etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 14
  COMMENTS: Dormant application to young (4-leaf-stage) weeds. Effective on little mallow (cheeseweed). Useful combined with glyphosate or oryzalin. May be combined with other postemergent herbicides for specific weeds. Apply following harvest up to February 15 (February 1 in the Coachella Valley). Apply by ground one time per season in 40–100 gal water/acre on firm soil. Must not be mechanically disturbed or poor weed control will result. Effective as a pre-and postemergent herbicide. Residual period: 4–10 months.
 
D. 2,4–D* 0.95–1.425 lb a.i. 48 40
  (Orchard Master etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 4
  COMMENTS: For use on established trees one year or older. Effective on most broadleaf annual weeds. Provides partial control of field bindweed. Apply as a directed spray to weeds, using low-pressure, flooding nozzles between the tree rows. Best results are obtained when applied a few days after an irrigation. Do not allow drift onto the trees or injury may result. No more than two applications allowed during the growing season. Residual period: 4–6 weeks.
 
E. FLUAZIFOP-P-BUTYL 0.125–0.375 lb a.i. 12 14
  (Fusilade DX)
  WSSA MODE OF ACTION GROUP NUMBER1: 1
  COMMENTS: For control of annual and perennial grass weeds. A crop oil concentrate at 0.5 to 1% v/v or a nonionic surfactant at 0.25 to 0.5% v/v must be added to the spray solution. Diammonium phosphate (10-34-0) can also be added to the spray solution, and improves control in areas with hard water. Add the diammonium phosphate to the water prior to adding the herbicide and surfactant. Avoid contact of spray with foliage of trees. Apply in 5-40 gal water, with spray pressures of 30 to 60 psi. Best results are obtained when applied within 7 days after irrigation. Do not apply to grass that is stressed or poor control may result. Repeat applications may be required for johnsongrass and bermudagrass. Residual period: less than 1 month.
 
Herbicide combinations
  Note: Combinations are most often used to broaden the weed control spectrum. At the rates recommended below, perennial weeds will not be controlled. Other combinations can be used depending upon the weed spectrum present in the orchard.
 
A. GLYPHOSATE 0.5–1 lb a.i. 4 17
  (Roundup etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 9
  . . . PLUS . . .
  OXYFLUORFEN 0.1–1 lb a.i. 24 0
  (GoalTender)
  WSSA MODE OF ACTION GROUP NUMBER1: 14
  COMMENTS: For broad-spectrum control of emerged weeds. Apply in a minimum of 10 gal water/acre in dormant trees. Helps increase control of cheeseweed, filaree, chickweed, and grasses. Glyphosate effectiveness is increased with low-water volume and oxyfluorfen is more effective at the higher volume. Avoid drift and follow directions for application period of oxyfluorfen.
 
B. GLYPHOSATE 0.5–1 lb a.i. 4 17
  (Roundup etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 9
  . . . PLUS . . .
  ORYZALIN 4 lb a.i. 24 0
  (Surflan etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 9
  . . . or . . .
  NAPROPAMIDE 4 lb a.i. 12 35
  (Devrinol 50DF)
  WSSA MODE OF ACTION GROUP NUMBER1: 15
  COMMENTS: Use is being dropped from Devrinol label. Read label carefully to be sure crop is listed on label of product used. Combines pre- and postemergent control of most annual weeds with residual up to 6 months. Combination choice depends on weed spectrum and how rapid incorporation will occur. Napropamide needs irrigation within 7 days, oryzalin within 21 days. Apply post-directed to small seedlings when cotton is at least 8 inches tall.
 
C. ORYZALIN 4 lb a.i. 24 0
  (Surflan etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 3
  . . . PLUS . . .
  OXYFLUORFEN 2 lb a.i. 24 0
  (GoalTender)
  WSSA MODE OF ACTION GROUP NUMBER1: 14
  COMMENTS: Combined to give broad-spectrum control. Apply preemergence or combined with paraquat or glyphosate if weeds have emerged. Irrigate within 21 days if rain has not occurred.
 
D. GLYPHOSATE 0.5 lb a.i. 4 17
  (Roundup etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 9
  . . . PLUS . . .
  2,4–D* 0.5 lb a.i. 48 40
  (Orchard Master CA etc.)
  WSSA MODE OF ACTION GROUP NUMBER1: 4
  . . . PLUS . . .
  SURFACTANT 0.5–1%    
  COMMENTS: Combined to give broad-spectrum control. Apply postemergence to young, growing weeds. Avoid drift or contact with leaves.
 
+ Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) 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.
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. For more information, see http://www.hracglobal.com.
 
  Familiar commercial pesticide names are included to help readers recognize active ingredients, and do not represent all the labeled products that contain that chemical. For current registrations of herbicides consult a licensed, registered, Pest Control Advisor or the pesticide label.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Plum
UC ANR Publication 3462
Weeds
A. Shrestha, Kearney Agricultural Center, Parlier
W. T. Lanini, Weed Science/Plant Sciences, UC Davis
F. J. A. Niederholzer, UC Cooperative Extension, Sutter-Yuba counties

Top of page


Statewide IPM Program, Agriculture and Natural Resources, University of California
All contents copyright © 2014 The Regents of the University of California. All rights reserved.

For noncommercial purposes only, any Web site may link directly to this page. FOR ALL OTHER USES or more information, read Legal Notices. Unfortunately, we cannot provide individual solutions to specific pest problems. See our Home page, or in the U.S., contact your local Cooperative Extension office for assistance.

Agriculture and Natural Resources, University of California

Accessibility   /PMG/r611700411.html revised: January 8, 2014. Contact webmaster.