INTEGRATED PEST MANAGEMENT
Commercial Pecan
Insect, Disease, and Weed Control
Recommendations for 2006
Alabama Cooperative Extension System / Alabama A&M and Auburn Universities
 
WEED CONTROL
 
     Herbicides are recommended for pecan orchards to provide an 8- to 12-foot-wide, weed-free strip between the tree rows. This weed-free strip between rows will reduce weed competition in both the young and the old trees, and it will help increase harvesting efficiency as well as prevent mower damage.      Keep the area between tree rows as a mowed sod, 1 inch or less in height. This sod-herbicide system provides an all-weather roadway for spraying and harvesting equipment and is an effective floor for mechanical harvesting. Also, this system eliminates mechanical disking, which often dam-ages pecan roots and spreads crown gall.
 
 
 
Table 13. Pecan Weed Control
Herbicide Trade Name (Rate/Acre Broadcast)   Herbicide Common Name
(Active herbicide/Acre)

Comments

Preplant Incorporated (PPI)
PROWL 3.3EC
(2.4-4.8 pt.)
or
PROWL H2O
(4-8 pt.)

TREFLAN
TRIFLURALIN
TRILIN
(1-2 pt.)
 

pendimethalin
(2-4 lb.)


 

trifluralin
(0.5-1 lb.)

 Apply preplant or preemergence ONLY to nonbearing trees to control annual grasses and small-seeded broadleaf weeds.  Will not control emerged weeds.




Before planting trees, apply to soil as a broadcast spray and incorporate into soil within 8 hours. Use lower rate on coarse soils. Controls most annual grasses and many small-seeded broadleaf weeds.
Preemergence (PRE)

Gallery 75DF
(0.66-1.33 lb.)

GOAL 1.6E
(6-10 pt.)
 

 isoxaben
(0.5-1 lb.)

oxyfluorfen
(1.2-2 lb.)

Apply ONLY to dormant trees. Goal should be applied to the soil and to the base of trees. Controls winter annual weeds. May be tank-mixed with Devrinol, Surflan, or Solicam for residual grass control. DO NOT apply after budswell.
 
KARMEX DF
(4 lb.)
or
DIREX 4L or
DIURON 4L
(3 qt.)

diuron
(3.2 lb.)

 Use ONLY where trees have been established 3 years or more. Controls many annual grasses and broadleaf weeds. Apply before weeds emerge, in spring for summer weed control or in fall for winter weed control. If summer and winter weed control is de-sired, apply half the recommended rate in spring and half in fall. DO NOT use in areas where tree roots are exposed. If used as an early postemergence treatment, add a surfactant at the rate of 2 quarts per 100 gallons of spray. Best results are obtained on succulent weed seedlings. DO NOT use on sandy or loamy sand soils. DO NOT allow livestock to graze in treated areas. Karmex may be tank-mixed with Surflan. See label for appropriate use rate.
 

PRINCEP CALIBER 90
(2.2-4.4 lb.)
or
PRINCEP 4L or
SIMAZINE 4L
(2-4 qt.)

 simazine
(2-4 lb.)		 Apply to orchards established more than 1 year. Controls many annual grasses and broadleaf weeds. Apply before weeds emerge, in spring for summer weed control, or in fall for winter weed control. If summer and winter weed control is desired, apply half the recommended rate in spring and half in fall. Apply to orchard floor and avoid contact with tree foliage or green stems. Will not control established weeds. DO NOT use on sandy or loamy sand soils. DO NOT allow livestock to graze in treated areas. See label for appropriate use rate. Princep may be tank-mixed with Surflan or Gramoxone.
 

SOLICAM 80DF
(2.5-5 lb.)

 

 norflurazon
(2-4 lb.)

 

 Apply under bearing and non-bearing pecan trees. DO NOT apply until the soil has settled around transplanted trees. Make only one application per year either as a fall postharvest treatment or as an early spring treatment. DO NOT graze treated areas. Solicam can be tank-mixed with Gramoxone.
 
SURFLAN AS
(2-6 qt.)

oryzalin
(2-6 lb.)

 Apply under bearing and non-bearing pecan trees. DO NOT apply to newly transplanted trees until the soil has settled and no cracks are present. Use the low rate for 2 to 4 months of weed control, the medium rate for 6 to 8 months, or the high rate for 8 to 12 months of weed control. Controls many annual grasses and small-seeded broadleaf weeds. DO NOT allow livestock to graze treated areas.
 
Herbicide Trade Name (Rate/Acre Broadcast)   Herbicide Common Name
(Active herbicide/Acre)

Comments

Postemergence (POST)

FUSILADE DX
(1 pt.)
+
Crop Oil Concentrate
(2 pt.)
or
Non-ionic Surfactant
(0.5 pt./25 gal. spray mix)
 

 fluazifop-butyl
(0.2 lb.)

crop oil concentrate


non-ionic surfactant		 Apply as a directed spray using a maximum of 25 gallons of spray solution per acre. Use hollow cone or flat fan nozzles. A non-phytotoxic crop oil concentrate or non-ionic surfactant must be used with this herbicide. Use a crop oil concentrate with Fusilade to control perennial grasses, such as bermudagrass and johnsongrass. Repeat application may be needed if regrowth occurs. Broadleaf weeds and nutsedges (nutgrass) will not be controlled by this herbicide. DO NOT harvest within 30 days of treatment.
GRAMOXONE MAX
(1.25-2.5 pt.)
or
BOA
(1.5-3 pt.)
+
Non-ionic Surfactant
(0.5 pt./50 gal. spray mix)
 		 paraquat
(0.5-1 lb.)




non-ionic surfactant 		 One-year-old trees may have green bark and be injured by herbicide contact. DO NOT allow the spray to contact green stems, fruit, or foliage. Controls many annual broadleaf weeds and grasses and top-kills perennials. Apply as a directed spray when weeds and grasses are succulent and new growth is 1 to 6 inches high. Has no residual activity. Also useful as a knock-down chemical on sod middles. Observe safety precautions. DO NOT allow livestock to graze on treated areas. Paraquat is a RESTRICTED USE pesticide.
POAST 1.5E
(1.5-2.5 pt.)
+
Crop Oil Concentrate
(2 pt.)
 		 sethoxydim
(0.25-0.5 lb.)

crop oil concentrate		 Apply only to NON-BEARING pecan trees that will not be harvested within 1 year after application. Apply as a directed spray in a maximum of 20 gallons of spray solution per acre. A repeat application may be needed. Broadleaf weeds and nutsedge will not be controlled.

RELY
(3-6 qt.)

 glufosinate
(0.75-1.5 lb.)		 Apply under trees of all ages, bearing or non-bearing, for control of annual and perennial weeds and grasses. DO NOT apply within 14 days of harvest. DO NOT allow livestock to graze in treated areas.
 

ROUNDUP)
or
TOUCHDOWN
or
GLYPHOSATE
(other generic forms available)
+
Non-ionic Surfactant
(1 pt./25 gal. spray mix)
 

 glyphosate
(1-4 lb.)		 Apply under NON-BEARING trees that are more than 2 years old.  May be applied to BEARING trees of any age. DO NOT allow spray to contact foliage or green stems of trees.  Controls a broad spectrum of annual and perennial weeds and grasses.  DO NOT allow livestock to graze in treated areas.  See label for specific rates.

SEMPRA CA
(0.67-1.33 oz.)
+
Non-ionic Surfactant
 

 halpsulfuron
(0.032-0.063 lb.)
+
non-ionic surfactant		 Apply as a directed spray to pecans that have been established 12 months or longer.  Provides control of nutsedge and several other weed species.  DO NOT allow spray to contact stem or leaves.

WEEDAR 64
(3 pt.)

 2,4-D amine
(1.4 lb.)		 Apply to vegetation between DORMANT trees for control of emerged winter annual weeds.  DO NOT apply within 2 weeks of budbreak.  Clean spray equipment thoroughly after using the product.
 
Herbicide Trade Name (Rate/Acre Broadcast)   Herbicide Common Name
(Active herbicide/Acre)

Comments
Chemical Mowing

ROUNDUP
or
TOUCHDOWN
or
GLYPHOSATE
(generic forms)

 glyphosate
(0.12-0.5 lb.)		 Inhibits bahiagrass seedhead formation and suppresses vegetative growth of bahiagrass and bermudagrass.  Use the low rate for bahiagrass or for bermudagrass growing under shades.  Apply 2 weeks after green-up or after mowing to a height of 3 to 4 inches.  DO NOT apply more that twice per season.  See label for Additional comments.
 
 

Table 14. Herbicide Classification By Mode of Action.

AMINO ACID SYNTHESIS INHIBITORS: Rely, Roundup, Touchdown
CELL MEMBRANE DISRUPTORS: Gramoxone
GROWTH REGULATORS: 2,4-D

 LIPID SYNTHESIS INHIBITORS: Fusilade, Poast
PHOTOSYNTHETIC INHIBITORS: Karmex, Princep, Solicam
ROOT GROWTH INHIBITORS: Devrinol, Surflan
 
     
Weed Control section prepared by Michael G. Patterson and John W. Everest, Extension Weed Scientists, and William D. Goff and Monte Nesbitt, Extension Horticulturists, Alabama Cooperative Extension System.
 
Table 15. Estimated Effectiveness Of Recommended Herbicide Treatments On Important Weeds Infesting pecans In Alabama And Properties That May Affect Water Quality.1
 

HERBICIDES
WEEDS Treflan
(PPI)		 Gallery
(PRE)		 Karmex
(PRE)		 Princep
(PRE)		 Solicam
(PRE)		 Surflan
(PRE)		 Boa,
Gramoxone
(POST)		 Fusilade,
Poast
(POST)		 Rely
(POST)		 Roundup,
Touchdown
(POST)
Bahiagrass 2 0 1 1 4 0 3 8 8 8
Bermudagrass 2 0 0 0 4 0 3 8 8 8
Blackberry 0 0 1 1 2 0 3 0 -- 6
Crabgrass 9 0 8 8 8 8 7 9 9 9
Florida Pusley 9 6 8 9 8 8 6 0 -- 9
Goosegrass 9 0 8 8 8 8 8 9 9 9
Lambsquarter 5 9 9 8 5 5 8 0 8 9
Morningglory 0 5 5 7 5 0 8 0 -- 9
Nutsedge 0 0 0 0 7 0 4 0 7 7
Pigweed 9 9 9 9 9 9 9 0 8 9
Prickly Sida 0 6 4 9 9 0 6 0 --
Ragweed 3 9 8 8 8 4 8 0 8 9
Texas Panicum 9 0 4 4 4 7 9 9 8 9
Surface-loss Potential 2 S S M M M M S M S S
Leaching Potential 3 S S M M M S S S S S
1 Ratings are based on observations of research plots and field use under average weather conditions for several years by weed control workers in Alabama and the South.  Leaching and surface-loss potentials are based in part on herbicides chemical characteristics and pesticide behavior models developed by USDA scientists as well as on field experience.
2 The surface-loss potential indicates the tendency of the pesticide to move with sediment in runoff.
3 The leaching-potential indicates the tendency of the pesticide to move in solution with water and to leach below the root zone.
KEY TO CONTROL RATINGS AND ABBREVIATIONS
Ratings on a scale of 0 to 10: 0 = No Control; 10 = 100% control; -- = Information not available
PPI = Preplant Incorporated; PRE = Preeemergence; POST = Postemergence.
S= Small; M = Medium; L = Large