INTEGRATED PEST MANAGEMENT
Commercial Pecan
Insect, Disease, and Weed Control
Recommendations for 2006		  

Alabama Cooperative Extension System / Alabama A&M and Auburn Universities
 

DISEASE CONTROL
 

Timely fungicide sprays applied at recommended rates are necessary for a successful pecan crop. The first sprays must be applied in time to protect the developing foliage and nuts against fungal infection. Early application of fungicides is particularly essential because prevention of early-season buildup will reduce scab incidence throughout the remainder of the growing season.
     Cover sprays are scheduled with specific time intervals between sprays to ensure that a protective fungicide cover is always present. Extremely wet, humid periods which en-courage disease development or exceptionally high pest populations may necessitate additional sprays. Be sure to record the date when you apply each spray because the timing of cover sprays is based on the time of the previous spray. The conditions that encourage disease development (such as extremely wet weather) or orchards containing cultivars that are predominantly susceptible to scab may necessitate additional fungicide applications. See Tables 7 and 8 for the susceptibility of cultivars.
     The severity of late-season shuck diseases (Glomerella) depends on the degree of tree stress the orchard is subject to. Excessive or insufficient rainfall, tree canopy density, heavy crop load, lack of sunlight, insect and disease pressure, and unsuitable cultivars all increase stress in the orchard. Control of late-season diseases depends on a care-fully managed early-season fungicide spray program. The critical period for fungal infection appears to be from budbreak through late May. Thus, proper timing and application of early-season sprays are important for controlling disease.
     Disease resistance management is a primary concern in pecan production because of the sensitivity of the triazole Fungicides.  Enable and Orbit are both
 

 triazole fungicides. Triazole fungicides can exert selection pressure on disease organisms and may cause a population shift to organisms with reduced susceptibility to the triazoles as a group (such as both Enable and Orbit). For this reason, it is recommended that neither Enable nor Orbit be used alone or in an alternating spray program with one another throughout the entire growing season. Enable should be tank-mixed with Super Tin or Agri Tin, or the Orbit/Super Tin or Enable/ Agri Tin co-packs should be used during cover sprays. This will assure long-term efficacy of these products.
     Pecan growers should select either a block spray pro-gram or a full-season spray program to follow during the season. For a block spray program, the best choices are using either Enable 2E, Enable/Agri Tin co-pack, or the Orbit /Super Tin co-pack at 10- to 14-day intervals from budbreak through pollination. This will usually require a total of three fungicide applications followed by a cover spray program of Super Tin or Agri Tin at 14- to 21-day intervals to the end of August. Shorten spray intervals if weather conditions favor disease development.
     A full-season spray program requires only one fungicide or one combination of fungicides for the full season. Alter-native fungicides for this program include Agri Tin, Super Tin, or the Orbit/Super Tin or Enable/Agri Tin co-packs, or a combination of a half-rate tank mix of Enable 2E with Agri Tin or Super Tin.
     Apply the fungicides at 10- to 14-day intervals from budbreak through pollination. Apply at 14- to 21-day intervals during the cover spray period to the end of August. Shorten spray intervals if weather conditions favor disease development.
 
Table 5.  Properties Of Fungicides Used On pecans That may Affect Water Quality.

Common Name		 Trade name Surface-Loss Potential 1 Leaching Potential 2
Dodin Acetate
Propiconazole
 		 Syllit, Dodine
Orbit, Propimax		 Large
Medium		 Small
Medium
1 The surface-loss potential indicates the tendency of the pesticide to move with sediment in runoff.
2 The leaching potential indicates the tendency of the pesticide to move in solution with water and to leach below the root zone into deep percolation.
 
Table 6. Pecan Disease Control.    
Disease Fungicide
And
Formulation		 Amount Per Acre
For Medium-Size
Trees

Comments

Budbreak
Time Of Spray: Just as buds begin to split and show green.
Scab, Downy Spot        
AGRI TIN
or
ENABLE/AGRI TIN
or
ENABLE 2E
or
ENABLE 2E
+
ELAST F
or
ENABLE 2E
+
SUPER TIN 80WP
or
HEADLINE
or
ORBIT 45WP/SUPER TIN 80WP
or
PRISTINE
or
PROPIMAX EC
or
SUPER TIN 80WP
or
SOVRAN
or
STRATEGO		 See label.

See label.

8 oz.

4 oz.

2.5 oz.

4 oz.

3.75 oz.

6-7 oz.

See label.

10-14.5 oz.

4-8 oz.

7.5 oz.

2.4-3.2 oz.

10 oz.
 		 Begin applications at prepollination stages when the young leaves are unfolding. A wetting agent (such as LATRON B-1956) should be added to Enable and Enable/Agri Tin to achieve optimum disease control. DO NOT alternate triazole fungicides (such as Enable or Orbit) full season. DO NOT use Enable/Agri Tin co-pack, or Enable + Super Tin, or the Orbit/Super Tin co-pack in cover sprays if either Orbit or Enable are used alone for prepollination sprays. DO NOT use Enable alone in postpollination sprays. Overuse of triazole fungicides (such as Enable or Orbit) can allow strains of the scab fungus that has reduced sensitivity  to these products to flourish. DO NOT use more than three consecutive triazole fungicide sprays without an intervening application of a non-triazole fungicide (such as Super-Tin). DO NOT apply more than 1.5 quarts of Enable per acre per season. The Orbit/Super Tin and the Enable/Super Tin co-packs consist of two water soluble packages which must be used together. DO NOT use them separately. DO NOT open Super Tin or Agri Tin water-soluble packs. DO NOT use Dodine 65 WP on Moore, Van Deman, Shawnee, Barton, or other susceptible cultivars. To avoid possible plant injury, DO NOT tank-mix Dodine with Orbit.  DO NOT use any surfactant with Dodine or the Dodine + Enable tank mix.   Apply Propimax on a 14-day schedule.  Under severe disease conditions, use the high rate.  DO NOT  exceed four applications or 32 ounces per acres per growing season.  DO NOT apply more than 30 ounces of Stratego per acre per season.  DO NOT apply more than three sequential applications of Stratego before alternating with a fungicide with a different mode of action.  DO NOT make more than three applications of Stratego or other strobilurin-containing fungicide (Abound, Sovran) per acre per year. CRITICAL: Proper timing and application of the early-season sprays are necessary to reduce late-season diseases such as Glomerella shuck and kernel rot.  Use the higher rate of Sovran in orchards with a history of high scab pressure or during wet periods. DO NOT make more than three consecutive applications of Sovran.   DO NOT make more than two sequential applications of Pristine before alternating to a non-strobilurin fungicide.  DO NOT use Dodine full season.
 
Prepollination Spray
Time Of Spray:  When catkins are green and flowers are beginning to show (14 days after Budbreak Spray).
Scab, Downy Spot

Same as for Budbreak Spray

  This spray and the Budbreak Spray are essential for control of scab.  Thorough coverage is essential to prevent scab from becoming established in the orchard. Review Comments under Budbreak section.
 

Pollination Spray
Time Of Spray:  When catkins are shedding; nut tips & stigma turning dark brow (14 days after Prepollination Spray).
Scab, Downy Spot

Same as for Budbreak Spray

  This spray is also important in controlling early scab buildup.  Review Comments under Budbreak section.
 
Disease Fungicide
And
Formulation		 Amount Per Acre
For Medium-Size
Trees

Comments

Cover Sprays
Time Of Spray: 14 days after Pollination Spray AND every 21 days thereafter until the end of August.*
Scab, Brown Spot, Downy Spot
ABOUND
or
AGRI TIN
or
ENABLE/AGRI TIN
or
ENABLE 2E
+
SUPER TIN 80WP
or
ORBIT 45WP/SUPER TIN 80WP
or
PRISTINE
or
SOVRAN
or
SUPER TIN 80WP		 6.2-12.3 oz.

See label.

See label.

4 oz.

3.75 oz.

See label.

10-14.5 oz.

3.2-4.8 oz.

7.5 oz.		 A continued fungicide program is necessary to keep both foliage and developing nuts healthy. Fungicide applications for scab control may be omitted after August 30 provided the scab incidence is low and climatic conditions are not extremely humid. Abound may reduce damage from Anthracnose (Glomerella). The addition of a non-ionic surfactant may improve coverage of Abound. Use the higher rate of Abound or a shorter spray interval when weather conditions favor disease development. DO NOT make more than six applications of Abound per acre per year. A wetting agent (such as LATRON B-1956) should be added to Enable and Enable/Agri Tin co-pack to achieve optimum disease control. The Orbit/Super Tin and Enable/Agri Tin co-packs consist of two water-soluble packages which must be used together. DO NOT use them separately. Use Orbit/Super Tin co-pack, the Enable/Agri Tin co-pack, or Enable plus Super Tin tank mix for controlling zonate leaf spot, fungal leaf scorch, downy spot, vein spot, or liver spot. DO NOT alternate triazole fungicides (such as Enable or Orbit) full season. DO NOT use Enable/Agri Tin co-pack, Orbit/Super Tin co-pack, or Enable + Super Tin in cover sprays if either Orbit or Enable are used alone for prepollination sprays. DO NOT use Enable alone in postpollination sprays. Overuse of triazole fungicides (such as Enable or Orbit) can allow strains of the scab fungus with reduced sensitivity to these products to flourish. DO NOT apply more than 1.5 quarts of Enable per acre per season. Late-season fungicide applications are ineffective in controlling Glomerella shuck and kernel rot. DO NOT open Super Tin or Agri Tin water-soluble packs.  DO NOT apply Sovran as the final spray in the season. DO NOT alternate Abound, Sovran, or Stratego sprays full season, and DO NOT make more than three consecutive sprays of these products before changing to Super Tin or Agri Tin for at least two sprays. Use the higher rate of Sovran in orchards with a history of high scab pressure or during wet periods. DO NOT make more than three consecutive applications of Sovran. DO NOT use any surfactant with the Dodine + Enable tank-mix.  DO NOT apply more than 30 ounces of Stratego per acre per season.  DO NOT apply more than three sequential applications of Stratego before alternating with a fungicide with a different mode of action.  DO NOT make more than three applications of Stratego or other strobilurin-containing fungicide (Abound, Sovran) per acre per year.  DO NOT make more than two sequential applications of Pristine before alternating to a non-strobilurin fungicide.
 
Powdery Mildew
ENABLE 2E

Sulfur 		8 oz.

4-6 lb. 		DO NOT apply more than 1.5 quarts per acre per season.

If powdery mildew begins to develop, combine sulfur with a fungicide used for controlling scab. DO NOT tank-mix sulfur with Dodine.
 
Powdery Mildew, Zonate Leafspot
AGRI TIN
+
TOPSIN M WSB
or
SUPER TIN 80WP
+
TOPSIN M WSB		 See label.

1 lb.

7.5 oz.

1 lb.
 		 DO NOT apply  Topsin M after shuck split. Always apply Topsin M with another fungicide. A half rate of Super Tin or Agri Tin can be used in orchards where scab resistance to  Topsin M has not occurred.
* During periods when weather conditions favor disease development or when disease pressure is high, it may be necessary to apply fungicides on a 14-day schedule.
           
Table 7. Disease Susceptibility Ratings Of Pecan Cultivars Commonly Found In Older Orchards In The Southeast.
 

Disease
Cultivar Scab Downy Spot Fungal  Scorch
Elliott 1.4 1 3
Davis 1.7 -- 3
Curtis 2.0 3 2
Farley 2.4 2 2
Owens 2.5 4 2
Moreland 2.7 -- --
Cape Fear 2.8 2 4
Brooks 3.0 -- --
Moneymaker 3.0 5 4
Stuart 3.0 5 2
Moore 3.4 -- 3
Pabst 3.7 -- 3
Van Deman 3.7 -- 4
Success 3.8 3 --
Desirable 3.9 2 2
Alley 4.0 -- 3
Frotscher 4.0 -- 3
Mobile 4.0 -- 3
Mahan 4.1 3 --
Delmas 4.3 -- 3
Schley 4.3 1 4
KEY TO RATINGS
 1 = No incidence of pests; 5 = Very severe incidence;
  -- = Information not available.
Table 8.  Disease Susceptibility Ratings Of Pecan Cultivars Suggested for Planting In The southeast.

Disease
Cultivar Scab Downy Spot Fungal Scorch
Jubilee
Melrose
Syrup Mill
Gafford
Gloria Grande
Elliott
Jenkins
Davis
Carter
McMillan
Sumner
Kiowa
Owens
Jackson
Moreland
Cape Fear
Pawnee
Stuart
Surprise
Shawnee
Maramac
Woodward
Forkert
Desirable
1.1
1.1
1.3
1.3
1.4
1.4
1.6
1.7
1.8
1.8
1.9
2.5
2.5
2.6
2.7
2.8
2.9
3.0
3.0
3.0
3.3
3.4
3.9
3.9
--
--
1
1
--
1
1
--
1
1
2
2
4
--
--
2
2
5
--
3
--
--
4
2
--
2
1
1
3
3
1
3
1
1
2
1
2
2
--
4
2
2
--
1
1
--
2
2
KEY TO RATINGS
1 = No incidence of pests; 5 = Very severe incidence;
  -- = Information not available.
           
Rosette (Zinc Deficiency)
Foliar sprays with zinc are suggested for a rapid, temporary correction of zinc deficiency. Use foliar zinc sprays only when zinc deficiency has been positively diagnosed, preferably by leaf analysis. Applying zinc to trees that are not zinc-deficient may reduce yields. For trees with diagnosed zinc deficiency (less than 50 parts per million zinc in leaves), apply 35 to 50 pounds of zinc (100 to 140
 		 pounds of 36-percent sulfate) per acre and disk into top 6 inches of soil. In addition, apply foliar sprays according to Table 9. Further zinc applications, if necessary, should be made on the basis of foliar analysis results from monitor trees not sprayed with zinc.

 
Table 9. Foliar Zinc Sprays Suggested For Zinc-Deficient Pecan Trees.1
Spray No.2 Time To spray Formulation Amount Per 100 Gallons Amount Per Acre
    
     1.
     2.
     3.
     4.
     5.
 
Budbreak
2 weeks after budbreak
4 weeks after budbreak
7 weeks after budbreak
12 weeks after budbreak
zinc sulfate (36%)
or
NZN
2-4 lb.


1.25-2.5 qt.
8 lb.

5qt.
1 Trees with less than 50 ppm zinc in leaves.
2 If fewer sprays are to be applied, omit the third and/or fifth sprays. For zinc-deficient non-bearing trees, continue sprays at 3-week intervals until August.
 
Table 10.  Pest Management For Non-Bearing Pecan Orchards.
Disease And Insect Fungicide
And
Insecticide		 Amount Per100 Gallons *

Comments

Budbreak
Time Of Spray: Just as the buds begin to split and show green
Foliar Diseases    
AGRI TIN
or
ENABLE/AGRI TIN
or
SUPER TIN 80WP
or
ENABLE 2E
+
SUPER TIN 80WP
or
ORBIT 45WP/SUPER TIN 80 WP
 		 See label.

See label.

5 oz.

4 oz.

3.75 oz.

See label.		 Refer to Comments under Budbreak section in Table 6.
Hickory Shoot Curculios
PHASER 3EC   Apply curculio sprays at budbreak for the earliest cultivar. If repeat applications are needed, apply Phaser after a 10- to 14-day interval.
Pecan Bud Moths
CONFIRM 2F <LI> 8 oz.  

Cover Sprays
Time Of Spray: Three weeks after budbreak spray and as needed throughout the season
Aphids
PROVADO 1.6F <LI>

 

 3.5-7 oz. Observe the treatment "action levels" for bearing trees when making aphid control decisions. Fungicides are usually not necessary after foliage has matured (June 1). If disease pressure is high, additional fungicide applications may be needed.
Foliar Diseases

SUPER TIN 80WP
or
AGRI TIN
 

 See label.

See label.		 Refer to Comments under Cover Sprays section in Table 6.
*  Based on dilute sprays of 150 gallons per acre
 
FUNGICIDE AND INSECTICIDE RATES
     Correct fungicide and insecticide rates are essential for good disease and insect control. Each tree should receive the amount of pesticide recommended in the spray schedule.
     The volume of spray necessary to cover a tree thoroughly will vary with the type of sprayer used. The correct spray concentration, therefore, is determined by the volume of spray each tree receives. The various pesticide concentrations or the amounts of formulations to prepare 500 gallons of spray are indicated in Table 11.
 		 The rates are established for medium-size trees between 25 and 35 feet tall. For trees less than 25 feet tall, use 25 percent less material or multi-ply the amount recommended for medium trees by 0.75.
     For trees over 35 feet tall, apply 25 percent more material or multiply by a factor of 1.25. Rates listed here reflect the lowest rate recommended if a range is listed on the label. Adjust the rate according to your situation.
 
Table 11.  Recommended Fungicide And insecticide Rates For pecans.
Pesticide And Formulation

Amount Of
Formulated Material Per Medium-Size Tree

Gallons Of Spray Applied To Medium Tree
20 18 15 12 10 7.5 5
   

Pounds Of Wettable Powder Per 500 Gallons
Brigade 10WSB 0.08 lb. 2.0 2.2 2.6 3.4 4.0 5.4 8.0
Imidam 70 WP 0.20 lb. 5.0 5.6 6.6 8.4 10.0 13.4 20.0
Sevin 80S 0.25 lb. 6.25 7.0 8.3 10.4 12.5 16.7 25.0
Super Tin 80 WP 0.04 lb. 1.0 1.1 1.3 1.7 2.0 2.7 4.0
Syllit 65 WP 0.17 lb. 4.2 4.6 5.6 7.0 8.4 11.1 16.7
Vendex 50 WP
 		 0.17 lb. 4.2 4.6 5.6 7.0 8.4 11.1 16.7
Dimethoate 1.33 oz.

Pints Of Liquid Formulation Per 500 Gallons
2.1 2.3 2.8 3.5 4.2 5.5 8.4
Di-Syston 8E 0.08 pt. 2.0 2.2 2.6 3.4 4.0 5.4 8.0
Guthion 2EC 0.20 pt. 5.0 5.6 6.6 8.4 10.0 13.4 20.0
Kelthane MF 2.67 pt. 2.2 4.6 5.6 7.0 8.4 11.0 16.8
Lorsban 4EC 0.08 pt. 2.0 2.2 2.6 3.4 4.0 5.4 8.0
Penncap M 0.17 pt. 4.2 4.6 5.6 7.0 8.4 11.1 16.7
Phaser 3EC
 		 0.20 pt. 5.0 5.6 6.6 8.4 10. 13.4 20.0
Mustang 0.25 fl.oz.

Fluid Ounces Of Liquid formulation Per 500 Gallons
6.25 7.0 8.3 10.5 12.5 16.7 25.0
Asana 1.9 E 0.42 fl.oz. 10.5 11.7 14.0 17.5 21.0 31.5 42.0
Confirm 2F 0.67 fl.oz. 16.5 18.3 22.0 27.5 33.0 44.0 66.0
Cymbush 3E 0.22 fl.oz. 5.5 6.0 7.3 9.2 11.0 14.7 22.0
Enable 2E 0.66 fl.oz. 16.5 18.3 22.0 27.5 33.0 44.0 66.0
Mustang Max 0.25 fl.oz. 6.25 7.0 8.3 10.5 12.5