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Plan Your Pecan Spray Schedule Before the Season

By Will Chaney
Sr Pecan Operation Associate 2

Posted Feb. 26, 2020

In a commercial pecan orchard setting, it is important to have a spray schedule planned before the season starts. Although you cannot be fully prepared for every issue that might arise, some planning can assist you in your management goals. Chemicals can be a costly input into your operation; more planning up front will save you time and money during the season.

Insecticide Spray Schedule

Rotation of chemical classes should occur as often as possible. Spraying the same class repeatedly can lead to a buildup of resistance from the targeted pest. Insecticides are not always necessary. Spraying for insects when you really don’t need to will often reduce your beneficial populations, leaving you in a worse situation than when you started. You might look into multiple chemicals for each pest in case one of the chemicals for the targeted pest is not available. This also gives you options during late-season applications. If you had to change your plans early in the season and used a class you had originally not intended to use, this could affect later planned applications in the season. Examples of a spray schedule including application rates are outlined in the insecticide spray schedule.

Example Insecticide Spray Schedule

When applying chemicals, always follow the label on the bottle over any other recommendation. The label is the law.

Time of ApplicationInsect to Be ControlledPesticide (rate/100 gal water)Insecticide Resistance Action Committee (IRAC) Mode of Action
After bud-break and shoots of susceptible cultivars are about one-inch in length.
  • Phylloxera
  • Lorsban: 2 pints per acre
  • Trimax Pro: 2 fluid ounces per acre
  • Group 1B
  • Group 4A
Following Pecan Nut Casebearer moth catch for two consecutive days, scout for eggs seven to 10 days later. Insecticide should be applied 14 days after first moth capture.
  • Pecan Nut Casebearer
  • Intrepid: 2F 6 fluid ounces per acre
  • Confirm: 2F 12 fluid ounces per acre
  • Altacor: 3.2 fluid ounces per acre
  • Group 18
  • Group 18
  • Group 28
If orchards have a history of shuckworm infestation, a spray should be applied in early June. In early August, two to three additional sprays should be applied. Initiate August sprays at half-shell hardening and repeat at two-week intervals until shuck split if shuckworm activity continues. It is not necessary to spray in August if pecan weevil controls are applied.
  • Hickory Shuckworm
  • Dimilin: 2F 12 fluid ounces per acre
  • Intrepid: 2F 6 fluid ounces per acre
  • Apta: 24 fluid ounces per acre
  • Altacor: 3.2 fluid ounces per acre
  • Group 15
  • Group 18
  • Group 21A
  • Group 28
In early season, do not treat yellow aphids if they are the only insect problem. Rely on beneficial insects to suppress early season populations. In prolonged dry periods, lower, chronic aphid populations may require treatment to prevent the build-up of unacceptable levels of honeydew and sooty mold.
  • Yellow Aphid Complex
  • Beleaf: 2.4 fluid ounces per acre
  • Fulfill: 4 fluid ounces per acre
  • Nexter: 8 fluid ounces per acre
  • Group 9C
  • Group 9B
  • Group 21A
Trees known to have a recent history of weevil problems should be selected for monitoring. Emergence should be monitored in each infested grove with traps, knockdown sprays or a combination of these methods. Spray at once if excessive nut drop results from pecan weevil feeding punctures before pecan shells begin to harden. After pecan shells harden and nuts reach the “dough” or “gel” stage, treat when weevils emerge (especially following rains) and continue at seven-to-10-day intervals until emergence stops.
  • Pecan Weevil
  • Mustang Maxx: 4 fluid ounces per acre
  • Brigade 2EC: 9 fluid ounces per acre
  • Lambda Cy 1EC: 4 fluid ounces per acre
  • Sevin XLR Plus: 4 quarts per acre
  • Group 3A
  • Group 3A
  • Group 3
  • Group 1A

Fungicide Spray Schedule

In your fungicide spray program, you should rotate chemical classes with each application or as often as possible. This will prolong the effectiveness of the chemicals by preventing a buildup in resistance. Are your cultivars susceptible to a certain disease? If they are not, then a less aggressive spray plan may be adequate. However if your cultivars are susceptible, then an aggressive spray plan is required to control diseases. Weather can play a major role in the severity of the disease. Dry years will produce fewer scab issues in the orchard than wet years. Another consideration is if the orchard is grazed or not. Some fungicides cannot be applied to areas where you are grazing livestock. If you graze your orchard, you will want to make sure the chemicals you are using allow for grazing; if it does, what is the re-entry interval (REI) before the livestock are allowed to return to the orchard. Below is an example of a fungicide spray schedule with both grazed and non-grazed options.

Planning your chemical use in advance can improve your operation plans and improve your bottom line. It can also free up time during the season that can be used to focus on chemical safety. Be sure to use proper safety procedures such as using proper personal protective equipment (PPE). Be knowledgeable about the signal words used on pesticides (caution, warning and danger) and what each means. Understanding these words will change how you handle each chemical. Read the label on each bottle because labels can be different even among the same product. Know the REI and the pre-harvest interval (PHI) of the chemical you are using. Following the label recommendations can prevent accidents that will cost your operation time and money.

Example Fungicide Schedule

When applying chemicals always follow the label on the bottle over any other recommendation. The label is the law.

Time Of ApplicationDisease to be controlledPesticide rate per 100 gallons of waterFungicide Resistance Action Committee (FRAC) Mode of Action
First Pre-pollination Spray (Non-grazed)
When leaves of disease susceptible cultivars are about one-inch in length.
  • Leaf ScabVein
  • SpotDowny Spot
  • Elast: 48 fluid ounces per acre
  • Ziram: 7 pounds per acre
  • REI: 48 Hours
  • Group U12.
  • Elast may cause leaf burn on Moore, Van Deman and Barton cultivars.
  • Group M3
Second Pre-pollination Spray (Non-grazed)
About 2 weeks after the first spray if weather is warm and leaves are growing rapidly.
  • Leaf ScabVein
  • SpotDowny Spot
  • Abound: 9.5 fluid ounces per acre
  • Other strobilurin
  • Group 11
First Leaf and Nut Cover Spray (Non-grazed)
Two to three weeks after last spray. Often in early May.
  • Leaf and Nut ScabVein
  • SpotDowny Spot
  • Enable 2F: 8 fluid ounces per acre
  • other DMI
  • Group 3
First Leaf and Nut Cover Spray (Grazed)
Two to three weeks after last spray. Often in early May.
  • Leaf and Nut ScabVein
  • SpotDowny Spot
  • Quash: 3 ounces per acre
  • REI: 12 Hours
  • Group 3
Second Cover Spray (Non-grazed)
Cover sprays should be made at two- to four-week intervals. Two-week intervals are used during periods of frequent rainfall in orchards with very scab susceptible cultivars.
  • Nut Scab
  • Brown spot
  • Gnomonia
  • Super-Tin: 4L 12 fluid ounces per acre
  • REI: 48 Hours
  • Group 30
Second Cover Spray (Grazed)
Cover sprays should be made at 2 to 4 week intervals. Two week intervals are used during periods of frequent rainfall in orchards with very scab susceptible cultivars.
  • Nut Scab
  • Brown spot
  • Gnomonia
  • Pristine: 14.5 ounces per acre
  • REI: 12 Hours
  • Group 7/11
Third Cover Sprays (Non-grazed)
  • Nut Scab
  • Headline: 7 fluid ounces per acre
  • REI: 12 Hours
  • Group 11
Fourth Cover Sprays (Non-grazed)
  • Nut Scab
  • Agri-fos
  • Fosphite
  • Rampart: 2 fluid quarts per acre
  • Group 33
Fifth Cover Spray (Non-grazed)
The last two cover sprays, which are often made from late July through August, can be eliminated if there is little scab on the nuts and rainfall is sparse.
  • Nut Scab
  • Super-Tin 4L 12 fluid ounces per acre
  • Group 30
Sixth Cover Spray (Non-grazed)
  • Nut Scab
  • Agri-fos
  • Fosphite
  • Rampart: 2 fluid quarts per acre
  • Group 33

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