Calendar of Pecan Growth Stage

 

(Click on Plant Stage or Month to see activities and pests)


If you need more information, please consult our online publication "Managing Insect and Mite Pests of Commercial Pecans in Texas"





Dormant Period (December - March)

Activities
- Review and consolidate previous season's records
- Compare with previous years
- Plan routine activities for coming season
- Clean up orchard
- Inspect trees for trunk/limb problems, especially scale, borers, phylloxera, pruners, etc.
- Thin and prune unproductive trees
- Note cover crop (if present) success or failure
- Plan dormant oil treatment for application at bud swell if needed
Pests
Obscure scale controlled during dormant season when is weakened and subject to suffocation by dormant oil application. The tree is in a dormant stage so is not suffocated by dormant oil if applied according to label instructions. Treatment may also reduce phylloxera, aphid, and mite problems. It should only be used after a pest problem has been identified. Dormant oil applied when tree is actively growing can cause limb damage and even tree loss.

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Budbreak (March)

Activities
- Apply fertilizer to ground if needed (often split application with second 6 weeks later)
- Apply first zinc treatment
- Check for phylloxera and scale again, as well as other early season leaf feeders

Pests
Pecan scab and pecan phylloxera can cause economic damage at budbreak. The overwintering scab stroma on last year's shoots begin to fruit in the warming days of spring. Rainfall and heavy dews that usually occur in this season wash spores from nearby stroma onto newly breaking buds. These young buds and developing shoots are tender and highly susceptible to infection by scab. Improved varieties vary in susceptibility and resistant varieties should be used in more humid environments. Spot treatments are possible to protect more susceptible varieties.

Phylloxera eggs hatch in early spring and nymphs crawl out to one year old wood. As soon as buds break, phylloxera crawlers attack young, rapidly expanding tissue. Within a week after feeding starts, crawlers are enclosed in galls and are protected from sprays. Timing of insecticides for phylloxera control are keyed to buds breaking in spring.

Zinc nutrition is important at budbreak. Tender buds and developing shoots are highly absorptive of zinc at this stage. Leaf expansion and shoot elongation occurs rapidly when zinc is applied at budbreak.

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Post Budbreak - Pollination (March - May)

Activities
- Apply zinc at 2 - 3 week intervals
- Make second fertilizer application (if split treatment)
- Conduct weed control as needed and check cover crops if used
- Monitor weather for pecan scab conditions and foliage for sawfly, catocala, leaf casebearer, spittlebug, mites, borers, aphids, and other potential problems -- treat only if a damaging pest is present in damaging numbers
Pests
A variety of foliage feeders attack foliage of pecan trees from budbreak to pollination. Once leaves mature they are seldom a problem. Due to the wide assortment of species involved, the "damage window" covers about 6 - 8 weeks. Although these pests do not usually reach economic levels they should be monitored during this time frame to ensure the development of strong, healthy foliage. These would include pecan leaf curl mite, pecan sawfly, pecan leaf casebearer, pecan catocala, pecan bud moth, and various mirids.

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Pollination - Nut Set (May - early June)

Activities
- Make last zinc treatment on bearing trees (continue to August on young trees)
- Monitor weeds and pecan scab
- Inspect nut crop and sample for pecan nut casebearer if nuts are worth protecting
- Time casebearer treatment, if needed, to coincide with hatch/nut entry so a single treatment will do the job
- Inspect foliage for last of early season pests and beginning of mid season pests like walnut caterpillar, fall webworm, leafminers, aphids, mites, etc.
- Maintain weed control
Pests
At pollination the overwintering generation of the pecan nut casebearer (PNC) lays eggs for first generation PNC. Although nuts are susceptible to damage from PNC anytime after pistillate bloom, the PNC does not reach the egg laying moth stage until at least pollination. The earliest laying can be expected to occur is shortly following this plant stage. Monitoring PNC by using a degree day prediction model or the new PNC pheromone, or both, will help time scouting activities.

 


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Initiation of Water Stage (July - August)

Activities
- Monitor for shuckworm, stiinkbug and black aphid, spray only if needed.
- Place weevil traps under trees and spray to protect nuts in the gel-dough stage if needed.


Pests

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Nut Set - Gel Stage (June - August)

Activities
- Assess orchard, disease and insect management success to this point in season
- Monitor pecan scab conditions and foliage for mid season pests including conotrachelus in nuts at onset of water stage
- Take soil, leaf, and water samples according to latest guidelines for analysis
- Be sure second summer generation of pecan nut casebearer treatment is really needed before applying it
- Make fall foliage disease fungicide treatments in early August if needed
- Maintain weed control
Pests
Plant shoot development matures just after pollination in mid-May or early June and nutlets grow rapidly until initiation of water stage (mid-July to early August) when nuts are susceptible to attack from a fungus called stem end blight. This disease attacks the embryo of the nut as the integument starts. During this approximately 5 week period, nuts may need to be protected with a fungicide.

Stink and plant bugs should also be controlled during this plant stage as they are suspected of transmitting stem end blight from one nut to the next.

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Gel Stage - Shuck Split (September - early November)

Activities
- Monitor for pecan weevil, hickory shuckworm, stink bugs, and other nut feeders and treat if needed
- Carbaryl has been the best material for pecan weevil (see paper for management of this key pest)
- Inspect foliage for mites, black aphid, other aphids, fall webworm, twig pruners, etc.
- Prepare orchard floor for harvest
Maintain weed control
Pests
Pecan Weevil
Pecan weevil emerges from ground in late summer and early fall in central Texas. If soil conditions are right for emergence this is usually mid-August to mid-September. Nuts infested before late gel or early dough stage fall off the tree and larvae of these eggs do not develop due to lack of a kernel to feed on. However, eggs oviposited in nuts that have reached late gel or early dough stage will hatch and larvae will successfully feed and mature. These mature larvae then drop to the ground and pupate to emerge from the soil 2 or 3 years later.

Shuckworm
Three weeks after initiation of water stage, hickory shuckworm becomes potential threat to nut quality. Sprays are timed to the half-shell hardening stage. Moth activity has been shown to increase as the nut undergoes shell hardening. Before the shell hardens, hickory shuckworms are present in low numbers. Nuts infested before shell hardening do not develop properly and fall off the tree. These nuts usually account for an insignificant nut loss and do not complicate harvesting procedures.
After shells harden (approximately half way down the shuck), larvae can develop within the shuck, without entering the packing tissue and embryo, which allows nuts to continue to develop on the tree. The quality of nuts attacked early are affected the most and often fall as full sized pops that are harvested and must be removed from the harvested crop. Nuts attacked later, although not pops, are often seriously reduced in kernel weight which reduces total crop weight and price received per pound.
By late season when the hickory shuckworm is found in damaging numbers and the nuts are in a susceptible stage of development, moth activity is spread over approximately a 3 week period. During this "damage window," starting at half-shell hardening, nuts should be protected from damage by hickory shuckworm, if a history of shuckworm damage exists in that particular orchard.


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Shuck Split - Leaf Drop (mid October - November)

Activities
- Inspect harvest for problems missed in management program (pecan weevil, stink bugs, sticky shuck, premature germination, etc.)
- Note foliage condition and where, then diagnose the problem, if any (mites, aphids, borers, disease, drought, etc.) and if too vigorous (susceptible to frost damage?)
- Examine fertilizer/zinc program and leaf and soil analysis results
Pests

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Annual Activities
Repeat each season
Keep good records on weather, equipment, fuel, pests (diseases, insects, weeds and animals), crop development, yield, prices, soil/foliage/water analyses, all treatments (time, product, amount, application method, etc.), and inspection following treatments gauging results achieved

 

Time Lapse Between Plant Stages
Plant Stages Time Lapse
Budbreak to pollination 6 - 8 weeks
Pollination to water stage 8 - 9 weeks
Water stage to half-shell hardening 3 weeks
Half-shell hardening to early dough stage 2 weeks

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For more information, contact:
Bill Ree
Extension Program Specialist
Texas A&M University-Riverside Campus
Bryan, TX 77806-2150
Phone: 979-845-6800
Email: w-ree@tamu.edu

Department of Entomology at Texas A&M University
Site hosted by Department of Entomology,
Texas A&M University

Contact Us by Email Last modified: Friday, August 18, 2006