Category Archives: Pecans

Irma’s Aftermath

We were very fortunate in Thomas County since the eye passed east of us. Our winds were in the 40s with gusts in the 70s. There is still obvious damage to our field crops. Here are some pictures of what we have now:

Peanuts

The only negative effect will be altering our digging time, if the field needed to be dug in that time period. We had some peanuts already inverted, but they are drying and will be picked this week. The soil is drying with a few days of sunny weather.

Cotton

It’s about 50/50 with wind damaged fields. Where wind hit hard, cotton is all tangled up. And any bolls/lint that fell off the plant is for sure lost. This is going to affect us on our picking efficiency and spraying. UGA Extension Cotton Agronomist Dr. Jared Whitaker says, “One thing to consider is that cotton that is just beginning to open is the heaviest it will be throughout its life and when opening proceeds, it will allow the plant to stand up.  However, one thing that I’ve seen that I haven’t in the past with blown over cotton is the “rooting out” around the stem at the ground level due to winds from several different directions. This could complicate the issue of cotton standing up and exacerbate the issue of standing up.”

There is more damage to younger cotton that will not be known at this time. Right now, you see a lot of reddening of the plant at the top. This is from stress, but multiple factors can cause this stress. We looked a blown over field today where it was obvious whiteflies were not treated. You will also notice stemphyllium leaf spot this time of year with loss of potassium. But the wind can also cause this symptom, and will hurt cotton in providing energy to those bolls.

Pecans

UGA Extension Horticulturalist Dr. Lenny Wells’ preliminary estimate is that about 30% of the state’s total pecan crop has been lost. This has become the most damaging wind event ever seen by the Georgia pecan industry. Again, most of the damage east and north of us. In Thomas County, we are a little under that 30% based on what I am seeing.

We mostly have limbs / nuts lost, but also some trees down. These are similar trees we lost with Hurricane Hermine – mostly in that 5 – 15 age range. Here is some more information from Dr. Wells:

Growers should take photos of their damage and report it to their local FSA office in order to receive financial assistance with cleanup. Cleanup funds normally pay 75% of the USDA-set cost of a mature tree ($300) up to a maximum of $200,000 per entity. Younger trees will be valued at varying levels depending upon age. In addition, the Tree Assistance Program (TAP) will pay for tree loss when 15% or more of the orchard is destroyed. This pays 65% of the cost of the tree up to a maximum of $120,000 per entity.

This money is not available immediately but your FSA office will gather your report. Requests for cleanup funds are made to Congress and they will then appropriate the funds so it may take a while.

Growers have many questions regarding how to handle fallen trees and the mass of green nuts blown from the trees. The success of righting blown down trees varies considerably with age of the tree. Trees less than 8-10 years old (trunk diameter < about 10 inches) can generally be righted with pretty good success, if leaning less than 45 degrees. Success rate is highly variable when leaning more than 45 degrees.  Success of righting these trees will be much greater when trees are pruned back as if they were to be transplanted with a tree spade because the newly-limited root system must be able to support the tree that remains. The larger the tree, the more you should prune off when righting.

Uprooted trees or those lying flat on the ground should be removed, especially large, mature trees. Such trees often never perform as they should and will be likely to be blown down again at a later date. Uprooted trees usually exhibit visible broken roots on the side opposite of the direction of fall. The major roots on the opposite side of the tree are also generally broken as well. Such trees usually have much more root damage than is apparent.

I’ve had many questions about salvaging the green nuts blown onto the ground and having them de-shucked. In most cases, the expense involved in this will outweigh  the benefit. While there are a significant number of nuts on the ground, in most cases, the volume will be less than most growers think. Pawnee shucks were splitting or open and many of these nuts came out of the shuck and are on the ground. Many would have been ready for harvest this week so these nuts can be salvaged once the debris is cleaned up. Early October harvest nuts like Caddo, Oconee, Elliott, Moneymaker etc. may be far enough along to attempt de-shucking if growers are inclined to do so. However, they need to bear in mind the cost of an additional harvest, transport, cleaning, and de-shucking when making this decision. Later varieties like Desirable, Stuart, Cape Fear, Sumner,. etc. are likely not mature enough for de-shucking even though the kernels may be filled out. If the nut does not pop out of the shuck when stepped on or rolled with your foot or if the shell is still white and the markings have not developed growers should not attempt de-shucking.

There is potential for further damage to appear at a later date from nuts getting knocked around in the storm. This often bruises or damages the shuck and affects development or maturity of the nut and may lead to stick-tights. However, my early observations are that this bruising is minimal. I do not see a lot of bruising as of yet on the shucks so I am hopeful  but it is still a bit early to tell whether or not we will escape this type of damage.

All in all, the Georgia pecan industry has suffered a significant blow but it could have been much worse than it is given the severity of the storm.

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Pecans: Black Aphids & Mites

Reports here are that black aphids are out but numbers are not necessarily high yet.

UGA Extension Entomologist Dr. Will Hudson has this INSECT update for us:

Black Aphid damage

Black Aphids

Growers across the state are seeing an increase in black aphids. For growers with old Schley trees this has been going on for a while, but the other susceptible varieties like Sumner and Gloria Grande are experiencing a build-up now.  Remember, if you see nymph clusters you need to take steps to protect your foliage and avoid the kind of damage that can affect your crop next year.  Imidacloprid still controls black aphids pretty well, but requires the higher rate on the label (several formulations are available; the 2 lb materials need 5.6 oz/acre).  Other neonicotinyls like Belay and Assail are also effective.  If you also have yellow aphids then Carbine, or Fulfill would control both. Closer is one of the most effective options at the moment.

Mite damage on pecan leaf

Mites

We are also seeing some mite flare-ups in scattered orchards. Mites can be controlled with abamectin products (Agri-Mek, Abba Plus, etc.), Portal, Acramite, or Nexter.  The Nexter will get both aphids and mites, and may be a good choice where those pests are present and a weevil spray is needed or likely. Check labels for rates and surfactant requirements.

Insecticide Rainfast?

Dodging showers can be a challenge if you need to treat lots of acres with few sprayers, and sometimes the rain catches you or pops up right after application. If it starts to rain while you are spraying, stop the sprayer.  It will do little good to apply an insecticide (or fungicide) that will be washed off immediately.  If the rain comes after you finish, you may be okay if the spray has dried on the leaves.  A good rule of thumb is that if you get a rain within 1 hour or less of spraying and you will need to retreat.”

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Pecan Fruit Thinning

If you have over 60% of the terminals bearing fruit, the trees will benefit from thinning. This will improve quality this year and generate a better return crop next year. UGA Extension Horticulturalist Dr. Lenny Wells says early to mid-October harvest varieties should be about ready for thinning next week. Most of our varieties should respond when thinning next week and at least the first half of the following week. Sumner possibly even a little later. To know exactly when to thin you will have to slice nuts open and look at the development of the ovule inside the nut

When do you thin?

In most years, there is a window of only 10 – 14 days in which fruit thinning can be done successfully. Research has shown that… nuts should be removed when the ovule (cavity inside nut in photo below) is 50% to 100% expanded, but before the kernel enters the dough stage. Thus, the calendar date for fruit thinning of pecan will vary with cultivar and location, as well as from year to year.

After the female flower has been pollinated and fertilized, the ovule (the tissue that becomes the kernel) begins to expand and lengthen from the tip of the nut toward the stem. As the ovule expands, the space inside is filled with a watery substance called liquid endosperm. After the ovule extends to the stem end of the nut, and the nut reaches full size, the shell begins to harden from the tip backward. When the ovule is completely expanded, the kernel begins to fill and nuts pass from the water stage to the gel stage, to the dough stage.

Ovule (cavity) on the right is 70-80% expanded where left cavity is just starting.

To observe of nut development, slice through the nut to expose the ovule. When the nut is removed from the tree, an oval shaped scar is left on the shuck. Cut the nut lengthwise at a right angle along the long axis of the oval scar. A straight, lengthwise cut exposes the expanding ovule and liquid endosperm within the nut. Thinning should occur when the ovule or kernel has extended to half the distance toward the stem end of the nut. The larger the nut size, the earlier in the ovule expansion period thinning can take place, because larger nuts are easier to shake off the tree

How much to remove?

The amount of nuts to remove varies with nut size, cultivar, crop load, and environmental factors. Judging the tree’s crop load is another important factor in the decision to thin. This is a practice that takes experience. The percentage of nut-bearing terminals can be developed by observing the number of fruiting terminals counted from an observation of 50-100 random terminals on a tree.

Trees with almost 100% of the shoots bearing fruit and a cluster size greater than three are overloaded and should benefit from thinning. Optimum crop load varies with cultivar and may range from 50-70% fruiting shoots. Varieties with small nut size can be thinned more lightly than those with large nut size. For example, optimum crop load on cultivars greater than 70 nuts per pound may be 60-70% fruiting shoots. Nuts in the size range of 50-70 nuts per pound, like Cape Fear or Stuart, have an optimum crop load of 50-60% fruiting shoots. While varieties with large nut size of less than 50 nuts per lb may have an optimum crop load of only 45-50% fruiting shoots.

Additional Tips

The major mistake growers make when first time attempting to fruit thin is not removing enough nuts. When shaking begins, don’t be alarmed by the number of nuts that fall. Trees should be shaken two to three seconds at a time, evaluated, and then shaken again if needed. This process should be repeated until the operator has a feel for how hard to shake to achieve the desired results.

Increased profit potential through enhanced size, quality, and return crop has so far been shown with mechanical fruit thinning on Cape Fear, Creek, Pawnee, Schley, Stuart, Sumner, Kiowa, Cheyenne, Shoshoni, and Mohawk. This does not mean that the practice is not profitable on other cultivars, but simply that it has not been adequately tested for those cultivars not mentioned. It is likely that most pecans with fruiting characteristics similar to those previously mentioned would respond favorably.

 

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Pawnee Nut Drop

UGA Extension Pecan Specialist Dr. Lenny Wells has this to say about Pawnee nut drop:

We have seen a fairly large Pawnee drop over the last week. It is not uncommon for Pawnee to shed a few nuts this time of year but this year’s drop looks a little heavier in places. Still, I don’t think its anything much to worry about in most cases. Most of the Pawnee trees I have seen with a heavy drop under them still have a heavy crop on them. The drop probably helped them more than hurt them. The trees should be able to produce better quality and have a better chance of a return crop.

Aborted Pawnee nuts prior to drop. Photo by Dr. Lenny Wells

 

Stages of Pecan Nut Drop (Sparks and Madden, 1985)

As the graph above shows, pecans undergo 4 separate fruit drops during the growing season, most of which are related to pollination problems. Pawnee is about a month ahead of most of our other varieties, so this drop would coincide with the 3rd drop in the graph above (which is based on Desirable). This drop occurs just before rapid fruit expansion and is due to the failure of the endosperm to develop properly. This drop is known to be accentuated by self-pollination. The low chill hours of this past winter and the resulting effect on budbreak (see Warm Winter and Pecans) could have affected cross pollination, leading to more self-pollination. If so, we may see a similar drop on other varieties in a few weeks.

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Pecan Fungicide ‘Rainfast’

 

With rain and humidity, we are having ideal conditions for scab. Some growers essentially continue to spray around the clock. A common question is, “How long does my fungicide need to dry before rain?” This is a question pathologists have worked on for some time, but there are many variables involved making it difficult to generate data. UGA Plant Pathologist Dr. Tim Brenneman recently offered the following suggestions based on his studies with pecan and also on similar studies he has conducted in peanut:

Highly systemic materials like phosphite must be absorbed into the plant. It may require as much as 1/2 a day for this process to take place so that the material can be highly effective. While DMIs and strobilurins or combination products like Absolute, Top Gard, Quadris Top, and Quilt have some systemic activity they are not as systemic as the phosphites. Still, they would need a little time to be effective, so several hours to half a day would be ideal. A surfactant (80/20 or other) would increase the uptake speed of these materials and would likely provide some benefit in the conditions we’ve had over the last week or so. However, do not include a surfactant with Phosphite.

While the DMIs and Strobis have some systemic activity they still function largely as protectants. Other materials like Dodine (ELast) or Tin are pure protectants. These materials (Dodine and Tin) would be the most prone to wash off when rain arrives shortly after spraying. Dodine does adhere tightly to the plant cuticle, which likely helps it. Rainfall that occurs less than one hour after spraying makes the fungicide pretty well ineffective. Any rainfall within 24 hrs after spraying with a pure protectant will likely reduce the effectiveness of control to some extent. For each additional hour between the spraying and rainfall you gain additional control.

Ideally, all fungicides should be applied prior to rain events. If circumstances prevent you from getting a spray on in time and you have to spray after a rain event, the DMI/Strobi combinations would be the best choice.

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Pecan Fungicides Begin

Young Trees

All of our pecan fungicides have begun at this point. We have lots of newer planted trees in the county, here are some being sprayed last week. UGA Extension Horticulturalist Dr. Lenny Wells says trees in the first few years need to be sprayed but not on a detailed spray program. For very young trees, a few fungicide applications in a season with some Tin is good. Once the trees approach production age, we need to add a few more sprays throughout the season and get closer to a full spray program.

Timing

In our area, we have been hit so hard with scab that we tend to get our fungicide sprays out real soon. Dr. Wells always says we can wait a little longer than we do. He was down last week looking at a fertilizer situation, and we looked at trees around that were leafing out at different times. He explained the issue with spraying early is not having enough leaf area for the fungicide to contact.

The most difficult part is managing orchards for more than one cultivar, which all are pretty much the same. If Desirables are in the orchard, we have to begin spray on their schedule since they are more susceptible for scab. If an orchard doesn’t have desirables and mostly Stuart, you can wait until those leaves come out. Here is a few pictures of optimum fungicide initiation Dr. Wells and I looked at in an orchard last week.

Left – This is time to spray Desirable
Right – This is too early for Desirable

Optimum time to initiate Stuart fungicide sprays

Fungicide Schedule

Below is an 8-spray fungicide schedule from UGA Extension Horticulturalist Dr. Lenny Wells provided as an example to use for pecan scab management in light of emerging scab insensitivity issues surrounding some fungicides. Since Tin is an integral part of our fungicide arsenal for pecans, and we do see some orchards with insensitivity to Tin, we are recommending saving any Tin sprays for the nut scab period since this material is better on nut scab than it is on leaf scab.

1. Absolute

2. Tebuconazole+Topsin M+Phosphite

3. Absolute+Phosphite

4. Elast/Tin

5. Absolute

6. Elast/Tin

7. Elast/Tin

8. Elast/Tin

If rainfall during the growing season is excessive, more than 8 sprays will be required for management of scab on susceptible cultivars. Therefore, the following program serves as an example of how to accommodate this need:

1. Absolute

2. Tebuconazole+Topsin M+Phosphite

3. Absolute+Phosphite

4. Elast/Tin

5. Absolute

6. Elast/Tin

7. Elast/Tin

8. Quadris Top

9. Elast/Tin

10. Elast/Tin

These examples serve only as two possible options for fungicide programs to manage scab. Many more could be developed. If an orchard has a documented high level of insensitivity to any of the fungicides listed above, the grower should contact one of the UGA Extension for specific recommendations.

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2017 Pecan Beginner’s Course

The 2017 Pecan Beginners Course will be held at the UGA Tifton Campus Conference Center in Tifton. GA on Tuesday, April 18, 2017. There is a registration fee of $10 . Registration at the door will be $15 until we reach capacity of 300 people. Please pre-register so that we will have a head count for the meal. Lunch and refreshments will be provided.

Register at the following link: Pecan Beginners Course Registration

The program for the course is found below:

9:00        Welcome                                                                                           

9:10        Cost of Pecan Production                                                                            

Lenny Wells, UGA Horticulture

9:30        Pecan Varieties                                                                                                                                               

                Patrick Conner, UGA Horticulture            

10:15     Break

10:45     Pecan Irrigation                                                                               

Lenny Wells, UGA Horticulture

11:15     Pecan Tree Planting & Establishment                                   

Lenny Wells, UGA Horticulture

12:00     Break for Lunch               

                Meal Sponsored by Savage Equipment                                 

1:00        Pecan Insect Management                                                                                                         

Will Hudson, UGA Entomology

1:45        Pecan Fertilization

Lenny Wells, UGA Horticulture

2:30        Break

2:50        Pecan Disease Management

                Jason Brock, UGA Plant Pathology

3:20        Pecan Weed Control

Timothy Grey, UGA Crop & Soil Science

4:00        Pecan Equipment

Lenny Wells, UGA Horticulture

Please contact Debbie Rutland @ 229-386-3424 for further infromation

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