Monday, October 30, 2017

The 2017 harvest begins

    After a couple of hard frosts over the weekend, we began harvesting pecans today (photo above). Although the shucks of all our cultivars have split, only the earliest ripening pecans were dry enough to harvest. Pecans, like all grain crops, should be less than 12% moisture at harvest so that they can be stored without danger of molding. Pecans harvested at a higher moisture content must be dried with forced air to prevent spoilage (again just like grain crops).
   Today we harvested Osage, Jayhawk, Shepherd, Norton, Henning, Grotjan, Canton, and USDA 64-11-17. The tree being harvested in the photo above is Osage. All of the cultivars harvested today split their shucks a month ago in late September. The first day of harvest is also a good day to work out potential problems with our harvesting equipment. Thankfully, everything ran smoothly!

Friday, October 27, 2017

Seeing the benefits of pecan disease control

    By mid October, you can really see the difference fungicide applications make towards preserving pecan leaf health. This past year we made three fungicide applications to all of our orchards at the Pecan Experiment Field except for a five acre block of native trees that did not receive any pesticides.

    The photo at above shows our fungicide treated pecan trees in mid-October. The leaves on these trees are still healthy and green. Healthy leaves capture energy from the sun and covert that energy into carbohydrates. Carbohydrates are then used to fill this year's pecan kernels and promote pistillate flower production next Spring. Maintaining healthy foliage throughout the growing season is the best way to reduce a pecan tree's natural tendency for alternate bearing.

    Now look trees that did not receive fungicides during the growing season (photo above). By mid-October, some of the native trees had lost most of their leaves while most had taken on a bronzed appearance. These trees are already shutting down for winter. Lesser amounts of carbohydrates are created by damaged foliage and that limited supply of energy is totally directed towards filling this year's crop of nuts. This leaves little of no energy for pistillate flower formation next year. Unchecked pecan foliar disease ultimately accentuates the alternate bearing pattern.

    Pecan diseases not only impacts leaf health but they can have direct effects on nut yield. The photo at right shows two clusters of Stuart pecans. The cluster on the left is covered with scab. On the right, the nuts still show signs of scab infection but to a much lesser degree. All of these nuts appear to be splitting open but the heavily infected nuts are one half the size. Pecan scab causes yield losses in three ways; early nut abortion, reduction in nut size, and a reduction in percent kernel.
   The primary reason we apply fungicides to pecan trees is to control pecan scab. However, the secondary impacts of disease control on leaf health is equally as important. The introduction of pecan scab resistant pecan cultivars will make disease control easier but does not eliminate the need for fungicide applications.  The control of leaf disease, especially during wet summers, is important for maintaining tree health and productivity.

Monday, October 23, 2017

Our latest pecan cultivars have split shuck

Stuart, 23 Oct. 2017
    Well adapted pecan cultivars are ones that split their husks well before the average date of first fall freeze. In our area of SE Kansas, the average date of first fall freeze is October 21. 
    Today, I photographed shuck-split of our latest ripening pecan cultivars currently under evaluation at the experiment station. Stuart is an old southern cultivar that might be the widest recognized cultivar in the world (photo at right). However, Stuart is not well adapted to our area. Most years, Stuart has fuzzy and dry tasting kernels, indicating that this cultivar did not have a long enough growing season before temperatures start to turn colder in the Fall

    Oconee is a newer USDA  cultivar that produces a beautiful nut (photo at left). However, like Stuart, Oconee ripens too late for us. Oconee is scab resistant and would make an excellent choice for growers with a longer growing season.

Wednesday, October 18, 2017

That one pecan that doesn't open

   Over the past several weeks I've be photographing pecan shuck-split and collecting nut samples. If you look at enough nut clusters like I do, you will usually come across a cluster that has one nut that doesn't seem to split at the same time as all the others (yellow arrow, photo at right). In fact, the shuck stays green and tight all the way until first Fall freeze and never opens. Whats going on here?

   The cluster pictured above yielded four nuts (photo at left). Three of the nuts were easily removed from split shucks. The forth was tightly held inside a green shuck. 

    I cut each nut in half to inspect the kernel within (photo at left). The three normal pecans were fully packed with kernel. The nut with the tight green shuck had the remnants of a kernel that stopped growing at the water stage (early August). Judging from the color of the unfilled seed coat, this kernel was aborted by the tree for some unknown physiological reason.  If the seed coat had been colored jet black, the nut would have been the victim of stinkbug feeding. If the nut had been hollowed out by pecan weevil, I would have found worms inside the green stick-tight. In each case, lack of kernel fill prevents the pecan shuck from opening properly.

Tuesday, October 17, 2017

Pecan germination in the shuck

   Vivipary: A ten dollar word that describes the premature germination of a pecan in the shuck during the Fall of the year.  Normally, pecan seeds are fully dormant in October and require a 90-day chilling period to stimulate germination. However, a heavy nut crop and unusually warm, moist, weather conditions during shucksplit can trigger vivipary. In the photo at right, the yellow arrow points to a pecan root emerging from a recently harvested pecan. When a sprouted pecan is harvested and dried under normal harvest conditions, the little root dies and the embryo inside the shell decays. Ultimately, embryo rot totally destroys the value of the kernel.
    Fortunately vivipary is a rather rare phenomenon in northern pecan areas. This year I've found only 2 sprouted nuts among the thousand of nuts I've collected for evaluation this winter. Most years I never see vivipary at all.

Monday, October 16, 2017

Pecan cultivars ripening by Oct 16

Lakota, 16 Oct. 2017
   Today, I took another tour of the grove to look for ripe pecans and enjoy the crisp Fall air and beautiful sunshine. I found five more pecan cultivars with split shucks (at right and below). This year, Giles and Lakota appear to be ripening a little later than normal while Caddo and Maramec have split earlier than normal. Caddo definately appears to have a scab problem even after 3 fungicide applications. Lakota is scab resisitant. The good news is that our spray program gave acceptible scab control on Giles, Maramec, and Mohawk.
Giles, 16 Oct 2017
Caddo, 16 Oct 2017
Maramec, 16 Oct. 2017
Mohawk, 16 Oct 2017

Tuesday, October 10, 2017

Pecan cultivars ripening in early October

Kanza, 7 Oct. 2017
    This week I found 7 more cultivars with split shucks. Many of these cultivars are scab resistant including; Kanza, Greenriver, Hark, Oswego, and USDA 64-4-2. It is so nice to find pecans with clean healthy shucks at the end of the season. In addition, our disease prevention spray program did a pretty good job on limiting the spread of scab on disease susceptible cultivars, Chetopa and Niblack.

Chetopa, 9 Oct. 2017
Greenriver, 9 Oct 2017
Hark, 7 Oct. 2017
Niblack, 9 Oct 2017
Oswego, 9 Oct. 2017
USDA 64-4-2, 9 Oct 2017

Monday, October 9, 2017

Time for Fall fertilization

    If you can believe the National Weather Service we have a 80% chance of receiving a light Fall shower tonight. So today, I thought it wold be the perfect time to make our annual fall fertilizer application (photo above). We spread 100 lbs of urea per acre using conventional fertilizer spreading equipment. With this urea application, we added 46 lbs of nitrogen to each acre of pecan trees.
    As pecan trees prepare to move into winter dormancy, they produce a flush of new root growth. These actively growing roots aggressively take up the added nitrogen and store it in woody tissues to be mobilized next spring. With a ready supply of nitrogen, the tree will make vigorous new shoots and ample pistillate flowers next year.
   We have been making a Fall fertilizer application in addition to the regular Spring application for over a decade and have seen an overall increase in nut production and a decrease in alternate bearing.

Monday, October 2, 2017

Pecan cultivar shuck-split: October 2, 2017

Faith, 2 Oct. 2017
    The weather man is predicting an extended wet period starting in a couple of days. So today, I thought it would be a good idea to take advantage of the sunshine and check pecan cultivars for shuck-split. I found 13 cultivars with newly split shucks (photos at right and below).  As you look over the photos, keep these observations in mind.
Gardner, 2 Oct. 2017
 1) Peruque and USDA 75-8-9 should have shuck split last week but serious scab infections delayed shuck opening. Both cultivars are almost completely black with scab lesions.
 2) I couldn't resist taking a photo of a very large Pawnee nut cluster. There are 9 nuts in the photo below. The average Pawnee nut cluster has 4 pecans this year.
Pawnee, 2 Oct. 2017
 3) Jayhawk has a very heavy nut set this year. The photo below shows 3 Jayhawk clusters all hanging from a single limb. With this much nut set in 2017, the 2018 Jayhawk crop will be light or non-existent.

Jayhawk, 2 Oct. 2017
Eclipse, 2 Oct. 2017
Major, 2 Oct 2017

Mandan, 2 Oct. 2017
Peruque, 2 Oct. 2017

USDA 61-1-15, 2 Oct 2017

USDA 61-1-X, 2 Oct. 2017
USDA 75-8-9, 2 Oct. 2017
Waccamaw, 2 Oct. 2017
Yates 68, 2 Oct. 2017