Picking on frozen ground

    Rain, snow and endless days of damp cloudy weather has made the 2014 harvest season difficult. When I think back over this year's harvest season, we've had only 8 days of suitable conditions for mechanical harvest.  So when the ground froze hard last night, we greased up the harvester and continued our second harvest (photo above). This year, we are collecting about 150 lbs./acre during our second pass over the orchard floor.
    Picking on frozen ground is a little tricky. Besides pecans, the harvester picks up small clumps of frozen mud. As long as the temperatures stay below 32 degrees F, the mud stays solid and the nuts remain relatively clean. Let those mud balls thaw out and you quickly have a mess of muddy pecans.     To avoid potential mud problems, we run the nuts through our cleaning system as soon as we have collected a hopper full of second-picking nuts. Getting those frozen mud balls out of the sack as soon as possible is critical. Thankfully, the cleaning reel we inserted into our cleaning system removes most of the mud balls before the nuts get to the inspection table.

Posey pecan: early history and current observations

Posey 2014

   During the late 1800's, a large native pecan tree growing on the east bank of the Wabash River became famous for its large nut size and thin shell. History does not record who found the original tree but local residents called the tree, "Grayville",  after the small Illinois town located across the river on the Wabash's west bank. One hundred years ago, esteemed members of the newly minted Northern Nut Growers Association decided "Grayville" was not a very marketable name for a northern pecan cultivar and choose to rename the tree,"Posey", in honor Posey County, IN.  Ironically, the original tree was actually located in Gibson County just north of the Posey county line.  Even though locals continued to call the tree Grayville for much of the early 1900's, the name Posey came into common use as the tree was propagated across the northern pecan region.
    The early 1900's was an exciting time for the naming and propagating of northern pecan cultivars. Names we know today, such as Major, Greenriver, and Posey, were first popularized back in those days. However, other cultivars from that era have largely disappeared from modern pecan orchards including; Busseron, Butterick, Hodge, Indiana, Kentucky, Niblack, and Warrick. It is interesting to me that Posey has survived so long despite some obvious flaws as a pecan cultivar. In 1925, Prof.  A.S. Colby, from the University of Illinois stated, "The Posey is said to be the easiest of the northern cultivars to crack and is of good size. It has the reputation, however, of being a shy bearer."

    I have also noticed that Posey never sets a really heavy pecan crop but I think a more serious cultivar defect is that Posey produces dark colored kernels.  In the photo at left, you can see how dark this year's Posey kernels are as compared to the current season's Kanza kernels. Since dark kernel color is associated with old or rancid pecan kernels, it has become increasingly difficult to market perfectly tasty Posey nut meats to the consumer.

Posey kernels

    In 1923, former NNGA President, T.P. Littlepage, made these observations about Posey. "The parent Posey tree grows in Indiana, and I had the pleasure of naming it. That tree is a good bearer, and it is the thinnest-shelled northern-grown pecan with which I am familiar. It is a very beautiful nut, with the exception that frequently one side of the kernel will not fill out as it does on the other side. It is not defective, but simply deficient."   In the  many years of growing and shelling Posey,  I had never noticed that Posey produces kernel halves of unequal length. However, this year I took the time to carefully remove the shell from several Posey nuts. The photo above shows two examples of what I found. In every case, one half of the Posey kernel was shorter than the other. The difference was sometimes pronounced (nut at left) and at other times only slight (nut at right). Looks like Mr. Littlepage was right.

   

     Posey has a couple of unique characteristics that make field identification of the cultivar easy. Posey nuts are surrounded by a thick, course-textured shuck that features prominent "wings" along the suture lines (photo at left). Posey nuts have dark colored shells and a strongly flattened shape (see photo above).

    The bark of Posey trees is also distinctive.  In the photo at right, you can easily see the graft union between the seedling pecan rootstock and a Posey scion.  The seedling rootstock has furrowed bark typical for pecan trees of this diameter. In sharp contrast, the Posey top exhibits a scaly bark appearance reminiscent of a shagbark hickory.
    Posey is a unique cultivar in many ways. However, it is a cultivar that is fading, slowly being replaced by better northern cultivars.

Native pecan yields for 2014

Native pecan plots 2014

    For 34 harvest seasons, we have been recording the yields of native pecan trees growing in 6, one-half acre plots at the Pecan Experiment Field. We just finished cleaning the last of the nuts from these plots and have weighed this year's crop.
    In the photo at right, the scars from the 2007 ice storm are still visible but you can see how well our native trees have grown back over the past 7 years. This year we harvested an average of 1127 lbs/acre from the native plots, down from the previous year's yield of 1640 lbs/acre (see chart below).
   

 
   Whenever I look at a plot of pecan yields, I always seem to concentrate on finding reasons for why the tree produce below-average yields in certain years. Nut yield in 2007 was depressed by a extremely late hard freeze on Easter weekend that destroyed many emerging shoots and pistillate flowers. Yield in 2008 was impacted by the loss of roughly 50% of tree canopies from a serious ice storm that occurred in December of 2007. In fact, it took several years for the trees to regrow their canopies and get back to full nut production.
    So what happened in 2014? After two big crops in 2012 and 2013, it seems like our trees decided to take a little break. However, I should point out that 2014's yield at 1127 lbs/acre is only slightly below our 34 year average of 1165 lbs/acre.

    When we harvest pecans, we always run over the field twice. In the table above, the 2014 yields for our six native pecan plots are presented in pounds per acre. These numbers give you some idea of how variable native pecan yields can be and how important a second harvest is for capturing the full value of a grove's nut production. In harvesting pecans, we shake and harvest the entire farm before going back for the second harvest.  This year the second harvest represented about 14% of our total yields.

The origins and history of Major pecan

   One of my bad habits is collecting old and rare books about fruit and nut tree growing. The other day, I picked up my copy of the 1912 Yearbook of the Department of Agriculture and discovered a lithograph of new and noteworthy pecan cultivars (photo at right). At the top of the page is an illustration of the Major pecan, a cultivar well known to northern pecan growers. The early history of the Major pecan is described in the text as follows.

   "The parent tree of the Major pecan is located in a native pecan forest near the mouth of the Green river, Henderson County, Ky. It is owned by Mrs. Laurie M. B. Major, of Henderson, in honor of whose late husband it was named. It appears to have attracted considerable local attention previous to 1907, when Mr. C.G. Taylor, of Princeton Ind., sent specimens of the nuts to Mr. W.N. Roper, of Petersburg, Va. The evident merits of the nuts and the account of the tree so favorably impressed Mr. Roper and his partner, Mr. E. Gill Hinton, that the latter went to the original tree during the summer of 1908 for the purpose of obtaining scions, and from the scions then obtained the first nursery-grown trees of the variety were propagated.
    The actual bearing record of this tree has not been kept, but it is stated by persons in the locality of it origin that during recent years it has borne regularly and that frequently the crops have been approximately 100 pounds.  It is a healthy tree 2 1/2 feet in diameter at breast height and 59 feet to the first branch."

Major nuts grown in S.E. Kansas. 2013

    After finding the above report on the Major pecan, I looked to my old copies of the Annual Report of the Northern Nut Growers Association to find additional descriptions of the original Major tree. W.C. Reed, of Vincennes IN, wrote the following in 1915.

     "Major. Crop 1912, 160 pounds saved, and from what information I can get this tree usually bears 100 pounds or more; tree about 3 feet in diameter, 120 feet high and 60 feet to first limb. Owing to its height and size it is very hard to get much an estimate in regard to the crop it may carry until it is gathered. Being located in the dense forest a large part of the crop is often carried off."

    Sadly, the original Major tree was cut down many years ago but the cultivar lives on today and has served as a parent for two important modern-day pecans--Kanza and Lakota.  One of the most vocal proponents of the Major during the mid-1900's was Indiana nurseryman, J. Ford Wilkerson. Mr. Wilkerson was an active member of the Northern Nut Growers Association and attended his first NNGA meeting in 1914. Mr. Wilkerson began cutting scions from old trees including the original Major tree in 1910. To celebrate 50 years of cutting pecan scions, he climbed to the top of a large Major tree that he had planted in 1913. J. Ford Wilkerson was 80 years old when this photo was snapped in 1961 (photo at right). An impressive feat, to say the least.   

One branch sums up the 2014 growing season

     Recently, I cut a single limb from an Osage tree that seemed to sum up the entire 2014 pecan growing season (photo above). First, let me tell you what all those letters in the photo mean.
  
     VS= vegetative shoot
        F= buds frozen by a late spring frost on April 15, 2014
        P= pedicle from the 2013 nut crop
     FS= fruiting shoot

    We harvested a good crop of nuts during the fall of 2013. Judging from the fruiting scars on the pedicle (the portion of the stem that supports a cluster of nuts) this shoot bore three nuts in 2013. When spring rolled around buds started to swell but were frozen by a late spring freeze. The remnants of two buds frozen buds are still firmly attached to the stem. After the freeze, two dormant buds lower on the one-year-old branch broke and started to grow.        
    As these two new shoots grew out in the spring, only one of the shoots produced a pistillate flower cluster. The bud that broke from the lowest portion of the one-year-old stem remained vegetative. This is fairly typical for pecan. The oldest buds (lowest on the stem) on last year's wood have the least potential to produce female flowers.
    When we harvested the 2014 crop, we collected about half as many nuts as we harvested in 2013. Judging from what we can see on this single branch the reasons for lower yields in 2014 become clear.
   

Mohawk: A precautionary tale

   We only have one Mohawk tree left growing at the Pecan Experiment Field (photo at right). Thirty 35 years ago, Mohawk was among the most popular cultivars being grafted in our region and we had dozens of Mohawk trees growing on the farm. At first look, Mohawk had everything a pecan grower would want--large nut size, thin shell, early ripening, and young trees that were both very precocious and productive. The story of Mohawk and the reasons this cultivar has been removed from pecan orchards all across the US is a tale that I always keep in mind as I evaluate new pecan cultivars.     

Mohawk pecans, 2014

    The story begins in 1946 when USDA pecan breeder, Louis Romberg, applied Mahan pollen to a Success pistillate flower. The resulting seed was germinated and grew into a tree that was later named Mohawk in 1965.
     At one time, the Success cultivar was the most popular cultivar grown in the Southeastern US. Success originated as a seedling tree planted in 1875 on a farm near Ocean Springs, MS.  This cultivar produces large thin-shelled nuts but as  the tree matures, nut production becomes erratic and kernel quality suffers terribly during "on" years. As plantings of Success increased across the Southeast, this cultivar became susceptible to pecan scab by 1931.
   Mahan is another cultivar that can trace its origins back to a Mississippi seedling pecan orchard. The tree originated from a seed planted in 1910 near Kosclusko, MS and was named after the nurseryman that first propagated the cultivar. Mahan is known for its very large nut size and long pointed nut shape. However, Mahan is now better known as a cultivar that never fully fills the inside of that large shell with kernel. Mahan is severely alternate bearing and often suffers cold damage following a heavy crop year.

     When Louis Romberg decided to cross Success with Mahan, he was hoping to produce a new pecan cultivar that would exhibit the best qualities of both parents--large nut size, precocious flowering, and heavy nut production. In the photo at right, a single Kanza nut is flanked by two Mohawk nuts. Mohawk is indeed one of the largest pecan cultivars that will ripen before frost in our area. As a young tree, Mohawk produces big beautiful nuts that are well filled and impressive to the consumer. But like both of its parents, serious problems arise when the tree reaches maturity (around 20 years old).    

    Mature Mohawk trees are similar to Success trees in that they frequently set too many nuts on the tree. This leads to poor kernel filling and the development of alternate bearing.  The photo at right illustrates the poor kernel filling of Mohawk as compared to a plump well-filled Kanza nut. Note how much space there is between the shell and kernel of the Mohawk. In addition, the kernel is fuzzy and the tips of the nut meat are shriveled. 
     Mohawk is also similar to Mahan in terms of susceptibility to cold injury. The vast majority of Mohawk trees that once grew on the research station were removed after winter cold killed trees to the ground. This type of extreme cold injury always occurred following a heavy crop year.
     As we grow and evaluate new cultivars, I always keep the story of Mohawk in the back of my mind. What may look like an outstanding new cultivar when a tree is young may turn out to be a real dud when the tree reaches maturity. The history of pecan cultivar development is littered with examples of pecans that fall apart at tree maturity. I'll name a few just off the top of my head: Shoshoni, Chickasaw, Creek, Dooley, Giles, Maramec, and Mohawk. 

Another great day for harvest

    Today was another absolutely beautiful day for harvesting pecans. We broke out the old Lockwood pecan picker to harvest one of our cultivar trails (photo at right). This Lockwood machine may be over 40 years old but it still the best machine for harvesting the small, two-tree plots in this trial. Each cultivar is painted with a different color code to make identifying plots easy from the seat of the shaking tractor or harvester. Trees with yellow paint are Greenriver. Red and green paint on the same tree indicates a Chetopa while blue and white means Giles. There are 9 cultivars in this trial with each cultivar having a different color code. It definitely makes for a colorful orchard.

       When the Lockwood picker was designed back in the late 1960's, pecans were handled in burlap bags. Once the hopper gets full of nuts, we pause the machine, drop the out-feed gate, and the nuts come pouring out (photo at left). This system was originally designed to pour nuts into a burlap bag but we have refitted our Lockwood with a longer out-feed chute capable of  dropping the nuts into an portable elevator.

    The elevator lifts the nuts up and drops them into a waiting super sack (photo at right). This way, we can use a tractor for all the heavy lifting instead of getting a sore backs.
   We mounted the elevator on an axle and wheels to allow us to move it around the pecan grove.  A gas-powered,  electric generator provides the electricity needed to power the elevator.

The rush to harvest pecans is on!

   On this day after Thanksgiving, many Americans spent the day rushing about in huge crowds of people at the local shopping mall. But on this warm and sunny day, we spent the day rushing around the pecan grove harvesting nuts. In fact,  the entire river bottom was humming with the sounds of pecan harvest as growers throughout the area worked to harvest the 2014 crop.

   At the Pecan Experiment Field, we use a stick rake (photo above) to remove fallen limbs knocked to the ground by the tree shaker. Once the sticks are raked off the orchard floor, we use a pull-type harvester to sweep pecans up off the ground (photo at left).
   After putting in a long day of harvest today, I gained two impressions of this year's native pecan crop. Yields are below average and we are shaking out a lot of dead wood. These outcomes  are probably related to the several years of drought we've experienced recently and the late spring freeze of 2014.

Mid-November cold injury

Osage, 24 Nov. 2014

   Last week we experienced extremely cold temperatures for mid November. On November 18th, we recorded a low temperature of 6 F (the -14 C). So this week, I decided to check the condition of some of our mature, nut-bearing trees.
    Each photo that accompanies this post shows the bark peeled back on a fruiting shoot (on the left) and a vegetative shoot (on the right). The caption below each photo identifies the cultivar.
  

Kanza, 24 Nov. 2014

Chetopa, 24 Nov. 2014

Maramec, 24 Nov 2014

    In peeling back the bark of several cultivars, I found a range of cold
injury. Osage, which produced a light crop this year, had a healthy green color inside the bark. Kanza and Chetopa showed signs on internal browning while Maramec was severely injured by the cold.
     In looking at the Kanza shoots you will note that the fruiting shoot appears to have more internal browning than the vegetative shoot.  I noticed this same relationship between fruiting stress and cold injury with Pawnee last year. In contrast, Chetopa shoots seemed to have the same amount of cold injury regardless of shoot type.
    Both Maramec shoots displayed severe internal browning. However, the fruiting shoot appeared to have suffered greater cellular freezing.
    In years past, I have seen cold injured trees break bud normally in spring and set a good crop of nuts. Pawnee trees injured last winter produced a good crop this fall. It will be interesting to watch how cold injury in mid-November impacts flowering and fruiting next spring. I have the feeling that Kanza and Chetopa will overcome the damage they suffered and produce nuts next year. Maramec may be in trouble for 2015.

Kanza performance 2014

2014 Kanza crop

   If you have been following this blog for some time, you know that I have been documenting the yield and performance of a three acre block of Kanza trees. This year we harvested a good crop of nuts, averaging 1268 lbs/acre (see table below).  
     In looking over the records for this block of trees, it is interesting to see the impact of below-average rainfall on tree performance. During the years 2011, 2012, and the first half of 2013 the trees suffered from serious water shortages. Drought conditions impacted tree grow rate, nut weight, and yield. In 2013, mid-summer rains helped to increase nut size but yield had already been impacted by the previous season's drought. You see, each spring's pistillate flower production is largely determined by growing conditions during the nut filling period the previous summer. 

   

Cracked Kanza nuts, 2014

    In 2014 tree grow rate responded to better soil moisture conditions and total pecan yield increased. However, the dry spell we experienced in mid- summer decreased nut size and increased the number harvested stick-tights.    
    Over the years, we have progressively thinned this Kanza block as trees begin to crowd. The thinning plan for this orchard and our tree removal progress has been posted to this blog. When planted, this block of trees contained 144 trees spaced 30 feet by 30 feet. So far we have removed 17 trees but the thinning plan calls for the eventual removal of 72 trees in total (resulting in a 42 ft. x 42 ft. spacing). However, by taking a thin as needed approach to tree thinning,  we have maintained total block yield despite experiencing problems with drought.

Grafts survive cold snap

    When I woke up this morning the temperature outside had dropped to 6 degrees F (-14 C). For mid-November that's pretty darn cold. When I drove by some of my young pecan grafts today, I noticed some of the leaves were still frozen on the tree (photo at right). These leaves had frozen back on November 4th during our first hard freeze, but when leaves remain on the tree it indicates that those branches had not fully hardened off in preparation for winter before the cold weather hit. With the extreme cold this morning, did my young grafts suffer cold injury?

   To check for winter injury, I took my pocket knife out and cut into the main stem of the graft and peeled back the bark. Winter injury on pecan first appears as brown streaks in the  inner bark. The inner bark of this tree was healthy and green (photo a left). The two small, circular, brown spots you see on the inner bark are wounds caused by insects that feed on the stem last summer. 

    This young graft had several, small-diameter shoots at the top of the tree (see photo above). These shoots had developed in mid-summer as a result of a second flush of vegetative growth. This was also the portion of the tree that was still holding on to its frozen leaves.
    Were these shoots injured by the extreme cold? To check, I cut into the wood for look at the inner bark (photo at left). I found nice green inner bark. At this point in time, this Kanza graft looks in good shape.

   Early this year, I decided to top-work a few Jayhawk pecan trees to some new cultivars. When you graft such large trees, the scions grow extremely fast and tall. Vegetative growth can continue late into early-Fall and that new tender growth can be prone to winter injury. The photo at right is one of the top-worked trees I grafted last spring. The graft union is painted white and the scion grew a healthy five feet in height this past summer. Note that the branches below the graft have lost all their leaves while top of the new graft has leaves frozen in place. I needed to check this graft for cold injury.

   I cut into the stem of the new graft and peeled back the bark. The inner bark was still green and healthy (photo at left). No cold injury here.
  

Winter arrives in mid-November

    Last week we harvested a lot of pecans despite the below normal temperatures. Conditions were dry and the harvest machinery was working great. Unfortunately, 3 inches of snow fell yesterday and the grove was blanketed in white (photo above). It will take some time before the snow melts and the ground dries enough to resume harvest. In the mean time, we'll be in the barn running harvested nuts through the cleaner.  

Kanza, stick-tights and crop load regulation

  Kanza has become a very popular pecan cultivar because no matter the weather, Kanza always seems to produce a quality kernel (photo at right). Over the past four years, I've been watching our Kanza trees closely and I think I've  discovered one of the ways these trees preserve kernel quality even when faced with stressful weather conditions.  It looks like Kanza trees self thin a portion of their nuts to ensure full kernel filling for the rest of the crop.

    We recently harvested a block of Kanza trees and had dumped a load of nuts into the pecan cleaner. When I looked at the nuts swept up by the harvester, I noticed a large number of stick-tights. The photo at left shows an example of field run Kanza nuts before cleaning. There were plenty of good Kanza nuts mixed in with a few sticks, leaves, and dirt clods. But what stands out are the nuts trapped in blackened shucks.
   It turns out that about 12% of Kanza nuts collected by the harvester this year were stick-tights. Just looking at the photo it seems like the percentage should be higher but a nut stuck in the shuck takes up a lot more space than a nut out of the shuck. 

   I separated out several of the stick-tight pecans, peeled the shuck off, and cracked open the nuts. In every case, I found a brown, paper-thin kernel inside. It looks like each of these stick-tight pecans stopped kernel development at the water stage leaving only the seed coat inside the shell.
   The question becomes--"Why did these nuts stop developing during the water stage?".  During the summer of 2014, we experienced an extended period of dry weather that started during the final stages of nut sizing and continued until late August. In addition, our Kanza trees had set an above-average crop. Most pecan cultivars react to these circumstances by aborting a portion of their crop in what is commonly known as a water stage drop. Nuts dropped in mid-summer often disappear by harvest as they decompose in the ground cover.
   Kanza is different. A Kanza tree stressed by drought and crop load turns off the nut development process during water stage for a portion of the crop but those nuts remain on the tree until harvest. 
   The good news is that Kanza seems to do an excellent job of regulating its crop load to ensure that fully ripe nuts are well filled. The bad news is that cleaning the Kanza crop following a mid summer drought will take a little more time to remove numerous stick-tights. 

Pickin' pecans

Harvesting Pawnee pecans

Shaking a Pawnee pecan tree

     What a great day for harvesting pecans. The weather was warm and sunny and all our harvest machines were operating perfectly (see photos). Unfortunately, the weatherman has forecast  a massive cold wave to push through the Midwest starting tonight. If we don't get much rain overnight, we'll be back to harvesting the rest of this week. But with high temperatures predicted to be only in the 30's (F), we'll need to break out the coveralls, warm hats and gloves and try to stay warm. It won't be as fun as it was today, but we need to beat the squirrels, crows, and deer to our nut crop.

Without a kernel inside, pecan shucks don't open.

    The Kanza cluster, pictured at right, contained four pecans. Three nuts had wide open shucks with pecans ready to fall from the tree. The fourth nut had a shuck that was still tightly closed and showed no sign of splitting open. In a previous post, I mentioned that a pecan weevil infestation can cause the shuck to remained firmly attached to the nut. However, in this case, there was no indication of weevil activity. Was this one nut just slow to open up or had something gone wrong inside the nut?   

   In the photo at left, you can clearly see that three nuts had normally split shucks while the fourth was still bound inside a closed shuck. The nuts emerging from split-open shucks had developed their normal shell color and were packed with kernel (note nuts cut in cross-section at the bottom of the photo).
    It took a little effort, but I could force the tightly held shuck off  the fourth nut. The shell inside had not yet developed normal shell color and I found a paper thin remnant of a pecan kernel inside.
   Back in August, the development of  kernel inside the stick-tight nut stopped during the water stage and a normal kernel never developed. Without a developing seed inside the shell, ripening hormones are not produced in the fall and the shuck does not open.

   

Hard freeze helps open pecan shucks

   On the first day of November, we had the first hard freeze of the season as temperatures dropped to 23 degrees. What always amazes me about the first hard freeze of the season is how quickly pecan shucks open up once all green shuck tissue is killed by cold temperatures. This year, I was able to photograph some pecan clusters two days before the freeze then again two days after the freeze.

   The first cultivar I looked at was Kanza. In the photo above, the Kanza nuts with green shucks had been split for over four weeks but the nuts were still tightly held inside. Freezing temperatures killed all green tissues and turned the shucks black. This rapid color change (from green to black) is caused by the formation of ice crystals that rupture cell walls and destroy cellular integrity. Once the cells are broken, the shuck loses moisture rapidly and dries quickly. What is fascinating to see is how quickly the  shucks pull away from the nuts following a hard freeze.  

    Ripening at the same time as Kanza, I also photograghed USDA clone 75-8-5 (photo above). Unlike Kanza, the green shuck of 75-8-5 pulls away from the nut exposing the nut inside. Once the freeze killed the shucks, 75-8-5 nuts looked ready to fall from the tree.
    The behavior of green shucks following shuck-split affects how fast a pecan dries on the tree. Before the freeze, I harvested a Kanza nut and a 75-8-5 nut and removed one half of their shucks. In the photo below you can see how loosely the 75-8-5 nut is held in the green shuck. In comparison, the Kanza nut is closely held by a much thicker-walled shuck. The Kanza shuck has actually trapped moisture on the outside of the shell preventing the nut from curing  (see photo below).
   If  I wanted to harvest pecans as early as possible, USDA 75-8-5 would be dry and ready to shake long before Kanza, even though both cultivars split shuck on the same date. Kanza really needed the Nov. 1st freeze to open up and allow the pecan to dry.
      

Peruque susceptible to bird damage

    One of the biggest complaints growers have in growing the Peruque pecan cultivar is that it seems especially prone to bird damage. Today, we harvested several Peruque trees and I was amazed by how many bird pecked nuts I had to pull off the inspection belt when we cleaned the machine harvested nuts (photo above).
    All these holes were created by one of several species of woodpeckers or flickers. These birds use their long narrow beaks to drill through Peruque's thin shell to get at the kernel inside. Woodpeckers are typically insect feeding birds that search tree bark or decaying branches for their prey. However, the high fat content of the pecan kernel is just too hard for a woodpecker to pass up.
    What bothers me the most about this type of bird damage is that woodpeckers eat only a fraction of the pecan's kernel. Why not finish the entire nut so I don't have to deal with finding damaged nuts on the cleaning table.
    Peruque is not the only cultivar that seems to attract woodpeckers. Other thin-shelled pecans like Pawnee, Mohawk, Maramec, Shoshoni and Creek suffer their fair share of  bird pecks. Peruque stands out as super-susceptible to bird attack because it ripens so much earlier than other cultivars in the orchard. We have all heard the phrase, "the early bird catches the worm", but when talking Peruque pecans the phrase should be-- "the early pecan feeds the bird".

Tight green shucks point to pecan weevil attack

     By this date in late October, all northern pecan cultivars and local native pecans have fully ripened and split shuck. But as leaves start to drop, you might notice a few pecans up in the trees that still have bright green shucks that are still tightly bound to the shell. On closer inspection, you might find a hole in the shuck. This hole could be the exit tunnel for a hickory shuckworm moth but if you take your knife and cut away the shuck you might find the hole continues straight through the nut shell (photos at right).  If the hole goes straight into the nut, what you have discovered is the exit hole for a pecan weevil larvae.
    The weevil larvae that developed inside these pecans completely devoured the kernel inside then chewed a hole through the shell and shuck to exit the nut. Once outside the nut weevil larvae drop to the ground, burrow into the soil, and form an underground cell. The larvae will pupate in the soil before emerging as and adult 22 months later (weevils have a two year life cycle).    

    I pulled a nut cluster off a tree because I noticed all three nuts in the cluster had not split shuck (photo at left). At first look, I saw only two of the nuts had weevil exit holes. But what about the third nut?

    Turning the cluster over, I found the third nut was also destroyed by pecan weevil (photo at left). Since a single adult female weevil can lay eggs in 7 to 15 nuts, it seems likely that the larvae in these three nuts originated from the egg laying activities of a single mother. It is also interesting to note that exit holes occur at seemly random locations on each nut. This may mean that once a larva finishes eating all the kernel inside the shell, the closest exit point is always the best.  

Pecan cultivars ripening in late October

Maramec split 20 Oct 2014

   This week, the latest ripening cultivars in our trials split shuck. I don't even bother testing later ripening cultivars because there is a 10% chance of a hard freeze  (28 F) by October 22 at my location in southeastern Kansas. In fact, I have seen all four of the cultivars pictured here freeze in the shuck following a cooler-than-normal summer and early fall freeze.
    Although all of the photos in this post were taken today, several of the cultivars ripened earlier in the week. Maramec was shuck-split by Monday, Oct. 20. Caddo and Oconee were next, splitting open by Wednesday, Oct. 22. 
    And finally, there is Stuart. It took me a little while to find a Stuart nut cluster with split shucks to photograph. I estimated that less than 10% of the nuts on the tree had split shucks by today, Oct. 24th. Stuart might be one of the most widely recognized pecan cultivars in the world but is is definitely not adapted to growing in our northern pecan climate.

Caddo split 22 Oct 2014

Oconee split 22 Oct 2014

Stuart, 24 Oct 2014