Saturday, August 30, 2014

The end of the rainbow

  You may have heard the tale of a pot of gold at the end of a rainbow. But last night, I saw a rainbow that ended in my pecan grove which is a sure sign that I'll be harvesting a pot of golden pecan kernels in the Fall.

Friday, August 29, 2014

End-of-summer graft check-up

    Its Labor Day weekend and it time for an end-of-summer graft check-up. I've had some great growth on my bark grafts with many scions growing over 5 feet this summer (photo at right). This tree appears to have more leaves at the top of the tree than in the middle and lower portions of the scion. What you are seeing is the result of a normal slow-down of shoot growth that happens towards the later part of the summer. As shoot growth slows, the distance between buds decreases. Likewise, the distance between leaves along the stem becomes shorter as growth slows. More leaves in a shorter stem span gives this tree its top-heavy appearance.
    All summer long I've been removing stalked buds from this tree so I wanted to make sure new stalked buds hadn't formed since I checked the tree back in late July. I looked at the top of the tree (photo at left) and discovered only sessile buds and a well formed terminal bud. This is good news. This tree has stopped growing and can now start hardening-off in preparation for winter's cold.
    Not all my trees have stopped growth for the year. The graft pictured at right was still creating new leaves and had formed stalked buds near the top of the tree. My first step was to prune all the stalked buds just like I had been doing all summer. But at this time of year, I made one more cut. I pruned out the tip of the central leader to encourage the tree to start shutting down. A scion that grows vigorously, well into the Fall, is at greater risk for mid-winter cold injury.
    I also checked on the condition of each tree's graft union (photo at left).  It appears like the tree is healing over nicely. The scion has covered over nearly three quarters of the stock's cut surface. The white paint I applied in early August served to prevent sun-scald to the union and inhibit insects from feed on callus tissue. However, the best thing about the white paint is that now I can look across the field and easily spot which trees I've grafted.

Tuesday, August 26, 2014

Minimal scab in 2014

Scab lesions on Dooley pecans
    Up until late August, the 2014 growing season in SE Kansas can best be described as having below average rainfall. Back in June, we were receiving regular rain showers prompting us to apply a fungicide along with our pecan nut casebearer spray. Once July hit, we started missing significant rain showers and our grove started to dry out. With this year's dry mid-summer, pecan scab never became a serious threat to our pecan crop.
   This morning I visited trees of two cultivars that are normally very susceptible to pecan scab; Dooley and Peruque. I was interested to see how these two cultivars have faired with the minimal scab spray program they received this year.

Scab lesions on Peruque pecans
    Scab lesions can be seen on the shucks of both cultivars. However, in both cases, the scab lesions were small and largely superficial. Just last year, we didn't even harvest our Dooley crop because scab had destroyed every single nut. In 2013, Peruque wasn't much better as we were forced to discard numerous scab infected stick-tights off the cleaning table. What a difference a year makes!

Friday, August 22, 2014

Kernel fill progressing with the return of summer heat

    This week's high temperatures, especially night-time temperatures that didn't drop below 75 degrees F, have helped pecan nut development advance. This morning I collected nuts from 5 pecan cultivars to check on stage of nut development (photo at right). Of the cultivars I harvested, only Giles nuts are still expanding in size. Colby, Goosepond, Peruque. and Kanza have all completed nut expansion and are now filling kernel.

    By cutting each nut in half I could see how these 5 cultivars were progressing in terms of kernel fill (photo at left).  It looks like Goosepond has almost completed kernel filling while Peruque has only a slight crease down the middle of each kernel half to fill. In comparing Goosepond and Peruque, look carefully at the inner shell partition that separates the two halves of these pecans. Notice how the inner partition in the Goosepond nut is thinner and has turned dark brown in color as compared to the thicker, light-tan partition in the Peruque nut. A change in color of the middle septum, from light to dark, is an indication that nut kernel expansion has fully compressed the inner packing material inside the shell.  
     The Colby nut has developed some solid kernel but you can still see the translucent 'jelly' layer that indicates rapid deposition of new kernel material. The slight thickening of the seed coat  (a thin jelly layer) reveals that Kanza has only just begun kernel deposition. The kernel of the Giles nut is still expanding and the nut has not yet reach full water stage.
     This year, kernel development seems to be behind schedule. Although we have suffered through some stifling heat this past week, the summer of 2014 has been cooler than normal and those cool temperature have retarded nut development. Lets hope we catch up before frost hits this Fall.