Fruit & Nut Resources

Had an opportunity to volunteer for a US AID project in Egypt, so I took it.  Will be working with peach, plum and apricot growers in the Nile delta.  Departed Friday, through JFK, to Milan to Cairo.  Got here yesterday, good nights sleep and its Sunday now, first day of the work week here and have my briefing at noon.

Should be an interesting two weeks and I hope to add photos every couple of days while I am here.jk

Scott Korcz writes in and adds some photos about a problem with his ‘Harvester’ peach tree this spring.  Here are the photos he supplied

You can see that Scott has a good mulch layer down to conserve moisture and eliminate weed competition, but this tree has a couple of problems going on.  First, this tree is showing classical symptoms of insufficient chilling.  These trees should grow out of this during the summer, but the lack of lateral budbreak will need to be addressed in the next dormant pruning.

Also have some nutrient deficiencies going on here.  These trees need nitrogen.  The general yellow color of the older leaves tells us its time to add a little N.  With a wood chip mulch, it will be important to water it in well so the nitrogen travels through the chips and down into the root zone where it is available to the plant.  I also see both iron and zinc deficiency on the newer foliage.  Iron chelate applied to the soil and watered in well will overcome the iron problem, but the zinc problem is a little tougher to deal with on peach trees.  Zinc sulfate can be applied to the soil and watered in, but tends to get tied up pretty quickly in the soil, so frequent applications may be needed.  Zinc sulfate should not be sprayed on peach trees- it will defoliate them.  Over time, as the mulch breaks down, natural chelates will be formed in the soil and this should be less of a problem.  Just another reason to mulch your trees!

The Womack Family in DeLeon, Texas, is an incredible resource for commercial and casual fruit growers in Texas.  Womack Nursery was started in 1937 by James H. Womack. Larry J. Womack took over in 1964 and still grafts fruit and pecan trees today! His son, Larry Don Womack, currently leads the business which supplies fruit and pecan trees, berries, grapes, graftwood, grafting supplies, roses and some shade and ornamental plants to commercial growers and homeowners alike. They are an important source for appropriate varieties of fruits for the state of Texas.

Womack Nursery hosted an open house, grafting workshop on April 17th at their headquarters west of DeLeon on State Highway 6.  Approximately 56 people got to see and listen to tips and techniques of pecan grafting, including the inlay bark graft, 4-flap graft, and patch bud methods. Many of us in the world of research and extension think we know how to graft, but nurserymen like the Womacks and their skilled laborers are the real “masters of grafting”.  They literally perform these techniques hundreds of thousands of time, and there is a different level of skill and experience that they are able to share.

Larry J. (background) and Larry Don Womack (foreground) beginning their Spring Grafting Workshop

Larry J. Womack demonstrates pecan inlay bark graft

Experienced grafting hands

First,  my apologies for not being more regular in my posting.  As I am  sure you all know, this is the time of year us fruit people are in the field most of the time.  We have also been trying to keep funding for our grape projects, so needless to say its been hectic.

In response to a request, I wanted to post a photo or two of what happened to our fig cuttings after we cut them and placed them in callus boxes.  Six weeks later callus had formed at the basal end of the cuttings and roots had begun to grow out of the callus tissue.

At this point, the cuttings were planted into one gallon pots with soil-less mix, no fertilizer and allowed to force.  About two weeks later shoots began to force and the foliage expanded on the growing cuttings.

This photo was taken about two weeks ago and as you can see, we had a great take.  Yesterday we applied our first light fertilizer application.  We like to use Mir-Acid and even though the figs don’t so much need it, we add in a little iron chelate to keep the foliage of all our greenhouse material a dark green.  Fredericksburg city water is pretty easy on plants, but still has lots of calcium that over time will bind iron making the chelate a good addition to our routine. Pomegranate cuttings which were taken a couple of weeks later were stuck yesterday.  Good callus had formed, but they are a little slower to start generating roots.  Photos of them soon.

Well, the cool spells that are coming in have helped hold trees and vines back a little, but every crop we work with is showing signs of life.  Grapevines have wooly buds, blackberries are forcing, peaches are pushing, one more extended warm spell will mean bloom and budburst in everything.  Even pears, normally one of our later blooming crops is showing signs of life.  Last week on a windy, cloudy day, I spent a few hours pruning in our pear block in Fredericksburg.  We have fourteen European hybrid and Asian hybrid varieties, all with quality superior to that of ‘Kieffer’ and ‘Orient’, that we have been growing without insecticide or fungicide input.  So far at least, fire blight, while present, has not been a serious problem to our block.  We planted Pyrus betulifolia whips in the winter of 2009 and budded them that spring.  Here is a picture of the trees in the spring of  2011.

So with pears starting to force, it was a pleasure for me to take an afternoon away from the computer and the phone and get these trees pruned and trained.  We have been using an array of tricks to break the strong apical dominance of many of the European hybrid varieties, some with success and a few setbacks.  At first, we tried an old trick taught to me by Ron Perry who taught Hort 319 and 401 at A&M in the late 70’s.  Ron asked his wife for some ruined pantyhose, cut them into lengths and tied them around the base of the tree.  From there he tied erect pear limbs down with bailing twine- one end on the limb and the twine secured to the hose on the trunk.  This allowed for the trunk to grow and not (theoretically) get girdled by the hose.  In our case, maybe it was the cheap hose we bought at Dollar General and maybe it was how vigorously the pear trees grew, but we did have some girdling.  With high winds, there was some tree breakage.  Luckily, most broke above the graft union, so we had scion re-growth.  Pain to deal with, but at least we didn’t lose the trees.

We have since gone to limited pruning and the use of limb weights to train pears.  The problem, is that with numerous strong erect shoots competing for dominance in the pear trees, if you prune most of them off, the invigorating action of dormant pruning means that you have twice as many dominant shoots the following year.  The trick is to break apical dominance without the invigoration of pruning.  Here is one of our ‘Ayres’ trees going into its fifth growing season.  Trees have made substantial growth in the past two years

By breaking apical dominance, lateral growth is initiated and with adequate sunlight exposure, these laterals turn into fruiting spurs.  Spurs are perennial fruiting structures and spur development puts these pear trees into a bearing mode rather than a vegetative mode.  Some varieties, like ‘Warren’ are not at all precocious… some take ten years for first crop if left to their own devices.  Triggering early spur development helps get them into production faster.

Pears are strong terminal bearers, so developing lateral growth means more flowers and more fruit. Now that the trees are larger, we use nominal pruning to remove the limbs growing back in to the interior of the tree and limb weights to increase the angle of scaffolds limbs and help develop more fruiting spurs.  The weights consist of 20 oz Dixie cups with 12 guage tw wire formed into a hook, filled with concrete.  After three years the cups are falling apart, but the weights are still in good shape.

These tricks worked last year and we had a great bloom and fruit set.  Unfortunately, on May 7th, we had thirty minutes of golf ball sized hail that beat the crud out of everything.  Figs were almost completely defoliated and it ruined our crop on pomegranates, pears and most of the vineyard.  Here you can see some pretty nasty wounds caused by the hail, but fortunately, the trees are in good health and the wounds have healed over remarkably well.

Lots of nervous peach growers.  In Fredericksburg we are sitting right at 660 hours of winter chilling, 100-150 hours short of what we really need to break dormancy on many of the standard varieties.  Some growers are opting to apply Dormex, a growth regulator that helps overcome insufficient chilling.  The risk is that once it is applied, there will be nothing holding the buds back and advancement could mean increased risk of spring  frost.  Yes, farming is a gamble.

Yesterday, a number of growers brought in shoots of different varieties to check on bud development to help in knowing if/when/ and how much Dormex to apply.  Here is an example of what we saw

Top photo is a bud still receiving chilling, middle bud is transitional and bottom bud is ready to open.  With more than two weeks of February still to go, its going to be an interesting spring!

I was invited to speak at the Virginia Vineyard’s Association’s annual meeting in Charlottesville this past week and on the way back to the airport, Tony Wolf, Viticultural Specialist with Virginia Tech offered to give us a brief tour of a local vineyard.

In this photo, Carl Tillam, vineyard manager, Tony Wolf and Hans Walter Peterson, Finger Lakes Grape Specialist get a chance to tour a Petit Verdot block outside Charlottesville.  A welcome cold spell with a few days of light snow is just what the growers are looking for to keep vines dormant until later in the spring.  From my interaction with the VT faculty and staff, having a few days to visit with Virginia grape growers and a chance to taste some world class wines, Virginia obviously has its act together.  Unlike Texas, The Commonwealth of Virginia continues to invest in the research, education and marketing efforts needed to advance their industry.  As a state, we should pay attention!

Well, forget everything I said about having a good chilling season.  Our warm spell for the past ten days has certainly not been good for perennial fruit crops.  These high temperatures roll back the chilling accumulation, although we cannot really say how much.  We are stuck at about 550 hours of winter chilling in Fredericksburg, TX.  We need the groundhog to see his shadow this Saturday or we are in serious trouble.  Not enough chilling to set a crop and if we do bloom, the chances of losing the crop to frost/freeze are pretty good.

Think snow!

After over ten years of applied research across the state and over a year of publication preparation, we are happy to release a practical overview and management guide on Pierce’s disease.  During the late 1990’s, this bacterial pathogen was devastating vineyards in the Texas Hill Country and was moving into production areas north and west of where it was thought to occur.  A cooperative research between USDA/APHIS and Texas A&M research and extension personnel as well as colleagues at the University of Houston-Downtown and the University of Texas at Tyler provided funding for us to begin to answer the pertinent questions about the transmission and epidemiology of Pierce’s disease in Texas.

This guide reviews the history of the disease in Texas, California and other grape producing regions of the country.  The results of eight years of insect trapping have resulted in a rouges gallery of insect vectors as well as a review of some of the field conditions that impact vector number and disease incidence.  In addition, practical management information and a review of ongoing work will provide growers in Texas and other growing areas east of the Rockies with a new resource to aid in the management of this disease.  This guide can be downloaded and freely distributed from the following url:

https://aggie-horticulture.tamu.edu/wp-content/uploads/sites/6/2010/10/Texas-Grape-Growers-PD-Management-Guide.pdf

Hope you all find this useful.

jk

Its the middle of January and at this point, growers are starting to wonder how the year is shaping up for winter chilling.  Commercial growers can apply growth regulators to overcome insufficient chilling, but they need to know and make the application in early February if it is needed.  For most, they may wonder, or worry, but we still want to know how we stand in comparison to other years.  I posted some comments last month about the kind of equipment we use to record weather data, but wanted to share a little more about what that equipment gives us.  I normally download weather data every couple of weeks, tally hours below 45°F, and keep a running total.  Our Hobo Dataloggers give us this kind of a graph:

We can then export those data into an excel file and count chilling segments  (we have the dataloggers set to record temps every 15 minutes).  As of today, January 14, 2013, the we have recorded 487 hours of winter chilling below 45°F, which is about on par with what we have been seeing the past few years.  The chart below can give you some perspective on how we stand compared with the past six winter seasons.

It appears we are on track, at least so far, for a normal, to above normal chilling year.  I commonly get questions about climate change and variety selection.  Often people wonder that if our temperatures are getting warmer, shouldn’t we be planting trees with chilling requirements somewhat lower than the old average chilling zones we have been using.  Our answer is that at least so far, this change has not really affected our chilling totals.  The amount of chilling we receive from season to season does fluctuate, but in Fredericksburg, where the average is about 800 hours per winter, over the past six seasons, we have been over the norm.  This will cycle and we will get some warm winters in the future, but from what we can tell, no need to change the chilling range of the varieties we are planting.