Over the past couple of weeks, we have updated a few EDIS publications (online extension) and they include a comprehensive overview of all the commercial and backyard (or dooryard) varieties that are grown in Florida.
The largest peach that was ever grown weighed in at 25.6 ounces and was produced in Coloma, Michigan! The designation of August as National Peach month coincides with the largest production of peaches in the United States coming from both the east coast and the west coast.
Florida kicks everything off in late March and early April from orchards as far south as the Immokalee area. Many of the grocery stores have made room for our flavorful, tree-ripe product and promote “Fresh from Florida“. Some have even featured growers in the state on their marketing, which is very refreshing to see. We get to see the growers that work hard every day to bring a premium product to the marketplace and creates a connection between the consumer and producer.
As we increase the acreage and production of Florida peaches, we are seeing more product throughout Southeastern grocery stores. There has been fantastic response to the product, with consumers realizing fruit quality and flavor is as important as size and appearance. Research conducted by the National Peach Council found that if a consumer has a bad eating experience it takes about 2 weeks for them to try peaches again. Coincidentally, a new variety has probably rotated in by that point with differing fruit characteristics.
We all need to let consumers know that peaches from the U.S. are available in April, and they are from Florida!
All throughout Florida, we have had a lot of rain this summer. Unfortunately, peach rootstocks do not like flooding, and there are not very many flood-tolerant rootstocks in peach.
Flooding affects the soil by:
Replacing pores that had oxygen in them with water. This can lead to anaerobic (low oxygen) conditions that can damage peach roots.
Accumulating toxic compounds (e.g., sulfides, CO2, soluble iron and manganese) that are produced by the waterlogged soils, or from the dying rootsystems themselves (e.g., ethanol, acetaldehyde, and cyanogenic compounds).
How much can a peach tree stand? 2-5 days can cause death, but only a few hours and trees will start to show signs of flooding stress, which include:
Tree death (if water is present over 48 hours)
If a peach tree is under significant flooding stress, it can put the tree at a disadvantage when trying to fight off root and crown rots (like Phytophthora, spp.) In peaches, phytophthora root and crown rot is a leading cause of tree death when significant precipitation has fallen, or trees are planted in poorly-drained sites. If you cut into the lower trunk or root system with a shovel and you find brown areas or lesions, instead of yellow-white fleshy roots and wood, then the tree most likely has a damaged root system (see right).
What can I do?
Unfortunately, fungicides for root and crown rots must be applied before the infection is realized, and post-infection applications are not effective. The best thing is to improve the drainage in the area where trees are being flooded so that trees do not experience anoxia (low oxygen) conditions during subsequent periods of heavy rainfall. If you have an area that is prone to flooding, periodic applications of soil fungicides may be appropriate, but ALWAYS check your regional or state-wide spray guide for more information and guidelines. For many products, a restricted-use pesticide license is required to purchase and apply the chemical.
Although there are no root rot-resistant rootstocks, peach rootstock breeders are hopeful that they can “stack” tolerances for other diseases such as Armillaria root and crown rot and Peach Tree Short Life in with those rootstocks that might be tolerant of Phytophthora root and crown rots.
I’ve started working on topics for the upcoming winter pruning workshop in Fort Pierce in December, and also planning for next year’s annual field day in Citra, FL – and wondered what topics you would like to see?
I saw this article as I was perusing the Puget Sound Wine Growers Group List that I am still a part of – http://www.wired.com/design/2013/07/inforpr0n-winemapz/ – and I was surprised to see that the premium wine growing regions in Washington State and California will at some point be too warm to grow great fruit.
What does this mean for the rest of the country and even the globe?
Increasing carbon dioxide (CO2), rising temperatures, and changes in precipitation pattern will affect agricultural productivity.
Livestock production systems will be greatly affected by temperature stresses.
Climate change effects on crop and livestock production for the next 25 years will be mixed.
Climate change will make current stresses (e.g., drought, flooding, salinity) even worse on plants and animals.
Agriculture is dependent on processes that support crop productivity including maintenance of soil and water quality AND quantity.
Higher incidence of extreme weather events will have increasing influence on agricultural productivity.
The vulnerability of agriculture to climate change is strongly dependent on the responses taken by humans to moderate the effects of climate change.
We can adapt.
What was really interesting when I was with WSU in Prosser, WA – the viticulturist there examined possible increases in maximum temperature as a driver of climate change in the region. However, what we found was that while minimum temperatures were increasing, maximum temperatures were fairly steady over 85 years.
What impact might minimum temperature increases have? We could start observing more varieties with fruit set problems, like that of ‘UFOne’. With ‘UFOne’, researchers at UF found that when the night temperatures were over 55 °F, fruit set was poor. It could be that the pollen is being shed before the ovary is ready, or that pollen tube growth (on its way to fertilize the ovary) is arrested and the pollen never makes it to the ovary.
The warm night temperatures might also affect acid levels in the fruit – which are important in developing quality flavor profiles. Fruit with little acid often end up tasting sweet, but flabby and don’t linger very long on your palate, making for a bland eating experience.
I’ll end this with a picture of surface temperature projections through to 2099 in two different scenarios, one in which CO2 emissions are controlled (low) and one in which CO2 emissions continue to remain high. I am hoping that technology will help us moderate emissions so that we can achieve the lower temperature scenario for the future.
Last week I had the wonderful opportunity to be present some research data on the nitrogen work that we are doing in my program in Matera, Italy. Matera, Italy is located in southern Italy, in the region of Basilicata. It is a United Nations Educational, Scientific and Cultural Organization (UNESCO) world heritage site which means it has special cultural significance. In fact, there is evidence that Paleolithic man lived in the limestone caverns of Matera. It was definitely humbling to be around dwellings in which people have continuously lived for over 9,000 years. We also toured a very large cistern, in which I was super claustrophobic!!
There were many wonderful talks on the peach genome, genetics and breeding, orchard management, and fruit quality, both pre- and post-harvest. For a list of abstracts presented: http://www.unibas.it/peach2013/abstract_list.pdf. One thing I thought was interesting was a presentation by Dr. Ted DeJong, from UC Davis in which he stated that early ripening peaches will always struggle to get the fruit size that later ripening varieties do, and that one option might be to increase the carbon storage. Given a finite volume of the tree structure, I wondered – how much carbon (starch) do we store now? An interesting future research project as we work to optimize fruit size in our subtropical climate.Finally, the peach field excursion was the most interesting as we traveled southwest towards the “toe” of the boot in Southern Italy to Sibari. In Matera, much of the agriculture is dryland-based, with many olive orchards and volunteer fig trees. However, as you go further to the west, the rivers of the Apennine Mountains provide water through an irrigation system, for many hectares of citrus, stone fruit, and grapes. We also saw rice production, cherries, and more olive orchards – which was a great diversity.
Our first stop was to CampoVerde, a large group that grows, harvests, and packs nectarines, peaches, table grapes, pears and apricots. Their packing line, equipment and fruit was much as it is in the U.S. – although they had a large “farmstand” packing line, that packed fruit into plastic containers with handles. Each contained about 7-8 pieces of fruit, and were stacked in plastic stackable lugs.
Nectarines being run over packing line, Sibari, Italy
Next, we went to Assofruit Italia, just outside of Policoro. This cooperative just started in 2010, with an unusual twist – young people leading the company. It was so refreshing to see young people (late 30s, early 40s) investing in the stone fruit industry and agriculture in general. This group interestingly has about 300 hectares (~740 acres) of peach trees under plastic cover that they use to speed fruit development. They can gain up to 4 weeks advanced ripening, placing them in the same timeframe as Morocco, which is the first to ship fruit to Europe. Even with fruit on the market at the same time as other countries in the European Union, the area has a superior reputation for fruit quality and flavor, and so they can get a good price for their fruit compared to other areas in Europe/Africa.
We returned through Metaponto as we headed back to Matera, and visited the ruins of Metapontum, which was an ancient Greek colony. It was founded between 700-690 BC and the most famous inhabitant was Pythagoras, who invented the Pythagorean Theorem (a2 + b2 = c2). The theatre and the foundations of four of the temples dedicated to Apollo, Hera, Artemis, and Athena have remnants that exist, with some modern attempts at protecting what remains.
After our visit to the ruins, we headed back to Matera for one last day of talks on fruit quality. An interesting instrument that I am considering looking at for use to determine harvest date here in Florida is the Index of Absorbance Difference, which measures the amount of chlorophyll in the peach fruit. This helps to determine when the fruit are physiologically ripe. I can see this being a challenge with 100% blush varieties however, like ‘UFBeauty’ and ‘FlordaBest’. It’s called a “DA Meter” and was developed in cooperation with Professor G. Costa at the University of Bologna (http://www.trsnc.com/ingl/f_01_gb_news.html). A future research project that needs funding!
It was a wonderful trip, and I got another stamp in my passport! But, it was wonderful to kiss my kids on their cheeks again after enduring U.S. Customs at JFK.
As I have traveled over the past six months or so, I have seen many trees that possibly have nematode issues; that is the trees flush out with early growth and sometimes bloom early, yet they lag behind later in the year from normal trees (Figure 1).
Figure 1. Nematode-affected tree showing reduced growth, due to an outcross of ‘Flordaguard’ rootstock.
What do you do if you suspect that nematodes have infected a tree in your orchard?
The first thing that I usually do is politely ask the grower if it’s ok to pull up their tree. Often you will notice the either early or delayed growth from the rest of the orchard approximately one year from planting, so the trees are easily pulled up from the soil. In many cases, we end up finding nematode galls throughout the root system (Figure 2). These root knot galls are caused by the peach root knot nematode (Meloidogyne floridensis). If you do find these, then dispose of the tree and replant with a new tree that is budded onto “true-to-type” ‘Flordaguard’ rootstock. Having said this, in a nursery situation, it is often hard to catch those escapes that are outcrosses, and for those nurseries that use seeds to propagate ‘Flordaguard’ rootstock, outcrosses occur approximately 5% of the time, with another 10-15% being rogued out due to slow growth or small diameter caliper.
Unfortunately at this point, we don’t have any good solutions other than planting our varieties on nematode-resistant rootstocks, like ‘Flordaguard’. We have an ongoing project to figure out why ‘Flordaguard’ is resistant, as well as evaluating other rootstocks that may be resistant from the USDA-ARS Peach Rootstock Breeding program in Byron, GA. In many cases, fumigation may work – and we have a separate project to examine the effectiveness of the recommended rate as well as a half-rate of Telone II as a pre-plant fumigant in reducing the impact of peach root-knot nematode.
If you would like to submit a nematode sampling for identification, please send a sample to the UF Nematode Assay Lab – http://edis.ifas.ufl.edu/sr011. As always, please contact either myself or your local county extension agent regarding orchard issues. We are always here to help!
Well, this year has been a tough one already for those in Northern and North Central Florida in the peach business. On the night of February 12th, our orchard at the Plant Sciences Research and Education Unit in Citra, FL experienced an advective freeze. Remember those? We haven’t had a windy freeze in a while – definitely in over 3 years. The final temperature was about 25°F, with steady 15 mph gusts. The water was turned on about 3 am, as a break came in the wind; however the wind picked back up in the morning, effectively destroying any protection that we tried to put out with our ice loads.
We had pretty good ice formation, with much of our wood covered in ice. Our irrigation for frost protection is set up on 20 x 20 spacing with 8 foot PVC pipes and brass impact overhead sprinklers.
A few heartbreaking pictures:
These were ‘Flordaprince’ on the left, and ‘UFSun’ on the right. The only difference is that the ‘Flordaprince’ was pruned, while the ‘UFSun’ had not been pruned . This resulted in severe limb breakage, with some of the trees only having one remaining scaffold. We had to pull two younger ‘UFSun’ trees.
After the ice melted off, we noticed that many of the flower petals were brown and freeze damaged; even the flowers that were at a “pink bud” stage had started to brown. When we cut through the flower, the pistil on many of these flowers were dead.
As the picture shows, during the night we had enough ice formation to fully encase the flowers and the buds – and the ice was fairly clear, meaning that the ice formed quickly without any air bubbles. Air bubbles could potentially affect the insulation factor of the ice, and reduce the effectiveness of the ice formation.
This tree on the left ended up with some of the ice that had air bubbles in it, but the full effect of the ice formation was hampered by the steady winds over 10 mph, gusting to 15 mph throughout the night.
About five days after the freeze, I went through to check what fruit was alive or dead. Fruit where the embryo was alive were green throughout, with a clear pit forming, while those fruit that were dead were brown, including the surrounding pit tissue (see below). While most of the time our freezes are radiative, we had a one-two punch here in Northern Central Florida, with an advective freeze on the night of the 12th, and a radiative freeze on the night of the 13th.
A number of researchers and growers around the country are looking at alternatives to combat these freeze situations, including using tunnels during the frost season and even wind machines. Although wind machines were once used unsuccessfully in the citrus industry during the major freezes in the 80s, the technology has advanced with better engines, blade design, and greater effective area, reducing the number required per farm. In addition, the use of a wind machine or other frost protection method like tunnels can reduce the water utlized during freeze events.
Here’s to hoping for a better year next year for our research and breeding program!
Thus far 2011 has been a great year! We had a pretty warm spring that was relatively dry and most growers harvested a fantastic crop of peaches. Some growers were harvesting as early as late March, a few weeks earlier than the typical start date in early April.
Our program staff has expanded with the addition of a Ph.D. graduate student, who is working on determining optimal rates of nitrogen for subtropical peach production and a new biological scientist who has been a HUGE help in the orchard this season. Unluckily for him, he started at the beginning of harvest, and was thrown into the lion’s den of research.
We are working on several research projects in the program:
Impact of Nitrogen Rate on Peach Tree Growth and Fruit Quality
Rootstock evaluation for resistance to M. floridensis and genetics of resistance
Economics of orchard establishment and production
Impact of IBA concentration on rooting softwood, semi-hardwood, and hardwood cuttings
Impact of gibberellic acid on tree growth and fruit quality
The other part of my program is Extension and outreach – and we have had several field days that started with our annual Citra Field Day on April 27, 2011, then the May 2011 Conserv II Field Day, and a Variety Showcase in Hastings, FL. I am also involved in a couple of national grants that do research and extension on a national level – RosBREED, and Tree Fruit Genomic Database Resources (tfGDR). These projects serve to further the Rosaceae industry (the parent family for peaches, plums, nectarines, and other crops) and I am trying to integrate outreach and breeding to trumpet the successes of these programs and involve stakeholders that help us to get funding on a national level. If you have questions about these projects or the tools provided by these projects, please let me know!
If you would like to be notified of these events, please send me an e-mail at firstname.lastname@example.org to get on my peach mailing list.
Finally, we installed a research and demonstration orchard down at the Indian River REC in Fort Pierce, FL last week – and it was stinking hot! We tried to start at 7 am, and it still wasn’t early enough! We will be using this orchard for field days in the future and rotate between our Citra orchard and the Fort Pierce facility.
I also continue to get around the state to see new orchards being established and teach groups of growers about production techniques – I can’t get around to everyone, but let me know if you need some help and we can usually solve the problem with e-mails and phone calls!