by Karl H. Kazaks
A variety of topics were covered at this year’s Virginia Tree Fruit Schools, held on five occasions around the commonwealth, in the southern Blue Ridge, the Roanoke Valley, at two locations in central Virginia, and in Winchester. The first four meetings drew crowds of about 50 or more, with the final meeting in Winchester drawing almost 100 people.
The meeting in Cana, held at the Hungry Farmer restaurant, included attendees from North Carolina’s northern piedmont.
Jim Atwell, VDACS’s pesticide services representative for southwestern Virginia, gave a presentation on pesticide and worker safety updates for 2015, part of the training that enabled attendees at the schools to be recertified as private pesticide applicators.
The EPA has issued a number of proposed new protections for pesticide use that differ from current standards, Atwell said. Under the proposed new regime, workers must be trained every year, instead of every five years, and recordkeeping of such training, currently not required, must be performed and kept for two years.
When, after application of a chemical, the restricted-entry interval is more than 48, under the new proposals growers will be required to post no-entry signs for that no-entry period. The current rule doesn’t specify a particular time period for restricted entry as requiring notice, and permits verbal notification unless otherwise stated by pesticide labeling.
At present, there are no minimum age restrictions for pesticide handlers. The new rules will set a minimum age of 16, with exemptions for family members.
Other new rules include the adoption of OSHA standards for respirators and the creation of buffer zones around treated areas to protect people from pesticide overspray.
Some of the changes would make life easier for growers. The definition of immediate family would change to allow the inclusion of grandparents and in-laws, and hazard communication rules would be amended to require growers to have a clearinghouse of SDS (safety data sheets, what used to be called MSDS), rather than post-application posting of specific information about chemicals.
Dr. Keith Yoder, heroically battling a case of laryngitis, gave an update on glomerella leaf spot. The disease, Yoder said, was first reported in Tennessee in 1998, became a serious nuisance in North Carolina in 2005, and moved from there through southern and central Virginia, becoming particularly prominent in 2010 and reaching Winchester in 2012.
“It’s still spreading to new areas, and has presented itself as an annual threat the last several years,” Yoder said.
Caused by the sexual stage of the bitter rot fungus, the disease particularly impacts Gala. The cultivars Pink Lady, Golden Delicious, Fuji and Granny Smith are also susceptible to the disease.
The disease appears on leaves as necrotic lesions irregular in shape and purple in color. Its affect on fruit is similar to that of bitter rot, with a cone-shaped pattern of growth into the fruit. “It’s like a really bad case of bitter rot that also affects leaves,” Yoder said.
Recent research shows that the disease may be infecting orchards as early as mid-May, meaning that there may be four to six generations of the fungus in the orchard before you notice.
One way to reduce disease pressure is to spray urea on the leaves, which breaks down the inoculums.
When developing a spray program, remember not to focus only on glomerella. “You don’t want to let Brooks spot slip through,” Yoder said. Also, alternate your chemistries to prevent resistance development.
Dr. Doug Pfeiffer spoke about the complex relationship between neonicotinoids and pollinators, particularly bees.
There has been a connection made by many between the use of neonicotinoid pesticides and CCD, colony collapse disease, which has caused bee populations to shrink. But the connection may not be as direct as some think, Pfeiffer said.
“CCD is not a new phenomenon,” Pfeiffer said. There are examples of hive declines going back to the 1800’s, with more recent examples in the 1970’s and early 2000’s. It could be, Pfeiffer said, that other factors, such as the mites and fungi which infect hives — even sunspots — are playing a role in CCD.
Neonicotinoids have been found in beehives, but one study found 18 different pesticides in beehives. “Neonicotinoids get blamed because they show up in pollen and nectar,” Pfeiffer said. Some studies have shown neonicotinoids to be toxic, but the question is, was the dose given in those studies a realistic approximation of what bees are exposed to in nature?
Other factors, such as the reduction in forage, are also probably playing a role in CCD. “Neonicotinoids probably do have a role but are probably not the only factor,” Pfeiffer concluded.
“Planting flowering plants is one way to reduce the impact of the pesticides on bees and other pollinators,” Pfeiffer said. “Also, the suggested spray program this year limits the pre-bloom use of more toxic neonicotinoids. The more toxic ones are saved until the second cover spray.”
“The goal of the new spray bulletin,” Pfeiffer said, “is to get the benefits of neonicotinoids with less impact on bees.”
Dr. Greg Peck encouraged attendees at the schools to consider tall spindle or other high-density planting systems. Why? To maximize your productivity.
In Washington state apple growers are averaging a yield of 852 bu/A, in part because of their use of tall spindle and other high-density orchard systems.
“The high-density systems are designed,” Peck said, “to maximize the amount of sunlight we’re capturing by the orchard.”
In traditional orchards, only the outside leaves get sunlight. When you open the trees up, as in the high-density systems, you are able to get the sunlight infiltration further into the tree, thus encouraging a greater rate of flower bud induction throughout the tree.
The tall spindle system keeps trees under 12 feet in height, which can eliminate a lot of the labor cost of traditional orchards, with their taller trees and heavy reliance on ladder use. The tall spindle system also allows for the possibility of mechanized harvesting.
The system is more expensive, because of the trellising system and irrigation you need to install, as well as the time involved in planting and training the trees.
There’s also the cost of trees. Planting on 10 or 12 foot rows, with three or four feet between trees, brings a per acre total to 900-1,500 trees, compared to the 250 trees per acre found in traditional orchards.
“Because so many growers are moving to high-density orchards,” Peck said, “nurseries are running out of stock. One large nursery is sold out through 2017,” he said.
All total, the cost of installing a new tall spindle system would be (at a minimum planting size of five acres), 15 to 20 thousand dollars. That includes five thousand dollars per acre for the trellis, plus seven dollars a tree for a thousand or more trees.
Maintaining tall spindle systems is relatively straightforward. Use a single leader, not topping it until it reaches full height (10 to 12 feet, above the same distance as your row spacing), in year two or three. The feathers need to be tied down on the support wires. Side branches need to get pruned every three to five years, once they get to half the diameter of the trunk. Use a bevel cut to encourage new branches.
You will get fruit in the second or third year, with full production by year five. If you decide to install such an orchard in Virginia, Peck suggests using one of your best sites, with the least risk of frost damage. His logic: if you’re going to make the capital investment in such a system, you want to be maximize your chances of getting a good return.
Tree fruit schools help growers prepare for upcoming season
by Karl H. Kazaks