Top Story, April 15, 2014
Blueberry growers urged to use early, in-season treatment
By BILL PERSSON
HAMMONTON — Just as the cold weather was finally starting to show promise of breaking, the latest of the blueberry growers’ twilight meetings took place on March 20, at Columbia Fruit Farms in Hammonton.
At least 100 people attended the meeting, most of which was focused on disease and pest issues affecting blueberries.
Gary Pavlis, the cooperative Extension Agent from Atlantic County, who coordinated the program, spoke first.
A particular point he made concerned nutrient uptake at different pH levels.
Concerning nitrogen, Pavlis — a specialist on small fruit — stressed that blueberry plant nitrogen uptake at a pH level of 4.5 would be good. At a pH level of 3.5 the plant “will not pick it up.”
Dean Polk, IPM agent for fruit, at Rutgers Fruit and Ornamental Research Extension Center, in Cream Ridge, talked about insect pests affecting blueberries. “What I am going to do is spin-off what I talked about at the (recent blueberry) open house and give a little more detail on approaches to spotted-wing programs.
“What we want to do is create a situation where our main, season-long pests, or most of the season, meaning a close interval after the bees come out, are going to be (reduced) to blueberry maggots and spotted-wing drosophila — so we don’t have to contend with (several other insect pests affecting blueberries).”
Polk discussed condensing early-period spraying (before bloom and just after bloom) as a method to control some insect pests early in the season, rather than over a more extended period.
Polk said he considers this possible now because some of the newer treatments available work much earlier in an insect’s life-cycle, unlike some of the older-style products.
“So if you put material down that has a long residual (length of time over which a treatment remains effective), and the eggs hatch into it, those larvae will die,” he said. “So what I am encouraging you to do is as soon as you find the first (evidence in insect traps), is that instead of waiting, is to put a material on that has a long residual (examples given had a residual period of two-to-three weeks), and that will last through the emergence period and take care of the control a little bit earlier, and probably a little bit better, so your chances of having to (spray for a particular pest) later are going to be decreased.”
Cesar Rodriguez-Saona, Specialist in Blueberry and Cranberry Entomology at the Marucci Center, presented a discussion on plum curculio.
A weevil, plum curculio’s range covers the entire eastern half of the United States and extends into Canada.
Rodriguez-Saona said that although plum curculio can be a problem with other crops, it is especially a problem with blueberries because of the range of different blueberry varieties which bloom over an extended period of time, and because of the trend toward planting more early varieties.
In 2013, bud break was on March 27.
This year, bud break was estimated to occur on April 12, with bloom occurring on April 26, and harvest around June 17 for early varieties. These dates are important to note for planning spray applications.
Several speakers mentioned the importance of avoiding spraying during bloom periods because of the harm that could be done to bees visiting the blooms. Spraying prior to bloom and after bloom periods was indicated.
Mary-Anne Thompson, whose Paradise Hill Farm in Tabernacle, is predominately planted with heirloom cranberry varieties, has been gradually increasing her blueberry acreage.
Currently, her blueberry fields are planted mostly in “Blue Crop,” with a mid-season maturation, and “Elizabeth,” which matures just after Blue Crop.
She also has other varieties under trial.
Thompson thought that the meeting program was “very good” because of the emphasis on blueberry disease and insect pest information — which was provided early enough in the year to be able to utilize the information for the current growing season.
There were several pieces of equipment on display at the meeting, including the Rinieri brand, carried by Rodio Tractor Sales of Hammonton.
The next blueberry grower’s twilight meeting is planned for April 24, at Variety Farms in Hammonton.
The North American Blueberry Research and Extension Workers Conference is scheduled for June 22-26, in Atlantic City.
This is a scientific program.
Some of the topics included are: Breeding, genetics, culture, genomics, pests, and organic blueberry management.
There are also tours to several southern New Jersey locations relevant to blueberry production.
Further details can be found at group-res.com/NABREW/default.aspx.
For more information about the above events and others, and to view research publications and links to other blueberry websites, see the Marucci Center for Blueberry and Cranberry Research website: www.pemaruccicenter.rutgers.edu.
There are also many sites online showing nutrient uptake at a given pH level: Type “graph of pH level affecting nutrient uptake” into a search engine.