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Healthy Fruit 2001 Vol. 9:15

July 10

Facts de Pomme Francais (French Apple Facts from Jon Clements)

  • In 1999, apple production on 134,000 acres in France was 114 million boxes -- equivalent to the Washington state apple crop.
  • Golden Delicious is number 1 variety produced, but decreasing, followed by Granny Smith (level), Gala (increasing), Red Delicious (level), and Braeburn (increasing).
  • Annually 2.5 percent of acreage is replanted, however, with a goal of 7 percent.
  • French growers are doing great in orchard management, with 95 percent planted to M.9 rootstock and planting tree densities of 1200 trees per acre in 2000.
  • Apple scab is number one disease problem -- even worse than in NE US, believe it or not -- with codling moth and woolly apple aphid major insect problems. The French are currently VERY actively breeding (and prepared to introduce) high quality scab-resistant apples.
  • Fifty percent of orchards are enrolled in Integrated Fruit Production (IFP) which includes: orchard registration; register all orchard management techniques; basic hygiene in packing house; keep high quality throughout.
  • In 1998, 17.2 percent of French apple crop was exported, mostly to other European nations.
  • The French growers are extremely attentive orchardists, and are "inventing their own future" -- for example by actively participating in controlled variety marketing clubs that will insure the success of nurseries, growers, packers and brokers, and retailers.

Apple Maggot

The weather over the past 3 – 4 weeks has been optimal for emergence of apple maggot flies, which pop out of over-wintering puparia in the soil when the soil is warm and damp. Yesterday (July 9), we began our first round of collecting AMF form more than a thousand baited and unbaited sticky red spheres that we are evaluating for AMF control in parts of 18 commercial apple orchards.Results so far for the first 2 orchards show about 3 times more AMF than captured in these same orchards on the same dates last year. In one of the orchards, AMF exceeded threshold level numbers of 2 per unbaited trap (or 5 per baited trap) by at least twofold, suggesting that a spray against AMF ought to be applied within a few days. In the other orchard, captured AMF were at about one-half the threshold level recommended for treatment, suggesting that the grower could wait 7-10 days or so before considering a spray.

AMF thrive during weather where warm sunny days alternate with periodic showers, just the kind of weather we've been having. So this could be a year when we see considerably more AMF injury than last year.

Mites

Red mites are beginning to show up in substantial (over threshold) numbers in some orchards that received only a single prebloom oil spray. At this time of year, the threshold level suggestive of a miticide application is about 70% of sampled leaves having one or more motile mites (which translates into about 5 motile mites per leaf). The best type of leaf to sample for mites at this time is a mid-size leaf on a growing shoot (not a fruit cluster leaf). Pyramite is one of the best available options as a rescue material against mites at this time of year.

Leafhoppers

Orchards invaded by rose leafhoppers should be showing signs of leafhopper nymphs on foliage by now. If you have them in abundance, it's a good time to consider applying Sevin, Provado, or Thiodan. Orchards having predominantly white apple leafhoppers are now seeing the tail end of adult emergence. In a couple of weeks, nymphs will begin to show and that will be a good time to consider action if necessary. So far, potato leafhoppers are less apparent in much of Massachusetts than in the previous couple of years, but keep an eye out for them on non-bearing trees, where they can cause a lot of injury very rapidly.