TO: Lindsey Cayton
FROM: Eric Koperek =
erickoperek@gmail.com
SUBJECT: Diseased Pear Tree
DATE: PM 7:46 Thursday 9 June 2016
TEXT:
(1) Most likely cause of your problem is "fire blight" = "pear blight" = a rapidly spreading bacterial disease of pears, apples, and crab apples. Call your county agricultural extension agent to arrange for lab samples to be taken for confirmation.
(2) Do not fertilize pear
trees. Fertilizer (of any kind) promotes rapid growth which is highly vulnerable to bacterial infection. If your pear tree grows 6 to 8 inches each year it is healthy and is obtaining sufficient nutrients from the soil. Plant clover under your pear tree or spread mulch out to the
drip line. No other fertilizer is necessary or desirable.
(3) Do not use overhead irrigation on pear trees = do not get leaves and blossoms wet. Use drip irrigation hose or similar technology that keeps water
underground.
(4) Do not prune pear trees except to remove "The 3 D's": Dead, Damaged, or Diseased
wood. Dip pruning shears in 5% chlorine bleach solution after every cut to prevent spreading fire blight bacteria.
(5) Practice good orchard sanitation: Remove and destroy = burn pruned or fallen branches and diseased fruit.
(6) Fire blight in pears is VERY DIFFICULT to control without chemicals. Commercial pear orchards most often use anti-biotics (tetracycline sprayed to prevent bacteria from infecting pear flowers), micro-fine sulfur powder, or copper sulfate. These are natural = non synthetic compounds widely used to control bacterial and fungal diseases in agricultural crops. Other control agents include: Soluble silver, dilute iodine solution, and silver iodide solution. Liquid kelp MAY be of some use because of its natural iodine content although no scientific trials have demonstrated its effectiveness in controlling fire blight in pears. Similarly, you might try the ancient Vedic practice of spraying diseased plants with buttermilk solution (1 part buttermilk + 9 parts pure water = 10 total parts by volume). Buttermilk contains lactic acid bacteria which lower the surface pH of flowers and leaves making an unhealthy environment for disease causing bacteria and fungi. Note: Any sprays regardless of content must be reapplied after each rain for the entire blooming period. The control agent must be present BEFORE pear blossoms open to prevent bacterial infection.
(7) Breeding for fire blight resistance in pears is an exercise in futility. There are no varieties with immunity or any useful amount of resistance.
(
Most commercial pear orchards are located in dry = semi-arid or arid climates where rain is infrequent and irrigation essential. Fire blight bacteria spread easily by wind blown rain or mist.
(9) If weather is cold and rainy during pear flowering you are going to have bad problems with fire blight = you might have to spray every day for weeks to control this disease.
ERIC KOPEREK =
erickoperek@gmail.com
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