Alex657913 писал(а): По сортам яблони в пром.садах могу сказать. что абсолютно неустойчив пепин шафранный, среди него очень большие потери, неустойчива антоновка, синап и анис, белый налив, довольные большие потери среди кортланда (ходя и считается среднеустойчивым). вроде устойчив мальт багаевский. По другим сортам надо спрашивать.
"Resistance to fireblight has been incorporated in several good apple varieties. Those recommended for North Dakota are: Hazen,
Red Duchess, Dakota Gold...
Crabapples for North Dakota that show good fireblight resistance include Kerr, Dolgo, Red River, Centennial, Centurion, Jack (or Korean), Siberian, Manchurian, White Candle, Thunderchild, Radiant and Vanguard. The varieties Radiant and Vanguard are susceptible to apple scab. The varieties Spring Snow and Red Splendor show intermediate resistance to fireblight.
Resistant varieties are not immune to fireblight and can be infected in severe fireblight years; however, the level of infection in resistant varieties will be less than in susceptible varieties, which may be destroyed in a severe season. Control measures are more likely to be effective in resistant than in susceptible varieties. There are some reports that the understock used on apples may affect susceptibility. The Malling-Merton and East Malling understocks appear to increase susceptibility over seedling understocks.
Apple varieties that have been reported susceptible to fireblight include: Mantet, Wealthy, Lakeland. Crabapple varieties reported susceptible to fireblight include: Almey, Hopa, Strathmore, Purple Wave, Flame, Snowdrift, Whitney, Royalty and Calocarpa (also called Redbud or Zumi).
It is most important to detect blight in the early stages of development and start control measures immediately. After most of the branches of a tree are infected, there is little hope of saving it. In advanced cases of blighted cotoneaster it is better to remove the plant, including the roots, and to start a new one in its place.
Fireblight cankers serve as avenues for entry of canker-causing or wood-decay fungi. Untreated fireblight cankers, especially holdover cankers on larger branches, may serve as infection sites for fungi of two types: those causing death of bark tissue (= canker fungi) and those attacking the wood of the tree (= wood-decay or wood-rot fungi).
Several different pathogenic fungi are capable of infecting through old fireblight cankers. The most commonly encountered in North Dakota is the black rot fungus Physalospora obtusa. This fungus causes perennial cankers which enlarge each year until the branch is girdled. (A more complete description of black rot is given later in this circular.) Black rot cankers which follow fireblight are frequently mistaken for continued damage by fireblight.
Fireblight cankers on main limbs or trunks may also be infected by wood-rotting fungi. The chance of this infection can be reduced by painting exposed wood with an alcohol-base shellac followed by a commercial tree wound dressing such as a water emulsion of asphalt."
Да и некогда российским грушам болеть - они каждый год восстанавливаются от морозов. 
