Dear Suquita, Fire Blight can be devastating, especially when there is a lot of young vigorous growth present and or when the weather is warmer than normal during bloom helping to promote the disease. Growing pears slowly with little or no fertilizer is helpful to avoid lots of new growth. You can and should prune out the cankered branches during dormancy. Prune below the cankers several inches. This not a guarantee that the canker will be gone, but you are greatly lessening the potential spread next spring. Sterilize the pruners between cuts. Do not prune any major branches that would encourage new vigorous growth next spring. Growth should slow once your pears return to bearing as the energy will go into the fruit and not new vegetative growth.
If you are going to spray, be sure to follow the label information on frequency, timing and duration when using either a dormant spray treatment or Streptomycin as a anti-bacterial spray treatment Sincerely, Richard Hentschel
