[Guest blog post by Judy]
Hello, my fellow fruit-lovers!
It has been very cool and wet here this past spring and summer. Of course, these are ideal conditions for bacterial diseases to infect our fruit trees, as well as other trees and shrubs. Since bacterial diseases are so common among fruit trees, I thought you home growers might like some background on one of the most prevalent bacterial diseases affecting apple and pear trees – Fire Blight. I am also going to give you some ideas on how to fight this disease!
Fire Blight is a contagious, systemic, bacterial disease. This means that bacteria (erwinia amylovora) attacks the blossoms and then moves up the twigs and branches (through the tree system). The name “Fire Blight” comes from the scorched appearance of the leaves and bark. Affected areas appear black, shrunken and cracked. Blossoms will turn brown, wilt and die about 1-2 weeks after infection occurs.
Fire Blight also exhibits an amber-colored ooze (which is heavy with bacteria) from the bark of the tree. When the temperature begins to climb between 60°-80°F, it brings the bacteria out of dormancy and creates optimal conditions for spreading the disease. Bees, insects, birds, splashing rain, and wind easily spread Fire Blight disease.
Along with apple and pear trees, Fire Blight affects quinces and other members of the Rosaceae family (including most common rose varieties and raspberries).
But, we donʼt want to turn this into a science class! So letʼs move on to how to handle Fire Blight.
Cultural practices. Any excessive amount of new growth on your tree is easily susceptible to Fire Blight infection. To avoid this, we recommend feeding with a low-nitrogen fertilizer. Be sure to also remove any suckers– as young, tender growth, they will also be vunerable to infection.
Chemical. A good Fire Blight Spray can control infections and should be applied every 7-10 days (from bloom time through the spring storm period). Removing the blighted wood from infected shrubs and trees can help save them. Prune off all infected branches at least 10-12 inches behind the blighted area. Burn the affected branches, if possible.
Clean up. Be sure to do a complete clean-up around your trees when fall rolls around. Collect all pruning debris, any mummied fruit, and leaves. Move them away from the trees and burn them. This will prevent the bacteria from over-wintering in the debris.
**Because Fire Blight is highly contagious, take care to disinfect tools. Sterilize the tools in a household bleach solution (ten parts water to one part bleach). Dip clippers between cuts. Be sure to wipe clippers dry to prevent corrosion. Alternatively, you can use alcohol wipes to clean your clippers between cuts, both protecting your trees and your tools.
There’s not one single practice that will insure complete control of Fire Blight. When we’re dealing with Fire Blight here at Stark Bro’s, we prune out the blighted areas immediately and do a thorough clean-up to prevent re-infection and minimize spreading. Your best defense is a combination of cultural, chemical and clean-up control methods.
I hope this information gives you a good understanding of Fire Blight and helps to make your fall, winter and spring productive and disease-free!
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