I’m in the middle of a battle with a very tiny pest: the Erwinia amylovora bacterium. Fire blight is wreaking havoc on our apple trees. It’s a serious problem in our entire area, and I’ve had several friends who lost trees to this virulent disease.

Fire blight is aptly named, since the affected leaves and branches look like they’re scorched. In the early spring, you can often see areas on the tree that ooze a sap from the cankers where the bacterium overwinter that leaves dark streaks on the branches and trunk of the infected areas. Once the tree starts to blossom, oftentimes the flowers will darken and shrivel, and leaves will often die seemingly overnight.

Protect Against Fire Blight

You can transmit fire blight a couple of ways: you can transmit the bacterium when you prune the tree and dont diligently clean your clippers between each cut, or by bees and other insects during pollination. It’s particularly easy to spread when we you have a humid spring with warm temperatures. When it’s in the area, it’s a hard one to avoid.

The best way to protect your orchard is to choose fire blight resistant varieties. Some of the best are Carroll, Haralson, Lodi, and Wellingtons. This doesn’t ensure they won’t become infected, but they have better chances than other cultivars.

Pruning

If you do see fire blight on your trees, you need to take immediate action. Prune without mercy, regardless of what time of year it is. Cut off the infected branch at least 12 inches past the symptomatic area. Then peel back the end of the branch (which should look like healthy wood) if you see a tan ooze or streaking, prune farther back on the branch. And absolutely thoroughly clean your clippers or saw with a 10% bleach solution or rubbing alcohol in between each cut to prevent from spreading it.

I’ve had some commercial orchardists tell me they prune their fire blight infected trees with a shovel, which means they completely remove them, but for us small growers we dont have thousands of trees at risk or the time/money to regrow them it’s hard to take them out that easily.

Sprays

The only spray that’s effective on fire blight is streptomycin, but its extremely hard to find anymore since people were overusing it. Just like any antibiotic (and we’ve all read stories on the superbugs that have emerged because of casual use of them), it has to be used properly and at the right time. The streptomycin spray is helpful in preventing spread during the bloom time so spraying it at any other time is a waste.

Last year we lost an entire tree and had to severely prune 2 others in an attempt to save them. I took off half of the only mature apple tree we have in an attempt to save it. They havent bloomed out, yet, so Im not sure if I did enough. A neighbor and avid orchardist lost 3 of her 6 trees, a couple of which were fairly resistant to fire blight. She also pruned out the fire blight as soon as she saw it, which indicates how difficult it is to battle.

But I, being a glutton for punishment, purchased a very expensive, unique tree from a local nursery called Triple Play. It was the horticultural equivalent to Prada shoes. Triple Play is a cluster of 3 varieties Fireside, Haralson and Red Regent. Haralson is good on the fire blight front, but I’m not so sure about the other two. Of course, since Fireside is one of the best apples Ive ever eaten, its worth the attempt. So I will be diligent in spraying this spring, will not over fertilize the trees (because nitrogen encourages quick growth that is more susceptible to the disease) and will prune if a leaf looks even slightly sick. Wish me luck!