Ask an apple grower what diseases they're most afraid of, and they're likely to mention fire blight. And with good reason. If an outbreak occurs, the disease can be devastating, and it can decimate entire orchards.
Fire blight has been around for a long time. It was first reported in a pear orchard in upstate New York in 1790. Cause by the bacteria Erwinia amylovora, fire blight infests trees via new buds or nicks on leaves and branches, which then develop oozing cankers and infected foliage turns a necrotic red-brown as though burned. If left untended, the bacteria grows beneath the bark moving toward the core of the tree, killing it.
Fire blight overwinters in cankers on branches and mummified fruit. Once the necessary weather conditions appear, the bacteria will move up to new blossoms and stems and also by way of rain, pollinators or pruning.
While the disease attacks many different parts of a pome fruit tree, blossom time is when the trees are most susceptible. The disease is most prevalent in warm, rainy or humid weather early in the season. Infections most commonly occur at bloom and during the three weeks following petal fall. Disease symptoms can continue to advance throughout the spring and summer months on leaves and branches.
Washington State University (WSU) reports that the signs of fire blight include:
- Overwintering cankers that can appear black, grey or violet
- Older cankers that have dry, sunken tissue
- Tips of shoots that wilt rapidly to form a "shepherd’s crook" of burned foliage
- Leaves that appear scorched or burned (hence the name fire blight)
The bark of infected rootstocks may show water-soaking, purplish to black discoloration, cracking or signs of bacterial ooze. Blossom symptoms become apparent a week or two after infection and include signs of discoloration. The full list of WSU's signs and symptoms can be found here.
With the growing season just around the corner, UPL suggests growers establish a game plan for the disease. "It's important for growers to think ahead and be aware of the symptoms so that they can recognize the first signs of fire blight," says David Davies, Marketing Manager, Specialty Crops, UPL. "The addition of KASUMIN® Bactericide, with its unique mode of action, is a boost to apple and pear growers battling fire blight. KASUMIN is an effective tool to help fight this destructive disease, including streptomycin-resistant isolates in apples and pears."
Kasugamycin, the unique active ingredient in KASUMIN, features a high level of preventative activity, making it effective on a wide variety of plant pathogenic bacteria including fire blight. KASUMIN is available as a liquid formulation, and field testing has shown it can be effectively tank-mixed with other fungicides to increase the spectrum of disease control.
Most effective when it is used in rotation, KASUMIN shows no cross-resistance to other bactericides. And along with apples and pears, it can be used as part of a resistance management program for cherries and walnuts. KASUMIN offers effective control of fire blight, cherry blossom blast and streptomycin-resistant bacteria.
Learn more about getting ahead of fire blight with KASUMIN by visiting this link.
