Fire blight (Erwinia amylovora) in pome fruit crops can spread quickly under the right conditions, and if not managed the disease can ultimately kill trees. If untreated, Fire blight can devastate an orchard, causing severe economic losses.
While the disease attacks many different parts of a pome fruit tree, blossom time is when the trees are most susceptible. 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.
In-season management is key to prevention. Since young, fast-growing tissue is most susceptible to infection, the Ontario Ministry of Agriculture advises growers to look for ways to reduce the vigor of the trees with sound cultural management. This includes reducing vigorous shoot growth by not overpruning or overfertilizing.
Additional recommendations from the Ministry include:
- Monitoring and disease forecasting, using decision-support models
- Conducting frequent scouting after observing the first indication of the disease
- Removing current-season infections as soon as they are noticed
- Maintaining good IPM practices by controlling insects such as aphids, leafhoppers and plant bugs that can spread Fire blight
Control of Fire blight is possible with numerous products, including streptomycin, although resistance concerns has started to appear in some areas. Growers looking for alternatives can use KASUMIN® Bactericide, registered in Canada for control of Fire blight.
The active ingredient in KASUMIN, kasugamycin, has a unique mode of action, making it effective against Fire blight, including streptomycin-resistant strains of bacteria in apples and pears. Kasugamycin has proven to be effective when it is incorporated in a rotation program with streptomycin.
