Horticulture Hotline 07/11/22
By Bill Lamson-Scribner
A bacteria called fire blight seems to be nailing Bradford Pears and Loquats this spring. Fire blight attacks plants in the Rosaceae family which include apples, plum, cherries, hawthorn, photinia, pyracantha, roses, spirea, pear and many others. Always plant resistant varieties to ensure you do not get this disease. Remember resistant does not mean immune.
On the Bradford Pear and the Loquat the foliage usually does not fall off the branch and the branch will have a distinct shepherd’s hook curve at the tip. The dead foliage hanging on can sometimes be confused with twig borer damage.
Fire blight often leaves the branches looking burnt or a deep rust color. This is how the disease got its name. The bacteria over winters in cankers, then in the springtime the bacteria oozes out of the cankers and attracts insects and bees that help spread the bacteria. Rain, wind and pruning tools also move the disease from one plant to another or spread the disease on the same plant. Fire blight usually goes into natural openings on new wood and then moves to older wood, killing the branch.
To control fire blight, cut out infected limbs 8-10 inches below the signs of damage. When making cuts on an infected tree, be sure to disinfect your pruning tools with a 10% bleach solution (1 oz. bleach, 9 oz. water). Since fire blight enters new succulent growth, avoid excessive nitrogen fertilization. Avoid overhead irrigation or splashing water as these spreads the bacteria. Consider using a general insecticide in the spring to discourage insects from spreading the disease.
Since fire blight is a bacterium, an antibiotic such as Agrimycin could be used to reduce infection. Kocide, Junction and Mancozeb will also help in the control of fire blight. The easiest product to remember the name of is simply called Fire Blight Spray by VPG. All these products should be used in the early spring when the plant is blooming and applied according to label rates and intervals of applications.
The crazy dry weather we had this spring made are insects, fungi, and irrigation systems do funny things; however, with the recent rains we are getting back to the normal mosquitoes, grey leaf spot and moles. If you do any traveling, I would recommend you put out something for chinch bugs (especially St. Augustine) and armyworms (08-00-08 Acelepryn, 07-00-14 Allectus or others) preventatively. Chinch bugs and worms do a lot of damage very quickly, and can ruin a lawn that you have been working on all summer. If you see moths in your yard especially in the evening or low flying wasps, worms are right around the corner. Moths lay the eggs that develop into the grass munching worms.
With the rains and the way St. Augustine grass is growing some Strobe or T-Methyl would help prevent grey leaf spot.
Always read, understand and follow product label. The product label is a Federal Law.
