Fire Blight and Prevention

 

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.

2022 So Far

 

Horticulture Hotline 07/04/22

By Bill Lamson-Scribner

 

So far 2022 can be described as dry, windy and hot! If you have an irrigation system, you got the opportunity to see exactly how good your coverage of water over your lawn your irrigation system provides. Many people didn’t realize that when the wind is constantly blowing and we are not getting any rain that grass is going to turn brown or just never come out of dormancy. Wetting agents came to the rescue of many people that tried them.

 

The good news was there was less need for fungicides because the environmental conditions (dry) weren’t favorable for turf fungus. Powdery Mildew does like dry weather and it was loving the environmental conditions on ornamentals (especially Crepe Myrtles).

 

Japanese beetles didn’t miss their annual chance to devour your roses and crepe myrtles. They emerge from the ground, eat, mate, and go back in the ground within a few weeks. Sneaky rascals!

 

What bothers me the most is you have battled through the weather (we are finally getting some rain) and paid huge water bills to have your yard looking nice, and once it starts to look good, fall army worms and then sod webworms attack the grass. Look for areas that appeared to have been mowed low and with a dull blade. You can see that the leaf blades have been chewed. Also thatch type debris will be churned up on the surface. Moths will fly low, during the day but mainly in the evening, dropping eggs across the lawn. Birds and low flying wasps are also predators of army worms. Thanks to cell phones, I took a cool picture of a wasp attacking the head of an army worm. I think my definition of ‘

cool’ has changed over the years.

 

Since army worms are in direct contact with the ground, they are very easy to control. Bug Blaster, Bifen, Sevin, Cyonara and Acephate will all put a hurting on army worms. If you get them while the worms are small, Thuricide (Bt), EcoVia EC and Spinosad are organic products that will also work well. Since the population of worms is so high and hit so fast, keep your eye out for a second hatching. Prostrate growing weeds like spurge, lespedeza and Virginia Buttonweed seem to come in the fastest to the damaged areas.

 

If your yard has thatch, dry spots, or compaction issues, now is a great time to address these issues. At Possum’s we have a granular organic product (BGK 7500) that is full of microorganisms that are thatch eaters. Easy to apply with a fertilizer spreader and very effective. Some of the zoysia grass lawns really benefit from regular use of this product.

 

With the recent rain, gray leaf spot is still alive and doing well and fire ants are mounding up everywhere – be careful where you step! Mosquitoes are out and biting, and the grass is growing like crazy. Scout around your yard for potential breeding sites for mosquitoes. It is amazing how many areas can hold enough water for a mosquito to breed. A magnolia leaf or a bottle cap can hold enough water for a mosquito to breed. Flies, wasps and other biting insects are stinging. Fresh fruits and vegetables have brought in the fruit flies and drain flies.

 

Make it a Great Week!

 

Always read, understand and follow product label. The product label is a Federal Law.