Back To School?

 

Horticulture Hotline 07/25/22

By Bill Lamson-Scribner

 

 

I have been writing this column since around 1989. Right after Hurricane Hugo, I started this column (with the help of many others from the Post and Courier family) to try to help people out with their landscape situations after “The Storm”.

 

The crazy, hot, dry, windy spring had my hibiscus doing something I have never seen them do in a very long time of growing this plant. They were dropping the buds off of the plant because of the heat. At first, I thought the little devil the thrip was doing damage, but it was not thrips, it was the heat. Although a tropical plant, they don’t like those high ninety days any more than we do.

 

With over 33 years of articles in the archives (over 1700 articles), it is easy to spot trends. I see (in my article’s crystal ball) that during the next two weeks’ army worms will be looking to add a little fiber to their diet in the form of your turf grass.

 

While mowing the grass during the heat of the day, I noticed a few moths in my grass. I have also noticed several moths flying around in my yard in the evening, and I have been told by many of my fellow moth watching friends that they are starting to see them as well. Moths fly around, lay eggs (an adult female can lay over 1000 eggs in groups as small as 50 and as large as several hundred), then the hungry worm emerges and eats your grass. They eat a lot of grass very quickly. The spineless insects do not care that you worked all spring and summer on your lawn. They munch down on it quickly and weeds move in.  The worm then becomes a moth and the cycle begins again.

 

Many people will be taking vacation before school starts or dropping off that loved one to college. I’m going to get something out on my yard (08-00-08 + Acelepryn) in the next few days, so I don’t come home to a munched-on lawn. These worms do a lot of damage fast.

 

07-00-14 + Allectus (if you need a little fertilizer to get you through the summer), Wisdom, 08-00-08 + Acelepryn (long term control) or Sevin G would help prevent the grass munchers from eating the grass you have tried so hard to cultivate over the summer. If you prefer to use organic products, EcoVia is an NOP (National Organics Program) compliant product that works great.

 

While driving around and looking at my own yard, the grass is looking a little “washed out” from the high temperatures, rain and the lack of fertilizer. Most people’s spring fertilizer has been consumed by the plant and turned into clippings. 07-00-14 + Allectus, 08-00-08 Acelepryn or Perk are two good fertilizers with a control product impregnated or a good fertilizer to get you through until it is preemerge time again. If you are working from information derived from a soil test or custom program, stick with those recommendations, and get something out for worms.

 

While you are out there working in the yard, remember the sunscreen (sun cancer seems to be another way our reckless youth catches up with us), sun protection clothing, and water (rotate in a sport’s drink as well). Mosquitoes?

 

The Rain Has Fallen

 

Wasp, biting flies, flies, fleas, fire ants, fruit flies, drain flies, gray leaf spot, grass eating worms (finally saw some moths yesterday laying eggs – worms to follow), chinch bugs and mosquitoes, ahh, summertime in the Lowcountry is here once again!

 

The rains and high tides have the mosquitoes are out in full force. The Buck Full Moon really has people complaining about the super high population of mosquitoes. Mosquitoes are the number one killer in the world of people and a huge vector for disease.

 

A few things that you can do yourself in the battle against mosquitoes is scout around the yard for anything that holds water. Old tires, saucers under potted plants, bird baths, old flower containers or pots stacked in a corner, dog toys, kids’ toys, a container by the grill you use to soak wood chips in, a cooler, an old fountain, an upside down 5-gallon bucket that has a lip that holds water, a trash can lid

with a dent, brick work that needs repointing, a hole in a tree and a dog’s water bowl all make great places for mosquitoes to breed. Empty the water out these areas (refill the dog bowl and the bird bath daily). A tarp covering a boat or wood pile can have many pockets that hold water. Sagging gutters hold water.  A few empty bottles or cans can end up being thousands of mosquitoes! A bottle cap can be a breeding area. Many mosquitoes can breed in just an ounce of water. I was at a seminar and the speaker was encouraging people to limb up Magnolias (every horticulturalist gasped) so you could easily rake up the leaves because the big leaves held water and therefore were a breeding spot for mosquitoes.  

 

Between pop up thunderstorms, people going on vacation, and people just not mowing enough, gray leaf spot has exploded on St. Augustine grass. I am seeing gray leaf spot on Zoysia as well.

 

Gray leaf spot (Pyricularia grisea) goes with St. Augustine like grits go with shrimp! Or like chinch bugs go with St. Augustine! To battle gray leaf spot, you are best employing many cultural practices and using limited control products if necessary.

 

Gray leaf spot looks like someone burned or dripped acid on the leaves of the plant.  There are little oblong spots on the leaf.  Eventually, these spots grow together and the leaf blade dies.  Whole areas of your grass can disappear at once when these leaf blades die.

 

Culturally there are several things to do to minimize your problem with gray leaf spot.  This disease likes high humidity and excessive nitrogen fertilizer.  To help alleviate the high humidity, mow your grass to a level that seems abnormal to St. Augustine.  Try to get it down to 2 ½ - 3 inches depending on the variety of St. Augustine grass.  Also try to mow every 3 – 5 days with a bagger. I don’t usually recommend a bag, and if you don’t have one, just keep it mowed.  This mowing will help get sunlight down to the crown of the plant, drying the leaf blades as quickly as possible.

 

With mowing it is always hard to get someone to modify the frequency of cuts. “The landscaper only comes every 7 or 14 days” or “I mow every Saturday morning”, is what I usually hear. If you don’t want to cut it yourself (saving a trip to the gym and I have been told a cold beer or IPA is extra good after mowing) in between visits by the landscaper, maybe you could hire a neighborhood kid or your kid to just mow the grass. No edging, blowing or string trimming, just a quick mow.

 

Another alternative to you mowing is applying a growth regulator to your turf. These products work great at slowing your turf’s growth rate. Growth regulators are used extensively on golf courses and athletic fields. Growth regulators do a great job of managing your turf’s growth rate on your home lawn as well.

 

Consider trimming trees or shrubs to increase air movement through your yard.

 

This fungus like most fungi likes hot humid weather.  Minimize the amount you water as much as possible.  Wait until your lawn is getting a blue/green color and your foot prints stay in the lawn after you walk across it before you water. Unfortunately, you can not control rainfall as easily. In the Lowcountry, afternoon thunderstorms are a way of life, so keep the grass mowed as low as you can so it will dry out quickly. 

 

Hold off of the nitrogen fertilizer until you can get this disease under control.  If you need some color, you could add a product like Possum’s Minors to give you some green without all the nitrogen. Watch starving your grass because a malnourished yard is more susceptible to disease. Very low rates of an organic fertilizer or cotton burr compost might help it recover.

 

At Possum’s, I know we have had several customers that swear they control this disease by using our wetting agent with biostimulants, cotton burr compost, and / or SeaHume along with the above cultural practices. You will need to water less with the use of these products, and wetting agents help keep the leaves on the grass plant dry. These products are not fungicides, but customers have seen a correlation of using them and having less disease issues.

 

If you have to resort to a control product, make sure the product is labeled for Pyricularia grisea.  There are many leaf spot diseases on labels of control products but only certain products work on gray leaf spot on St. Augustine and Zoysia. We had one customer come in that had been applying a product that controlled Drechslera spp. and Biopolaris spp. leaf spot; however, the product was not labeled for Pyricularia grisea (watch where you shop). 

 

Strobe Pro G, Heritage and Fame are granular systemic products that are absorbed through the roots and will do a good job on gray leaf spot. Preventive applications for chinch bugs and grass eating worms will save you a panic situation in the future.

 

Always read and follow product label.

 

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.