St. Augustine Decline (SAD) is a virus causing a chlorotic mottling orstippling of St. Augustinegrass leaves. St. Augustinegrass and centipedegrassare the only turfgrasses that the virus is known to affect. The virus iswidespread in Texas and has been reported in Louisiana and Arkansas.
Description. In the early stages of infection, St. Augustinegrassleaves show a chlorotic mottling or stippling. As the mottling progresses,leaves develop a chlorotic appearance. Usually 3 or more years after theearly symptoms are observed St. Augustinegrass becomes weakened to the extentthat bermudagrass invades the lawn. Also, grass infected with SAD and growingunder shade or other stress conditions will begin to thin out and be replacedby weeds.
St. Augustinegrass infected with SAD is also slower than healthy grass torecover. In the spring following an unusually cold winter, much of the diseasedSt. Augustinegrass does not recover.
Lawns infected with SAD will respond to fertilization, but the symptomsremain. Early fall and late spring applications of complete fertilizer andsummer applications of iron will help maintain good color of SAD infectedlawns.
Early stages of SAD are often confused with iron chlorosis, but the twocan be readily distinguished. Leaves showing chlorosis caused by iron deficiencyare either uniformly yellow or show characteristic yellow stripes parallelto the mid-vein of the leaf. Iron chlorosis also appears first in the new,or young leaves; whereas SAD produces the mottling in young and older leaves.Iron chlorosis is readily corrected by a foliar application of iron sulfateor iron chelate.
The SAD virus, like all viruses, is a microscopic particle found insidethe cells of St. Augustinegrass. Inside the plant cell, the virus reproducesand spreads to other cells throughout the plant. As more and more cellsbecome infected with the virus, the vigor of the plant is reduced, renderingit more vulnerable to other diseases and environmental stresses.
Control. The SAD virus is mechanically transmitted by mowing equipment,edgers and other tools. Mowing companies that mow several lawns with thesame equipment can transmit the virus from an infected lawn to a healthylawn. Cleaning the mowing equipment with steam or a 10% chlorox solutionwill help prevent the spread of the virus.
However, the best control for the virus is to introduce resistant varietiesof St. Augustinegrass into the lawn. Presently, Floratam, Floralawn, Raleighand Seville are SAD-resistant varieties of St. Augustinegrass. Simply plugthe resistant variety into the existing lawn on 2- or 3-foot centers. Theresistant grass will crowd out the diseased grass over a period of a yearor more. There are no chemical controls for SAD.
FAQs
There is no cure for St. Augustine decline. To help prevent the spread of the virus from infected lawns to healthy lawns, steam clean mowing equipment after mowing. Disinfecting mowing equipment with a 10 percent bleach solution can also help prevent the spread of the virus.
What is the St Augustine decline virus? ›
St. Augustine decline (SAD) is a viral disease of St. Augustine grass in Louisiana and across the Gulf Coast region. The virus that causes this disease, Panicum mosaic virus, also causes a disease of centipede grass called centipede mosaic.
What is wrong with my St. Augustine? ›
The most common diseases observed on St. Augustinegrass are gray leaf spot (Pyricularia grisea), large patch (Rhizoctonia solani), and take-all root rot (Gaeumannomyces graminis var. graminis), while the most common insect pests are chinch bugs and white grubs. Disease and insect damage can often look very similar.
How do you fix chlorosis in St. Augustine grass? ›
Correcting Iron Chlorosis
In turfgrasses, 5 to 20 pounds of elemental sulfur per 1,000 sq. ft. are applied to reduce soil pH and iron chlorosis. Also, sulfuric acid may be added through the irrigation system in dilute concentrations to lower soil pH.
How do I bring St Augustine back to life? ›
The best way to revive St. Augustine grass is to give your lawn 1/2 to 3/4 inches of water once or twice a week, provide your soil with the correct nutrients, and eliminate any pests or diseases that may be killing the grass.
How do you treat St Augustine disease? ›
Treatment
- Use fungicides containing at least two ingredients such as azoxystrobin and thiophanate-methyl.
- Avoid excess watering and ensure proper soil drainage to avoid water retention.
- Reduce the amount of nitrogen fertilizer you apply to your St. Augustine lawn because it holds water.
Take-all root rot is a fungal disease that. causes weak, brown, dead patches in turfgrass. In Texas, the disease severely affects St. Augustinegrass (Fig. 1) and bermudagrass (Fig.
What are the symptoms of St Augustine grass disease? ›
St. Augustine Diagnostics
- St. ...
- Slow green-up in spring is one of first signs of Take All Root Rot in St. ...
- Chinch bugs show up in hot, sunny areas in summer.
- Gray leaf spot results in diamond-shaped lesions on blades and runners.
- Round patches with yellowed or brown grass blades are typical of fall attacks of brown patch.
The natives of Tampa Bay were decimated by European diseases such as measles, smallpox, and influenza, as well as, by warfare and slaving raids. By 1711, there were no organized Native towns in Florida except near St. Augustine, where the Castillo de San Marcos offered some protection from northern incursions.
What happened with St Augustine? ›
Augustine died on August 28, as the Vandals invaded Hippo. Following Augustine's death, his body was laid to rest in Hippo.
It is clear from a 21st century psychiatric perspective that Augustine was suffering from PTSD. D. M. Bourneville's case history amply documents that diagnosis. Charcot did not invent the human suffering that he called hysteria, he just gave it the wrong name.
When to apply fungicide to St. Augustine grass? ›
A good “rule of thumb” to follow on warm-season grasses is to initiate fungicide sprays when nighttime low temperatures reach 70° F. Stop applications when nighttime lows are forecast to be below 70° F for five consecutive days. Typically, applications are made at 14-day intervals.
What thickens St Augustine grass? ›
To achieve a thicker St. Augustine lawn, consider the use of grass plugs. These small, well-rooted portions of sod can work wonders for your lawn.
Does Epsom salt help chlorosis in plants? ›
A deficiency of magnesium will cause a corresponding reduction in chlorophyll production (leading to leaf chlorosis often used as an indicator of magnesium deficiency.) Epsom salts added to adequately-fertilized plants will not increase chlorophyll production for that species.
Should I put iron on St Augustine grass? ›
To prevent yellowing caused by iron chlorosis, apply liquid or granular iron fertilizer throughout the growing season.
How do you encourage St Augustine growth? ›
Fertilizing your St. Augustine grass is a major key to its growth. Fertilizer high in phosphorous will help get the roots established post-installation, but it must have very low or no nitrogen. Later on, you should use a fertilizer with nitrogen to help improve the grass's growth rate.
How do you stop St Augustine from spreading? ›
You can either repeatedly pull it up by hand or you can create a sort of "chemical barrier" by using a non selective herbicide, just as glyphosate, that will kill both the st. augustine and your bermuda. Using this herbicide and pulling by hand will be an on going process to continue to keep the St.
