Hi I’m Daphne Richards, our question this week comes from
Christine Sills who is having trouble with Zian Zoysia lawn in the front yard. Last year it was healthy and thick like her Zoysia in the back, then last June a yellow spot started
developing and expanding. Now it’s a round circle of bare dirt.
Christine says that the problem area is sloping and doesn’t collect much water so she hesitated to think the problem
was disease oriented, and a lawn maintenance company told her
that she had chinch bugs because she wasn’t watering enough. Despite
the company’s treatments, aeration, and monthly fertilizers things
were just getting worse. So what’s going on here? There are a lot
of details to take into account So we first sent Christine’s photos to
Whizzie Brown my fabulous entomology colleague at the Texas A&M
AgriLife Extension Service to see if she thought the chinch bug
diagnosis was correct. But she says that’s not likely. Insect
damage tends to be more patchy and the damage here is clearly round and
spreading out uniformly. That uniformity of expansion is more
associated with cultural practices. In other words irrigation, fertilization,
and soil compaction problems, or with disease issues. Since Christine
mentions that she had the area aerated and fertilized we concluded that the damage
was likely caused by brown patch a fungal disease that thrives in just
the conditions that were present in Christine’s yard at the time she
first noticed problems. Brown patch is most likely to become a problem during
the late spring or early summer when days are very warm but nights are
still relatively cool. Heavy dew is also most prevalent under
these conditions giving the fungal spores all the elements
that it needs to have explosive growth. So what should be done to rejuvenate the
area and keep the disease from returning and spreading? First I’d suggest aerating again to be certain that there will be good
drainage. Next remove all the affected turf plus a little extra around the perimeter just
to be sure you’ve removed all the potential for any
errant spores to regrow. Then treat preventatively with a
labeled fungicide and resod the area and be sure not to
overwater especially during spring and early
summer when air is much more humid. Our plant this week is Annual Vinca
commonly called Periwinkle. Many people stopped planting this heat
loving annual due to its sensitivity to aerial
Phytophthora a fungal disease that wipes out entire beds the Vinka almost overnight. My colleague have done some fabulous work developing cultivars that are almost
entirely immune to this disease and the Cora series has proven to be a
real Texas superstar. I received a few of these plants several
years ago when we were just starting to trial them
across the state and they continue to look great in my garden. They thrive in the heat and full sun of the
harshest Texas summers and return from seed year after year
even during our recently extremely wet spring with days upon days
of rain and weeks of clouds and high humidity, my Vinca look great! Plant Cora Vinca from transplants in full sun or light shade in late spring or early summer when soil
temperatures have warmed up. Once established Vinca will do just
fine with moderate moisture and only light fertilization. With beautiful bright pink,
light pint, or white flowers these Periwinkles
get about a foot-and-a-half tall and about as wide. There are also trailing
types which look great in containers and hanging baskets.
Our viewer picture this week goes to Mary who took out the front yard lawn to plant
lots of organic vegetables. She and her husband are even growing some for a
neighbor who isn’t able to garden these days. Thanks, Mary! What a wonderful thing to do. We love to hear from you so please visit us at KLRU .org to send us your
questions, projects, and pictures. on