If you are not sure what the thatch situation is on a site you manage, go take a look. Take a trowel, pocket knife, or soil probe, and poke around. If it’s starting to build up in your cool-season turf, take action now. You don’t want a thatch problem to bite you in summer 2018.
Early last week we saw a couple last gasps of the summer diseases, with some Pythium on a tall fescue lawn:
It was greasy, it was mushy, and after “a night in the box” there was classic Pythium mycelium. Foliar Pythium is rare on tall fescue lawns, usually coming in during very wet weather on sites that have received a little too much water and perhaps a little too much N. When this one came in, it was after one last blast of some heat, but with cool, cool temps on the horizon. Now that we are coming into this nice, consistent cool weather it’s really too late to consider fungicides, and instead we can concentrate on fall renovations AND tweaking cultural practices to help reduce disease risk next year. There was also a last hiccup of brown patch from a golf course fairway. Same story – with lows in the low 60s and even 50s, those diseases should stay quiet and hopefully we won’t see them until 2018.
Next door in Missouri, Dr. Miller is reporting some continued sightings of Pythium root rot (which is different from foliar Pythium) and basal anthracnose. I would agree we are not out of the woods yet. You can see his photos HERE.
We humans are enjoying the cool weather, and our cool-season grasses are too. However we are coming up on the time when our warm-season grasses start to shut down, and the season when the large patch pathogen likes to infect our zoysia. Sometimes we see symptoms in fall if conditions are very cool and wet. I have not seen any around here yet, but in Missouri some is firing. Our main time of seeing the symptoms is spring.
In Kansas, applications in September have been quite effective in reducing symptoms through most or all of the following spring. With this early cool weather, leaning towards earlier rather than later in the month may be wise. Next door in Missouri they’ve seen good results with EARLY spring applications as well – read about it HERE in Dr. Miller’s excellent post about application timing. In Kansas, when we’ve tried mid/late spring applications when symptoms are already pretty apparent, they don’t work well, if at all. For details on the newest products you can check the large patch section here (click to page 18)
We recently received a sample with anthracnose crown rot. Anthracnose can be tricky to diagnose from a distance or a drive-by. The symptoms can look like other diseases or stresses such as physiological root decline. Another tricky thing is that those same stresses can make the turf more prone to anthracnose. Yikes! It’s worth investing in a high-quality hand-lens, and with a good hand lens and a steady-hand you can often see the anthracnose structures lurking down at the base of plants. Sending to the lab as a follow-up is another good step, since we can look for other pathogens that might be lurking in the roots.
The photo below is through a dissecting microscope, but those same dark spines can often be seen with a hand lens. Look for structures on green tissue, not brown/dry tissue. Anthracnose is pretty good at colonizing stuff that is already dead, as an opportunist. When we see it on juicy green tissue that is when the disease is active.
For more on anthracnose, including several photos you can check this page:
Many of the practices to reduce anthracnose also promote overall turf health. That is, when you implement agronomic practices to promote good rooting you also reduce the risk of anthracnose and other problems. You may not be able to do ALL of the beneficial agronomic practices you would like, due to budgetary limits or lack of equipment or golfers’/greens committee opinions, but the more you can fit in, the better.
On this blog we are usually talking about plant health, but here’s a quick switch to human health. We want all of our Kansas green industry folks to stay healthy and safe in the summer heat.
You already know this, but sometimes it is worth reminding ourselves that heat stress and dehydration can be very serious. A friend-of-a-friend of mine got very dehydrated once on a camping adventure, and she was very sick for several days (dizzy, vomiting).
Take extra care of new crew members who are not used to the heat. For one thing, those folks are less used to it. Second, a new crew member may feel the need to just buck up and take it and be afraid to speak up that they need some shade or a water break. So keep an eye on everyone, but especially those that may be more vulnerable.
“Bagworms are primarily a pest of conifers but have expanded their host range to include a number of broadleaf plants, including: rose, honeylocust, and flowering plum.” For more information, head on over the the Entomology Blog for bagworm info from Dr. Raymond Cloyd
Looks like we’ve got a short-term period of cooler temperatures over the next several days. Midsummer heat relief is good for us, and it’s also a great time to do some of the cultural practices we often avoid during midsummer heat.
Creeping bentgrass and annual bluegrass don’t like the heat, and really don’t appreciate it when we implement certain cultural practices during hot weather. On greens that have shallow roots and experience indirect heat stress, any kind of stress brought about with cultural practices can sometimes be the “straw that breaks the camel’s back.” Consider implementing some of the following during short stretches of cool weather:
1) Solid tine aerification. Opening up the surface of the green can help get oxygen to roots and prevent a “sealing off” of the surface that can arise when organic matter accumulates.
2) Verticutting. Using vertical knives to cut leaves and stolons is certainly a stress to the plant, and now is a good time to do it if your greens are grainy (a la Johnny Miller!), or are accumulating more organic matter at the surface than desired.
3) Sand topdressing. Topdressing during midsummer can be stressful to the plant especially if it the sand is dragged into the surface.
4) Product applications. Some products can potentially cause more injury to creeping bentgrass and annual bluegrass when applied during hot weather, including liquid fertilizers, plant growth regulators, wetting agents, and even some fungicides. Labels on some products specify temperatures in which they should be applied. Use the break in the temperatures to apply products that may be needed.
5) Mowing and rolling. If you haven’t done it yet, raise the mowing height if you can, and roll a few days each week instead of mowing. Having more leaf area is always a good thing for the plant.