Scouting Report: July 16th
Frequent heavy rains and high humidity inundated the region this week. Those that were able to escape the heaviest rains still were not able to escape the high dew points and the problems associated with that.
Radar estimates indicate that upwards of 10 inches of rain fell across parts of northeast Illinois this week. Storms appeared to train across the same areas from Monday through Wednesday morning.
A 10–15 mile drive was the difference between an 8 inch rain event and a 3 inch rain event. As a result, many courses experienced varying degrees of flooding. Flooding was due to direct rainfall and over-run creeks and rivers.
Many golf course superintendents shared their experiences on twitter.
Massive clean up efforts began immediately as waters began to recede. Silt accumulation, bunker washouts, and clearing plant debris were just a few of the issues many were faced with. Let alone the health of the turf while being submerged in water. Communication is critical during these times. There is no miracle treatment for turfgrass submerged under feet of water.
Soggy soils mixed with high winds were not a good recipe for a few trees in the area. In this case, an old American elm tree lifted up the sod as it fell across a fairway.
Unhappy turf and algae accumulation was also a common sight as waters receded. I began to think algae and mold had a distinct ‘fishy’ smell to it. But then realized that smell was actually from fish that ended up in places they shouldn’t be.
Hopefully those most affected have a chance to dry out. Fortunately temperatures cooled off by Friday morning and soil temps shouldn’t have skyrocketed under high heat and sunny conditions.
As mentioned earlier, those that escaped the heaviest of rains, were not able to escape the issues associated with high humidity and high dew points. This led to numerous reports of disease outbreaks and other pest problems.
Weeds
Grassy weeds continue to pop up. This week I have seen a fair amount of crabgrass and goosegrass. I have also seen some of our other lesser known grassy weeds. Barnyardgrass.
This grassy weed has an affinity for moist soils. Newly sodded or seeded areas may have issues with barnyardgrass. Postemergence control of this weed is usually through applications of herbicides. Herbicides that contain the active ingredient Quinclorac has demonstrated effectiveness in university research.
Culturally, maintaining healthy dense turf is a good way to prevent this weed from establishing. This is true for not only barnyardgrass control, but for other grassy weeds as well.
As an example, healthy dense tall fescue is able to resist encroachment from crabgrass.
Insects
Japanese beetles are skeletonizing linden tree leaves right now. Populations of these adult beetles are very high right now.
Japanese beetles are in a hurry to do two things right now. Feeding is priority number 1. However, priority number 2 isn’t too far behind.
Egg laying could be occurring right now in Illinois. The eggs will hatch and give rise to grubs that will feed on turfgrass roots. Grub feeding occurs in the late summer months, fall, and again during springtime. As mentioned in last weeks report, insecticide applications may need to be bumped up a couple of weeks this year.
In the western suburbs of Chicago, sand wasps continue to make mounds in select bunkers. These wasps are docile and did not try to sting me as I approached their homes.
Diseases
Disease activity was rampant this week in Illinois. Free moisture, high humidity, and warm nighttime temperatures are a key environmental ingredient for many pathogens.
Brown patch was observed this week on creeping bentgrass putting greens. This disease becomes increasingly evident when nighttime temperatures approach 70 degrees under humid conditions.
Brown patch is caused by Rhizoctonia solani. This pathogen is a necrotrophic fungi that secretes toxins and enzymes into the plant that kills plant cells. The pathogen then feeds on the decaying plant material.
Culturally, reducing leaf wetness and limiting high rates of quick release fertilizer are a way to reduce brown patch severity.
Another disease that is favored by warm nighttime temperatures and extended periods of leaf wetness is Pythium blight.
Pythium blight was observed in the western suburbs of Chicago this week. A newly sodded area that was maintained under high nitrogen fertilization was attacked by this disease.
This week we also observed diseases that target turfgrasses maintained under low nitrogen fertilization.
Anthracnose is a disease that frequently attacks annual bluegrass in the Midwest. Symptoms of this disease include a yellowing or bronzing of affected areas that can appear sunken. With a hand lens, one can also observe the signs.
Black acervuli can be observed with a hand lens in the affected turf areas. This disease can be a friend or foe. In this case, it was considered a friend as the superintendent was trying to reduce populations of annual bluegrass.
However, this disease is also a foe when you manage large populations of annual bluegrass and can not tolerate substantial turf loss. This disease can also be a foe when it starts attacking creeping bentgrass.
Anthracnose on a biotype of ‘Penncross’ creeping bentgrass was diagnosed this week. The symptoms were similar to those caused by Bipolaris leaf spot or red leaf spot.
In the lab, I was able to observe acervuli protruding the bentgrass sheath and leaf tissue. The acervuli house numerous banana shaped spores called conidia.
A slight increase in nitrogen fertilization and the use of a strong rotational fungicide program is a great way to limit anthracnose severity. This disease can also sneak up when too many fungicides are used that target dollar spot. There are a handful of fungicides that are labelled for dollar spot but not anthracnose.
Fairy ring and mushrooms also took advantage of the recent rainfall.
Type II fairy rings produce a dark green ring of turf. These rings become most evident during fluctuations of rainfall and dry down periods. Occasionally these rings also produce puffball mushrooms that surround the rings.
Saturated soil conditions did give rise to mushrooms in the area.
These mushrooms are harmless and become a non issue after a single mowing pass. Other mushrooms may hang around longer. Especially in non-turf areas where mowing does not occur.
Something else that may need to be mowed off this week are etiolated bentgrass plants.
The cause for etiolation continues to be debated. Some researches have found associations with bacterial organisms while other camps do not form a direct link between the two. My advice is to avoid any drastic measures to ‘cure’ these etiolated tillers. Sometimes these issues have a way of working themselves out on their own.
This week finished extremely wet. Especially for those on the north side of Chicago. However, this week did start off dry for those on the south and southwest side.
Take-all patch continues to rear its ugly head in select areas. Managing stress is critical in combating this disease. Symptoms tend to be exacerbated when soils become dry. Fall and spring fungicide applications may be necessary for optimal control of this disease.
Looking ahead
Oppressive heat and humidity may be on hold until the middle of the week. One thing I began to notice last week was that bentgrasses are starting to get ‘puffy’ on tees and fairways. These areas can become increasingly difficult to mow under hot temps and humid conditions.
Diseases such as anthracnose can become increasingly severe on annual bluegrass. It is critical to scout early for this disease. A good hand lens should be able to detect acervuli in leaf tissue.
