Summer’s heat and humidity are just around the corner – and so is the
potential for various insect infestations and turf diseases that can wreak
havoc on your golf course’s appearance and playability.
Some of the most common diseases that affect both cool-season and
warm-season turf are dollar spot, brown patch, anthracnose and Pythium
blight or root rot. Red thread and/or pink patch are cool-season turf
diseases often seen in the spring that can carry over into early summer.
Fairy ring, rust and leaf spot are additional concerns. And, as if the
opportunity for turf diseases isn’t enough, insect activity is also at its
peak during the summer months.
“Plant pathologists often refer to the ‘disease triangle,’” says Eric
Miltner, Ph.D., research agronomist for Koch Turf & Ornamental (Koch). “In
other words, three conditions must be met for a disease outbreak to occur: a
susceptible host, a pathogen (organism) and conducive environmental
conditions. The host and pathogen are always present, and the pathogen is
simply waiting for those prime environmental conditions – warmer temps,
moisture, humidity and poor nutritional status, for example – to take hold.
And, as we all know, many of these conditions are characteristic of the
summer season.”
Water – in the form of natural precipitation or irrigation – plays a
significant role when it comes to plant disease. Most summer turf diseases
are caused by fungi which require moist conditions to thrive. Managing
moisture in the plant canopy, thatch and root zone is critical to keep
diseases at bay.
“Balance is important, because turf obviously needs adequate moisture to
stay healthy,” Miltner says. “And, healthy turf is better equipped to
tolerate or recover from diseases or infestation. That said, turf that
receives too much water can become more susceptible to fungal pathogens.”
Insects can take over turf in the summer months simply because of their life
cycles, with reproduction, growth and maturation taking place during warmer
temperatures. Simply keeping a close eye on your turf and watching for the
pesky little creatures is one of the most important preventative measures
you and your staff can take. Look for any insect species that has caused
problems on the course in the past, as those are most likely to return.
“Every superintendent is going to have to deal with pests at some point,”
Miltner says. “That’s why good, sound agronomic practices are necessary
year-round. Maintaining turf and plants in the healthiest possible condition
will help it tolerate pests and recover from injury when it occurs.”
Keeping turf healthy includes maintaining balanced nitrogen (N) conditions.
Some diseases thrive when N is too low; others thrive when N is too high.
Keeping nutrients at an intermediate level will prevent favoring disease
pathogens over the host turf.
“Koch’s slow-release or
controlled-release fertilizers
can meter nutrients into the soil, conserving labor and resources,” Miltner
adds. “Adequate nutrition is also key in tolerating insect infestations.
Healthier turf can tolerate higher threshold insect populations before
damage reaches treatment levels, and healthier turf also recovers more
quickly.
“Find the right balance based on your course, environment and conditions.
Following the recommendations for your region based on turf species is a
good start.