Using an IPM Program to Manage Turf Pests
With the spring thaw comes melting snow, warming temperatures and greening of the turf. All is right with the world, correct? Not always. As most experienced managers of turf playing fields and golf courses know, pests that have stayed dormant throughout the winter, beneath a blanket of snow in some places, begin to emerge in the spring, ready to cause damage.
Fortunately, an Integrated Pest Management program, built on scientific data and best cultural practices, can provide turf managers with a manual in how to manage the pests, whether they come in the form of insects or disease. There are some pests that are more common problems for golf course managers.
What are the common turf enemies?
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Annual Bluegrass Weevil
The Annual Bluegrass Weevil damages annual bluegrass and creeping bent grass on fairways and greens. Originally detected in 1931 and contained to the greater New York area for decades the insect has in recent years begun to migrate down the coast and toward the Midwest. The bluegrass weevil overwinters in the rough, near tree lines and other protected areas of a golf course. Then, in the spring, it emerges from the rough and moves toward the fairway where the females will lay eggs on the shortly mown turf. When the adults emerge, early in May or later, depending on the region, they begin to damage the turf by chewing notches into the blades of grass. The larvae also can damage the turf by causing small yellow spots on the short turf grass.
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Dollar Spot
Dollar Spot, identifiable by a signature round, brown to straw-colored circle and sunken spots about the size of a silver dollar, thrives on the leaf tissues of turf but doesn’t damage the roots or crowns. Dollar Spot tends to be a more common problem on golf courses and is a rarer problem on sports turf landscapes. Common in early spring through the fall, it thrives during times of high humidity, warm days and cool nights. Infected grass debris can be spread to other areas from people’s shoes, animals, wind, water or mechanical equipment. While it can subside during hot, dry summer months, it’s a disease that golf course managers spend a lot of their budget trying to control: Superintendents in Wisconsin spend 60 to 75% of chemical budgets spraying for dollar spot.
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Brown Patch
A common turf disease caused by a fungus, Brown Patch appears as a grayish-purple “smoke-ring” that can be up to about 20 inches in diameter or it can show up as a blighted, discolored, irregular shaped patch anywhere from a couple inches to two feet in diameter. Bent grass, ryegrass, annual blue grass and tall fescue are particularly susceptible to Brown Patch, which thrives when the daytime temperatures hover between 70 and 90 degrees Fahrenheit. It commonly appears when the nights are cool and the turf stays wet for prolonged periods.
What is Integrated Pest Management
Integrated Pest Management (IPM) is an overarching umbrella that covers the management of these and other diseases and insects that can damage turf. Researchers develop IPM models, which are based on scientific data collected over time. Many of the models are regional in nature because what might be a problem in northern turf won’t be a problem in the south. There are even differences in the modeling for turf in the Southwest and Southeast.
Golf course superintendents and turf managers then use the models to help predict when to apply fungicide or insecticide to control the pests that may damage their turf grass or blight its appearance, get the most benefit from those applications and avoid over-application of those treatments whenever possible.
IPM models to control insects, such as bluegrass weevils, are designed almost exclusively based on degree days because research has proven different stages of insect life based on that information. For example, a 100-degree day might be the time when the bluegrass weevil migrates from the rough to the fairway, so a superintendent knows that is when they want to spray to control that particular pest. Conversely, IPM models for diseases are based almost totally on a combination of such weather variables as temperature, light and moisture. For example, a model for diseases might advise that if temperatures have been hovering within a certain range and the leaves of the turf are staying wet, it’s time to spray.
Integrating Models with Weather Data
Fungicides and insecticides come with instructions for appropriate and regular applications. For example, a fungicide might say to do the first spray in May and then spray every two weeks to keep a disease under control and the course looking beautiful. However, a disease model — when used with current weather data — will provide more site-specific management information: If there’s been no rain or dew since the last spray, then it’s not necessary to spray a fungicide again yet. A superintendent monitoring degree days to know when it’s time to apply an insecticide, might notice that their degree days are at 93 and notching up 5/100 a day. From that data, it’s clear that if they have to spray at the 100-degree-day mark, they won’t hit that rate for another 14 days.
Weather stations such as Spectrum® Technologies WatchDog® line of weather stations enable customers to take data collected by the weather station and plug it into the IPM models through SpecConnect™. The disease and pest models are then brought up with the weather data, providing a golf course manager with precise information about exactly what is happening in their climate so they know when and how to treat.
Spectrum®’s weather stations have sensors that measure wind speed and direction, temperature, dew point, RH, rainfall and solar radiation. The WatchDog® stations are customizable, allowing golf course superintendent to measure parameters essential to their operations when it comes to IPM, such as calculating degree days and evapotranspiration rates.
The size of a golf course demands site-specific management because what is happening on one particularly shady hole might not be occurring in an area of the course that gets a lot of sun. The WatchDogsup>® Retriever and Pups Wireless Network can provide site-specific information through the network of Pups that relay back conditions to the Retriever. Golf course superintendents are then able to gather even more detailed information about areas of their course that may be experiencing insect and disease pressures.
Spectrum® offers an Integrated Pest Management disease and insect package that allows turf managers and golf course managers to determine when conditions are right for disease to begin forming or pests to start moving into the fairways. The disease alerts available through SpecConnect™ or SpecWare™ can help superintendents better manage the timing of pesticide and fungicide application and improve the overall health and appearance of the turf.
SpecConnect™ disease and insect models allow golf course superintendents to use the field-tested and validated algorithms in the models, coupled with weather data, to forecast when problems will start to crop up and to know when it’s time to start applying treatments.
Financial and environmental benefits
The benefits to using an IPM model coupled with site-specific weather data are both economic and environmental. When a golf course manager is spending upwards of 60 percent of their budget to spray for a particular disease, being able to avoid one of those treatments will conserve money. At that same time, as communities become more concerned with the environmental ramifications of chemical treatments, being able to minimize the amount of these treatments is an environmentally responsible way to manage the pests that can threaten the health and appearance of the turf.
To learn more about how a Spectrum® Technologies Integrated Pest Management disease and insect package can help you better manage your golf course, contact the experts at Spectrum® Technologies.
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