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Billbugs are another major turf pest. Their larvae look very similar to white grubs but are legless, with cream-colored bodies and dark brown heads. They damage both warm- and cool-season grasses by feeding on or inside the stems, crowns, roots, stolons and rhizomes.<\/p>\n
Other bugs attack turf too. \u201cSome of the caterpillars, like sod webworms, their mature larvae will start feeding again in the spring and cause damage,\u201d says Doug Richmond, PhD, associate professor of turfgrass entomology and applied ecology at Purdue University, West Lafayette, Indiana. \u201cBrown cutworms continue feeding under the cover of snow and surprise people in the spring when all of a sudden the turf doesn\u2019t green up.\u201d<\/p>\n
The signs<\/h2>\n
A lawn shows signs that something is wrong: thinning turf, dead areas, brown spots. But these could mean a lot of things besides bugs chewing on the roots. \u201cThe first thing I look for is turf going off-color like it\u2019s going through drought, maybe starting to turn yellow,\u201d says Robert Avenius, north central region technical manager for TruGreen, Memphis, Tennessee. To make sure grubs are the cause, he does the \u201ctug test.\u201d Grab a hunk of grass and give it a firm but light yank. If a section starts to pull up easily like untacked carpet, you know the root system has been chewed away by grubs. You will probably be able to see the culprits lying there just below the surface.<\/p>\n
A lawn full of dug-up spots is another clue. \u201cThose are telltale signs of animals digging for grubs: raccoons, skunks, armadillos, depending on where you are in the country,\u201d says Richmond.<\/p>\n
\u201cYou\u2019ll see almost comical little nose prints on the ground from skunks sniffing for grubs,\u201d says Nicole Hendrickson, a sales representative at Advanced Turf Solutions, Fishers, Indiana, and vice president of the Midwest Regional Turf Foundation. \u201cBy the time that happens, you\u2019ve got a bad infestation issue.\u201d<\/p>\n
The next step is finding out just what pests the turf is infested with. \u201cThere are a lot of look-alikes for these pests,\u201d says Ricardo A. Ramirez, PhD, associate professor and entomologist, department of biology, Utah State University in Logan. He offers this example. \u201cAt a golf course where I was trapping beetles, the superintendent came over and said, \u2018We\u2019ve been getting a lot of Japanese beetles here.\u2019 This surprised me, because there are very few in this part of Utah. He pulled a very shiny green beetle out of the trap to show me \u2014 but it was a predatory ground beetle (a beneficial insect that eats other insects and their larvae). He was confused because they also have shiny iridescent green bodies.\u201d<\/p>\n
To treat or not to treat<\/h2>\n
A client might notice a grub and call you to come spray. That doesn\u2019t mean you should, however. \u201cJust because there\u2019s one grub in the lawn doesn\u2019t mean you have to do something about it,\u201d says Ramirez. \u201cIt\u2019s only when you have a large population and the lawn is really starting to look terrible that you need to take action.\u201d<\/p>\n
Preventive spraying for common pests could actually cause more problems than solve them. \u201cIf you know that a property has a history with a certain pest, then a prophylactic spraying could be done,\u201d says Hendrickson.<\/p>\n But don\u2019t spray before you even know there\u2019s a problem. \u201cThat\u2019s a good way to encourage pesticide resistance,\u201d says Rodriguez.<\/p>\n Turf can tolerate the presence of grubs up to a certain threshold number, and each species is different. You don\u2019t need to treat until that threshold has been reached, says Richmond. If a lawn or field is green and vigorous, it can tolerate a much higher population. \u201cYou could have many more grubs in the ground before a problem becomes evident,\u201d says Richmond. \u201cBut if the turf is poorly maintained, or the soil is compacted, that lowers the tolerable threshold.\u201d<\/p>\n \u201cSay you do a tug test, and it reveals five Japanese beetle grubs in about a 1-foot square,\u201d continues Richmond. \u201cNot a serious concern; I\u2019ve seen as many as 20 Japanese beetle grubs per square foot where you would have never known anything was there. But in some parts of the country, they have European chafer, another white grub species. Once you get to the five grubs per square foot level with that insect, you\u2019re less likely to be able to mask the damage just with proper management practices.\u201d<\/p>\n A \u201cfloat test\u201d will tell you just how many grubs you have per square foot. Mix 2 to 4 tablespoons of liquid dish soap in 1 gallon of water. Mark off 1 square yard of lawn and sprinkle the solution evenly over the suspect area. Wait 10 minutes, then count the grubs that have come up.<\/p>\n After you\u2019ve determined that treatment is warranted, when should you do it? This will vary a bit depending on where you are. You don\u2019t want to do it too early or too late. Timing this can be tricky for landscapers with hundreds of lawns to treat.<\/p>\n Many do it right around July 4. It should be done when the larvae are just starting to hatch out, whenever that is in your region, because they\u2019re easier to kill at that stage. \u201cWhen the larvae are small, you can control them very nicely,\u201d says Avenius. \u201cWhen they get bigger, to the size of a shrimp, they are a lot tougher to control. You\u2019ll need a different insecticide and more of it.\u201d<\/p>\n If the grub problem goes unnoticed until later in the year, even through August, it\u2019s still possible to get it under control. \u201cIt will take longer, but you can still treat,\u201d says Hendrickson. \u201cThere will be a mixed population at that point, some first instar grubs along with some third instars.\u201d<\/p>\n Following the principles of integrated pest management can help keep a client\u2019s turf from getting infested in the first place, says Ben Dasch, maintenance division director at Keane Landscaping, Wylie, Texas. The foundation of IPM is employing sound cultural practices that promote healthy, vigorous turf capable of tolerating or quickly recovering from insect damage, and every landscaper already knows what these are: proper fertilization, proper irrigation, removing excess thatch, aerating and cutting grass to the right height.<\/p>\n For example, a good cultural practice like cycle-and-soak watering can prevent Japanese beetle females from laying their eggs, which need water to hatch. But a soggy lawn is practically an engraved invitation.<\/p>\n IPM means dealing with pests as conservatively as possible, not routinely spraying before you even know if a problem exists. You only reach for the pesticides when there\u2019s no other option. \u201cThe goal of IPM is not to eliminate insects, but to keep insect pests below damaging levels,\u201d says Richmond.<\/p>\n Choosing the right variety of grass is also part of it. \u201cThe likelihood of or severity of insect damage can be reduced by picking turfgrass species that are well-adapted for that specific site,\u201d says Richmond.<\/p>\n Some grass types, the endophyte-enhanced varieties, harbor a secret anti-bug weapon. An endophyte is a microscopic fungi found in many types of perennial rye, tall fescue and creeping red fescue. \u201cThe fungus produces a toxin that makes it unattractive to certain above-ground pests, especially billbugs, as a food source,\u201d says Ramirez.<\/p>\n Dasch focuses on building up the strength of any lawn he inherits the care of, because he thinks it\u2019s the best, least toxic and cheapest form of pest control. That is the essence of IPM. \u201cAnd that\u2019s the beauty of having a nice, healthy lawn,\u201d he says. \u201cIt\u2019ll defend itself just as a healthy human immune system fights off the germs it encounters on a daily basis. A lawn is going to function the same way, if it\u2019s got nutrient-rich soil and its grass base is good and healthy.\u201d<\/p>\n Your local university extension is a good place to get help with pest identification, treatment options and advice on best management practices. They\u2019ll have the most up-to-date information about the pests found in your region.<\/p>\n We\u2019ll never kill every last grub on the planet (nor would we want to). But with the right practices, we can keep their numbers way down and give our clients\u2019 lawns, fields, courses and campuses a fighting chance.<\/p>\n Keep common spring pests from feasting on clients\u2019 lawns.<\/p>\n","protected":false},"author":28,"featured_media":5008,"parent":0,"template":"","main-categories":[28],"class_list":["post-4119","features","type-features","status-publish","has-post-thumbnail","hentry","main-categories-landscape"],"yoast_head":"\n![\"\"](\"https:\/\/innovativepixel.com\/IGIN\/wp-content\/uploads\/2021\/06\/grassroots-campaign-3.jpg\")
When to treat<\/h2>\n
Keeping the grubs away<\/h2>\n
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Where to get help<\/h2>\n
This article originally appeared in Irrigation & Green Industry magazine.<\/em><\/h6>\n
Mary Williams-Villano<\/strong><\/a> is a contributing editor to Irrigation & Green Industry and can be reached at pouncerspy@gmail.com<\/a>.<\/em><\/h6>\n","protected":false},"excerpt":{"rendered":"