Creature Feature

A warmer than normal winter in many parts of the U.S. has been welcomed by most people, especially those who usually get socked with sub-zero temperatures and piles of snow. Most golf courses have embraced it heartily, hearing the cash registers ringing more often and much earlier than normal. But from a turfgrass health perspective, the mild winter has caused a bit of worry to superintendents who fear larger pest populations and earlier activity.

Depending on whom you talk to, a mild winter leading to more insects can be called one of two things: a myth or a scientific fact. Some describe it as Doomsday, while others plead with people to not ring the panic bell but be mildly concerned with it.

According to Rick Brandenburg, professor of entomology at North Carolina State University, it’s far from an old wives’ tale. The one thing he cautions against, however, is making a broad, sweeping statement about the phenomenon.

“One size doesn’t fit all. A mild winter in one part of the country with one particular insect may have one effect, whereas a mild winter in another part of the country with a different insect may have a completely different impact,” says Brandenburg. “The one thing we cannot do is to just make this generalized statement of, ‘Oh, this is what’s going to happen because we had a mild winter,’ because that would be very inaccurate.”

The reason most people think that a mild winter will lead to more pest problems, says Brandenburg, is because a hard winter kills many of them off. But that, he says, is a bit of a misstatement as well. Again, one has to take into account the region they’re in. Brandenburg compared North Carolina to New York.

“If we had Japanese beetle grubs in the soil in North Carolina, those would survive the winter,” he says. “But if we had a cold winter, then some of them would probably be killed. But look at these same grubs in the soil in New York. I assure you our worst winter wouldn’t be anywhere near the worst by New York standards.”

Brandenburg also used the mole cricket to illustrate why people err when they make generalized statements about mild winters and insects. He called them a tropical insect, and thus when they’re subjected to a warm up of 5 degrees in winter in North Carolina, they’ll still think it’s really cold.

“Even though it was warm, we saw no surface activity from mole crickets in winter because it still was too cold for them to get active, so I really don’t think the mild winter will affect the abundance of insects in much of anyway,” says Brandenburg.

He also mentioned that a lot of turfgrass pests have a pretty wide range of temperatures to which they’re resilient.

North Carolina, Brandenburg says, had a somewhat milder winter than normal this year, with January temperatures in the 60s as opposed to the 50s. But that difference, he says, isn’t enough to push insects’ activity up weeks upon weeks in advance of when they would normally appear.

“The January and February temperatures, even during a warm winter, are still typically below the threshold for which insects would develop and show up early,” says Brandenburg.

An exception, he says, is in the Northeast concerning the annual bluegrass weevil. He says superintendents in that region are already catching them in traps, but it’s an insect that’s well adapted to cold temperatures and will come out very early if given a warming period.
 

Even though Brandenburg believes the quantity of insects won’t go up, he does think as a general rule that they’ll probably show up sooner, up to two to three weeks sooner this year. The March temperatures, he says, will be a big predictor of that.

“In my experience, January and February don’t have much of an impact on when insects show up,” he says. “March is when we really can get warm temperatures that affect insects. In a lot of areas in the East, it will be in the 70s and, in some places, the 80s, whereas the average temperature might normally be 55. Insects take note of that and start developing and moving forward.”

Like Brandenburg, Richard Rees, product development manager for Bayer Environmental Science, doesn’t expect to see vast changes in the insect population in 2012. But next year could be a different story.

“The net potential for early insect activity in 2012 is high, but increased populations would likely not be seen till 2013 when things begin to wake up in spring,” says Rees. “For species that have multiple generations per year, the early start could mean that the normal path of generation growth in late summer and fall will be completed, which could lead to carryover populations in 2013, leading to substantially higher populations than normal.”

Brandenburg’s bottom-line advice to superintendents is to look at the key pests in their areas, what the weather was like and what that weather means to those key pests. He also encourages superintendents to analyze degree-days and compare them to last year and the 30-year average.

“If it says you’re three weeks ahead of schedule in degree-days, then you need to go out and scout three weeks ahead of normal, which helps prevent you from getting caught off guard,” he says. “A winter this mild really gets the guys on the firing line thinking about insect development and how to monitor it, so it could be a good educational moment for them.”

Of course, all bets are off if another freeze comes through, says Rees.

“If some of the early insects have emerged, they’ll be taken out before the first generation egg-laying hatch, and that could mean populations would start to decline,” he says. “But from all accounts, it appears the warm-up we’re experiencing, particularly in the Southeast, is here to stay, and there is no indication that there will be any deep changes.”
 

Jason Stahl is a Cleveland-based freelance writer and frequent GCI contributor.

Regional Bug Breakdown

GCI checks in with the USGA’s regional directors on the effect the mild winter is having on insects.

Northwest Region
It’s business as usual, says Director Larry Gilhuly, with his region having gotten its normal mild winter.

“I don’t expect any major insect population issues,” says Gilhuly. “And we don’t have a lot of activity where guys go out in advance to spray because we just don’t have those problems.”

Gilhuly used one of his region’s pests, the European crane fly, as an example of one you don’t necessarily treat for in advance.

“It’s not that you spray that much unless you see the activity, and it doesn’t always happen in the same place all the time.”

Northeast Region
The Northeast Region is seeing earlier activity of annual bluegrass weevils, which is the No. 1 pest in that region, says USGA Turf Advisor Adam Miller.

“Because of a lack of a true winter and a warmer spring, they’re moving a little more than normal,” says Miller. “That kind of has a lot of people wondering if they’re going to be more problematic than usual -- and they’re usually challenging enough.”

Miller is advising superintendents to mix application timing. Also, to monitor their activity with pitfall traps and Lemon Joy soap flushes to get the best gauge on activity. Superintendents also need to rotate insecticide applications so as to avoid creating potential resistance issues.

Miller says his region is also seeing increased populations of crane flies, particularly in parts of New England and New York, which can be traced back to a wet fall that increased the survivability of the eggs that were laid. But it’s only a problem for a small percentage of the Northeast.

Miller says he doesn’t anticipate problems with white grubs because he says their mortality isn’t dependent on winter since they simply move deeper in the soil as it gets colder.

North-Central Region
Director Robert Brame says he hasn’t seen real concern from superintendents on insects gone wild.

“Right now, guys are more worried about Poa annua seedheads,” says Brame. “That’s getting more attention than insects. But certainly guys are watching all of the above.”

Brame admits grubs could be an issue since their survival is based on soil temperature, but he says most superintendents in his region haven’t had an issue with them over the last several years.

“They’ll follow their standard protocol for treatment. It’s just a matter of timing,” he says. “And obviously, they’ll keep a close eye on things and do scouting. That’s a key component of any pest management program.”

Florida Region
Director John Foy says superintendents in his region started seeing mole crickets in mid-March, which he says are always his region’s main concern. The adult activity, he says, appears to be a little heavier than normal so far, but he can’t say whether populations will be higher.

“We’re not really advising superintendents to do anything different other than their normal program,” says Foy. “These are overwintering adults, so they’re kind of difficult to kill. Superintendents are starting to do spot treatments with a contact-type insecticide, so it’s kind of a standard mode of operation.”

As far as grubs are concerned, several species are becoming more of a concern in Florida, and Foy expects activity to begin even earlier.

Mid-Continent Region
Due to the drought, Director Charles “Bud” White is expecting a little less insect activity in early summer. Fall armyworm and nematodes were really bad last year, he says, and with the conditions the region will experience, he expects them to be a problem once again.

“There may not be tons, but with the conditions the way they are, what is there will be active earlier,” says White. “Some of them may get another life cycle the next year, but that doesn’t mean they’ll start out to be a lot more necessarily.”

Grubs could come out sooner, White says, due to warmer soil temperatures from 70-degree days in early March.

White’s advice to superintendents is to monitor life cycles and make earlier applications for grubs this year.

Mid-Atlantic Region
Director Stanley J. Zontek says his region’s main concern is the annual bluegrass weevil, which being out earlier makes the timing of insecticide applications more challenging.

“Some females can overwinter with sperm from the fall, so they can actually start laying eggs pretty quickly,” says Zontek.

With 70-degree temperatures in March, Zontek predicts that even if it gets cold again, it would have to be cold for a long time to have an effect on turf pests. “And what are the odds of that?” he says.

Zontek says an entomologist would probably say the insects showing up early are immature adults and haven’t reached the mating or egg-laying stage yet, therefore you can delay spraying. But the superintendents he has talked to have a more practical view on controlling them.

“They say, ‘If I see them, I’m going to kill them. If that means I have to come back with another treatment, than you know what? We made so much money over the winter that we can pay for it, and I would rather try to kill the insect than worry about saving some money.’ And it’s hard to argue with them because they’re responsible for the golf course.”

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