McGraw Lab -Turfgrass Entomology at PSU

Wow- what happened to the summer!  It has been a crazy ride since the last blog post.  I didn’t mean to go 3 months in between blog entries!  (then again, not sure if people read this!)

To play catch up, here is a run-down of some of the projects we have been working on in the McGraw Lab and some notable observations from the summer:

Effects of Cultural Practices on Annual Bluegrass Weevil :

My Masters student, Ben Czyzewski, had a busy summer collecting lots of data on the effects of mowing heights and N fertility on the ability and preference of ABW to oviposit into putting green turf.  Studies have not been conducted on putting greens before, given that this type of work requires destructive sampling.  However, these areas receive the greatest amount of chemical inputs.  Ben’s work will help us determine probability of the insect to survive low mowing heights, the preference for different fertility levels, and how ABW develops in each.  We hope to use this information to develop Best Management Practices for ABW.  Look for Ben to share his finding on the turf talk circuit this fall and winter.

Can wetting agents improve persistence of entomopathogenic (insect parasitic) nematodes?

EPNs can be extremely effective alternatives to chemical insecticides for numerous turfgrass pests.  However, their ability to persist in densities capable of reliably reducing pests like ABW, can be limited in turf settings due to the lower soil moisture needed to maintain optimal playing conditions.  We have been experimenting two species of EPNs (Heterorhabditis bacteriophora and Steinernema carpocapsae), and two turf/soil conditions (short cut bentgrass on sand rootzones, rough-height turf on soil) to examine if wetting agents can slow the rapid decay of EPNs after release and improve the uniformity of EPNs in soils over time.

Baculoviruses of Caterpillar Pests

We have been examining the effects of naturally-occurring baculoviruses (BV) on our major caterpillar pests in as part of a collaboration with Auburn University (Dr. David Held) and Univ. of Wisconsin (Dr. Chris Williamson).  Baculoviruses commonly infect invertebrates (especially caterpillars), and are incapable of infecting mammals.  Therefore, they have potential as a biopesticide of some of our foliage feeding pests. Our lab examined the effects of BV applications on Fall Armyworm (our collaborators are examining the effects on tropical sodwebworm and black cutworms).  We have examined the impact that spraying BV occlusion bodies have on caterpillar mortality and development.  Results generated from these studies will aid in determining the feasibility of long-term control of some of turf caterpillars.

Carl-the-ABW Sniffing Dog 

Our most unusual and yet rewarding experiment of the year has to go to the work we have been doing with Scentworks: using canines to detect the presence of ABW in turf.  We have received a lot of inquiries about how this research is going.  Carl -is a 4 year old beagle that has been trained by Bun Montgomery (Scentworks) and Jason Webeck (Good Night, Sleep Tight). Canines have been working in the scent detection of bed bugs for many years.  The group is looking to take the information that they have gained in that field and apply it to the early detection of ABW in areas where the pest is not currently located or determining the presence/absence of ABW around a property with known infestations.  The initial results  from two blind trials (involving hiding containers of ABW in the turf) have been very encouraging.  We look forward to seeing where this project will go.  I will be giving a presentation with Bun at the Eastern PA Turf Conference in January.  Here is a video of Carl in action (the sitting action is him alerting to a hidden vial of ABW): IMG_4312

ODD OBSERVATIONS

BTA on Athletic Fields

I performed a house call on a baseball field that was suffering from dead Poa annua in Early July.  The damage first appeared in the outfield, closest to the woodline, and moved in over time.  The manager thought he had the first case of ABW on an athletic field.  With much sampling we found larvae with legs!  It was too early for our traditional, annual white grubs to be present.  With the help of a microscope I was able to see that they were Black Turfgrass Ataenius.  This was my first case of BTA on athletic fields.  Normally they are problems in golf turf (bentgrass and Poa at fairway height).  Ironically, I received another report of the same problem later in the week.

European crane fly in central PA

I am never off the job!  I detected a crane fly adult while playing golf in mid July.  I captured the adult and brought it back to the lab.  There are potentially thousands of crane flies that could be in the golf course environment, but only 2 worldwide that damage turf.  Both are native to Europe.  I sent pictures of the sample off for another set of eyes to look at it, which was confirmed to be Tipula oleracea, the common crane fly (As far as the 2 exotics are concerned, this is the lesser of the two evils).  The timing of the flight was odd, though they have the potential to occur in small numbers throughout of the summer.  I am not overly concerned at the moment – we will keep an eye on the situation and monitor for flights during the fall (Sept-October) and again next spring (April-May).

Annual Bluegrass Weevil update:

We have had a rapid change in the development of our ABW populations in PA since my last blog entry (though it appears we are in a slight cool down at the moment).  Early instar larvae  were abundant in samples from across the state mid-week last week (May 13th).  Our plant indicators that signal optimal larvicide timing  (Rhododendron catawbiense – which I have been misspelling for a long time)  have gone into full bloom in a relatively short time frame.  If you are intending on putting down a larvicide, now would be a good time, as the population of larvae residing in the plant are beginning to appear in the soil.

It is hard to gauge what will happen over the next couple of weeks with ABW populations.  I have visited a lot of sites where it has been very difficult to find adults or larvae.  It is my thinking that many people scouted intensively and made well-timed adult applications.  If you are having a hard time finding larvae in your  “hot-spot” areas, you may not need a larvicide (*This is entirely dependent on past population sizes, damage, sampling intensity, and how much risk you are willing to take on).  Conversely, I have observed courses with damage appearing much, much earlier than anticipated.  The unusually dry Spring may have stressed the turf to the point where damage is appearing weeks ahead of schedule.  Make sure you provide adequate irrigation to areas where you have had a history of damage.  It may not help you avoid ABW damage, but it will certainly increase your safety net.

Turfgrass Ants

Ants have ramped up mounding in the last week.  The dry conditions seemed to have exploded populations.  Controlling ant mounding at this point is going to be rather challenging.  You may need to start thinking about interventions in the Fall, as many treatments made in early summer will provide only temporary relief.

Earthworms

Our earthworm activity is running opposite to the activity of ants.  The unusually dry spring has reduced soil moisture, and in turn, earthworm activity.   We failed to expel worms with seed meal extract this week (earlier in the Spring it was Wormageddon -to coin a phrase from Doug Middleton of Ocean Organics).  So what gives?  Earthworms are adverse to dry soils.  When soils dry they either burrow deeper in the soil or aestivate (essentially hibernate) in a “mucus chamber”, enter a non-feeding state, or by curling up in a knot-like ball. But dont worry: they’ll be back!  Fall is another big season for earthworm casting.  We will keep you up to date on this project’s progress.

Annual Bluegrass Weevil :

We have bypassed Spring and gone straight into summer.  The past week has seen almost vertical climbs in growing degree days (GDDs). State College is currently at 215 GDD (Base 50). Forsythia development went from full bloom (where it had been for 2 weeks) to half green half gold late last week.  This would have been an ideal time to make an adulticide application.  However, in many cases, the plants went well beyond half green half gold over the weekend.  I still  believe that many who did not get a chance to make an application until this week are still OK.  If you have not made an adult application, I would recommend focusing on larvae at this point.  Be vigilant and scout for larvae INSIDE the plant.  Removing soil cores and placing the soil and plant material in a saturated saline solution will irritate the larvae out of the plant. They will float to the surface of the solution, but may require a hand lens for identification.  Rhododrendron catawbiensis will be our next indicator.  Full bloom has been correlated with the time the insects move from within the plant to the soil, and can be targeted with many of our larvicides.

ANTS!

Turfgrass ant activity has sprung up in a major way.  The hot and dry conditions have brought major mounds to collars and roughs surrounding greens and tees.  Few mounds have made it to the center of the greens.  The traditional approach to managing ants has been to make a chemical application when mounds start to appear.  Most choose a pyrethroid, as it leads to rapid decreases in mounding.  However, it is short lived.  The mounding will resume in 7-10 days.  Please dont get into a situation of repeating applications (esp. with pyrethroids).  Some people have told me they make 10+ applications per year to control ants!  This is a dangerous strategy especially if you have ABW in the same areas (i.e. creating pyrethroid resistant weevils).  Neonics are an alternative, although the shut down of mounding is much more gradual (no instant satisfaction).  If you are using a neonic, either use an granular product or make sure that you irrigate immediately after a liquid application to ensure the residue does not dry on the leaf.  These strategies will help reduce risk to foraging pollinators.

Black Cutworm:

Black Cutworm is an annual pest of bentgrass areas on golf courses in PA.  However, it is incapable of surviving the winters.  The moths migrate on the wind from southern locations where it is capable of overwintering.  Currently, Black Cutworm moth captures are high in several counties in PA.  Check out this update from PSU entomologist Dr. John Tooker (John works in corn- the other monocot!) to see if your area is under high alert.

http://extension.psu.edu/plants/crops/news/2015/05/black-cutworm-update

It is important to capture BCW infestations early.  The smaller the larvae, the better chance you have of controlling the caterpillars.  Be on the lookout for dew trails in the morning (prior to mowing) as the younger larvae are capable of travelling great distances when foraging.   Older larvae barely leave their  holes and cause a sunken ball mark-like damage. If you have had serious BCW issues in the past, make sure that you are not dumping clippings on the edges of greens and tees.  The eggs are laid on the distal end of the plant and are capable of surviving mowing.  Dumping clippings on the edges of greens allows them to hatch out and wander back on to the green.

The past week was relatively cool in most parts of PA, with only a few Growing Degree Days (GDDs) being accumulated.  Our research sites in western and central PA accumulated 4 and 12 GDDs (Base 50 F) respectively, between April 22 and 28.  Forsythia bloom has been hanging around full bloom for two weeks in State College (118 GDD as of 4/30) and at our monitoring site at the Bucknell University Golf Course (120  GDD as of 4/29).

We have seen a surprising amount of adult activity on the short turf despite the relatively few GDDs accumulated.   Adults captured in vacuum samples were up substantially from the previous week at Bucknell, despite no real change in our plant indicators.  Southeastern PA also showed the same trend: little movement beyond the 10-25% green Forsythia, but adult captures were on the rise.  We were able to net a whooping 3400 weevils in 3.5 hours of vacuuming (of one edge of a Par 5!) on Monday.  (The face of Danny Kline -master technician- shows the extent that our lab will go to get you your weevil data).

We were able to dissect many adults captured from various locations this week.   The majority of males remain immature, though the percentage of mature males continues to tick upwards.  Females are ready to drop eggs, but few (< 10%) were found to be mated.  We will be continuing to monitor reproductive development and scout for egg in the next few weeks.

Based on the extended forecast I fully expect that many sites in PA will be at the 1/2 green and 1/2 gold stage by mid week next week.  This is the ideal time to apply your adulticide.

I know that many people have been scouting with vacuums this year (Awesome! Echo- I need a sponsorship).  Many have been startled by the amount of weevils they have detected.  I fear that this “performance enhancing sampling method” has caused many to jump the gun and apply an insecticide.  We sampled a couple of sites that had made an application a week or more ago.  We did collect many dead weevils at these sites, but many, many more were alive. Pyrethroid resistance tests performed on these individuals produced negative results, indicating that the application did not last long enough to knock down the weevils arriving late to the game.  If this sounds like your situation, consider holding off until 1/2 green 1/2 gold stage next year to make the most of your adult application.  For now, dont make matters worse by following up with the same chemical class, and possibly think about targeting larvae instead.

ABW Report

Our lab spent much of the week looking for annual bluegrass weevil (ABW) adults, and trying to get a handle on where the majority of the adult population is located.  Vacuum sampling between overwintering sites and short turf areas revealed that the VAST majority of weevils in central PA (> 95% at most sites) are still in the roughs.  We found several sites where some weevils had made it all the way to the fairways, but most, if not all, were south-facing turf stands where it is likely to heat up faster than other areas on the course.

The results of the sampling are what I would expect based on what we are seeing for plant development in the area. Forsythia full bloom has arrived (or is very near) in most areas I have visited in Pennsylvania.  Much of the Forsythia in central PA is not quite at 100% full bloom, but could get there with a couple of warm days.  This has anecdotally being correlated with the start of the migration.  This is only the tip of the iceberg!  I have heard that several people have already initiated their adulticide applications.  This is incredibly early (in my opinion).  All of our true adulticides have a very short residual (at best 10-14 days at best).  With colder temperatures expected over the next few days, we can expect that applications made this week are likely to have minimal effect on ABW populations, and therefore will require a re-application at a later date.

If you are concerned about the few weevils that made it to the short turf: don’t be.  Dissections of weevil collected this week showed that their reproductive systems remain undeveloped.  Remain patient and keep scouting.

Earthworm castings are appearing in full force within the last couple of weeks.  Though Earthworms are beneficial to soils, their fecal matter (casts) make for some unsightly turf and can cause issue with machinery.  We often observe castings being issues in the spring and fall, when there is ample moisture.  The cool and wet weather that is forecasted for next week will not help in lessening the severity of damage.

On a recent visit to a central PA course, casts in excessive of 8 per square foot were observed on fairways and tee boxes.  The turf in these areas was thin, as casts left on the surface smother the grass below.  We have some earthworm trials in the works this spring at this site, and are excited to see the effects that some biorational products have on reducing extreme castings.

It seems like many places south of Pennsylvania are a buzz with annual bluegrass weevil (ABW) activity this week.  It does seems like we are rocketing out of the slow start to spring.  So, what has the recent warm weather done for ABW migration from overwintering sites in central and western PA?

As of April 8th, State College has accumulated 27 Growing Degree Days (GDD) since March 1 (Base 50 F).  I have not seen any movement on Forsythia development.  Today I traveled to the Pittsburgh area to catch up with Eric Wygant at Shannopin CC, one of our research cooperators, to gauge ABW activity in the western part of the state.  Shannopin had accumulated  quite a few more GDDs than State College (47).  However, I did not notice any Forsythia bloom on and around the course or the city.

The weather was ideal for ABW vacuum sampling (65 degrees and partly cloudy).  Vacuum sampling at regular intervals from overwintering sites (tree line, leaf litter) to fairways showed that the majority of adults (75%) were within 5′ of the tree line (rough), and that less than 10% had traveled all the way to the fairway (in this case 20-25′).

So, my best recommendations at this point is to remain calm, watch for Forsythia development, and check back here for more updates and happenings in the Turf Entomology lab at PSU.

Albrecht Koppenhofer (Rutgers University) and I are conducting an annual bluegrass weevil (ABW) management survey to get a better understanding of regional extent of damaging ABW populations and the tactics used to control the pest.

I will be sharing the findings during a seminar at the Golf Industry Show in San Antonio on February 24th (Monday) and in an article in Golf Course Management.  All individual responses will remain anonymous. 

Your answers will go a long way to helping researchers design experiments and develop Best Management Practices.  The survey should not take you more than 5-10 mins.  If you wish to participate, click the link below:

http://goo.gl/forms/vcNHRRVc24

Thanks,

Dr. Ben McGraw, Penn State University

November is a time for golf course superintendents to be thinking about making snow mold applications and putting the course to bed for the year.  Even for turf entomologists, the threat of turf loss due to insect feeding seems like a distant memory.   However, last week I handled phone calls and received samples from a course in Westchester Co. NY, (just outside of NYC) that indicate that Tipula oleracea (the common crane fly) is not only present in the area, but in numbers capable of damaging greens and tees at this time of the year.

The superintendent did an excellent job of detecting the problem early in the start of the invasion curve.  He was alerted to the problem by following bird activity (in this case droppings and pecking).  With a little bit of digging he was able to find the larvae (picture above) in greens and tee boxes.

It is much easier to tell which of the two European crane flies (ECFs) species you have by examining the adults, but since the adults are probably long gone and given the relative size of the larvae at this time of the year, it is most likely that this is the common crane fly. This particular ECF has the ability to fly further distances than its close relative Tipula paludosa. Therefore, superintendents in the area need to be monitoring the turf starting in late April-mid May for signs of crane flies.  Two things you can look for: (1) pupal cases sticking out of the turf and (2) adult swarms.

Pupae work their way from the soil to the surface, and their casings protrude out like little twigs.  This is easily seen by looking at ground level for these little “sticks” on short mown turf (esp. tee boxes).  At higher heights of cut, the pupal casing might be seen resting on the top of the turf canopy (when the adult crane fly evacuates it) and is slightly harder to find.

When adult ECFs emerge from the pupal casings, they can often be seen flying low across the turf.  Alert your rough mowers to look for swarms of “giant mosquitoes” (we know they are not mosquitoes) coming out of the turf as the mower approaches.

One final note:  I welcome your samples for ID.  I failed to mention to the superintendent that you should send your larval samples in a vial of alcohol (rubbing alcohol, cheap grain alcohol, vodka are all fine for short term storage).  I was at a conference on the West Coast when the larval samples arrived.  I found this five days later when I returned:

It appears that exotic crane flies have invaded a new territory area in North America.  I received a sample for identification from Adam Van Dyke of Professional Turfgrass Solutions based out of West Jordan, Utah.  Adam is a consultant extradordinaire, who scouts a lot of turf and conducts research trials.  He has observed leatherjackets (larvae of crane flies) in the past damaging putting green turf.  This time he was fortunate enough this time to collect some adults flying across the turf.  The specimens that were sent to me were identified as Tipula oleracea, the common crane fly.

Crane flies are relatively large mosquito-looking (emphasis on looking) Dipterans that are present across the globe.  There are literally thousand species of crane flies worldwide and several harmless, non-turf damaging species that can be found in many turf situations.  Two species of European crane flies are present in North America that will actually damage turfgrass by feeding above and below ground on plant parts.  Additionally, many vertebrate predators (birds, skunks, raccoons) will often cause secondary turf damage when they tear up the turf looking for a tasty treat.

The common crane fly (Tipula oleracea) can be found in its native distribution from southern Europe to northern Africa.  Tipula paludosa, commonly referred to as the European crane fly, can be found in northern Europe.  Both the species occur in similar geographic regions in North America, with extremely large and damaging populations on the east (Ontario to Upstate NY) and west coasts (British Columbia to northern California).

Though Utah is a long way from State College, this tale can benefit turfgrass managers on this coast.  I spoke with Rod Ferrentino, the east coast version of Adam this afternoon.  He reports that masses of crane flies are currently flying in upstate NY.  The common crane fly has two generations per year.  Adults can be seen flying over the turf in the spring (late April, early May) and again in the fall (August, September) in the east.  The European crane fly emerges as an adult only in the fall, and thus both species can be seen around this time.

If you suspect that you have crane flies, it is important to try to get a positive identification.  There are many ways to collect adults.  The easiest way is to use an insect net, but often a hat will do if they are dense enough.  Many superintendents have collected crane flies off of screen doors or white painted maintenance buildings.  If you can get an adult, place it in a small plastic container or test tube and send it along.  We would be happy to take a look (mail to: B. McGraw, Penn State Univ., 243 ASI Building, State College, PA, 16802).

As an aside: Matt Petersen of Roanoke University wrote an excellent paper on the potential spread of both species of crane flies in North America in the journal of Biological Invasions (reading not for the faint of heart).  His computer models actually predicted that this species could potentially spread to Utah.  Well done Matt!

Up until this week, we had been receiving a lot of calls and e mails with concerns about turfgrass ant activity.  The warm(er) weather in central PA and throughout the region over the last two weeks seemed to explode ant activity.  This is somewhat surprising as mounding (and ant activity) should be declining from that of the earlier part of the summer.  Work conducted in the early 2000s by Reid Maier and Dan Potter at the University of Kentucky documented the seasonality of mounding caused by the turfgrass ant (Lasius neoniger) in that region.  Their work on Kentucky golf courses showed that mounds increased steadily between March and May, only to decline sharply after July or August.  So, the good news is: the mounding should not be increasing.  However, most people have asked what they can apply at this time of the year.  Even if you have had major ant issues, I suggest waiting until next year before tackling the problem, and start with your control measures as soon as you see activity build in spring.   Applying insecticides at this time of the year might clean up some of the ants on the surface, but will do little to reduce the overall colony or issues for next year. Turfgrass ant colonies are composed of a single queen (who is only responsible for laying eggs) and her daughters or workers (who are responsible for pretty much everything else). The males in the colony are similar to male bees (drones).  They pretty much sit around and do nothing but wait for the opportunity to fly out of the colony to mate with a future queen….and most likely die in the process.  The daughters (workers) are the muscle of the colony.  They are likely the ones you have observed in the last few weeks, scurrying about the surface, foraging for prey.  Inside the colony, workers take eggs from the queen and see that they mature into legless grubs, then pupae, before becoming an adult ant.  When you apply a surface insecticide, you are wiping out some of the foraging workers.  When they do not return to the colony, the queen can respond by making more workers.  Therefore, if you can control the queen, you will have better results.  However, if you can eliminate many of the foragers in the beginning of the season when the colony is just taking off, the colony may struggle to find prey to support the new queen’s egg laying activity.

Even the pristine turf at the Valentine Turf Research Center is not immune!  A visit to Valentine revealed the characteristic mounding activity of the turfgrass ant.  Mounds at Valentine were scattered across a rectangular research plot.  However, the majority of mounds are located near the edges of the close mown turf.   This is also what can be observed on sand-based rootzones on a golf course tee or green. The colony is formed by a single queen.  The main entrance to the colony (and presumably the queen) is located on the edges of the green/rough border and not actually on the green or tee.  Usually, this is composed of native soils.  The mounds that we have an issue with on greens tend to be satellite mounds that are connected to the main colony.  The turfgrass ant will dig horizontal shafts into green and emerge on the surface.  The short height of cut and the ease of digging through sand rather than native soils, may allow the ants to create more mounds and forage more effectively.

So what could be going on with the increase in mounding activity in the Fall in the Northeast and Mid-Atlantic? It is important to note that the turfgrass ant is the dominant ant in open fields and pastures, and other disturbed sites (e.g. plowed fields).  The same study conducted by Maier and Potter revealed that turfgrass ants responded to sand filled holes by increasing mounds in these areas.  Could it be that recent aerficiation events have led to an increased ability for ants to move into areas and create mounds? We will see.  Next season, our lab will be ramping up investigations into how the turfgrass ant responds to the turfgrass environment in the northeast.  We hope to have a better understanding of how our cultural practices affect their presence and mounding activity.