Dr. David Smitley
Dave Smitley Professor
Entomology Department
517.355.3385
Department of Entomology at Michigan State University
North Carolina State University (1985)
Dr. Smitley works closely with the turfgrass, nursery and floriculture industries on identifying and solving insect pest problems. Applied research is followed with extension recommendations for growers. In 1991, Dr. Smitley worked with Dr. Bauer to introduce Entomophaga maimaiga, a fungal pathogen of gypsy moth, into Michigan. E. maimaiga is now widespread throughout the state, and is helping to suppress gypsy moth. Dr. Smitley is now studying the impact of E. maimaiga on gypsy moth populations. In turf, Dr. Smitley has been investigating the role of predators and the bacterial pathogen, Bacillus popillae, in regulating populations of Ataenius spretulus and Aphodius granarius on golf courses. In the last five years, he has also researched winter mortality of gypsy moth, interactions of water stress and honeylocust spider mite, and the host preference of gypsy moth among ornamental trees and shrubs.
Turfgrass Entomology Research 2008 - 2009 Long-term Suppression of Ants on Golf Courses. Research tests supported by industry and by MTF this past year have demonstrated 6 months of ant suppression following a single application of Aloft, Arena or Meridian at the highest labeled rate in May or early June. The number of ant mounds observed throughout the season in treated plots is reduced by 50% compared with untreated control plots. Other nicotinoid insecticides are also being tested at this time to see how they compare. Additional funding from MTF allowed us to follow-up on an idea proposed by Dr. Harry Niemczyck (retired from OSU) to treat much larger areas in order prevent re-colonization by ants in nearby untreated areas. In ¼-fairway plots (replicated 6 times) we were able to reduce ant mounding by 90% compared with only a 50% reduction in our standard-sized plots (10’ x 20’). This means that if golf course superintendents treat 30’ beyond the edges of tees, greens and fairways, it will dramatically improve ant control, especially along the edges of fairways, tees and greens. Apparently re-colonization from nearby untreated areas is much faster than we had realized. Dr. Niemczyck and I are also sharing test results to work on this problem together. His approach has been to provide 10 different golf courses in Michigan with one of 5 nicotinoid insecticide products for treating entire fairways. He has also seen outstanding test results at many sites, but at some locations the products to not appear to be working as well, for unknown reasons.
Biological Control of Japanese Beetle with Ovavesicula. With the support of MTF and from Project GREEEN, I have introduced a pathogen of Japanese beetle that was originally found in Massachusetts but not Michigan. In the last year we have continued to collect data that compares populations of Japanese beetle at sites where Ovavesicula is active with sites where it is absent. Japanese beetle grubs do not survive the winter as well where Ovavesicula is active and populations were reduced by 25 to 50% per year. We are continuing this work including proposals that extend this project nation-wide.
Turf Resistance to White Grubs. This year I re-started some of our previous research on turf resistance to grubs, by writing a new GREEEN proposal. In previous research it appeared that types of turfgrass with the largest root systems were the most resistant or tolerant of white grub feeding damage. In my new approach I want to expand the concept of resistant turf to include management practices that stimulate large root systems. I plan to improve the proposal from last year based on review comments and submit a new proposal to Project GREEEN in January.
Turfgrass Entomology Research 2012
David Smitley and Terrance Davis
November 7, 2012
How to Prevent Grub Damage to Lawns and Golf Course Roughs Without an Insecticide (With Trey Rogers and Kurt Steinke). After a second year of collecting soil cores and washing roots on samples from 264 plots at the HTRC in August of 2912, we obtained results similar to what we found in 2011: cultivars of Kentucky bluegrass and fine fescue produce the largest root mass and are therefore the most tolerant of grub feeding. Our conclusion is that most home lawns can be protected from serious grub damage by daily irrigation (or by watering during dry periods), modest levels of N (1.0 lbs per year), and by growing Kentucky bluegrass or fine fescue. Data in 2012 was particularly useful because of the very dry conditions in July. Also, in 2012, more European chafer grubs were found in perennial ryegrass than any other turf type.
Late Fall Grub Treatments May not Work. Merit, Aloft, Dylox and Sevin treatments were applied to replicated research plots in a golf course rough on October 24, 2011. For comparison to a standard or optimum grub treatment, one set of plots in the same grid had been treated in July of 2011 with Merit. Turf samples were dug from all of the plots in April, 2012, and grubs were counted. In the untreated control plots we found an average of 10.1 grubs per ft2 (a mix of European chafer and Japanese beetle). None of the late October treatments significantly reduced the number of grubs per plot (Merit, Aloft, Dylox and Sevin treatments averaged 7.3 to 11.2 grubs per ft2 ). However in plots treated with Merit in July we found only 0.9 grubs per ft2. Although the late fall treatments were not irrigated after the insecticides were applied, the soil was moist and it rained again within 3 days of application. It may be possible to improve the results by irrigating immediately after application. At this time, in Michigan, I do not recommend insecticide applications for grubs after October 15th.
Irrigation After Treatment is Critical to Obtaining Good Grub Control. In the last 10 years many lawn care professionals have reported that imidacloprid or another highly effective insecticide failed to control grubs, even when applied at the correct rate, and at the correct time of year. We have also observed some failures in our grub control research tests. One of the factors known to influence the effectiveness of insecticides applied for grub control is irrigation. In order to evaluate the impact of irrigation we conducted a meta-analysis of all of our grub control research tests conducted over the last 20 years. Fortunately for this analysis, about 1/3 of all of our grub tests were conducted by spraying or spreading insecticides without any follow-up irrigation. Only insecticide products appearing in at least 5 years of testing, and with at least 3 irrigated and 3 non-irrigated treatments, were considered. In all cases imidacloprid and other nicotinoid insecticides (Merit, Arena, Aloft, Meridian, etc.) provided a high level of control
( > 80 % control) when they were applied between May 1 and Aug. 30, if they were irrigated immediately after application. All of the cases of failure (0 – 40 % control) occurred when no irrigation was applied. Similar results were observed for Dylox and Sevin, although the average percent control was less ( > 65 % control when irrigated immediately after application). Our conclusion is that most grub control failures are caused by failing to irrigate immediately after application, regardless of the type of formulation (sprayable or granular).
Ant Research Information
1998 Ant Research
2001 Ant Research
2002 Ant Research
2003 Ant Research
2004 Ant Research
2006 Ant Research
Dave Smitley Professor
Entomology Department
517.355.3385
Department of Entomology at Michigan State University
North Carolina State University (1985)
Dr. Smitley works closely with the turfgrass, nursery and floriculture industries on identifying and solving insect pest problems. Applied research is followed with extension recommendations for growers. In 1991, Dr. Smitley worked with Dr. Bauer to introduce Entomophaga maimaiga, a fungal pathogen of gypsy moth, into Michigan. E. maimaiga is now widespread throughout the state, and is helping to suppress gypsy moth. Dr. Smitley is now studying the impact of E. maimaiga on gypsy moth populations. In turf, Dr. Smitley has been investigating the role of predators and the bacterial pathogen, Bacillus popillae, in regulating populations of Ataenius spretulus and Aphodius granarius on golf courses. In the last five years, he has also researched winter mortality of gypsy moth, interactions of water stress and honeylocust spider mite, and the host preference of gypsy moth among ornamental trees and shrubs.
Turfgrass Entomology Research 2008 - 2009 Long-term Suppression of Ants on Golf Courses. Research tests supported by industry and by MTF this past year have demonstrated 6 months of ant suppression following a single application of Aloft, Arena or Meridian at the highest labeled rate in May or early June. The number of ant mounds observed throughout the season in treated plots is reduced by 50% compared with untreated control plots. Other nicotinoid insecticides are also being tested at this time to see how they compare. Additional funding from MTF allowed us to follow-up on an idea proposed by Dr. Harry Niemczyck (retired from OSU) to treat much larger areas in order prevent re-colonization by ants in nearby untreated areas. In ¼-fairway plots (replicated 6 times) we were able to reduce ant mounding by 90% compared with only a 50% reduction in our standard-sized plots (10’ x 20’). This means that if golf course superintendents treat 30’ beyond the edges of tees, greens and fairways, it will dramatically improve ant control, especially along the edges of fairways, tees and greens. Apparently re-colonization from nearby untreated areas is much faster than we had realized. Dr. Niemczyck and I are also sharing test results to work on this problem together. His approach has been to provide 10 different golf courses in Michigan with one of 5 nicotinoid insecticide products for treating entire fairways. He has also seen outstanding test results at many sites, but at some locations the products to not appear to be working as well, for unknown reasons.
Biological Control of Japanese Beetle with Ovavesicula. With the support of MTF and from Project GREEEN, I have introduced a pathogen of Japanese beetle that was originally found in Massachusetts but not Michigan. In the last year we have continued to collect data that compares populations of Japanese beetle at sites where Ovavesicula is active with sites where it is absent. Japanese beetle grubs do not survive the winter as well where Ovavesicula is active and populations were reduced by 25 to 50% per year. We are continuing this work including proposals that extend this project nation-wide.
Turf Resistance to White Grubs. This year I re-started some of our previous research on turf resistance to grubs, by writing a new GREEEN proposal. In previous research it appeared that types of turfgrass with the largest root systems were the most resistant or tolerant of white grub feeding damage. In my new approach I want to expand the concept of resistant turf to include management practices that stimulate large root systems. I plan to improve the proposal from last year based on review comments and submit a new proposal to Project GREEEN in January.
Turfgrass Entomology Research 2012
David Smitley and Terrance Davis
November 7, 2012
How to Prevent Grub Damage to Lawns and Golf Course Roughs Without an Insecticide (With Trey Rogers and Kurt Steinke). After a second year of collecting soil cores and washing roots on samples from 264 plots at the HTRC in August of 2912, we obtained results similar to what we found in 2011: cultivars of Kentucky bluegrass and fine fescue produce the largest root mass and are therefore the most tolerant of grub feeding. Our conclusion is that most home lawns can be protected from serious grub damage by daily irrigation (or by watering during dry periods), modest levels of N (1.0 lbs per year), and by growing Kentucky bluegrass or fine fescue. Data in 2012 was particularly useful because of the very dry conditions in July. Also, in 2012, more European chafer grubs were found in perennial ryegrass than any other turf type.
Late Fall Grub Treatments May not Work. Merit, Aloft, Dylox and Sevin treatments were applied to replicated research plots in a golf course rough on October 24, 2011. For comparison to a standard or optimum grub treatment, one set of plots in the same grid had been treated in July of 2011 with Merit. Turf samples were dug from all of the plots in April, 2012, and grubs were counted. In the untreated control plots we found an average of 10.1 grubs per ft2 (a mix of European chafer and Japanese beetle). None of the late October treatments significantly reduced the number of grubs per plot (Merit, Aloft, Dylox and Sevin treatments averaged 7.3 to 11.2 grubs per ft2 ). However in plots treated with Merit in July we found only 0.9 grubs per ft2. Although the late fall treatments were not irrigated after the insecticides were applied, the soil was moist and it rained again within 3 days of application. It may be possible to improve the results by irrigating immediately after application. At this time, in Michigan, I do not recommend insecticide applications for grubs after October 15th.
Irrigation After Treatment is Critical to Obtaining Good Grub Control. In the last 10 years many lawn care professionals have reported that imidacloprid or another highly effective insecticide failed to control grubs, even when applied at the correct rate, and at the correct time of year. We have also observed some failures in our grub control research tests. One of the factors known to influence the effectiveness of insecticides applied for grub control is irrigation. In order to evaluate the impact of irrigation we conducted a meta-analysis of all of our grub control research tests conducted over the last 20 years. Fortunately for this analysis, about 1/3 of all of our grub tests were conducted by spraying or spreading insecticides without any follow-up irrigation. Only insecticide products appearing in at least 5 years of testing, and with at least 3 irrigated and 3 non-irrigated treatments, were considered. In all cases imidacloprid and other nicotinoid insecticides (Merit, Arena, Aloft, Meridian, etc.) provided a high level of control
( > 80 % control) when they were applied between May 1 and Aug. 30, if they were irrigated immediately after application. All of the cases of failure (0 – 40 % control) occurred when no irrigation was applied. Similar results were observed for Dylox and Sevin, although the average percent control was less ( > 65 % control when irrigated immediately after application). Our conclusion is that most grub control failures are caused by failing to irrigate immediately after application, regardless of the type of formulation (sprayable or granular).
Ant Research Information
1998 Ant Research
2001 Ant Research
2002 Ant Research
2003 Ant Research
2004 Ant Research
2006 Ant Research