| Just when your roses are looking great, the Japanese beetles arrive. What are these critters? Where did they come from? Why are they devouring my roses? What can I do NOW??!! Click on the link below to view Nancy Lindley's June 2002 article from Michigan Gardener magazine and learn what to do NOW to control these pests:
Meet the Beetles! (and how to get rid of them NOW)
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Continue reading if you want to learn why the Japanese beetle problem won't be so bad in the years to come ......................
How to Have Natural Japanese Beetle Control in Your Garden ..... courtesy of Michigan State University
Frustrated Michigan gardeners met in Battle Creek on Saturday, October 21, 2006 for "Grub Day". Over 150 gardeners braved rainy weather, descending upon the Binder Park Golf Course where they collected Japanese beetle grubs infected with natural pathogens. They took the critters home and "planted" them in their lawns to speed the spread of natural Japanese beetle control measures in the state. Click here for photos from the Greater Lansing Rose Society's website:
Many thanks for the staff at Binder Park Golf Course! There was no "Grub Day" in 2007. |
| Here is Dr. Smitley's report of his 2006 results and plans for 2007:
Biological Control of Japanese Beetle In Michigan
Through Parasite and Pathogen Introduction
David Smitley, Department of Entomology, Michigan State University
January, 2007
Synopsis of Proposal: In 1999, two insect parasites of Japanese beetle (Tiphia vernalis and Istocheta aldrichi) and one protozoan pathogen (Ovavesicula popilliae), were collected in Connecticut and introduced into research plots on 5 golf courses in Michigan. For each introduction site, control plots were established at a different golf course located nearby, for a total of 10 golf course sites. In 2005 we returned to the same golf courses to sample for Japanese beetle and the introduced parasites and pathogen. T. vernalis was not found, I. aldrichi was detected at 4 of 10 locations, and O. popilliae was found at all introduction sites and two control sites, sometimes at epizootic levels (> 20% infection). Populations of Japanese beetle on golf courses where O. popilliae is epizootic are now much lower than levels in 1999 and 2000. The proposed research will demonstrate long-term biological control of Japanese beetle by comparing the population density of Japanese beetle at 5 locations with little or no O. popilliae-infection to the same at 5 locations with moderate to high levels of infection.
Potential Impact on Michigan Plant Agriculture/Industries: Japanese beetle is the most serious pest problem for Michigan nursery growers, rose growers, blueberry growers and golf courses. The introduced pathogen now appears to be regulating populations of Japanese beetle well below threshold levels where it is established. Documentation of this biological control program through research is critical to convince scientists and agriculture officials to adopt an early pathogen introduction program in northern Michigan and states that have just recently become infested to prevent 15-30 years of heavy pesticide use and substantial economic losses due to unregulated outbreaks of Japanese beetle. This project will also use the original introduction sites to distribute O. popilliae to the rest of the state, and to other North Central States.
Specific Objectives:
1. Determine the impact of O. popilliae on populations of Japanese beetle.
2. Determine how many years after introduction of O. popilliae are required for the pathogen to build to levels that cause a reduction in populations of Japanese beetle.
3. Determine how quickly populations of I. aldrichi build over a 3-year period after it is initially detected.
4. Distribute O. popilliae-infected grubs throughout Michigan and begin distribution to other states in the region.
Report on Research Completed in 2006 (3-1-06 to 12-31-06):
At each of the 10 golf course study sites Japanese beetle grubs were collected in the spring and fall from 16 locations along the edge of the original fairway (inoculated or control, depending on the golf course), and from 16 locations along a different fairway from 50 to 150 m away. Forty grubs from each fairway were dissected to determine percent infection by Ovavesicula popilliae and milky disease. Japanese beetle adults were collected from each golf course in late July and early August using a standard Japanese beetle trap baited with eugenol. Adults were examined for Istocheta eggs.
Results in 2006:
O. popilliae infection of Japanese beetle grubs continued to increase at sites where it was introduced in 1999 and 2000 (Table 1). At Orchard Lake and Willow golf courses, where O. popilliae appeared to have originated as a result of our introductions into a 100 m2 plot area in 1999 and 2000, the infection of grubs has spread up and down the entire length of a fairway and infected grubs are now being found in the adjacent fairway. Infection levels at those sites have now increased to >30%, a level expected to have a significant impact on the density of grubs in that population. The impact of O. popilliae infection on Japanese beetle populations was measured by determining the survival of grubs from fall of 2005 to spring of 2006 (Table 2). At golf courses where more than 5% of the grubs were found to be infected, the decrease in grub density from fall to spring was 57.4% compared with 28.2% at sites where no O. popilliae was found (Table 3).
The incidence of adult Japanese beetles parasitized by Istocheta was similar in 2006 compared with 2005. Overall, Istocheta was again found at 4 of 10 golf courses, but in 2006 two of the golf courses were different from the ones where Istocheta was found in 2005. The percentage of beetles parasitized varied from 0.01% to 0.04%. The actual proportion of beetles parasitized was probably somewhat higher than this because the Istocheta eggs tend to fall of beetles when they rub against each other in the traps. Even so, this is a very low level of parisitization compared with Connecticut where it is not unusual to see Istocheta eggs on 10% of the beetles in a trap. Most likely the proportion of beetles being parasitized will increase each year. Even this low level of Istocheta activity represents a substantial increase since 1999 and 2000 when no Istocheta eggs were found at any location.
Table 1. Infection of Japanese beetle grubs with O. popilliae in 2005 and 2006 at golf course study sites where introduction and control sites were first sampled in 2000. O. popilliae apparently established naturally in the Kalamazoo and Battle Creek area (Binder Park, Eastern Hills and Kalamazoo CC) but in Southeast Michigan it was only found where we introduced it in 1999 and 2000 (Orchard Lake, Willow, Bloomfield Hills). Fairways where O. popilliae was introduced in 2000 are indicated with a '+'.
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Golf course site
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O. popilliae
Introduction
sites (+)
|
O. popilliae
% infection
2000
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O. popilliae
% infection
2005
|
O. popilliae
% infection
spring 2006
|
O. popilliae
% infection
fall 2006
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Medalist #5
|
|
|
11
|
0
|
0
|
Medalist #4
|
+
|
0
|
0
|
0
|
0
|
Binder Park #18
|
|
|
51
|
53
|
52
|
Binder Park #6
|
|
0
|
31
|
28
|
44
|
Eastern Hills #7
|
|
|
43
|
42
|
13
|
Eastern Hills #5
|
+
|
20
|
17
|
22
|
24
|
Kalamazoo CC #15
|
|
|
17
|
13
|
64
|
Kalamazoo CC #1
|
|
6
|
20
|
11
|
41
|
Bloomfield Hills #13
|
|
|
0
|
0
|
0
|
Bloomfield Hills #6
|
|
0
|
0
|
0
|
0
|
Willow #9
|
+
|
0
|
7
|
6
|
43
|
Willow #10
|
|
|
0
|
0
|
8
|
Orchard Lake #10
|
|
|
0
|
0
|
0
|
Orchard Lake #15
|
+
|
0
|
13
|
9
|
30
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Table 2. Density of Japanese beetle grubs in fall of 2005, spring of 2006, and decrease in density over the winter in relation to % Ovavesicula infection.
Golf Course
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Fall 2005
# of Grubs
|
Spring 2006 # of Grubs
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Decrease in grubs 2005-2006
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% decrease in grub density
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% Infection
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Willow
|
|
|
|
|
|
#9
|
6.25
|
4.31
|
1.94
|
31%
|
6%
|
#10
|
3.25
|
1.00
|
2.25
|
69%
|
0%
|
| |
|
|
|
|
|
Orchard Lake
|
|
|
|
|
|
#15
|
1.69
|
0.63
|
1.06
|
63%
|
9%
|
#10
|
3.81
|
2.56
|
1.25
|
33%
|
0%
|
| |
|
|
|
|
|
Bloomfield Hills
|
|
|
|
|
|
#6
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1.25
|
0.88
|
0.38
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30%
|
0%
|
#13
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2.13
|
1.81
|
0.31
|
15%
|
0%
|
| |
|
|
|
|
|
Pine Valley
|
|
|
|
|
|
SM
|
3.13
|
3.19
|
-0.06
|
-2%
|
0%
|
#4
|
3.63
|
2.94
|
0.69
|
19%
|
0%
|
| |
|
|
|
|
|
Cracklewood
|
|
|
|
|
|
#4
|
1.50
|
1.69
|
-0.19
|
-13%
|
0%
|
#6
|
5.94
|
5.38
|
0.56
|
9%
|
0%
|
| |
|
|
|
|
|
KCC
|
|
|
|
|
|
#15
|
1.81
|
0.75
|
1.06
|
59%
|
13%
|
#1
|
3.38
|
1.88
|
1.50
|
44%
|
11%
|
| |
|
|
|
|
|
Eastern Hills
|
|
|
|
|
|
#5
|
2.13
|
0.88
|
1.25
|
59%
|
22%
|
#7
|
4.38
|
1.38
|
3.00
|
69%
|
42%
|
| |
|
|
|
|
|
Medalist
|
|
|
|
|
|
#4
|
1.25
|
0.63
|
0.63
|
50%
|
0%
|
#5
|
2.69
|
0.75
|
1.94
|
72%
|
0%
|
| |
|
|
|
|
|
Binder Park
|
|
|
|
|
|
#4
|
4.38
|
1.94
|
2.44
|
56%
|
53%
|
#6
|
3.19
|
0.69
|
2.50
|
78%
|
28%
|
Table 3. Impact of Ovavesicula infection on survival of Japanese beetle grubs from fall 2005 to spring 2006.
Activity of O. popilliae
|
No. of sites
|
Mean % O. popilliae infection
|
Decrease in grub density (%)
|
|
Plots with no O. popilliae
|
10
|
0
|
28.2
|
|
Plots with > 5% infection
|
8
|
23
|
57.4
|
Table 4. Japanese beetle adults found in traps in 2005 and 2006 with Istocheta eggs attached. 1,000 beetles from each
|
Golf Course
|
Percent beetles with Istocheta eggs in 2005
|
Total number of beetles trapped in 2006*
|
Percent beetles with Istocheta eggs in 2006
|
|
Willow
|
0
|
17,388
|
0
|
|
Orchard Lake
|
0
|
24,627
|
.04
|
|
Pine Lake
|
.03
|
15,672
|
.01
|
|
Bloomfield Hills
|
.03
|
27,463
|
.02
|
|
Cracklewood
|
0
|
27,612
|
.02
|
|
Pine Valley
|
.03
|
53,731
|
0
|
|
Eastern Hills
|
0
|
41,791
|
0
|
|
Binder Park
|
0
|
23,881
|
0
|
|
Medalist
|
.06
|
17,164
|
0
|
|
Kalamazoo CC
|
0
|
27,313
|
0
|
*The total trap catch from two traps per golf course sampled for a 24 h-period starting on July 13, 20, 28, Aug 3 and 11. A total of 6,000 beetles were examined for eggs from each golf course in 2005, and 10,000 from each golf course in 2006.
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Project activities planned for 2007:
In 2007, Japanese beetle populations, pathogens infection and parasite activity will be monitored again as described for 2006. Survival from fall of 2006 to spring of 2007 will be analyzed to determine the impact of O. popilliae infection on Japanese beetle by comparing survival at sites with and without O. popilliae.
New work planned for 2007: Because O. popilliae appears to be having a significant impact on populations of Japanese beetle, 50 adult females from each study site will also be collected and dissected to determine % infection and reduction in egg production due to O. popilliae infection. Previous research in Connecticut suggested that a 50% reduction in egg production can be expected due to O. popilliae infection. Also, several discussions with insect pathologists at the Entomological Society Meetings made it clear that incidence of milky disease is much higher when live grubs are incubated for one week at 30° C prior to dissection. In 2007 we will incubate grubs before freezing them to increase the accuracy of milky disease detection.
Outreach and expected impact: Over 130 people from 20 different counties in Michigan came to our Japanese beetle biocontrol field day in late October to collect infected grubs and take them back their own part of the state. The Kansas Department of Agriculture has initiated a new biocontrol program based on this work. They will be coming to collect infected grubs in May of 2007 to introduce them into Kansas. Populations of Japanese beetle have already decreased enough at some sites in the Kalamazoo and Battle Creek areas that we are no longer seeing defoliation of linden trees and some superintendents are no longer treating all their fairways with Merit Insecticide to prevent grub damage. If what we have seen over the last 5 years is indicative of what we can expect in the future, sites where O. popilliae has been introduced will become heavily infected within 5 years and population of Japanese beetle will begin to decrease, until at 10 years after introduction insecticides may no longer be needed to protect linden trees from defoliation or fairway turf from dying in large patches.
Time line:
Research plots have already been established at the 10 golf courses that will be in this study. Japanese beetle grubs will be collected in May and October of 2007 and 2008. Some of the grubs will be incubated for 1 week at 30°C prior to freezing. Grubs will be thawed and dissected for pathogen analysis in the 6-month period after they are collected. Adult Japanese beetle will be trapped and examined for I. aldrichi eggs once per week for 5 weeks in July and August 2007 and 2008. A Japanese beetle field day will be held again in October in cooperation with MSU Extension, Michigan Department of Agriculture, MTF, MNLA and MBGA to assist in the distribution of infected grubs to as many locations as possible in Michigan and the surrounding states. Representatives from the Kansas Department of Agriculture will visit in May, 2007 to collect infected grubs and take them back to Kansas. Results from the first year of this research will be used to submit a USDA NRI proposal in December, 2007. At least two scientific journal publications will be submitted for publication in the third and final year of this project. |
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| Adult Japanese beetle |
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| T. vernalis feeding on a Japanese beetle grub |
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| Aldrichi depositing an egg on an adult Japanese beetle |
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Want to learn more?
Click here to view Dr. Smitley's complete description of his 2005 Japanese beetle control projects and here for background about Dr. Smitley and some of his other work. |
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