Vol. 20, No. 11, July 1, 2005

Excessively dry conditions persist in the west

Next issue: July 15

Dave Smitley, Entomology

Japanese beetles defoliate roses, linden trees, purple leaf plum, crabapples and many other flowers, trees and shrubs. Also, the C-shaped white grubs damage lawns and golf courses by consuming turf roots. Homeowners and golf courses use a lot of insecticides to prevent damage from Japanese beetle, which has been in an outbreak stage in Michigan for the last 10 years. However, in some eastern states, populations have collapsed. In 1999 and 2000, Dave Cappaert and I introduced pathogens and parasites of Japanese beetle to six golf courses in southeast and south central Michigan. We collected the pathogens and parasites from Connecticut and New Jersey where Japanese beetle has been established since the 1920s. Recently, Japanese beetle populations have dropped to very low levels in Connecticut and New Jersey and some of the surrounding states. We collected the pathogens and parasites believed to be most likely to cause this decline and introduced them into Michigan. The pathogens established quickly, but we were not able to find any of the parasites after they were introduced.

This year, I plan to return to the original introduction and control sites to see how well they are working. By comparing the incidence of pathogens and parasites and the density of Japanese beetle larvae at the introduction sites with the same at the control sites, we will be able to evaluate how successful the introductions were, and what impact they are having on Japanese beetle in Michigan. Furthermore, sampling for pathogens and parasites in 2005 should allow us to find a good location for a field day where representatives from each part of the state will be invited to come and collect natural enemies of Japanese beetle for distribution in their own county. I am optimistic that the natural enemies we introduced in 1999 will help keep Japanese beetle populations in check. We will soon know how effective they have been.

The initial collection and introduction of natural enemies was funded from 1999 to 2002 by Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs) and the Michigan Turfgrass Foundation. In 2005, Nancy Lindley of Great Lakes Roses started a campaign to raise money from homeowners in Michigan so we could continue this project. It will cost us $10,000 to sample the original introduction sites for adult beetles and grubs to determine how effective the introductions have been. We have received about a $1,000 so far in checks from $20 to $100. If you would like to support this project, you can write a check to Michigan State University and mail it to:

Dr. David Smitley
Department of Entomology
Michigan State University
East Lansing, Michigan, 48824

In return you will receive a thank-you letter for your donation, which can be deducted from state and federal income taxes and a research report at the end of the year, detailing the progress made. Make sure the check is made out to MSU and not to me. Thank-you for your support of this project.

Dave Smitley, Entomology

In Saginaw, Bay and Midland counties, most of the silver maple street trees are so heavily infested with cottony maple scale that the undersides of the branches look like they are covered with popcorn. The scale is not likely to damage the trees, but some homeowners are annoyed with the honeydew that drips down onto cars and sidewalks below in late summer, fall and spring.

The crawlers have emerged now, starting a window of three weeks, that is the best time to spray for cottony maple scale. Since they appear to be resistant to permethrin, a pyrethroid insecticide used in the mosquito spray program, you may want to try Merit as foliar spray sometime in the next three weeks.

Thomas Dudek
District Extension Horticulture Educator

Rose rosette disease (RRD) is a virus-like plant disease that has been observed in many Midwestern states on wild rose. The disease can be lethal to multiflora rose (Rosa multiflora) and once was considered a biological control strategy for eliminating multiflora rose in the environment.

RRD is a concern to nurseries that grow and sell roses as well as gardeners because it will also attack cultivated roses and cause death to them as well. The disease cannot be cultured in the diagnostic lab, so it must be identified by its symptoms on the plant. An excellent fact sheet on this disease was developed by Virginia Tech and can be found at the following web site:

http://www.ext.vt.edu/pubs/plantdiseasefs/450-620/450-620.pdf

Symptoms on the affected plant include rapid shoot elongation with excessive thorniness, witches broom-like growth on the plant, red pigmentation of stunted leaves and severely deformed flowers. Plants could be mistaken for those damaged by herbicide, but herbicide damaged plants generally grow out of the problem the following year. Plants affected by RRD die. Small eriophyid mites can transmit the disease from infected plants to healthy roses. Cultivars planted downwind from a RRD-infected plant are at risk.

The recommended miticide to protect healthy roses when RRD is found in the nursery is Sanmite. Removal and destruction of any RRD-infected plants is essential. Eradicate any multiflora rose within a 100-meter radius of your nursery to guard against a possible infection site. For detailed photos and a disruption of the disease read the above-mentioned fact sheet.

Kevin Frank
Crop & Soil Sciences

Do you remember last year? Last year was one of those years when the air conditioner seldom, if at all, needed to be flipped on, and Mother Nature provided plenty, even excessive, amounts of rain. Among the turf crowd, we often say that during summers such as 2004 if the grass you’re growing doesn’t look good, you should probably find another job. Well paybacks are h-e-double hockey sticks and so far it seems that 2005 has been one of those payback years, and it’s only July 1! Over the last several weeks the high temperatures and smothering humidity have certainly resulted in plenty of turfgrass stress throughout the state. There is relief from the heat this morning as my office temperature has now dropped below 82º, but the long-range forecast indicates the heat will return quickly next week.

There have been numerous inquiries in the last couple weeks about new seedings. The weather has really put the screws to young turfgrass trying to put down its roots. There is a reason that the optimum establishment time for cool season turfgrass is in the autumn. Seeding in the autumn avoids the heat, humidity, drought and some of the weed pressure that new seedings are struggling with now. We’ve heard of several cases of pythium blight this year, particularly on new seedings. Normally pythium in Michigan is somewhat rare but with all of this heat and humidity, that’s certainly not the case this year. Pythium blight thrives during periods of high humidity and high nighttime temperatures (temps above 68ºF). Pythium often is noticed first in poorly draining areas or in depressions where the soil stays saturated and dew forms early in the evening. Pythium moves rapidly and unlike some of the turfgrass diseases such as red thread, or rust that I view as primarily “asthetic” diseases, pythium will kill the turf and kill it fast. Turfgrass leaves infected with pythium will appear water soaked and the turf may look “sunken.” Pythium can also be identified by looking for cottony white mycelium early in the morning.

Another key used in the field is to smell the turf – areas infected by pythium often give off the aroma of dead fish. Savvy golf course superintendents that have a “feel” for pythium weather will often start scouting the golf course very early in the morning, sometimes even using flashlights!

New seedings can be susceptible to pythium because they are often being pushed to establish with frequent irrigation and high fertilization rates. The best advice for new seedings is to back off on the irrigation so that the amount of water applied is just enough to keep the surface soil moist and avoid high rate fertilizer applications. Another tip is to try and avoid irrigating in the evening, as this will extend the period of time the turf remains wet. Turfgrass professionals will apply fungicides to prevent pythium, and homeowners struggling with pythium should contact a lawn care company if they’re looking for control options including fungicide applications.

The 2005 Michigan Turfgrass Field Day at the Hancock Turfgrass Research Center is scheduled for August 16. The Field Day is an opportunity for turfgrass professionals to come and view the latest turfgrass research projects being conducted at MSU. The registration mailer is currently in production so stay tuned – it will be in your mailboxes soon. Registration will also be available at www.michiganturfgrass.org. Watch for further updates.

Jill O’Donnell
Christmas Tree ICM Agent

Even though the gypsy moth spray window has closed in the Lower Peninsula, growers need to be walking their fencerows and scouting their plantations (especially spruce) for signs of gypsy moth. This is the time of the year we are particularly concerned with the large larvae that have nearly completed their feeding and they begin to crawl around, looking for a dark protected place to pupate.

When the female moths emerge from the cocoons, they cannot fly. That means that there is a real good chance that they will lay their eggs right on the tree. Taking the time now to scout your fields may mean you avoid having the plantation restricted this fall.

The following is a reprint of an article written by Dr. Rob Richardson in the June 27, 2003 issue of the Landscape Alert. The information is useful for this time – Jill O’Donnell.

Anyone that has used herbicides will know that every weed is usually not controlled. In some cases, many weeds may not be controlled. Instances of herbicide failure may be due to several factors. These include poor environmental conditions, improper herbicide application or herbicide resistant weeds.

A second factor affecting activity of some herbicides is incorporation into the soil with irrigation or precipitation. Trifluralin (Treflan), for instance, must be incorporated within 24 hours after application or the herbicide will be degraded by sunlight. Failure to incorporate trifluralin and similar products will result in a loss of herbicide activity. Another weather factor affecting herbicide performance is the temperature. Very high or low temperatures may stress weeds and increase tolerance to herbicides just as drought stress may.

A final environmental condition that may affect postemergence herbicide performance is precipitation. If rain occurs too soon after herbicide application, then the herbicide may be washed off of weed foliage before it is absorbed into the plant.

It is also important to recognize whether a product is for preemergence or postemergence control. Most preemergence herbicides will not control emerged weeds and many postemergence herbicides do not have soil activity for residual weed control. Even if an appropriate product is selected, it will not work properly unless applied correctly. All herbicides should be applied in accordance with the herbicide label, as the labels contain important information about adjuvants, herbicide mixtures, sprayer output, and many other factors that will affect herbicide performance. Common application errors include using herbicide rates that are too low, failure to achieve adequate spray coverage of the target area, poor mixing or poor agitation of the spray solution, improperly calibrated spray equipment, poor application timing, and application after weeds are too large.

2005 update: We have received a Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs) grant to evaluate the extent of herbicide resistance in Christmas tree plantations. If you re a Christmas tree grower and you think you may have a resistant weed problem, please contact Jill O'Donnell, 231-779-9480.

Jennie Stanger
Consumer Horticulture Educator

In the May 13 issue, Rebecca Finneran gave excellent suggestions and reasons to obtain a soil test before fertilizing. The next step is to choose an appropriate fertilizer and correctly calculate the amount that will match lab recommendations for the area of soil and crop to be grown.

County MSU Extension horticulture staff, Master Gardener volunteers and landscape professionals often help consumers interpret the tests and calculate amounts of fertilizers to apply. A new soil testing website should help and enable some consumers to interpret and calculate their own quantities. It may work especially well when the MSU soil lab implements their plan to e-mail the test reports.

Master Gardener Diane Schroeder used her substantial web design skills to automate a spreadsheet for calculating fertilizer. For an easy start, the handy form is set up so that you can type in the measurements of lawn, garden or landscape areas around trees, hit a button and instantly read the total calculated square feet. It works for one or two rectangles, squares, triangles, circles and any combination of those shapes.

Then you type in the fertilizer recommendation from your MSU soil test and enter the main (nitrogen) fertilizer you would like to use, such as 27-3-3. Click on the “Analyze” button and you will learn how many pounds of your fertilizer to buy and apply to your actual area. If that is not a good fertilizer choice to meet the recommendation because it is too high or too low in phosphorus or potassium, you can see this clearly on the automatically adjusted graph. Then you can add or substitute one or two other fertilizers and analyze again until your choices match the recommendation closely enough to suit you. The maximum one-time nitrogen amount to apply to a lawn area is calculated, too, along with the total pounds of lime needed for the area.

This very clever worksheet is only part of the whole website I planned to help folks get the most out of an MSU soil test report. It explains every part of the report, even how to get a soil test and contains extra information that includes links and fact sheets about soil. Hopefully some Landscape Alert readers will find it a useful tool. With a lab report in hand, check it out on MSUE Monroe County’s portal page, www.msue.msu.edu/monroe. Click on “Home Yard and Garden” and then find the “Soil test, Get it?” button from there.

Jeff Andresen
Agricultural Meteorology
Geography

An upper air ridge across much of the Midwest has brought hot, humid summer-like weather to Michigan for much of the past week. Even though high levels of low-level moisture (the “raw material” of precipitation) have been in place recently with dew point temperatures in the mid and upper 60s to low 70s, there has been a pronounced lack of any atmospheric focusing mechanisms to generate large scale/widespread convection. As a result, the showers and thunderstorms that have developed have been widely scattered with only limited aereal coverage. Looking at the season as a whole thus far, precipitation deficits from the beginning of April now have reached as high as seven inches in some sections of western Lower Michigan with normal rainfall only on the order of 8.0 to 8.5 inches. NOAA Palmer Drought Index values calculated late last week now characterize all but the east central Lower Peninsula in either “moderate” or “severe” drought conditions.

There are prospects for some relief from at least the heat for the next couple of days. The strong cool frontal boundary that passed through Michigan Thursday (June 30) will bring much cooler and drier air into the state Friday and Saturday. A warm front will move through the state late on Saturday, possibly leading to the chance for some scattered rainfall mainly across northern sections of the state overnight Saturday into Sunday. Otherwise, dry weather is expected Sunday in most locations.

Warm and humid weather with the chance for showers and thunderstorms is forecast for early next week (Monday and Tuesday), as another cool frontal boundary moves into the region. Temperatures will temporarily fall back to below normal levels Friday before a gradual warming trend begins this weekend. Daytime highs will generally remain in the upper 60s to the 70s Friday, gradually warming back from to the low 70s north to near 80 south Saturday to the upper 70s north to upper 80s to near 90 south on Monday. Low temperatures will warm from the 40s and low 50s Friday morning, back into the 50s to low or mid 60s again by Sunday.

The NOAA Climate Prediction Center 6-10 day (for July 6-10) and 8-14 day (covering July 8-14) outlooks suggest that the upper air ridge which has been dominated weather across the Midwest for much of the past week will shift westward to the Rocky Mountain region with weak troughing taking its place over the Great Lakes. The 6-10 day outlook calls for near normal temperatures and above normal precipitation totals across Michigan, while a return of above normal temperatures and below normal precipitation is forecast during the 8-14 day time frame.