Landscape and nursery
§ Fall webworms make a splash
§ Honey locust knot
§ Nursery research conference report
Turfgrass
§ Status of grub infestations in Michigan
§ Turf establishment and renovation
§ Poison ivy control options
Around the home
§ Mosquito season – it ain’t over yet
§ A sad end for a feral honeybee colony
§ Photo resource for home vegetable growers
§ Get growin’ with MSU Extension Master Gardener Program
Other news
§ Weather news
Just about everywhere you go in southern
Pruning-out infested branches is the best strategy if you
can reach them. Spraying the foliage around tents with B.t., Sevin, Orthene, or a pyrethroid
insecticide will prevent further feeding injury, but the old tent will remain
visible. We have many natural parasites and pathogens of fall webworm that will
bring these infestations under control. Places with lots of fall webworm this
year may not have much next year. Outbreaks usually last two or three years.
MDA inspectors recently found and ordered destroyed a
shipment of honey locust (Gleditsia) infected with knots or
galls. The disease has been dubbed honey locust knot. The infected
plants came from a large supplier in
The disease is thought to be caused by a bacterium, Pseudomonas syringae pv. Savastano. This bacterial disease is relatively common on olive and oleander plants in the tropical/semi-tropical areas of the world. It is known that there are different strains of this bacterium. The bacteria enter and infect plants through leaf and blossom scars, wounds caused by pruning, mechanical damage, hailstorms or strong winds. Rain, sprinkler water and pruning tools can spread bacteria from diseased to healthy plants. Common names included tuberculosis of olive-tree, olive knot and oleander gall. This pathogen is noted having different strains that occur worldwide. The known hosts include olive, oleander and ash trees.
Descriptions of this disease indicate that the galls occur on twigs, branches, leaves, flowers and seedpods. Initially galls appear as small protuberances that subsequently develop into wart-like growths with roughened, fissured surfaces. Galls vary in size but average about a half to one inch in diameter with larger galls made up of several small galls that have grown together.
Growers and homeowners are encouraged to report instances of this disease to the Michigan Department of Agriculture. A list of offices and contact numbers can be found at: www.michigan.gov/mda, key word Regions.
Diseases of Urban Plants, University of Arizona, Cooperative Extension, Mary Olsen, Plant Pathologist, May 1999 = http://ag.arizona.edu/pubs/diseases/az1124/#og
Tuberculosis of Olive-Tree, HYPP
Pathology = http://www.inra.fr/Internet/Produits/HYP3/pathogene/6pssysa.htm
Dateline
Wenliang Lu (
As one would expect in the South, water issues were a
primary concern. Several papers were presented on water conservation and
remediation of run-off. Sarah White (Clemson) reported that the two-stage
constructed wetland she has been monitoring at a cooperating nursery is
extremely effective at removing nitrate nitrogen from nursery run-off. However,
the systems are much less effective at removing phosphorus. Graduate students
from Ted Bilderback’s lab (N. Carolina State)
reported on substrate amendments to reduce water use. Michele McGinnis reported
that amending media substrate with vermicompost
(earthworm castings) reduced water use by up to 11%. Jim Owen’s
research demonstrated addition of calcined clay to
media improved water and Pretention. Richard Beeson (
Frank Henning (
Alan Hodges (
Charles Hall discussed a recent survey of national nursery
marketing practices. A few tidbits: 61% of nurseries nation-wide sell natives plants,
Past SNA Research Conference proceedings are available on-line and this year’s proceedings will be added soon. A link is available on my department page (http://www.hrt.msu.edu/faculty/cregg.htm)
Japanese beetle and European chafer are by far the most
important grub pests of turfgrass in
Several species of native June beetle grubs occasionally
cause turf damage (especially when skunks or raccoons dig-up turf to eat them)
throughout the state. Oriental beetle has been found near
Ataenius and Aphodius are about the same as they were 10 years ago: a sporadic problem on golf courses throughout the state.
Two new products are now available for professionals to control grubs: Allectus and Arena.
1. Allectus: imidacloprid + bifenthrin (like Merit + Talstar). Bayer and FMC have joined forces to
offer a product that combines grub control with surface insect control. Imidacloprid has been a turf standard for grub control for
many years, and bifenthrin has good activity on
cutworms, ants, ataenius adults and annual bluegrass
weevil (not found in
2. Arena: clothianidin. Arena is a new turf insecticide in the same chemical class as Merit. In the first two years of testing, it has worked at least as well as Merit for grub control. Like Merit, it works great for grubs when applied in June or July for late summer and fall grubs. We are in the process of testing May and September applications to see if they work as well as the July application.
The summer of 2005 was the perfect example of why we recommend that the best time to establish turfgrass is in the later summer or early autumn. I have heard numerous stories of seeding failures from homeowners, lawn care operators and whoever else has tried to establish turf this summer. The high temperatures, sporadic rainfall and high humidity have resulted in very stressful conditions, plenty of disease and numerous seeding failures. Often, the common thread in many of the failure stories is from the inability of the person caring for the turf to avoid fertilizing or watering the turf out of the poor condition. By adding more fertilizer and water, the turf manager just increased the odds of disease wiping out the complete turf stand. OK, we’re past all of that now – the weather should be better – and turf seeded in late August to early September should bring sanity back to the landscape.
Some of you may be trying to rescue a less than stellar summer establishment; others may be starting from scratch. If you’re looking to rescue an earlier establishment, make sure to make a sober assessment of the amount of turf surviving. If the turf was simply thinned from the tough summer or there are small patches of dead grass, a fertilizer application and a return to cooler temperatures should help the existing turfgrass stand to recover and fill in those bare spots. If the damaged areas are large, for example I have seen sites where 15 x 30 ft. areas essentially have only sporadic green turf plants, and plenty of crabgrass, areas this large are going to require reseeding.
For the mid-Michigan area, the recommended latest seeding
date for ensuring success is about September 15. As you travel north, the
latest seeding date is going to creep up until you get to the
First and foremost you must ensure that you get good seed to soil contact, i.e. seed sitting on top of the soil or simply broadcast spread onto the soil without creating any holes or slits will probably not be successful. There are several options for creating the holes/slits to ensure seed-to-soil contact. Machines such as core aerifiers, power rakes, slit seeders or even hand raking small areas should get the job done. For established areas that may just need a light overseeding to improve density, a core aerifier is an option. Be careful with core aerifiers that the holes don’t get too deep; ideally you want to place the seed at a depth of 0.25- to 0.5-inch. For areas that need lots of help, slit seeders are the best choice, these machines operate by creating a slice in the soil that the seed falls directly into, ensuring seed to soil contact. Many lawn care companies offer this service or if you’re a do it yourselfer, slit seeders can usually be rented at the neighborhood rental store.
Making sure you have the correct species, especially if you
are “patching” an existing lawn, is a critical step to ensure satisfaction. One
concern many property owners have about seeding into an existing lawn is
whether or not the newly seeded turf will blend with the existing turf. I
wouldn’t lose too much sleep; lawns and landscape turf in
Spreading a light mulch cover on top of the newly seeded area will help the soil retain moisture and keep the seedlings from drying out. The recommended rate for using straw mulch is 1 bale of straw/1000 sq. ft. Be careful with how much mulch you apply, you don’t want to end up smothering those young seedlings. Apply enough so you can still see about a third to half of the soil underneath. There are also numerous, more sophisticated mulch products that are easier to spread than straw and expand with moisture to cover the soil. Even something as simple as turf clippings can be used as a mulch, once again don’t spread them too thick over the area.
At the time of seeding, apply a starter fertilizer at a rate of 1 lb. N/1000 sq. ft. to help those young seedlings get established. Make sure to keep the seeded area moist throughout establishment. In many cases, this may require watering several times a day. A good mulch cover will help the area stay moist so the site may be watered less frequently. Water lightly when irrigating, there is no need to see water puddling or running off the site.
To be safe, avoid applying all herbicides this autumn, i.e. no fertilizer + broadleaf weed control products. Young seedlings don’t tolerate herbicides very well and the guideline is usually to wait three "real" mowings before applying any herbicides or in some cases at least 60 days. By "real" mowings, I mean you’re actually cutting significant grass, not just running over the area to trim down any weeds. Finally, don’t be afraid to get out there and mow the area. Mowing turf helps it spread laterally and fill the area, so start those engines as soon as you start to see the grass creep up to about three inches.
Poison ivy is an aggressive perennial vine that takes some dedication and persistence to eliminate. Physical removal can be tricky because of the inherit perils of breaking out in a rash. Poison ivy is most susceptible to chemical controls when sprayed in the late summer and early fall. At this time the poison ivy will be transporting energy reserves to the root system to ensure next year's growth. Products containing triclopyr and 2,4-D or triclopyr and glyphosate (e.g. Roundup Poison Ivy Killer) are the most effective.
In addition to following the label directions, be mindful that either of these products will kill any broadleaf plants to which they are applied. If you use the product that contains glyphosate it will kill any green plants that come into contact with the spray solution. I would recommend making your first application in the next few weeks (before Labor Day) and then again one month later. It is OK if you don't see a lot of injury on the poison ivy after you make the applications. Actually, the healthier the top remains the better the product is being moved into the root system. You should notice a big difference next spring. I would keep a small amount of spray solution handy for follow-up, and spot treat the ivy at first signs of growth next year.
It’s been a relatively subdued year thus far for mosquito
activity and related disease threats.
This is not to leave you with the idea that every mosquito you might come across presents a grave danger. However, it’s still prudent to take precautions against being bitten. Disease transmission isn’t necessarily related to overall mosquito numbers – it’s more a function of the particular mosquito vectors present and the percentage of their population carrying the virus. Aside from disease risks, however, mosquitoes are simply annoying and protection from being bitten is most often a question of comfort. It’s important to remember that we have about 60 species of mosquitoes in the state and each has different “favorite” habitat, host range and seasonal activity schedule. The mosquitoes trying to bite you in the spring are not the same ones looking for blood in late summer. It’s one of the reasons that nuisance mosquito problems tend to be sporadic from year-to-year and within a season. Even if rainfall isn’t particularly heavy, there are plenty of aquatic habitats capable of serving as breeding sites and some species use these exclusively. Most particularly “bad” mosquito years or periods do involve an increase in temporarily flooded areas – e.g., river flood plains, roadside drainage ditches. In our region, summer rains heavy enough to keep low areas in fields submerged for over a week are usually a sign that we’ll be inundated with what are known as “summer flood water” species. If this group emerges along with either the spring species or late summer species that inhabit permanent water bodies, then nuisance becomes a term of understatement. Fortunately, we haven’t seen those conditions this year – rainfall hasn’t been excessive and the ground has rarely been saturated.
There are relatively few new approaches to minimizing your
chances of mosquito bites. The basic common sense approaches still apply.
Repair screens, minimize outdoor activity between dusk and dawn, eliminate
mosquito breeding sites where possible or practical, and use an effective
repellant. In past articles on mosquito avoidance, I’ve recommended using
repellants with 10 to 30 percent DEET. I still recommend these, but am happy to
report that there a few newly available alternatives that approach or equal the
effectiveness of DEET. The CDC now lists repellant formulations with picaridin (also known as KBR 3023. Sold under Cutter brand)
and lemon eucalyptus oil (active ingredient PMD = p-menthane-3,8-diol. Sold under Repel brand).
Both of these tend to be less irritating than DEET-based products and give
protection duration comparable to 15 percent DEET products. All three products
work to mask attractive odors and confuse host-seeking female mosquitoes. Picaridin has been widely used in
An additional protective measure that has recently emerged
on the market is the use of permethrin-impregnated
clothing and fabric. Permethrin, of course, is a
plant-derived insecticide with an excellent safety record and widespread use.
It’s approved for use in animal flea collars and for control of head lice in
humans, so it has low toxicity risk even with prolonged and direct
applications. Permethrin-impregnated bednets have been used for years as an effective means of
malarial control in
Editor’s note: This
week’s article is accompanied by several pictures. To view the first slide of
pictures, click here and then follow the “next” buttons to view
following images.
Wild (or feral) honeybees have been struggling to hang on
ever since the Varroa Mite and Tracheal mite were
introduced into
Honeybees are much more serious than wasps and yellow jackets when they decide to nest in our homes. With yellow jackets, one can simply kill the colony and leave the clean up to the carpet beetles. Not so with honeybees. Honeybees store many, many gallons of honey in their colony to get them through the winter, and it’s the honey that makes them far more complicated than yellow jackets. If one decides to kill off a hive of honeybees that has taken up residence in one’s home, then the honey, comb and dead bees have to be removed. Honeybees store their honey in wax combs. If the bees are not present to ventilate and cool the honeycomb with the beating of their wings, the wax melts and the honey is free to flow wherever gravity takes it. Besides the honey, there is the matter of the thousands of dead, rotting bees (very smelly) to contend with too.
Last spring, scout bees from a nearby honeybee swarm
investigated two holes in the wooden siding on the second floor of Jackie’s
Tim started the process by treating the outside entrances to the colony with a pyrethrin-based dust material and then waited a few days for the dust to work. The real dirty work then moved inside.
Since it is a lot less work to repair interior walls, it’s best to cut a hole on the inside wall where the colony is located to remove the comb. To insure the colony residents were no longer a threat, Tim determined the extent of the colony with a stethoscope and drilled several holes in order to douse the colony with a synthetic pyrethroid insecticide spray. Once that was completed, Tim cut a hole in the lath boards and plaster and removed the comb and dead bees. Fortunately, it was a small colony and there wasn’t a lot of comb to remove. Now all there is left to do is to repair the gaping hole in Jackie’s wall.
Too bad for the bees. Hopefully their comeback will continue, and they choose somewhere other than Jackie’s house to set up shop.
http://creatures.ifas.ufl.edu/misc/bees/varroa_mite.htm
http://creatures.ifas.ufl.edu/misc/bees/tracheal_mite.htm
http://creatures.ifas.ufl.edu/misc/bees/varroa_mite.htm
http://creatures.ifas.ufl.edu/misc/bees/tracheal_mite.htm
Home vegetable gardeners can tap into a web resource
specific to current vegetable growing problems in southeast
Retired veteran vegetable crop agent Paul Marks is scouting commercial vegetable crops part-time this growing season and posts weekly updates that often include photos of current problems. The whole list of reports and photos are available with the most current report at the top. His photos and comments may help home growers diagnose such summer vegetable problems as virus or powdery mildew on pumpkins; corn and squash vine borers; blossom end rot and poor pollination, etc.
Home gardeners may wish to contact their
I’ll bet you have heard the term many times; MSU Extension Master Gardener. Have you ever pondered what the heck it is? The black belt of gardening? The king of compost? The Jack of the beanstalk? The answer just may surprise you.
The MSU Extension Master Gardener program began in 1978 in
Much has changed since that first class in 1978 says
Kent/MSU Extension Master Gardener Coordinator Gordon Griffin. To qualify as a
MSU Extension Master Gardener, a candidate must successfully complete the basic
training course and a minimum of 40 volunteer hours in the area of horticulture
education. No requirements are necessary to enroll in the class except a desire
to learn about plants and grow. “We have had people come into this training
program completely “green” (no pun intended) as well as people that work in the
green industry or with a B.S. in horticulture,” said
The training program consists of twelve basic topics including plant science, soils and managing plant health. Specific classes like flower gardening, fruits and vegetables are taught by MSU Extension specialists and industry professionals. “I really never thought I would be interested in lawns,” said Stacey VanderEide a 2004 Student. “The teacher made the subject come to life for me and I am much more aware of my own lawn at home,” she said. Another benefit to VanderEide and many others is that they become more ecologically conscious as gardeners. “For instance, I learned that I could reduce water usage in the lawn if I raised the mowing height – now that’s smart,” she said.
MSU Extension Master Gardener programs begin in the fall or
winter and are offered at a variety of locations and times including daytime
and evening. Accessing a schedule for your area is as easy as tapping into the
State MSU Extension Master Gardener website at http://www.msue.msu.edu/mastergardener
then click on you county.
Drahiem sited volunteer activities that have gone well beyond the program founder’s expectations in the 70s. “We never envisioned all the types of work that MSU Master Gardeners would do, nor the skill level individuals bring to the program,” he said. People have used the MG program to launch a career in Horticulture and obtain a degree. “We also never envisioned that it would generate gardening businesses like it has,” said Drahiem. “New gardening businesses pop up every year, owned by an entrepreneurial MSU Extension Master Gardener.”
After several weeks of a persistent ridging pattern across the
central
Temperatures during the next few days will remain near or slightly below normal levels with highs ranging from the low and mid-70s north to mid-80s south and lows from the upper 40s north to low 60s south.
In the medium-range time frame, computer model guidance is
suggesting that the formation of an upper air troughing
pattern in the western