Extension Educator, Local Food Systems and Small Farms
Extension Educator, Horticulture
September 30, 2008
A common complaint this year has been the large amount of mushrooms and toadstools coming up in lawns. To begin with, these are in the decay fungi group. They are decaying old tree roots or lumber under the surface. This means there is no ready control for them, other than removing the material to be decayed.The best, and only, thing to do is physically remove them by raking, mowing, or picking. The spores grow when weather and temperature conditions are just right so you usually won't have them continuously, rather on an occasional basis.
September 30, 2008
Many people are commenting about the yellow and black "sweat bees" flying around everywhere the last week. The yellow and black insects that are commonly called sweat bees are actually syrphid flies.
Syrphid fly is a generic name given to an entire group of flies. There are some differences in appearance and color, but the yellow and black color is the major one in our area. The other names for syrphid flies are hover flies or flower flies. They tend to hover around your arms and face when you have been perspiring, and land to lap up the sweat. They are also commonly found on flowers, hence the flower fly name, and do a good job of pollinating.
Syrphid flies are actually beneficial insects. They help pollinate, larvae feed on dead organic matter, and the larvae are predators of aphids. They cannot sting, but their mouthparts can usually be felt when lapping up sweat from sensitive areas. You may feel a slight pinch.
Yellowjackets are the other common yellow and black insect this time of year. Yellowjackets can be very aggressive in biting and stinging. They are usually about twice the size of the syrphid flies, and the easiest way to tell them apart (without getting stung) is to count the wings. Flies have one pair, and bees and wasps have two pairs.
Yellowjackets are most frequently encountered when they scavenge for food. Their habit of feeding on nectar and sugar can create a nuisance. Yellowjackets are attracted to open cups and cans of soda and other sweet liquids. They are also attracted to open cans of garbage, bright flowery clothing, and floral scented perfumes. All outside garbage cans must be kept clean and well covered to reduce yellowjacket problems. Contact with the wasps can be decreased by reducing these attractions at picnics and other outings. In situations closer to home, the elimination of overripe fruit from gardens and orchards will dramatically decrease the number of scavenging yellowjackets. Holding gatherings indoors and using screens on windows will also help avoid yellowjacket problems.
As for the syrphid flies, no controls are going to be very effective. On the other hand, there really isn't much need for control. They are really a nuisance pest that is very agile. They will probably be able to avoid that aerosol spray. Inside the home, a swatter and a vacuum cleaner are probably the best tools.
September 30, 2008
During the late summer small insects, known as insidious flower bugs and minute pirate bugs, become real pests by producing painful bites on people. They are about 1/5 of an inch long with black and white markings on the back. They are beneficial insects most of the time while feeding on small insects and their eggs.
They are present all summer in area fields, flower beds, and other landscape areas. Most of the summer the insects are beneficial, but then they become quite the nuisance when their regular food source runs out. Their painful bite is caused by their beak breaking your skin. These insects don't suck blood or inject venom like mosquitoes.
People differ in their response to the bites. Some people react to the bites like mosquito bites, with swelling and itching. Other people have no reaction at all. Control of insidous flower bugs and minute pirate bugs is not practical. They are mobile, and the populations change greatly. Wearing dark clothing on may help, as the insects seem to be attracted to light colors. Repellents are sometimes effective, but not enough to make a recommendation. Try the repellents for yourself and see if they work for you.
September 25, 2008
To begin with, you may have noticed a very large number of brown needles on evergreens this fall. That may even have translated to large piles of needles under your evergreens in the past few weeks, especially white pines. Not to worry. Evergreens usually only keep one to four years of needles (one to two years growth for white pines) on the ends of branches. Depending on weather, the old needles will turn brown and drop off. Usually this is a gradual process that isn't noticed too much. This year it happened all at once. If the buds on branch tips are plump and green, odds are your tree is fine.
Several calls have come in concerning the proper time to prune or cut things back. Let's start with some flowers. Keep in mind that perennials keep building their food reserves until all the leaves and stems are brown. For peonies and other similar flowers, you want to wait until all the above ground plant parts are brown. Then you can mow them off, or cut them at ground level. This same principal goes for most perennial flowers – wait until the above ground parts are no longer green. For trees and shrubs, pruning is best done at other times. Flowering shrubs should be done after they flower, high sap flow trees are best done in December, and most other trees are best done in February. The evergreen trees and shrubs are best done in late June.
Crabgrass is nearing the end of its lifecycle. It comes up from a seed about the first of April each year, depending on temperatures. Seed has been viable for several weeks already, and that is what will make next year's crop. The seedling germination inhibitors do the best job on the annual grasses, and they can stop the cycle anytime you apply them. For now, let nature run its course since you really don't have any options anyway.
Lawn diseases have been very prevalent this year. We have had rust, brown spot, and dollar spot for the most part. Healthy grass has already begun to fill in spots, and will continue to do so through the fall. The rule of thumb is existing grass can fill in a spot as large as a dinner plate in one growing season. Extra fertility can help this happen, especially the P and K. To really thicken things up, and mow twice a week minimum until December, you can fertilize additionally the first week of October and the first week of November with fertilizers low in nitrogen. This means starter/winterizers or complete lawn and garden fertilizers.
Make sure you watch your pumpkins and squash as the wet soil conditions seem to be making things rot quicker than normal. Here are some rules for selecting pumpkins:
· Choose a pumpkin with a stem and never carry it by the stem. Pumpkins without a stem will not last long.
· Select a pumpkin with a flat bottom, so it will stand upright
· Avoid pumpkins with holes, cuts or soft spots. These areas will rot.
· Light colored pumpkins are easier to carve because the skin is not as hard as darker orange colored ones, but they will not keep as well.
· Wash the pumpkin with warm water and let it dry before carving. Use of a small amount of dishwashing soap in the warm water may help extend the life of the pumpkin.
· To make the pumpkin last longer, keep it in a cool place until ready to carve. After carving, coat the cuts with petroleum jelly.
· Carving should only be done three days ahead of Halloween. After cutting, the pumpkin will deteriorate rapidly.
· The use of a candle in the pumpkin will also make it deteriorate rapidly.
September 16, 2008
It seems like fall has snuck up on us. Of course the weather has been anything but predictable this year. It is very easy to notice the evenings are much shorter, and we have less time to do the things we need to do in the fall. Following is a list of things to get into your schedule over the next few weeks, and in some cases not to do.
Do a good job of raking up old fruit from under trees. This old fruit harbors many diseases and insects that could cause you problems for next year, if allowed to lay under the tree. Don't stop with the ground clean‑up, but also remove mummified fruit and small fruit from the trees and dispose of in another location.
We are now at the "breaking point" for the recommended time to seed grass seed. If you want to try it later, you may have excellent luck or have no luck at all. The next recommended seeding time is mid‑March to the 1st of April. Figure on about two pounds of seed per 1000 square feet of lawn for an overseeding, and four pounds per 1000 square feet for a newly tilled area. Hopefully the temperature and moisture situation will be more favorable than it has been earlier. In past years this meant too dry, and this year it means your seed may have been washed out or buried.
We are also at the breaking point for major renovation projects such as dethatching and aeration. However, the wet soils won't be very conducive to these practices. One thing that is going to work very well with the saturated soils will be rolling to level out uneven lawns. Usually if your problem is due to nightcrawlers, the problem will reoccur.
Now is a great time to go after those broadleaf weeds in the lawn. Make sure that you select the correct product, use the proper amount, and do not treat areas containing fall seeded grass. The rule of thumb is that you need to mow newly seeded grass at least 3 times before treating that area for broadleaf weeds. This means you don't try and do both in the same fall or spring seeding season. Broadleaf weeds that are perennial are sending large amounts of material to the roots to enable them to come up again next year, and translocated herbicides will be sent to the roots as well. Be warned this also means perennials such as shrubs are in the same boat.
Pruning chores for plants with a high sap flow should be done in December, while other pruning chores are best done in early February for deciduous plants, and in June for evergreens. Flowering shrubs are best done after they flower. Pruning now is often a recipe for greater chance of damage to plants. A hard freeze in mid-October will really wreak havoc on evergreens pruned at this time.And finally, the high rainfall amounts have led to flooding and saturated soils again. This will be extremely stressful on trees and shrubs. They require oxygen in the soil to keep roots active and alive. Since trees don't have gills, they can't get oxygen from water. Try to get standing water away from perennial plants as soon as possible. Two days can actually kill roots of some species. Of course, there isn't a lot you can do quickly for saturated soils. Long term you can look at improving the drainage or re-directing downspouts. The end recommendation is to keep things in good growing condition to allow them to recover quickly. This means fertilizer if you didn't apply it to the grass. We don't need to worry about water at this time. About eight pounds of 12-12-12 per 1000 square feet of branch area will help.
September 9, 2008
Many of you are interested in becoming Master Gardeners in Logan County. It's a great group of people, offers many volunteer opportunities, promotes community service, and nurtures your love of horticulture. We were scheduled to have training this fall in Logan County, since we have the opportunity to offer training alternating falls. However, all trainings have been put on hold due to some restructuring at the state and regional levels. The next batch of trainings will be this coming spring.What this means is no trainings locally for two years. Tentatively, there are trainings scheduled to begin in Bloomington and Springfield/Decatur this coming January. Trainings will go for at least 10 weekly sessions of approximately eight hours each. Cost has not yet been determined, nor have the specific dates. If you are interested in receiving information when it comes available, contact Don Miller in our office to be placed "on file."
September 9, 2008
Much damage has already been done to trees by diseases and insects. Fall traditionally brings more insects intent on devouring the leaves remaining. Let's begin by listing some of the culprits. Fall webworms, Eastern tent caterpillars, Tussock moth larvae, Walnut caterpillars, Cecropia moth larvae, and a host of others are all considered fall defoliators. What is defoliation? It is simply removing the leaves from a plant. This group of insects accomplishes the feat by eating leaves.
What does fall defoliation do to a tree or shrub? It does two things. First it removes the leaf tissue so that less food is made for the plant. Second, the insects, their webs, or their damage can be unsightly. In the end, damage happening to a tree or shrub in September is usually cosmetic, unless you have new transplants or plants that aren't healthy to begin with.
Most fall defoliators come to us as the larval stage (caterpillars) of a moth. When we talk about controls of the larvae, the fact that they are larvae of moths or butterflies makes them susceptible to the use of B.t. products such as Thuricide. Other control options include the standbys such as Sevin, diazinon, Othene, malathion, and others.
The way that insects live also dictates some of the control do's and don'ts. Fall webworms live inside a "web" all the time. They actually expand the webbing as they need to have more leaves to eat. They are usually worst on fruit and nut trees. You can even clip the nest (and the branch it is around) off the tree and burn it. I guess this tells you that defoliation caused by the insect isn't that great of a threat to the tree or you wouldn't cut the branch area off. If you want to spray fall webworms, you need to get the spray through the web. This may be a little harder than you think. If you don't have enough pressure, the spray just runs off the webbing.
In the case of Eastern tent caterpillars, they hatch out of a common nest. They then leave the nest to feed, but generally return in the evening to congregate in the area of the nest. They are not covered by webbing, and the time they are congregated is a great time to spray since they are usually in one area on the trunk or main branches of trees.
Of the other fall defoliators mentioned, the giant Cecropia moth larvae are quite a sight. If you are able to see one. They are very large caterpillars that can eat tremendous amounts of leaves in a hurry. There are other related moth larvae such as Prometheus moths, but they are all in the giant silk moth family and the moths usually have wing spans of at least four inches.
In summary, control of fall defoliators isn't usually justified from the plant's standpoint. Forested areas have heavy pressure from this group in insects every year, and the trees are still thriving. The exception is newly transplanted or struggling plants. If appearances are important, consider a control spray.
September 3, 2008
There have been many findings of the emerald ash borer in central Illinois over the past month, including Bloomington, Chenoa, LaSalle County, and Bureau County. What does this mean for us? It means the borers have been active and undetected in areas for a long period of time. That is part of the problem with the emerald ash borer: it can be in a tree for three to five years before any visual symptoms are available to help us diagnose the problem.
Add into the equation there are other diseases and boring insects that cause similar problems, and we end up with some confusion. Much of the information Illinois is using has come to us from Michigan State University, where they have been battling the problem for many years. Symptoms of infestation of emerald ash borer include canopy dieback, shoots coming from the base of the tree, splitting bark, serpentine feeding galleries under the bark, increased woodpecker activity, and "D" shaped exit holes. Remember, many other problems cause many of these same symptoms.
Emerald ash borer does not do well moving from one place to another on its own. Most of the help comes from humans moving firewood, lumber, or other items made from infested trees. This movement of products is why the insect "leapfrogs" from one place to another, often many miles away.
Many people have asked to have their ash trees looked at to see if they have it. That is all well and good, but remember it can be in your tree for up to five years before it shows any symptoms that can be seen. The other question is how do I save my ash tree? To that end, here are some of the things to look at when considering an attempt at insecticidal control.
Phil Nixon, Extension Entomologist, has several things to look at in his list. First, the only certain method to control emerald ash borer is to remove the tree. This sounds extreme, but any control attempt is only effective in the 80 to 90 percent range. Second, the cost of treatment over a span of years should be looked at. It might only cost $35 to treat for one year, but that will really add up over 20 years with increasing costs each year. And third, a tree in a regulated are is subject to removal by governmental agencies regardless of whether it has been treated or shows signs of infestation.
There are treatment options for professionals and homeowners. It is recommended to preventatively treat ash trees no more than 15 miles from known infestations. Control is usually more effective on smaller trees, and treatment is not as effective on trees already infested. The major treatment option for homeowners is to apply Bayer Advance Tree and Shrub Insect Control (contains imidacloprid) as a soil treatment on an annual basis. This treatment will be more effective in the spring, and it takes a month or two to translocate in the tree. Also remember your tree can still be cut down if it is in the zone of a known infestation, whether it has been treated or not.If you see emerald ash borer or its damage, you may call the Extension Office at 732-8289 or the Illinois Department of Agriculture at (800)641-3934. More information is available online at http://www.IllinoisEAB.com and http://www.emeraldashborer.info/