Extension Educator, Local Food Systems and Small Farms
Extension Educator, Horticulture
April 29, 2011
Everyone seems to have been waiting for warmer temperatures and the appointed date to begin broadleaf weed control programs. Well that time will come, believe it or not. For most of the broadleaf products to work, the temperature has to be over 55 degrees. The cool temperatures, and high winds, are playing havoc with applications; however, the weeds are still growing. These chemicals do work better when it is warmer and the weeds are actively growing. The first item of business is to know what type of weeds you want to control. This will make a big difference in what product or products you select.
The main products used for broadleaf weed control in lawns are 2,4-D, MCPP, dicamba, a combination of those three products, and triclopyr. Let's start with the triclopyr since it's probably the easiest to discuss. Its place in weed control is for hard to control weeds and woody plants. It also improves control of violets. It can be added to one, or more, other chemicals to provide broad spectrum control. Some blends now contain trichlopyr, so check the label. There are many trade names for products containing trichlopyr, and they seem to change every year. Just check active ingredients.
2,4-D is the old standby. It is good on carpetweed, chicory, dandelion, lambsquarters, plantains, and wild carrot. There are amine forms and ester forms. The ester will generally give better control of more weeds, is generally not water soluble (except for a hard inch of rain soon after application), but it does have vapor drift potential. MCPP is good on chicory, lambsquarters, and white clover. Dicamba is good on black medic, chickweeds, chicory, dandelion, dock, henbit, knotweed, lambsquarters, pearlwort, purslane, red sorrel, thistles, white clover, wild carrot, and yarrow. The combination of all three products will pick up all of those listed for the individual products, plus a few more such as mallow, speedwell, and wild onion. The combinations are sold under many different trade names so check the active ingredient list for ones you need.
My annual disclaimer for application of these types of products is: "Beware of potential drift from these products." Not only can the spray move under windy conditions while you are spraying, but particularly with dicamba, the products can drift as a vapor for up to two weeks after spraying with hot and humid conditions.
April 29, 2011
With a significant frost last week, many are questioning the effects on plants such as rhubarb. Yes, frosted rhubarb does release a poisonous acid from the leaves into the stems, but it usually takes a temperature of about 28 degrees to cause leaf damage. With most area temperatures reaching a low of 31 or 32, we would not expect the leaf damage. Check for yourself. Rhubarb leaves damaged by frost will first have water-soaked areas around the edges, then those areas will turn brown or black. If this does occur, you need to pull the stalks and start over.
Effects on other fruits are similar. Most significant fruit production is not affected unless temperatures in the 28 degree range occur. Apples, peaches, apricots, etc. would all be in this same grouping.
April 21, 2011
According to Kelly Estes, University of Illinois Entomologist, the brown marmorated stink bug (BMSB) has been making headlines in Illinois the past couple of weeks. After the first confirmation of this invasive insect was reported in the fall of 2010 in Cook County, additional reports have been received from Kane County, McLean County, and Champaign Counties in 2011.
Like many invasive species, BMSB has a long list of host plants, including many woody ornamental trees as well as several agricultural crops including fruit trees, grapes, tomatoes, corn, soybeans and others. Also, like many other invasive insects, it is easily moved from location to location by humans (hitchhiking on vehicles, movement of shipping materials, and movement of plants). In addition to feeding on plants, BMSB is also considered a nuisance pest to homeowners. Much like boxelder bugs or multi-colored Asian lady beetles, these stink bugs congregate on houses in late fall and move indoors. Homeowners are likely to first spot new infestations as these insects will initially feed on common landscape ornamentals.
Unlike many insect pests that only attack plants during certain times of the growing season, the BMSB will feed on host plants all season long. This causes great concern in fruit crops where they begin feeding early in the season and continue through harvest. Growers should monitor fruit for sunken areas where the insect has fed. These areas will be discolored and corky areas will be present under the skin of the fruit. In corn and soybean, BMSB feed on the developing pod or corn ear. They are able to feed through the husks and pods with their sucking mouthparts, causing shriveled kernels and beans, respectively. In tomatoes and peppers, feeding will also result in corky areas and discoloration, much like injury in fruit.
April 21, 2011
One group of problems showing up is galls. Galls are swelling of leaves, twigs, or other plant parts. Most are caused by mites or wasps. They damage the plant parts and the plant responds with a gall. In the case of leaves, the swelling is actually leaf tissue. This is something I like to refer to as similar to you getting a mosquito bite. The damage comes in and a swelling occurs. There is no way to get rid of it without tearing a small hole in the leaf. The maple leaf bladder gall will be easily spotted on silver maples in the area shortly, and oak leaves in the red oak group are also showing galls.
Oak trees probably have more galls than any other group of trees. Several samples have also been brought in of the stem types of galls. Fortunately, the oak galls are usually not the type to kill tissue beyond them. However, the galls aren't the most pleasant things to look at. That is the main thing – they are unsightly. There is no cure for galls, as they are caused by insects before you see the swellings. The timing would be impossible to try and prevent the insects.
April 21, 2011
April 15, 2011
What a difference a few 80 degree days made! One common maintenance chore evident this past weekend was that of dividing perennials. There is no set rule as to when to divide perennials. Some may need division every 3-5 years, some 8-10 years and some would rather you not bother them at all.
Perennials will send signals to let you know that they would like to be divided. The signals to watch out for include: flowering is reduced with the flowers getting smaller; the growth in the center of the plant dies out leaving a hole with all the growth around the edges; plant loses vigor; plant starts to flop or open up needing staking; or it just may have outgrown its bounds. These are the signs to look for and not a date on the calendar.
If division is indicated, spring is the preferred time to divide. Some fleshy rooted perennials such as poppy, peony, and iris are best divided in the late summer to very early fall.
Division is usually started when growth resumes in the spring. The process starts by digging around the plant and then lifting the entire clump out of the ground. Then, using a spade or sharp knife, start to cut the clump up so that each clump is the size of a quart or gallon sized perennial.
Discard the old, dead center and trim off any damaged roots. The divisions should be kept moist and shaded while you prepare the new planting site. After replanting, water well and protect the divisions from drying out. Division is no more complicated than this. Some perennials may be more difficult to divide than others because of their very tenacious root system. Division has as its primary goal the rejuvenation of the perennial planting, so it can continue to perform the way it was intended. Many home gardeners have found that the process of division is more traumatic to the gardener than it is to the perennial.
April 15, 2011
April 15, 2011
April 6, 2011
One of the main things to discuss today is the removal of nuisance fruit. You may be thinking about those apples or peaches, but really the nuisance fruit category includes things that are much more a nuisance like sweet gum balls, maple seeds, and crabapples.
There are several products available to eliminate nuisance fruit. The most common is ethephon, and it is used as a foliar spray to reduce or eliminate undesirable fruit or seeds. Some of the trade names include Florel and Ethrel. The product is effective at eliminating much of the fruit without affecting leaf growth and color, and it does not harm other plants that get some spray drift on them. It also does not affect the actual flowering of the treated trees.
With ethephon, the key is in the timing. The application must be made during flowering, but before the fruit set in. For most flowering trees there is a 10-14 day window of opportunity. Sweet gums are a little tricky since there are no showy flowers involved, so effective sprays should occur just as new leaves begin to emerge. Sprays should leave leaves wet, but not to the point of dripping. Good coverage of the tree is needed, so keep in mind the size of the tree when you are weighing this option. There are injectable products available, but must be applied by a professional. The injectable products have not been as effective as the sprays.
This product is a growth regulator that naturally occurs. Its natural production is stimulated by stress, so make sure you aren't treating a tree that is under stress from drought, high temperatures, diseases, or other environmental stresses. Treating stressed trees can cause severe injury to the plant such as leaf loss or scorching.
April 6, 2011
Crabgrass seed has already germinated, and will continue to do so throughout the spring and summer months. Preventative treatments will still do some good for seed that will germinate over the next six to eight weeks, but won't get seeds already germinated. The organic arsenicals, such as DSMA and MSMA, will control newly germinated grass. Remember, you should have a second preventative application around June 1 for summer control of crabgrass and other annual grasses.
The time to begin mowing has already arrived in some areas, and there are a few very simple rules for mowing grass. The first is to use equipment that is ready for the job. Make sure the mower has sharp blades. Dull blades will show up as injury on the grass blades like brown tips and jagged edges. Blades can be sharpened in several ways. Using a file or grinder are the more common methods.
Next is the rule of one-third. Never remove more than one-third of the leaf blade at any one time. This rule must be followed if you don't want to catch, or rake the grass. A good general mowing height for combination bluegrass and fine fescue is about two inches. This would mean that you would need to mow every time the grass reached three inches in height.
Bagging grass clippings may actually add to the build-up of thatch (that dead matted layer on the soil surface). Thatch is broken down by microbes at the soil surface. Without a food source, the microbe numbers crash, and any clippings remain, without breaking down.Mulching is OK. It isn't a cure-all, and it does take quite a bit of extra power to accomplish. The final word is that grass mowed on the on-third rule doesn't need to be caught or mulched. Bagging takes time and the clippings must then be disposed of. Mulching takes extra power and fuel.