Extension Educator, Local Food Systems and Small Farms
Extension Educator, Horticulture
April 30, 2010
Cedar apple rust is caused by a fungus that attacks two different groups of trees. The first group is apples and crabapples, and the second is juniper and eastern red cedar. In order to survive, the fungus must "move" from one group of host to the other.
On juniper, or eastern red cedar, small (3/8 to 1 and 3/16 inches in diameter) galls develop throughout the tree on needles and small twigs. When mature, these galls swell considerably and repeatedly produce orange, jello-like horns during rainy spring weather. As spring rains subside, the galls die, which may cause death of the twig from the gall to the tip.
On susceptible crabapples and apples, tiny yellow spots appear on the leaves after infection in the spring. As the spots mature, they become yellow/orange and swollen with a red border, and develop tiny black dots in the center of the lesion. By mid-summer, small cup-like structures with tubes are visible on the undersides of mature leaf lesions. The fungus may also infect fruit and tender twigs of very susceptible crabapple and apple varieties.
April 30, 2010
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. 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 23, 2010
April 23, 2010
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 23, 2010
A new weed problem has reared its ugly head in the Logan County area. Garlic mustard is making its presence known in many wooded, or formerly wooded, areas. No, garlic mustard is not exactly new, but it is expanding its range at a very speedy rate.
Garlic mustard is considered an invasive species, and some states have declared it a noxious weed. Illinois hasn't declared it such, at least not yet. The problem with garlic mustard is how quickly it spreads. It spreads so quickly it tends to choke out much of the desirable undergrowth in timber areas.
Garlic mustard is a cool season biennial herb with stalked, triangular to heart-shaped, coarsely toothed leaves that give off an odor of garlic when crushed. First-year plants appear as a rosette of green leaves close to the ground. Rosettes remain green through the winter and develop into mature flowering plants the following spring. Flowering plants of garlic mustard reach from 2 to 3-1/2 feet in height and produce button-like clusters of small white flowers, each with four petals in the shape of a cross.
Control of garlic mustard is somewhat difficult. Seeds can remain viable for at least five years in the soil. Small amounts can be pulled up (including the roots). Garlic mustard can re-grow from root material. For herbicides, glyphosate (Roundup) is the most often recommended. Remember glyphosate kills broadleaves and grasses it gets on. There has been some success with 2,4-D LV400 where there aren't concerns with other understory plants. Very large patches have been controlled with fire, but that completely destroys the understory of timbers. Remember to monitor areas for at least five years due to the seed dormancy period.
April 19, 2010
Early in the spring, there are many pests that become active. Many of these are timed by the saucer magnolia blooms, according to Orton's "Coincide" book. Spruce spider mites become active when magnolia blooms are in the pink stage. This means the 2010 weather is running about two weeks ahead of last year. Not much of a surprise given the temperatures we have experienced. These mites are one of the major downfalls of spruce in our area. One of the early symptoms is a "mottled" appearance to the needles. Another is fine webbing attached to needles.
To determine if you have spruce spider mites, hold a piece of white paper under a branch and shake it. The mites will look like moving dust specks on the paper. Many times, there will be some fine webbing, like spider web, visible on the needles as well.
Spruce spider mites can be controlled with sprays of acequinocyl, bifenthrin, cyfluthrin, insecticidal soap, or summer oil spray. The soap or oil sprays will require a second application about a week later to give good control. These mites normally remain active until mid-May, but the cool conditions may extend their life cycle, as happened last year. These mites will again be active in the cool fall weather.
Other spring pests are also indicated by the saucer magnolia. During the bloom stage, just finishing now, the ash plant bug, fall cankerworm, spring cankerworm, Fletcher scale, leaf crumpler, eastern tent caterpillar, juniper webworm, and Zimmerman pine moth are susceptible to control. As we get to the petal fall stage, European pine sawfly, Gypsy moth, hawthorn mealybug, honeylocust pod gall, and willow aphid become susceptible to control.
April 19, 2010
April 9, 2010
Many people have been asking about the Master Gardener Plant Sale for this year. It is scheduled for Saturday, May 1, 2010, from 9:00 a.m. until 12 noon in the Logan County Fair Special Events Building on the south end of the fairgrounds. They will have annuals, perennials, houseplants, heirloom tomatoes, peppers, and a few other assorted items.
April 9, 2010
A common maintenance chore in a perennial garden is that of dividing. 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 9, 2010
The green grass beckons. Of course, once you start mowing, you get to keep on doing it. There is certainly enough moisture, so add a little bit of heat and we'll be hard pressed to keep up this spring.
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 most 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. The variety of grass also has a lot to do with the thatching tendency.
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.
Mowing intervals depend upon grass growth rather than a calendar schedule. The spring and fall periods will require more frequent mowing than during the summer. That is in a "normal" year. Mowing frequently really reduces the labor needed for overall operations.
April 5, 2010
There are several "dead patches" of grass sprinkled throughout lawns in the county. Some of these patches are remnants of the crabgrass from last year, while others are more troublesome. These troublesome areas are starting to show a little bit of green coming on the "dead" stems. These types of patches are actually warm season grasses growing in your cool season grass lawn.
Warm season means just that. The grasses grow better in warm weather. They will green up about a month later, then brown out a month or more earlier than the rest of the grasses in the lawn. The warm season grasses can be escaped zoysia from a neighbor, or a weed type such as nimblewill. The end result is the same – these grasses are perennials, meaning they come up from the same root areas each year. This fact makes selective control, meaning getting them killed without killing the grasses you want, almost impossible. The control consists of letting these areas green up, then spraying them with glyphosate (Roundup), then reseeding. Since they don't green up early enough for the spring seeding times of March 15 until April 1, the best success is to usually spray these areas in early August and reseed from August 15 until September 10.
April 5, 2010
Each year, the winter annual weeds chickweed and henbit run number one and two in the early spring. Again, this year is seems like henbit is running slightly ahead. Winter annual weeds can actually germinate in the fall, carry through the winter, then get going very early in the spring. They also are done by the heat of the summer, leaving seed to germinate again later in the fall. Right now chickweed stands out in yards because it is quite abundant, and has a lighter green color than grass and most other weeds. I can't begin to tell you how to identify it, it gets even harder when there is common chickweed and mouse-ear chickweed. Henbit is easier to identify since it has purple flowers and smells like mint. As for control, that gets a bit easier.
The straight 2,4-D that is used on dandelions seems to act like a fertilizer for chickweed and other problem weeds. Combinations that contain 2,4-D, MCPP, and dicamba are rated very effective on chickweed, henbit, red sorrel, purslane, white clover, and others. Just remember the control time for most broadleaf weeds is early May. These combinations are sold under several different trade names. You can find these at most hardware, discount, and lawn and garden stores. Just check the label under active ingredients and check for two long chemical names and dicamba. You can also check to see that it says it will control chickweed and henbit. This group of chemicals is effective in the 50 degree range and up. It just takes a lot longer for control with very cool temperatures. As with any chemical control, read and follow label instructions very carefully. There will be some cautions on these product labels concerning injury to sensitive plants that you should be aware of. This is because dicamba can drift as a vapor for a few weeks after you apply it if the weather gets hot and sunny.