Welcome to Pest Alert. Categories for topics are as follows, H - Herbaceous plants and flowers, W - Woody Plants, V - Vegetables, F - Fruit and L - Lawns.
DISEASES
W ANTHRACNOSE SYMPTOMS are showing up on a number of deciduous trees. We have received numerous calls from homeowners that are concerned about finding "spots" and browning leaf margins on their trees. While premature foliage drop is never good, the loss of these leaves can not be prevented at this time of year. Control of these leaf diseases is best done in the spring.
WEED CONTROL
L FALL LAWN WEEDS. We are now approaching the time of year to treat white clover, field bindweed, ground ivy or other perennials. Mid-September through October are usually good target dates. It will work better, it's cooler and there is less risk of affecting sensitive plants like tomatoes, peppers, grapes and other ornamental and fruit plants. However, even in late fall, apply these chemicals carefully.
L THISTLES. Thistle seed found its way into many home yards and plants are now appearing. Biennials form rosettes -- several inches across. Dig them like a dandelion or use a fall herbicide containing 2,4-D and apply to the rosette in lawns. Canada thistle have smaller shoots and require retreating with a broadleaf lawn spray product for best results.
OTHER NOTES
V ASPARAGUS FERN GROWTH should be allowed to remain on the plant until it freezes this fall. It can be removed this fall or it may be beneficial to let it remain until spring. The fern growth will act to catch snow during the winter which will provide extra winter protection and moisture for next year's crop. Rhubarb foliage should also be allowed to remain until it dies down naturally.
W COMMON BUCKTHORN. We have received lots of samples of this commonly found shrub this year. Common buckthorn, Rhamnus cathartica is identified as a shrub or small tree with small, dark green, elliptical leaves, and produces clusters of small black fruit. Many homeowners confuse the form with a crab apple. The twigs also end in a small thorn. Apparently it was a good year for fruit production and lots of would-be jam and jelly makers are wondering if the fruit is safe to eat and use. While the fruit is not considered poisonous, it does have laxative properties, (cathartic - evacuating the bowels) therefore, eating the fruit is not recommended. Birds will often eat the fruit and then "deposit" the seeds all over the yard. Consequently, buckthorn seedlings are frequent weeds in many yards.
L BROWN BUFFALO GRASS LAWNS will soon be a common sight when the cool and frosty weather arrives. Also, people that have other warm season grasses like zoysia or blue gramma will see their lawns browning up too. Some lawns have already turned brown. If someone knows they have a buffalo grass lawn, they are probably expecting their grass to go dormant as temperatures get below 50!. However, for some homeowners, that may only have a patch of this warm season grass in their lawn, it may be quite disturbing. Buffalo grass typically grows in patches, is a lighter green than bluegrass, has small flattened seed heads and spreads over the ground by stolons. It can make a fairly nice, low maintenance lawn in some areas. But, it does brown-up early in the fall and is slow to green-up in the spring.
One significant benefit to this early dormancy is that it provides a very safe treatment window to control unwanted vegetation including broadleaf weeds and even cool season grasses. Roundup can be applied after the buffalo grass is completely brown to selectively control these unwanted plants. L LAWN FERTILIZATION is best done in the fall, especially for those lawns that are not highly maintained, i.e. watered all summer, clippings are removed and the grass is mowed fairly short. One or two applications should provide most of the low maintenance lawn's nutrient needs for the next year. Apply 1 lb. of actual nitrogen per 1000 sq. ft. now and again, if desired in 4 to 6 weeks. An ordinary, quick-release lawn fertilizer is all that is really needed but a fertilizer that has about 25% slow release nitrogen can be beneficial. "Winterizer" fertilizers, which are lower in nitrogen and higher phosphorous and potassium are not really necessary unless your lawn is deficient in these nutrients. However, a complete fertilizer should be used, one that has a ratio of 4:1:2 will work well. Applications of nitrogen are rapidly taken up by the plant, stored for winter and Fall utilized next spring for new growth. Fall nitrogen applications generally will NOT cause a huge flush of top growth because the plant is naturally slowing down top growth at this time of year.
W MANY TREES ARE BEGINNING TO DROP THEIR LEAVES a little prematurely due to the dry weather many areas of the state have been experiencing lately. While this is not a major concern, the early loss of foliage can leave the tree slightly stressed. If your trees are experiencing some symptoms of drought, wilting or curling foliage or premature loss of foliage, you should consider supplemental watering. Moisture applied at this time will not reduce winter-hardiness, and can increase it particularly for evergreens. Watering just before freeze-up is too late.
H PERENNIAL FLOWER FOLIAGE should be allowed to remain on the plant until the foliage has died down naturally. This will provide for the maximum amount of food to be stored in the plant's crown to better enable it to get through the winter and produce a good crop of flowers next year. It is true that the foliage can be removed earlier in the season with good results but a good general guideline is to wait until the end of the season.
Foliage removal is a major part of general garden sanitation which is especially important if the plants suffered from any foliage diseases this season. Iris and hollyhocks can benefit especially from this fall sanitation since they are prone to diseases that overwinter on the old foliage. Hollyhock rust has been very common this year with the wetter weather as has iris leaf spot. Thorough cleanup this fall may delay the onset of the disease next year.
W THE TIME TO BEGIN FERTILIZING YOUR TREES AND SHRUBS is coming up soon. Fall is an excellent time to attend to those fertilizing chores. Nutrients are quickly absorbed during the fall as soil conditions are usually excellent for root growth. In fact, most of the nutrients used to "fuel" spring growth are absorbed in the fall, not the spring. Nutrients applied in the fall, after the first hard frost, will not reduce the winter hardiness of the plant. See Extension Extra 6027 Fertilizing Landscape Trees and Shrubs for more information on analysis and rates.
V WINTER SQUASH AND PUMPKINS should be harvested before frost for best storage. Cool temperatures, below 40F can cause cold temperature injury to the fruit which can shorten storage life. Frost can cause more severe injury which can result in the invasion of decay organisms resulting in rapid softening and spoiling of the fruit. For maximal storage life, allow the fruit to fully ripen which is evidenced by good skin color a hard shell and often the development of a yellow or orange ground spot on the bottom of the fuit (generlly seen on squash). Cut the fruit from the vine with a pruning sheers to maintain the stem and carry fruit by the bottom and not the stem. If the stem breaks off, this creates a wound that allows decay pathogens to enter the fruit. Cure the fruit in a warm and dry location for a couple weeks before putting into storage at about 40F and 50% RH. Properly harvested, cured and stored fruit should store for 2 to 4 months.
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Most recent revision Monday, Sept. 21, 1998 by David F. Graper.