May 23, 1997
Leaves infected with the bacterial blight organism (Pseudomonas syringae) show brown spots that are surrounded by a yellow halo. Spots are initially pinpoint in size but can enlarge to 1/8 inch or more. As the disease progresses, spots tend to coalesce, causing leaves to become misshapen. Eventually leaves may be killed.
When the infection spreads around a twig, it becomes girdled and dies. This phase of the disease is evident as young shoots develop in the spring. Diseased shoots turn black, droop over, and die.
Orange rust is a serious disease of brambles. Black and purple raspberries are susceptible, as are most varieties of blackberries. Orange rust does not occur on red raspberries.
The new shoots of infected plants appear weak and spindly as they emerge in the spring. Leaves are small, yellowish, and sometimes misshapen. Within 2-3 weeks the undersides of leaves show small, orange spots (pustules). Infected leaves eventually wither and fall.
Location: ISU Cooperative Extension Offices listed below. Time: 10:00 am to 2:00 pm
Commercial and Private Tests will be available at each site. Tests will be administered by the Iowa Department of Agriculture and Land Stewardship on a first-come first-serve basis. Testing will be limited to the number of seats available at each site. It is recommended that you confirm the testing time and site prior to travel. Tests also are available at the Pesticide Bureau office, 1st floor Wallace Building, Des Moines, IA, all days that state offices are open.
Phomopsis tip blight is one of the two common diseases of junipers and is often associated with Kabatina tip blight. Although these two diseases cause almost identical symptoms, they differ in disease development and control. Kabatina tip blight first appears in February and March whereas Phomopsis appears from April through September.
Many ornamental shrubs in the home landscape may be propagated by softwood cuttings. Softwood cuttings are taken in late May through early July from the current season's growth. Cutting material should be flexible but mature enough to snap when sharply bent. Lilac, forsythia, weigela, barberry, potentilla, and viburnum are some of the shrubs that may be propagated from softwood cuttings.
Most of us are well aware of the importance of farm safety, but how many of us are aware of safety issues related to yard and garden activities? Here is a quick quiz to check your knowledge of some horticulture safety issues. Select only one answer for each question.
1. When mowing a slope with a riding lawn mower, should you: a. Mow up and down the slope
b. Mow across the slope
2. When mowing a slope with a walk-behind mower, should you: a. Mow across the slope
b. Mow up and down the slope
Perennial grasses, such as quackgrass and nimblewill, are some of the most difficult weeds to control in the lawn. Control is difficult because there is no herbicide that will selectively destroy these weeds. Also, pulling or digging these perennial grasses is often unsuccessful.