May 17, 1996
It is important to determine whether the browning evident on evergreen trees is caused by an infectious disease or by winter injury. Fungicide sprays are effective against needle diseases, but will not solve winter injury problems.
The bright orange, gelatinous galls caused by the cedar-apple rust fungus are showing up on infected cedar trees now. These galls are usually not noticeable during most of the year, appearing only as small (1/4 to 2 inch) brown galls. When rainy spring weather occurs, however, jellylike orange tendrils emerge, causing them to be quite noticeable.
Cedar-apple rust is caused by the fungus Gymnosporangium jumiperi-virginianae. The fungus needs two hosts to complete its life cycle, cedar and apple or crabapple.
While chrysanthemums are easy to-grow perennials, pinching, watering, and fertilizing are necessary to insure a good flower display in the fall.
Pinch newly planted and established mums from late spring to midsummer. Remove the stem tips when the shoots are approximately 6 inches tall. New lateral branches will develop along the stems. Pinch again when these new shoots reach a length of 6 to 8 inches. Pinching can be done with your fingers or a pair of clippers. Continue pinching until late June or early July. Pinching results in bushy, compact plants with additional flowers.
As gardeners plant their fruits and vegetables, they anxiously look forward to their harvest. For some vegetables, the wait is short. Radishes may be ready to harvest in 30 days. Apple trees, however, may not bear fruit for several years. Some small fruits and tree fruits may flower and produce fruit before the plants are well established. While it may be difficult, it is advisable to remove these flowers and not permit the plants to bear fruit. Removal of the flowers will maximize vegetative growth and increase yields in later years.
Mid-May is the start of the time when we can control many of the scale insects found on ornamental plants in Iowa. These sap-feeding pests derive their name from the scale or shell-like waxy covering on their bodies. Scales may attack most species of shade and fruit trees and ornamental shrubs and may be found on plant stems, twigs, foliage or fruit.
Evidence suggests that spring may finally be arriving in Iowa. The tulips are in bloom, the redbud trees are blooming, people are busily mowing their lawns...and ticks are starting to become active. While ticks can occasionally be found during the cold weather months, it is the spring that triggers their greatest activity. As a result, ticks are starting to be sent to our office for identification. So far, these ticks have all been either the adult stage or nymph stage of the Lone Star tick or the American dog tick .
Have you planned for the Worker Protection Standard (WPS) this spring? If you employ workers in your agricultural operation, you probably know about this Standard that went into effect January of 1995. Written by the U.S. Environmental Protection Agency (EPA), the WPS is designed to protect agricultural workers from pesticide exposure. You are required to comply if you use general or restricted-use pesticides and have employees that work in any aspect of crop production at a farm, forest, nursery or greenhouse.
When must I follow the WPS?