June 8, 1994
Two counties have called to report outbreaks of cottony maple scale on silver maple trees (Kossuth and Sac Counties). Other counties may eventually notice this problem also and are urged to report any major problems.
Last year, sweet corn growers suffered severe losses to common rust (Puccinia sorghi). This and other foliar diseases, particularly Northern leaf blight (Exserohilum turcicum), can be economic problems on susceptible varieties to some extent each year. Since rust does not overwinter in Iowa, we do not necessarily expect another severe rust year, but that will depend on the weather. Although resistance is available for these diseases, it is not always completely effective and some of the most desirable varieties are susceptible.
Hollyhock rust is caused by the fungus Puccinia malvacearum. The rust fungus causes raised, brown pustules about the size of a pinhead on the undersides of leaves. Yellow-orange spots develop on the uppersides of the leaves above the pustules. Pustules may also occur on the stems and other green plant parts.
In recent weeks, many home gardeners have begun to water their flower and vegetable gardens because of the dry weather. Important points for gardeners to remember when watering include:Water deeply and infrequently. Deep watering promotes the development of a deep, extensive root system. Frequent, light watering promotes shallow rooting. Deep-rooted plants will be able to survive hot, dry weather much better than shallow-rooted plants because they will be able to reach the moisture deep in the soil.
The strawberry harvest is underway in central and southern Iowa.
Those small gray flies in the yard and on the shrubs, flowers and vegetables are mostly seedcorn maggot flies. This field crop pest was very common this spring and caused damage to an estimated 100,000 acres of corn. The seed-damaging maggot stage lives in damp, high organic matter soil until growth is completed and the adult flies emerge.
The adult flies are harmless but are often present in such abundance as to attract attention. No control is necessary.
Cool-season grasses, such as Kentucky bluegrass, perform best in the spring and fall months in Iowa. Hot, dry weather is tough on cool-season grasses. Kentucky bluegrass, for example, responds to hot, dry conditions by going dormant. High temperature stress of cool-season grasses can be reduced by simply raising the mowing height. The additional leaf area shades and cools the crowns of the plants. The higher mowing height also promotes the development of a deeper root system. Deep-rooted plants are better able to withstand drought stress.
It's a common question and one that should have an answer, but there is not much that can be done to eliminate ants that are living in a sandbox. Of course, it does not appear that the ants cause any harm, and peaceful co- existence is probably the best approach. But for many parents and caregivers, allowing children to play in ant-infested sand is more than they can bear.
The last issue of Horticulture and Home Pest Newsletter presented various ideas to help you lightscape your home landscape . Since something always happens in do-it-yourself projects, here are some ideas to help overcome common problems.