July 2, 1999
The brightly colored flowers on beebalm (Monarda) are an eye-catching treat in summer. The flowers may be white, pink, red, or purple. While beebalms can be beautiful plants, powdery mildew often makes them unsightly. Powdery mildew appears as a grayish white "powder" on the upper leaf surfaces. Severely infected leaves drop prematurely. Disease symptoms are most severe on overcrowded plants and those growing in partial to heavy shade.
Cherry samples showing brown rot on the fruit have been arriving in the Plant Disease Clinic. Under wet conditions, light brown tufts of fungal spores form on the fruit, destroying the fruit rather quickly. Fruit losses are worst when wet, warm weather persists during the ripening period. Injured fruit are particularly susceptible to infection. Diseased fruit may fall to the ground or remain on the tree as mummies (dried shriveled fruit).
Several calls and samples from eastern Iowa counties would suggest this is another "banner year" for the false Japanese beetle, Strigoderma arbicola. The false Japanese beetle is a member of the Junebug family with a vague resemblance to the famous imported pest, the Japanese beetle. See the table below for a comparison of diagnostic characteristics.
This is an exciting year at the Home Demonstration Gardens at several ISU Research Farms. Not only are we growing several different varieties of new or unusual annuals and vegetables, but several Deans and Directors of Agriculture and Extension will be participating in the field days. The Deans and Directors will discuss George Washington Carver's influence on agriculture.