The excess rain challenges plants in a few ways. Less oxygen in the soil is one issue. Aerating the soil and time are the remedies. Disease pressure is greater during these wet periods.
Diseases are weather dependent. Moisture is the main requirement for diseases to flourish. With available moisture and the right temperature, diseases will be happy. If we could control rain and temperatures then there would be much less disease pressure.
Most of the phone calls that I have been getting have been about deciduous trees. Spots on the leaves that lead to leaf drop is common. The names of these leaf issues include rusts, anthracnose and peach leaf curl. All of these are interesting and fortunately not really a health concern for the plant.
Fruit rots have been common this spring. My sweet cherry crop was infected by brown rot. If it stays wet, the application of a fungicide to protect other developing fruit is a good decision. Prevention is more possible than a cure once the disease is active.
Another type of rot is root rot. Affected roots do not efficiently acquire water and nutrients. This leads to wilt stress, nutrient deficiency, branch dieback and general plant decline. Stunting and dead plants can be the result.
Just recently, a disease has been introduced to our area. It was first detected in the U.S. in California in 1995. Phytophthora ramorum, commonly referred to as "Sudden Oak Death," was brought into Kansas on susceptible Rhododendron plants. This disease, if established, can damage viburnum, lilac, periwinkle, red oaks and rhododendrons.
Managing diseases and other pests are part of being a gardener. Proper identification is the first step. The next one is selecting a treatment or doing nothing. I’m here to help at any of these steps.
If you would like additional information on a horticulture topic, please contact Gregg Eyestone at the Riley County office of K-State Research and Extension. Gregg may be contacted by calling 537-6350 or stopping by 110 Courthouse Plaza in Manhattan or e-mail: firstname.lastname@example.org and see the blog at www.riley.ksu.edu.