May 16, 2003
There are several types of aphids that feed on conifers. Feeding damage can produce needle discoloration (yellow or white), needle deformation, premature needle drop, stunted growth, or branch death. In addition, aphids secrete sticky honeydew that falls on objects beneath the feeding sites. An unsightly black sooty mold often grows on the honeydew residues.
Each spring at the Iowa State University Plant Disease Clinic, a flush of calls, e-mails, and samples arrive from people concerned about large "dead" patches of grass. The description of the problem usually includes an observation that the patch gets larger every year. Upon closer inspection of the grass, one can see that there are no spots on the blades or darkening of the roots or crowns (the part of the plant at the soil line). However, one also might notice that the "dead" plants aren t Kentucky bluegrass or ryegrass as expected.
This time of year, many people choose to include a new tree in their home landscape. There are important aspects to consider when selecting a tree that include special characteristics, traits, or tolerances that trees have or need to thrive on a proposed site. Investigative work now will help alleviate future headaches. Several important considerations are listed below. Will they tolerate de-icing agents if planted close to a street? Do the prospective trees have insect and disease-free track records?