No. 11/July 16, 2018

Cicada Killers
Cicada killers (Sphecius speciosus) are large wasps, about 2 inches long, with red-brown heads, black bodies and yellow banding on their abdomens.  The size of these wasps can be distressing but they are unlikely to sting passers-by.  Males establish and patrol an aerial territory where they attempt to mate with passing females.  When a person or another cicada killer enters that territory, the male may approach in a way that seems aggressive.  While this behavior is intimidating, the males are incapable of stinging and they only intend to harm other male cicada killers.

Goosegrass Gone Wild!
Timely, abundant rains combined with heat and humidity have contributed to the abundance of warm-season annual grassy weeds that we are seeing in Illinois lawns and landscapes.  One particular grass that has benefitted from these growing conditions is Goosegrass (Eleusine indica).  Recently I attended the Midwest Regional Turf Foundation Field Day at Purdue and the comment was made that it was like goosegrass had gone wild this year. This comical note made me think that perhaps it is a good time to reacquaint ourselves with this "wild" weed.

Verticillium Wilt
Verticillium wilt is a common and serious disease that affects over 300 hosts, including woody and herbaceous plants. There are a number of species of plant pathogenic fungi in the Verticillium genus known to cause wilt disease, with different strains or pathotypes of the pathogen exhibiting definite host plant preferences. The fungus is capable of surviving in the soil for several years. Once inside the plant the fungus colonizes the vascular system, restricting water movement and leading to the decline and death of the host. The disease is most severe in Illinois during cool to warm weather, and less prevalent in hot weather.

Pachysandra Leaf and Stem Blight
When sited properly, Japanese pachysandra (Pachysandra terminalis) is considered to be a mostly trouble-free species. However, it occasionally will have problems with scales and a few fungal diseases. Leaf and stem blight is the most common diseases on pachysandra.

Slime Mold on Turfgrass
The recent weather has set up perfect conditions for slime molds on turfgrass. Warm, wet, overcast weather helps slime molds to find their way onto turfgrass surfaces where they feed on microorganisms and other decaying organic matter. The primitive fungi can come in many colors from orange to white, blue or gray. The bright color can be seen in the early onset and then rapidly changes to dark patches.