Indiana Department of Natural Resources sent this bulletin at 08/06/2019 02:03 PM EDT
Weekly Review for Aug. 6, 2019
This informal report by the Division of Entomology and Plant Pathology is designed to update the Nursery and Greenhouse industry of insect and disease pests the Division has been encountering on a week to week basis and as a way to give a “heads up” of things to be on the lookout for. Comments and questions about this report are welcome and can be sent to your respective Inspector.
The USDA has declared August as Tree Check Month. This is a reminder for homeowners to take a few minutes and look over their trees for signs of Asian longhorned beetle. As with any invasive species, early detection is key to minimizing damage to the environment. We would also encourage folks to keep an eye out for other invasive species such as spotted lanternfly, thousand cankers disease of walnut, and even our “old friends” - gypsy moth and emerald ash borer. In addition, this is a great time to evaluate the overall health of your trees and consider future needs for tree planting, pruning, and removal.
The Indiana State Fair is in full swing through August 18. Many of our staff will be working the Invasive Species booth in the DNR Building this year. Please swing by and say hello!
Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov
I do not have much new to report this week. It is getting very dry in my region. I am starting to see mimosa webworm damage on thorn less honey locust in landscapes around Bloomington. Look for terminal leaves that are brown and webbed together. I did not see this during my nursery inspection and unfortunately I was not able to get any decent pictures. During an inspection I found oystershell scale on winterberry holly. This pest can be very hard to see because it is small and blends in with the bark color. Heavy infestations can lead to branch die back and even plant death if left untreated. Look for elongated, dark gray scales on woody tissue. I have been seeing a lot of powdery mildew during the last week. Powdery mildew was very heavy on lilac but I even found powdery mildew on a Japanese maple growing in a shady location. I also found symptoms of Cercospora leaf spot on winterberry holly. Look for purple to dark red leaf spots. During another inspection, I encountered an unusual leaf spot symptom on tree lilac in Bartholomew County. A sample has been sent to Purdue University for identification. I hope to have more information for you next week.
Ren Hall (Nursery Inspector & Compliance Officer) - RHall@dnr.IN.gov
I’ve been seeing webs and fall webworm caterpillars over the last few weeks in trees along the highways and at a few nurseries. Another interesting find I had was brown soft scale on an unknown tropical tree host at several box stores I was at for an unrelated traceforward.
I inspected a nursery in Elkhart County last week and found a lot of aphids on crabapples for some reason. Sooty mold on the leaves tipped me off, but sticky leaves, ants, and curled new growth were all there as well. I’m starting to see more leafhopper injury on maples, but not near as much as I was expecting by this point. I wonder if, like everything else, they are behind. Powdery mildew is also becoming more of an issue, especially in places with tight container spacing and overhead irrigation.
