Indiana Department of Natural Resources sent this bulletin at 08/09/2017 08:14 AM EDT
Weekly Review for Aug 9, 2017
Indiana Department of Natural Resources Division of Entomology & Plant Pathology Phone: (317) 232-4120 Our Website Inspector Territories
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.
Links can be found at the bottom of the page to manage your subscription to this list. Comments and questions about this report are welcome and can be sent to Eric Biddinger or to your respective
Inspector.
Over the past week I’ve seen the following problems: Red Headed Flea Beetle and damage to Meadow Sage and BoBo Hydrangea, whiteflies on Brown Turkey Fig and Hornbeam, heavy lace bug damage to azaleas and False Oleander Scale on ‘Little Gem’ Magnolia. I have included a photo of the False Oleander Scale on the Magnolia.
Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov
Only 0.05 inches of rain during the past week at my location. Yes, I am having a dry summer at my house this year and complaining about it too. During the past week I have been inspecting primarily nursery dealers and conducting walnut survey work. Two spotted spider mites continue to be a problem on butterfly bush. Look for yellowing leaves, stippling and mite colonies on the undersides of leaves. I am also seeing quite a bit of damage from the red headed flea beetle. This insect is difficult to find, but once you know what the damage looks like it seems to be all over the place. Adults cause foliar feeding injury on numerous hosts. Larvae can feed on the fine roots of potted plants. During the past week I observed damage to Hydrangea paniculata, Weigela and Fothergilla. It also is a good year for lace bugs. During the last week I observed lace bugs on azalea, hawthorn, linden, serviceberry and buckeye. This includes multiple species of lace bug. I have not seen lace bug on Pieris this year, but keep an eye out for this pest. All lace bugs cause coarse stippling and fecal spots on the under sides of leaves. Damage to broad leaf evergreens is most serious because they will show the damage in the following year.
Powdery mildew is quite common on many hosts by this time of year. I am starting to see tar spot on the red maple in my front yard. Look for small, black, slightly raised areas on the leaves. There is often a yellow halo around the edge of the black lesion. Leaf spot has been present on the river birch in my yard, but I have not seen serious defoliation compared to previous years. Anthracnose is beginning to develop on black walnuts in my region. This disease cause leaf spot and leaf drop in late summer and often causes early defoliation of black walnut trees.
It was a busy week. Got to quite a few places this week and found some interesting things. Found some yellow neck caterpillars this week. Actually found a ton of them, more than I have ever seen. The nursery had them on dozens of different species but the worst was the service berries with entire rows of bushes being completely stripped of leaves. I found an unknown leaf scale on some white oaks. Wooly apple aphids on some crab apples. But the most impressive find for the week was the herbicide damage. One nursery I stopped at had extensive herbicide burn which I suspect came from a neighboring soybean field that is upwind of the nursery. This year thousands of acres of soybeans have been damaged by Dicamba herbicide. Soybeans which have been engineered for resistances to dicamba are being planted next to fields with beans which are not resistant and the non-resistant beans are getting hit with drift and being damaged. I wonder if this nursery is another case of this.
