Indiana Department of Natural Resources sent this bulletin at 08/16/2016 07:57 AM EDT
Weekly Review for Aug. 16, 2016
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.
I did a nursery inspection in Elkhart County this week. There was a lot of Japanese beetle damage on trees (white oaks, weeping cherry, and linden, especially) at this particular site. Another surprising find was the high levels of lace bug on hawthorn, oak, and sycamore. Fall webworm was just starting out on a couple of redbuds, as well.
I did some early gypsy moth scouting this week. I was investigating a very high trap catch outside of Warsaw when I came across two white oaks near the trap with pretty heavy foliage damage. One tree had easily over 150 egg masses on it. Interestingly, when taking a closer look at the egg masses, I noticed a large number of small wasps fluttering around. This was an egg mass parasitoid, probably Ooencyrtus kubanae. This wasp can produce up to three generations before winter and possibly another in the spring. The result is up to 20 to 30 percent mortality of the eggs in an egg mass. I had thought about treating the egg masses with sun oil, but to protect this parasitoid and the benefit it is providing, I’ll hold off until the winter.
I inspected nurseries in Allen, Dekalb, Noble and Whitley counties this past week. There still weren’t a lot of new things I encountered this past week. I did find a spiny oak slug caterpillar on serviceberry. This caterpillar has spines on its body and can deliver a nasty sting if handled. I also found lace bug feeding on white oak, bur oak, swamp oak, linden, river birch and salvia. I also found a tulip poplar with heavy tulip tree scale. Sooty mold was developing on the branches and foliage. The sweet and sticky honeydew was attracting bald faced hornets.
Photo 4 – Spiny oak slug caterpillar
Photo 5 – Sooty Mold from Tulip Tree Scale
Photo 6 – Tulip Tree Scale on Tulip Poplar
Photo 7 – Lace bug on Linden
Photo 8 – Lace bug damage on Linden leaf
Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov
I have not been conducting inspections over the last few weeks, but wanted to make a few comments. The excessively heavy rainfall that is occurring in Southern Indiana will likely result in disease issues on white pines, blue spruce, Rhododendron, Pieris, Azaleas and Taxus. This will be especially true on sites with heavy clay soil. This weekend I had 4 inches of rain in a 26 hour period at my house in Bloomington. 4.8 inches of rain since last Wednesday and it is still raining steadily this morning. This is one of the wettest and greenest summers I have seen since I moved to Bloomington 14 years ago. Typically we dry out in August, but not this year. The excessive rainfall of this summer is causing numerous nutrient issues on plants. Hydrangea macrophylla, Ginkgo and dogwood are beginning to show significant symptoms of nutrient deficiency on my property. River birch, sweet bay magnolia and bald cypress are quite happy with the weather. I am starting to see decline in my lavender plants on my property. They performed very well during the 2012 draught but are declining and developing symptoms of crown rot this year. Gardening in the Midwest is truly a challenge. Hot summers, cold winters and generally just one extreme to the next. However, I will take ample rain over a draught any day.
The high temperatures, high humidity and no nectar flow makes for some cranky bee hives. This is when you have to work the hives real slow so the girls do not get too upset. Have the smoker going and be ready to close up the hive fast if they get too cranky. We do need to get in hives to check mite counts and check the bottom brood box to make sure the queen will have room to move down there this fall.
Not seeing much deformed wing virus in hives. Varroa mites are there though. So get treatments on. Some varroa mite treatments take 6 weeks. By getting them on now the treatment will be done by the end of September. The bees hatching out in October will be the winter bees and hopefully mite free. They will be healthy bees that can make it through the winter.
Talking to beekeepers at the fair, some places had so much rain this summer that they had to feed the bees. Others are hoping for some rain so we get a nectar flow with the goldenrod and asters. A few are getting a good amount of honey off. Just depends where you are in the state.
Anyone taking off honey now will have to make sure to take each frame and put it into a container or hive box and keep them covered as you take off the honey. The bees will find that honey so fast that you could have to shake the bees off twice just to get the honey away from the hives.
I have not seen much robbing yet. Strong hives will try to rob from the weaker hives, stealing every ounce of stored honey. The weak hive would then die late fall or this winter. Weaker or small hives or hives being feed can have their entrances reduced so the bees can guard the hive entrance easier. The other choice is kill the queen in the weak hive and combine it with another hive. Just make sure the weak hive does not have a small hive beetle problem or disease. If we do not get a fall nectar flow soon we may see more problems with robbing. This rain may help.
