Indiana Department of Natural Resources sent this bulletin at 07/26/2023 08:35 AM EDT
Weekly Review for July 26, 2023
This informal report by the Division of Entomology & Plant Pathology is a commentary on insects, diseases, and curiosities division staff encounter on a week-to-week basis. Comments and questions about this report are welcome and can be sent to your respective Inspector.
Welcome to our two new Nursery Inspectors who started this week: Will Drews and Bonnie Spindler. As they settle in, we’ll make some time to introduce them.
Japanese beetle has been hit or miss this year. Some nurseries have little damage, and some are pretty chewed up. Places that sprayed seemed to get pretty good control, but timing determined if they treated early enough to prevent most of the damage. Bagworms are still chugging along on arborvitae and other plants. Keep an eye out for them.
And finally, with this heat, be sure you are keeping things watered, especially the crews! Take it from me, heat exhaustion and heat stroke are no joke. Stay safe out there.
The State Fair starts Friday, July 28. Don’t forget check out the butterfly garden outside the DNR Building, and when you need to cool off, stop inside and visit us at the Invasive Species Booth, where you can try your hand at our new “Invasive or Not” quiz.
The U.S. Department of Agriculture Agricultural Research Service (USDA ARS) is soliciting input on its Stakeholder Comment Site for National Program 305 to help guide its research for the next five years. I encourage any beekeepers to voice their opinions as to what their biggest challenges are to beekeeping. Below is the description of their research focus from 2018-2023.
“As one of the most important components of crop production, NP305 includes bee pollination research. The honey bee (Apis mellifera) is the pollinator most often managed for commercial crop pollination. While the frequency of Colony Collapse Disorder (CCD) has decreased, honey bee populations continue to suffer. Bee health is threatened by pests, pathogens, pesticides, and poor nutrition. New techniques for management of honey bee diseases and pests are needed to maximize pollination. There is also an important need for conservation and in some cases commercial development of non-Apis bees (all bees other than honey bees) that effectively pollinate crops such as alfalfa, tree fruits, or greenhouse crops. As part of that goal, NP305 seeks to maintain the health and encourage proper management of bee pollinators and honey production. NP305 supports research to develop knowledge, strategies, systems, and technologies for a diversity of crops in a range of production systems, while increasing environmental quality and worker safety.”
The other week I was helping a coworker inspect a large nursery where we saw a lot of herbicide damage. Below are a number of photos of herbicide damage that I have cataloged over the years. The most common herbicide damage I see is from growth regulators that causes the distortion or abnormal growth of the leaf tissue. On occasion I see spotting or dead tissue from drift but it’s much less common.
While inspecting a daylily and hosta grower, I came across something I have seen only one other time. It appears to be hosta petiole rot (Sclerotium rolfsii var. dephinii). It starts with yellowing and browning of the lower leaves. The base of the petiole becomes soft, brown, and mushy. Eventually, they collapse and lay flat on the ground.
Other diseases I saw over the last couple of weeks were tar spot on Norway maples and red maple; powdery mildew on London plane tree, Amelanchier and dogwood; and Septoria leaf spot on oakleaf hydrangea and redtwig dogwood. Flea beetles have been making their presence known on weigela, hydrangea and sweetspire. I have not seen a lot of Japanese beetle, but when I did, it was on roses, rose of Sharon, crabapple and Newport plum.
I have noticed a large number of red-headed flea beetles on a variety of shrubs in nurseries throughout central Indiana the past few weeks. Their heavy feeding causes the plants to look unsightly and be considered undesirable by customers. This insect is thought by many to be one of the most important insect pests in the industry.
I continue to receive multiple calls per week incorrectly identifying the red milkweed beetle as the invasive spotted lanternfly. Red milkweed beetles are very active right now and are commonly found feeding on grassy edges of nurseries and gardens on their preferred host plant.
I visited a residence where the property owner reported trees looking potentially diseased. Upon arrival, I noticed several trees had symptoms of herbicide injury. Some common symptoms of herbicide injury may include cupped or curled leaves; lack of color in leaves (along veins, in between veins, along leaf edges or on entire leaves); elongated, strappy-looking or distorted leaves; twisted leaves or stems; dead spots on leaves; or stunted growth. Symptoms vary depending on the tree or plant species and the type of herbicide used. In many cases landscape shrubs and trees recover with time, but this depends on the amount of herbicide exposure and type of herbicide. Occasionally the injury is significant enough to hurt or kill a tree. Injury can happen from herbicides applied near the tree, in the lawn surrounding the tree, or can result from herbicide drift from nearby applications.
Eric Bitner (Nursery Inspector & Compliance Officer) - EBitner@dnr.IN.gov
