DNR - Entomology Weekly Review, July 2


Weekly Review for July 2, 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.

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Eric Biddinger (Nursery Inspector & Compliance Officer) - EBiddinger@dnr.IN.gov 

I had a notion to write a long article last week about what SOD and Boxwood Blight mean to our current ideas of nursery sanitation. But for starters, think about this: Boxwood Blight produces “sticky spores”. The number one method of spread will be contaminated tools and workers. Are landscape crews trained to identify this disease? Are supplies available to clean tools before moving to the next job? How about foot sanitation or shoe covers? There’s a lot to think about with these diseases. If we can help you work up a sanitation plan, please let us know.

As far as inspections go, I’ve started seeing bagworm and lacebugs here and there. Maple spidermite has been pretty isolated so far, but I expect it to explode with the heat this week. I did find a few red-banded leafhoppers – a cool looking critter - and a localized, but pretty heavy damage from maple petiole borer. My wife claims to have seen Japanese beetle, but I haven’t seen any yet.


Ren Hall (Nursery Inspector & Compliance Officer) RHall@dnr.IN.gov


I am starting off my weekly review with a little complaint. Last week I saw these signs (“Distressed plants - $1, $3, $5) at a dealer I was inspecting as part of a trace-forward situation for Sudden Oak Death and Boxwood Blight, two fungal pathogens of regulatory concern. It’s frustrating as an inspector to see box stores selling non-vital plants at all, let alone at a discount. I happened to find some of the plants I was looking for as part of the trace-forward on these clearance racks – “distressed” is right. This is just a caution to everyone to be wary of clearance racks.

Often those plants look bad because they are diseased, and they may not spring back the next year. They may also have more serious pathogens such as SOD, which not only kill the plant they’re on, but may infect the surrounding plants in the landscape as well. I did have a nice chat with the nursery specialist at one of my box store dealers and she expressed some frustrations at the lack of training they receive about plant diseases, and the pressure that is put on them to “move merchandise” (i.e., sickly plants) rather than discard it.

Some box stores I’ve come across, the managers and nursery specialists are happy to get rid of any plant that doesn’t look great, whereas others may want to hold onto plants that are clearly non-vital in hopes of making a few dollars, and sometimes they are under pressure from the higher-ups to do so.

Last week and this week I’ve been doing more dealer inspections in my territory. I went back to the dealer that had the Coleus with Impatiens Necrotic Spot Virus to make sure the plants got destroyed, and took some more pictures on different varieties. Almost every variety of Coleus and Perilla was infected. Because this virus is primarily spread by thrips, all of the plants were destroyed in an effort to prevent the spread of the virus to other plants.

On the topic of viruses, today I found two more plants that likely have viruses – a river birch with white ring spots and mosaic pattern, and an “Elvis Lives” Hosta (really, that’s the name) with very faint ring spots. I am sending samples of both to PPDL for further diagnosis.


Other issues I have seen recently are lots and lots of Japanese beetles, bronze birch borer holes on a dying birch tree, heavy shot hole fungus on Kwanzan cherry, powdery mildew on many different species, white pine weevil damage on white pine, cedar hawthorn rust on hawthorn, a cute little unknown leaf hopper feeding on “Rotundiloba” sweet gum, woolly aphids on tree lilac, and severe sawfly damage on roses.


One neat find I had last week is foliar nematodes on weigela. This was my first time coming across this problem, so thanks to my coworker Angela and PPDL for the diagnosis. The leaves had rectangular dark purple or black spots bordered by veins, and on the older leaves the color was almost camouflage.


Angela Rust (Nursery Inspector & Compliance Officer) - ARust@dnr.IN.gov

This past week I found some nursery stock heavily infested with Japanese Maple Scale – on Horse Chestnut, Crabapple and Black Chokeberry. I found a rust disease on St. John’s Wort and have included a photo of that. I also had a boxwood shrub with some branch dieback tested and both Volutella sp. and Fusarium sp. were found. I have included a photo of that as well.


Jared Spokowsky (Nursery Inspetor & Compliance Officer)Jspokowsky@dnr.IN.gov

I’ve seen bag worm activity on white pine, arborvitae, junipers and some willow. I’ve also seen extensive feeding damage from red-headed flea beetle on hydrangea, weigela, and sweetspire. I spotted some bronzing on bald cypress which turned out to be rust mites. The mites are a eriophyid might so they are extremely small. However, using a hand lens you can see numerous cast skins on the needles which look somewhat like dandruff.


I saw my first Japanese beetle of the season in the nursery. I’ve seen a couple in the landscape but they have been few and far between.


I also spotted some introduced pine sawfly feeding on white pine. In addition to the sawflies I found, some pupa casings both hatched and unhatched. For a minute, I also thought I had found an alien spaceship attached to the white pine I was inspecting but it just turned out to be a bagworm with sawfly afterburners.


With as much rain as we have been having, I would expect more disease pressure, but I have been surprised at the lack of diseases I have been finding. I have seen diplodia on Scotts and Austrian pine in multiple places.


Kristy Stultz (Nursery Inspector & Compliance Officer) - KStultz@dnr.IN.gov

I’m seeing the tell tail signs of white pine weevil in several areas. Where I have noted it, the tops are beginning to droop and egg laying sites are evident, but there are no exit holes yet. I’ve seen it in both spruce and Eastern white pine. Other issues I noted this week were downy mildew, bagworm and the first Japanese beetle of the season. Only time will tell if populations will be as large as the last few years.


No reports this week

Megan Abraham (Division Director & State Entomologist) - MAbraham@dnr.IN.gov

Eric Bitner (Nursery Inspector & Compliance Officer) - EBitner@dnr.IN.gov

Kallie Bontrager (Nursery Inspector & Compliance Officer) - KBontrager@dnr.IN.gov

Vince Burkle (Nursery Inspector & Compliance Officer) - VBurkle@dnr.IN.gov

Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov

Phil Marshall (State Forest Health Specialist) - PMarshall@dnr.IN.gov

Kathleen Prough (Chief Apiary Inspector) - KPrough@dnr.IN.gov

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