Indiana Department of Natural Resources sent this bulletin at 05/31/2017 01:28 PM EDT
Weekly Review for May 31, 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.
One staffing note. Congratulations to Scott Kinzie. He is retiring effective today. His responsibilities are being split up among the rest of the staff until his position can be filled. If you have previously worked with Scott, please contact the Central Office and one of the other Inspectors will get back with you.
Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov
Pest season is in full swing. Catalpa are blooming in my region and this means it is time to start looking for bagworm hatch. I have not seen any infestations yet, but they will be starting soon. Spruce spider mite damage was found on Alberta spruce growing in landscapes against buildings that provide protection from heavy rain and wind. I still have not seen maple mites. Twospotted spider mites have been an occasional problem on herbaceous plants grown in garden centers and greenhouses. During the last week I found twospotted spider mite on variegated sweet potato vine, Angel’s Trumpet and hops plants. Look for the stippling damage and leaf yellowing. I also found a small infestation of hemlock rust mite. It was on a few branches on the lee side of the tree. This is a cool season, Eriophyid mite that has a cigar shaped body. It cause a fading and rusty type of damage to the foliage. It usually goes away when warm weather returns. This mite species can occasionally infest Taxus. Leafhoppers are active on red maples and I did observe some leaf cupping injury in Monroe County. Woolly birch aphids are quite heavy on river birch in my region. Damage from bronze birch borer was found on European white birch and Youngii Weeping Birch. These two cultivars seem to be very susceptible to bronze birch borer and if planted I would recommend preventative treatment for bronze birch borer if you wish to have these cultivars survive to a mature size. Look for D shaped exit holes in the bark. Adults are bronze in color and have an elongated body. Drought and heat stress will predispose these cultivars to bronze birch borer.
Cedar apple rust continues to develop in my region. Some apple trees actually appear orange when observed from a distance. It is too late to spray this year. Look for orange spots with a raised appearance. Plant resistant varieties. During the last week I observed cedar apple rust on Gala, Honey Crisp and Wine Crisp apples. I also seen some cedar-hawthorn rust on Winter King Hawthorn. Swiss needle cast injury was found on Douglas fir. This cause defoliation of previous season’s growth and can make trees look thin and eventually die. Spot anthracnose was fond on flower dogwood in my region. I also found black knot on Canada red cherry. This disease is difficult to manage and galls can take more than one year after infection to fully develop. Look for blackened raised tissue girdling stems of any plant in the genus Prunus. According to some literature I have read you can see olive green areas form in the fall prior to the development of blackened areas appear in the following spring. I have personally never been able to see this, although I do not perform many inspection in fall. Nutrient deficiencies were encountered on river birch and Norway spruce. Leafspots were found on Caryopteris, Photinia and oak leaf Hydrangea.
Last week was pretty cool. I got a lot out of one grower inspection. I started off the inspection by noticing my first cicada of the year perched in the grass sunning himself. Shortly after that I almost stepped on a surprise in the grass. Next I walked up on some boxwoods that made my let out a groan. We have been looking for Boxwood blight for a number of years but despite our best efforts looking and it being reported in most states that surround us we have been unable to locate any here in Indiana (thankfully). I thought that had changed when I saw these boxwoods but it turned out to be a really bad infestation of boxwood leaf miner that had destroyed large amounts of the leaves. Then I have been on this kick to try and find stigmina needle cast on blue spruce so I can get better at differentiating it from rhizospherea needle cast. So during the inspection I thought I had what was a lot of rhixospherea on the blue spruce but some of the spore pustules looked ever so slightly fuzzy with a 10X hand lens. So I sampled a bunch of trees with the intent to send it off to the lab and confirm it. But the next day I was in the central office where we have some dissecting scopes so I decided to take a look at it under higher magnification and I believe it is Stigmina but its being sent to the lab for confirmation. In the process of reviewing the samples I saw some spider mites but the highlight was catching a minute pirate bug having lunch. I watched through the dissecting scope as it played cat and mouse with an immature soft bodied insect running around the needles in the blue spruce sample I had. Once the pirate bug finally skewered the other insect I watched as the body fluid was sucked out of it and it was crushed like a water bottle that was hooked up to a vacuum cleaner. I managed to take some photos with the iphone looking through the eye piece of the scope and they didn’t actually turn out to bad. And for the end of the week…..The Bag Worm are coming The Bag Worm are coming. This is the earliest I have caught them and it couldn’t have been very long after the hatch. For future reference I looked up the Growing Degree days and as of the end of Friday in Northern Ripley co. there were 853 growing degree days and my patriot blueberries are almost ripe.
I wanted to share a couple photos of the fungal disease White Smut on Gaillardia (Blanket Flower). Symptoms start out as whitish spots and eventually those spots turn brown. In most cases management can be achieved by removing and destroying leaves with symptoms as they appear.
Finished the last 5 samples of the 2016 USDA Honey bee Health survey. The 2017 survey will start in Mid-June. Bees are building up fast. Beekeepers are taking off early honey. Package bees are done for the year. Some are still waiting for Indiana nucs. The beekeeper raising them want to make sure the queen is laying a good pattern before handing them to the beekeeper. Captured swarms are also building fast.
Periodical Cicadas, i.e. 17 (or 13) Year Locust are emerging at this time. I have reports from Perry, Fayette, Hancock, Rush counties. Periodical Cicadas have red eyes and red wing veins. The annual or dog day cicada has green eyes and green wing veins. And they are larger than the 17 year cicada. Besides seeing the cicadas, you will see cast skins on the sides of trees and also mud tubes sticking up out of the ground. The female oviposits eggs in twigs that results in twigs to break over and create the 'flagging' symptom; red or brown leaves on twigs hanging in the tree crown. New tree plantations, planted this spring and last year, can have serious damage from ovipositing eggs. There is no economic treatment with insecticide. Damaged seedlings can be pruned to remove the damaged top. Specimen trees in the yard can be covered with soft screening to prevent female oviposition. I believe this is Brood Ten that is scheduled for 2021 and is early. Or it may be part of Brood Ten.
Please send me emails to report cicada you see with the location. And better yet, use Report IN app as it captures a picture and coordinates of the sighting. Or use any other method to capture a location. This will help track the occurrence of the cicadas. Later, when you see flagging, please let also me know.
