Indiana Department of Natural Resources sent this bulletin at 05/02/2017 01:04 PM EDT
Weekly Review for May 2, 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.
It looks like we might be in for another surprise this summer. Mount St. Joseph University is predicting that portions of Brood X (expected in 2021) might emerge this year. You can track this phenomenon at the MSJ Cicada website.
It has been many years in the making, but a portion of the Digital DEPP project is rolling out this month. You may see your Nursery Inspector using an iPad instead of a clipboard. For us, it means data that can be analyzed for trends, faster reporting, and more consistency across inspectors. For you it means a legible inspection report sent right to your email! This is a big step for us, so bear with us as we work out the bugs.
I’ve been inspecting nursery dealers in Allen, Wabash and Wells Counties and I’m seeing “Knockout” rose varieties with aphid damage in all 3 counties. I’m also seeing aphids on burning bush and a few on maple. Potato leafhopper was present on purple sandcherry in Wabash County, however they are in low populations right now and don’t seem to be causing damage yet. I’ve been noticing European snout beetle (Phyllobius oblongus) causing damage to some Allegheny serviceberry that I have in my yard. The beetles will chew notches in the leaves giving the foliage a ratty looking appearance. They seem to be a rather shy insect and like to hide on the foliage and will drop off the plant if you get too close to them. They will feed on a wide range of deciduous trees and shrubs so be on the lookout for them. I saw widespread powdery mildew on asters and garden phlox at one greenhouse in Allen County and localized infections on Centaurea in Wabash County. I’ve also been seeing shot hole fungus on Yoshino cherry, Septoria leaf spot on red twig dogwood and Cercospora leafspot on Hydrangea. On a final note, some of the native spring ephemeral wildflowers have been blooming quite nicely over the last couple of weeks so I thought I would include a photo of one of my favorites, shooting star (Dodecatheon meadia).
Photo 1 – European Snout Beetle
Photo 2 – European Snout Beetle
Photo 3 – Powdery Mildew on Aster
Photo 4 – Shooting Star (Dodecatheon meadia)
Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov
During the last week I have seen more aphid infestations. I found aphids on Spirea, basil, cherry and I am starting to see woolly birch aphid on the river birch in my back yard. Balsam twig aphid was found feeding on the terminal needles of Alberta spruce. This pest appears as tiny, white specks feeding at the base of terminal needles. Feeding damage from this pest results in twisted needles, but damage is typically not severe with this pest and it goes away once the growth hardens and temperatures increase. I found an interesting insect causing stippling type damage on golden rod in a production nursery. I believe this insect maybe chrysanthemum lace bug. Samples are being sent to Purdue for identification. This would be the first time I have ever encountered this pest. Unfortunately I do not have any decent pictures from the field because they are so small. Eastern tent caterpillar never became a serious issue in my region this year. Populations were very low. I am starting to see some leafhopper feeding activity on red maple and red bud.
Photo 5 – Balsam Twig Aphids on Alberta Spruce
Southern Indiana received 2-10 inches of rain over the weekend. Start looking for root rot issues on white pine, rhododendrons and yew. Cedar-Apple rust was found at low levels on edible apples. However, on Saturday, after all of the heavy rain and warm temperatures, cedar-apple rust fruiting bodies were abundant on eastern red cedar on the west side of Bloomington. The recent warm, wet weather may increase the infection level of this pest on susceptible hosts. Rust was also found on Penstemon. I did see one early case of apple scab on plant material that was shipped into Indiana. Nutrient deficiency on Kousa dogwood has been a frequently encountered problem during inspections. Interveinal chlorosis indicates a micronutrient deficiency which is often iron deficiency in plants that require acidic soils. I have also seen many lavender plants with Botrytis during the last week. Many of the lavender plants inspected also had crown rot from being planted too deep. Botrytis will likely become a problem on many susceptible host during the next week due to the cool, wet weather. Keep your flowers dead headed to reduce early infection and if possible increase air circulation in plants.
Photo 6 – Early Stages of Apple Scab
Photo 7 – Lavender with Botrytis and Planted Too Deep
Update: In an earlier Weekly Review (April 18, Photo 2 – Ed.), you may have seen pictures of plants with viral symptoms. Lab test confirmed Tobacco Rattle Virus on Peony and Foxglove samples collected during my inspections.
Reports of winter losses are high in northern Indiana at about 45%. Central and Southern Indiana reported losses were a little lower at about 30%. Many of these losses may be due to undertreating or not treating for Varroa mites. The main thing to emphasize to beekeepers is to know your Varroa mite counts through the season (March-Oct). Treat when you find 3 mites per 100 bees. Also to monitor after treating to make sure the treatment worked correctly.
Swarm season is upon us. The first reported swarm was March 25. Last week and this week looks to be the peak time for swarms. Swarm calls are coming into the office almost every day. Our website has a list of beekeepers who will come out for swarms.
My beekeeper friend and I set up two nuc boxes in trees near our apiary to attract swarms to them. Last week we had one swarm land on an apple tree by the apiary. This Sunday we had both nuc boxes occupied with swarms and another swarm in a peach tree. Between rain storms we were able to get this swarm into a hive.
Photo 8 – Bee swarm in peach tree
Of the three apiaries I inspected last Monday, two had swarm cells present but the queens had not swarmed yet. The first beekeeper did not want another hive, so she will get a beekeeper to put a swarm trap up and hope to get the swarm. The second beekeeper split the hive. We put the queen, half the bees, and 2 frames of brood in a new hive with some new or open comb so the queen has room to lay. The original hive, we left the capped queen cells alone since one of these will be the new queen. We gave it some new frames. The third hive looked like it had already swarmed. No eggs were visible, but capped queen cells present. Once a hive swarms you are waiting for the new queen to be able to fly out, get mated, and come back to the hive and start laying. From the time the queen hatches it is about 10 days before you will see eggs.
On Tuesday’s inspection, the beekeeper had split a hive that had queen cells and was packed with nectar. His second hive had swarmed already. We went through the splits to locate the original queen. We found her in one of the split hives. The other split had several capped queen cells. Observing worker bee activity at one of the queen cells, I would say that a queen is about to hatch out. A queen can make noise when she is in the cell and ready to hatch out. She will chew her way out, but the worker bees may help also. When going into the hive that swarmed we found a new queen in there. She had to be a new virgin queen. She moved fast and was trying to hide from us. A mated queen will move slower, and sometime just ignore you when you are inspecting the frame. He has several other capped queen cells in there. If another queen hatches, the two virgin bees can fight it out until one wins.
Hives I looked at the Bedford Beekeepers meeting on Saturday were bursting at the seams. The bees were putting nectar everywhere. Some hives were split at the meeting to demonstrate how to split a hive. The rest, the beekeeper will be busy splitting the hives to get them ready to move into pollination. He could also put honey supers on these hives to collect some of the nectar they were storing. That way they would store the nectar up in the honey super instead in the brood boxes.
I did notice the black locus trees had started to bloom in Bedford and Bloomington. Beekeepers in southern Indiana up to Indianapolis should have honey supers on to try and get this nectar. This is real light colored honey. If it rains hard the rain could knock the nectar out of the flowers. The rain also keeps the bee’s home. Let’s hope the rains lets up!
We had a lot of rain come through the far southwestern counties over the weekend. Some areas received 9 inches in only 2-3 hours and have had flooded roads. It looks like this week will be cooler with mostly a high of around 60. I've looked at several standing ash trees and also hickory trees for property owners over the last week, and it seems that sap rots and/or root rots were the primary cause of decline. In some cases I think there was likely injury to the root flares during mowing which may have led to the infection. I looked at about 800 logs for international export over the past week, ash and white oak. Overall the logs were all in very good condition. I found little insect damage in both the ash and white oak, and only 1 log with some sap rot symptoms. I think one of the bigger challenges, especially this time of year, is shipping out logs without soil and mud contamination on them.
I have begun to do nursery dealer inspections and since there was not a lot of material on hand in my region yet, issues have been minimal. Spider mites are the one issue I have seen at several locations, but never in very heavy numbers. However, 2017 is picking up where 2016 left off as far as Colorado Blue Spruce are concerned. I have been contacted several times by homeowners concerned about dieback in their blue spruce, and each time I do a site visit, I find needle cast. While fungicides can help protect healthy tissue from becoming infected, prevention should be the first consideration. Unfortunately, blue spruce are extremely susceptible. To help keep blue spruce healthy, remember to water during droughts without overwatering and think about tree spacing when planting so they can get plenty of airflow and won’t expand into other tree’s growing space.
