Indiana Department of Natural Resources sent this bulletin at 07/14/2020 10:37 AM EDT
Weekly Review for July 14, 2020
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.
Not a lot to report from last week. I came across a group of hawthorn trees with an especially heavy case of hawthorn juniper rust. I also found some buckeyes with a heavy case of buckeye leaf blotch. And another case of very heavily infested red maples with Japanese maple scale. The infestation was causing dieback and death in some cases.
Even in this hot weather, apiary inspections go on. A couple of hives I inspected are still recuperating from the cold weather in May. These are the ones for which beekeepers will need to feed and watch their queens closely. If the queen is not doing well, replace her. If there are not enough bees to keep up with the queen, the beekeeper can take capped brood from a strong hive to help boost population. If no brood is available, think about putting them in two or three deep nuc boxes, or two deep if you have less than 10 frames drawn out, or three deep if you have 10 or more frames drawn out. Time is running out for these hives to build up. If they do not build up by the end of July, the beekeeper can combine two weak hives or put the bees and frames into two deep nuc boxes. The big thing is to have drawn comb for that hive for winter.
The dearth period is here. Not much nectar is coming in, and the bees have stopped drawing comb. If your bees need to draw comb, get the sugar water on and watch to see if they finish drawing out the foundation.
Some beekeepers are getting a good honey crop off their hives. My hives are below average on honey production. I pulled honey off one hive that had honey stored when I looked at them 4 weeks ago. They did not draw out any more comb this past month, so no more honey from this hive. My strongest hive had some capped honey that I took off. Two hives have honey supers on but no capped honey. The hive I started from a swarm captured late May went queenless and has just a few bees left. I just shook the bees out in front another hive and took the frames away. Another hive had some brood in one super but not much else. I ended up combining it with a swarm that I got from a friend this weekend. The queen in the swarm was laying a good pattern.
Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov
Pockets of Japanese beetles are causing damage in some parts of my region. However, areas that have been extremely dry are not seeing much Japanese beetle emergence. Bagworm infestations are continuing to be a problem in some nurseries and landscape environments. Flatid planthoppers were found on turtlehead (Chelone) during the last two weeks. Look for small, white, fuzzy insects that jump when disturbed. Flatid planthoppers are much bigger than whiteflies and can cause some leaf curl on plants, but they usually do not cause serious injury. The warm humid weather is perfect for slug activity. I have seen slug feeding injury on Hostas in the nurseries and also feeding damage on marigolds in my yard. Leafhoppers continue to be abundant. Redbud and red maples are seeing quite a bit of damage look for coarse leaf stippling on redbud trees. Cedar apple rust continues to develop on susceptible varieties. High levels of infection can give trees an orange appearance from a distance. It is too late to spray this year. Symptoms of iron deficiency were found on blueberry plants. During hot dry weather we often rely more on irrigation to keep plants watered. What is your water pH? This can have a major impact on nutrient management.
Japanese beetle numbers seem to be way down this year in my area. There are pockets of damage, but overall those locations seem to be fairly infrequent within my nurseries.
A few finds this week include a healthy gang of bagworm on blue spruce, a few imported willow leaf beetles, and a red-spotted purple admiral butterfly.
Unfortunately, I’m seeing what appears to be botryosphaeria canker and dieback on redbud on my own tree this year. There’s no treatment, and as I’m not able to reduce the extreme water stress we’re seeing in many parts of central Indiana, it’ll be a wait and see game to see how badly the tree dies back. I can do some maintenance in the fall by pruning dead and diseased limbs. The spores overwinter as fruiting bodies on dead tissue, so I hope by my removing the inoculum, the tree will fare better next year.
