Indiana Department of Natural Resources sent this bulletin at 06/12/2018 02:26 PM EDT
Weekly Review for June 12, 2018
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.
I conducted inspections in Wabash County and also assisted with a
group inspection in southern Indiana last week. There are not many new things to report from Wabash County.Apple scab is becoming worse on
crabapples.Maple mites were a little
more abundant, but the rain we had over the weekend might slow them down.I also found eriophyid mites on bur oak, potato leaf hoppers on almost everything, and oystershell and cottony maple
scale on ‘Sun Valley’ maple.
Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov
Now it’s raining! Maybe in
a few weeks I can tell you how many root rot issues I am finding. I received reports of Japanese beetle activity in the Bloomington
area from some landscapers. I have not personally seen them yet, but they are obviously emerging
early this year despite the cold spring. Bagworms are starting to cause noticeable damage on evergreens in many
landscapes. You should be treating
infestations now to prevent serious damage from occurring. I have seen white pine weevil damage in
Serbian spruce, Norway spruce and white pine. Look for wilting leaders. Close
inspection will reveal small exit holes, frass, chip cocoons or even larva
inside the leaders. Prune out and
destroy heavily infested leaders. The
best time to control this pest is to treat adults before they lay eggs. Timing is always tricky on this one and once
you see the damage it is really too late to spray.
Leafhoppers have also been very abundant
during the last week and seem to be causing more damage this year compared to
other years. I found leafhoppers on red
bud, red maple, Fothergilla and oaks. Look for the coarse stippling on many hosts and on red maple you can
also see leaf cupping and stunted growth. Maple mite populations are continuing
to increase and I have seen noticeable damage on Autumn Blaze maples. I have also seen a few small infestations of
fall webworm on oaks and sweetgum in Monroe and Greene Counties. Look for webbing occurring on the outer ends of
branches. Small infestations should be
pruned out of infested tress.
Cedar apple rust continues to be found sporadically on susceptible host. Last week I found a great example on Brandywine crabapple. I am still not seeing widespread or severe apple scab infections so far this year. However, it is still early in the growing season. I found needle cast symptoms on Serbian spruce in Owen County. Samples were taken to see if needle cast could be confirmed in the lab. I also found symptoms of Nectria canker underneath the tree wrap on a crabapple tree in a garden center. Nectria can appear as multiple orange spots on the trunks of trees. It often can infect stressed hosts. I do not often come across this pathogen, but have seen it on occasion. I am continuing to see spot anthracnose on flowering dogwood, but I have not seen any Discula anthracnose this year. However, I did find symptoms of anthracnose on blueberries in Brown County.
I helped with a group nursery inspection
last week in southern Indiana. I found
one Japanese beetle already out and eating on a leaf. I did see tulip tree scale on some of the tulip
trees. One tree that was heavily
infested had wasps, flies and ants all over it. The noise from the wasps and flies at this tree made me look closer for
what could be there to attract them.
Most beekeepers who ordered nucs from
Indiana beekeepers picked them up last week. They may have to supplement these nucs with sugar water to get
them to draw out the comb. The dry hot
weather in May slowed the nectar flow down last week. With the rain we received
this weekend, hopefully the plants will start to produce nectar again. Indiana nectar flow is usually till the end
of June. With this year’s crazy weather,
we will have to watch and see.
The Beekeepers of Indiana have their
summer meeting this Saturday, June 16 at the Purdue Bee Lab. The entire day will be spent in hives
learning more about bees. If anyone is interested they can go to http://www.indianabeekeeper.com/ to check out the agenda and location. Bring a hat and veil with you.
FieldWatch Inc. has been around for 10
years now. It was originally created as
DriftWatch by Purdue University in 2008 to help protect specialty crop growers
from pesticide drift. FieldWatch is now
in 18 states and a Canadian province and provides an online national registry
for specialty/sensitive crop growers and beekeepers. Beekeepers can register for free at
BeeCheck.org. This allows commercial applicators intending to use insecticides to
locate local hives and communicate with the owners. Once notified, beekeepers
can take action to protect their hives, if necessary. If there is a pesticide
drift problem, beekeepers should call the Indiana State Chemist Office at
765-494-1582 to investigate.
I’m sharing a couple
of photos that I took last week.One
photo is of native lady beetles working hard on some aphids on mandevilla.There were actually quite a few native lady
beetles on this group of potted mandevilla. Always good to see our beneficial insects doing their thing. The second photo is of maple spindle gall on
Sugar Maple. These galls are caused by
the feeding of an eriophyid mite.
I've
seen quite a bit of interesting things lately.
The great bagworm hatch has begun as noted
previously but this past week I saw something that I had never seen in person.
I was doing an inspection in a nursery and came across an arborvitae which had
a heavy bagworm infestation. I found the typical bagworm damage to the foliage
but I also noticed the bark at the top of the trees looked a little strange.
Upon closer inspection you could see where the bagworm had peeled the outer
bark off the trees.
I also saw some Austrian Pine with a fairly heavy case of Dothistroma needle blight. I can usually find this on Austrians but I have also had this confirmed on Norway Spruce which shows similar symptoms but less pronounced.
I also saw European sawfly on Austrian pine. I can usually see damage from sawfly at some point during the season but I don’t always catch them in the act. A lot of growers who know what to look for and are actively looking for them can have a hard time finding them. Usually I don’t see a great deal of damage and they are not worth treating unless you find a really large outbreak.
At first I thought this was cottony maple scale but I had never seen it on the leaves. After doing some research Cottony maple scale Pulvinaria innumerabilis is only found on the twigs and branches while Cottony Maple Leaf Scale Pulvinaria acericola lays their eggs on leaves.
I found leaf miners on Boxwood, Magnolia, Sweetgum, English Oak, and Alders.
Lastly, I will close with another milestone which flew down the back of my shirt.
P.S. you don’t always have to look at trees and bugs while doing inspections.
While
doing inspections in Delaware and Madison counties this last week, I noted a
heavy infestation what appears to be Willow Blister Gall on Pussy Willow. These
mites spend the winter on the bark and branches and in spring move to the
developing leaves. While the damage is unsightly, it is not usually harmful to
the overall plant health. I also noted what is probably white pine weevil
damage. The tops of the 6’ tall trees are just beginning to show decline and
death, but there were obvious signs of infestation.
