Indiana Department of Natural Resources sent this bulletin at 04/24/2018 09:30 AM EDT
Weekly Review for April 24, 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 was going to mention that we are looking for Gypsy Moth hatch in
Northern Indiana.Angela wrote more
about the upcoming treatments in Fulton and Marshall counties.
I’ve been off to a slow start on inspections, but I have seen one
thing that really bothers me:Every year
I seem to issue stop sales for dead fruit trees in sales areas, especially
peaches and nectarines.These trees are
brought in early, typically from southern nurseries, and are not protected from
spring freezes while they are breaking bud.
Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov
This has been a crazy spring. Many landscapes have severe winter injury. I have even seen significant winter injury on Alberta spruce, especially on the southwest side of injured plants. Other plants I observed with serious winter injury include, Atlas cedar, Deodar cedar, plum yew, blue hollies, boxwoods and southern magnolia. I have even seen reduced flowering in callery pear. I was concerned my Yoshino cherry would not bloom this year, but flowers on Yoshino cherry were not affected in my region. I have heard reports of severe winter injury on newly planted inkberry hollies, but the hedge on my property suffered no winter injury because it has been planted for 10 years.
Pest activity is almost very low yet. I have been looking for eastern tent caterpillar, but they are still not active in my region. Most of the pests I have been finding have been on plant material shipped into Indiana from other states. I found low level populations of two spotted spider mites on Liriope and even some southern red mite on Sky Pencil Japanese Holly. Two spotted spider mites are pale yellow with dark spots on each side of the body. They are a warm season mite that is typically not a problem until summer. I was very surprised to see colonies alive at this time of year. Southern red mite prefers hollies and azaleas. Look for white cast skins, red eggs and red adults on the undersides of leaves. This is a cool season mite and can cause damage early in the years if we have a dry spring. I also found Japanese maple scale on Yoshino cherry. Look for elongate, white, scales on the bark of infested trees. They can look similar to white peach scale. Japanese maple scale and white peach scales overwinter as adult females, but white peach scales females are round with a small yellow spot in the middle giving them an egg like appearance. Boxwood psyllid may be active soon as the boxwoods are beginning to break bud in my region.
I found a few disease issues during my inspection. Botrytis has been a problem on many annuals and perennials due to the cool wet weather we have had. Look for grey, fuzzy spores growing on flowers and leaves. Severe cases on susceptible plants can reach the plant crown and result in plant death. Botrytis has primarily been encountered on begonias, primrose and geraniums. I also found bacterial crown gall at the graft union of a corkscrew willow tree. Bacterial crown gall appears as corky growths on host plants. Euonymus fortunei is especially prone to this disease and any plant found with bacterial crown gall should be destroyed because there is not any cure for this disease. One interesting thing I found during inspection was a die back that was occurring on Gaultheria procumbens (Wintergreen) The symptoms appeared similar to Phomopsis infections found on Vinca minor (Myrtle) in which small stems developed cankers and died from the tips back. I sent samples to the Purdue lab and they found Phompsis sp. Pestalotia sp. and Pestalotiopsis sp. in the samples. I was surprised that all three of these fungi were found in the sample. Damage was not severe on the plants but was noticeable.
Ren
Hall (Nursery Inspector & Compliance Officer) - RHall@dnr.IN.gov
I am Ren Hall, the new Nursery Inspector and Compliance Officer for the Northwest Central Region of Indiana, covering the following counties: Benton, Boone, Clinton, Fountain, Hendricks, Montgomery, Tippecanoe, Warren, and White. I have finished up greenhouse inspections in my territory and have started nursery dealer inspections. Expect to see me out and about doing grower inspections sometime soon! Another project I am working on the next few weeks is getting my counties’ firewood compliance agreements up to date. If you sell firewood for use in state parks, you need a firewood compliance agreement. Please contact me or the nursery inspector in your territory for more information.
My most interesting find so far this spring was on Brugmansia “Jean Pasco” (Angel Trumpet). I noticed an uncharacteristic mottling pattern on the leaves of this plant and sent samples to the lab. The diagnosis was Tobacco Mosaic Virus (TMV). TMV has hundreds of host species and can be easily spread from plant to plant by workers’ hands and tools, as well as from cuttings. Additionally, TMV may be present in tobacco products such as cigarettes. Therefore, tools and hands should be disinfected frequently, and workers should wash their hands after using tobacco. There is no treatment for TMV so the cuttings and stock plants needed to be destroyed.
While out on a nursery dealer inspection, my coworker Kristy pointed out to me several balled and burlapped white pines that were being girdled by the twine wrapped around the trunk holding the burlap in place. Don’t be fooled by the tree’s relatively normal appearance – girdling will eventually cause the tree’s death. When you buy trees, check for anything tied around the stem or branches such as identification tags, twine, hoses, or wires and do not purchase the tree if they are cutting into it. If you are planting or growing trees, check on them frequently as they grow, and remove or loosen anything supporting the tree so they do not girdle the tree.
A few other finds from the past two weeks: a severe spider mite infestation on Colocasia and sweet potato vines, aphids on Gardenia “Buttons”, and powdery mildew on two varieties of sage.
A few days ago, I noticed many cedar-apple rust galls on a row of juniper trees in my neighborhood in Indianapolis. This fungus requires two host species to complete its life cycle - junipers and apples/crabapples. While the twigs with galls will usually die back, the damage to junipers is mostly aesthetic unless a large number of galls are present. However, this fungus makes fruit of apple trees unsuitable for sale or eating and can cause premature loss of leaves. Death of branches or trees from repeated infections in apples and crabapples can also occur.
Nothing to report on the forest pest side. Bud break is slow this year. We are at green tip in Washington County. Redbud is in Flower. Closer to Ohio River bud break and leaf expansion is farther along. Have not seen any eastern tent caterpillar webs yet.
Bees are building up slowly due to this below average weather. When we had warm weather in February the queens were laying well. Then it was cold through March and early April. This lead to the queen slowing down or stopping all together. This was good in a way. By shutting down egg laying there was not as much need for food. Beekeepers have been feeding supplemental sugar blocks or sugar water so the bees have enough food to make it until we warm up. Glad to see some warm weather predicted for this week.
Many beekeepers were finally able to inspect their hives on April 12 and 13. It was finally warm enough to open hives. In an average year, beekeepers have been in their hives by mid-March and are adding honey supers in mid-April. I checked my own hives and they are doing well. All four made it through the winter. They are eating sugar blocks like crazy. Added more sugar blocks to two of the hives. The other two have sugar water on top.
On warm days the bees are out collecting pollen. I have seen red, yellow and white pollen coming in. The red pollen could be redbud and maples. Yellow could be dandelion and a couple of other flowers. The white pollen, I am not sure of.
Reports of winter losses are coming in from the state. Losses are going to be high in northern Indiana with some reporting up to 80% losses. The rest of Indiana reports are around 35% loss. Even at 35% loss, it is too high. An economic loss of 15% will allow the beekeeper to make up losses without hurting their business.
In several of the dead hives I have inspected, the bees starved to death. Not an ounce of honey anywhere and way too many adult bees. Bees need to have at least 80 pound of honey to make it through the winter. Beekeepers can supplement feed sugar water in the fall to get them to store it for the winter. Many beekeepers are putting sugar blocks on top so the bees can use it if they need to. They needed it this year.
Another interesting death is where the beekeeper reported that the bees literally died overnight. It was where one day was in the 60’s but that night and it dropped into the low 30’s and we had 10 inches of snow. The photos she sent show the larvae coming out of the cells. The adult bees died and were not able to feed the larvae. She may have had too many adult bees and too much brood to keep warm and feed. When I inspected the hive, there was some honey left in the hive, but there was a lot of undrawn comb. Having undrawn comb or foundation in a hive in the winter is not good. Foundation cannot store honey. The bees cannot cluster on foundation. The queen is not able to lay eggs. If all you have is foundation above the clustering bees, they will not move up into foundation. This can lead to starvation.
Packaged bees are coming into the state already. I just hope the beekeepers are feeding sugar water to them. We still have cold nights and the bees need that honey/sugar water to be able to shiver when they cluster at night. Packaged bees will be coming in April through May. By purchasing packages of bees, the beekeeper can put them into cleaned out dead hive. A three pound package of bees cost around $130 this year. I still remember when they were $50. The demand is so high that prices keep going up.
The weather has certainly been crazy this spring with all of our prolonged rains, brief warm ups and the occasional snows and freezing temperatures in Southwestern Indiana. I have not had too much of a chance to look at what is going on with insect and disease development yet, but did see some botrytis blight (gray mold) development on geraniums at a nursery dealer. With the nice forecast for this week and next week, I expect we will see a boom in insect populations. I’ve had a few people email insect photos for ID, which were leaf footed bugs and stink bugs. Ticks have been out for at least 3 weeks down here. Also, with all of the rain in this part of the state, there have been a lot of reports of problems with ants inside homes since about the third week of March. I will be starting survey within the next month for boxwood blight, sudden oak death disease and old world bollworm.
The Division is moving forward with plans to treat four locations in northern Indiana for gypsy moth. This project is a cooperative effort between Indiana DNR – Division of Entomology and Plant Pathology, Indiana DNR – Division of Forestry, and the U.S. Forest Service. In May one site in Fulton County will be treated with two applications of Btk and in late June, three sites in Marshall County will be treated with one application of mating disruption. Staff in northern Indiana are monitoring for egg hatch. This assists our project with the correct timing of the first application of Btk which is aimed at second instar larvae. No egg hatch has been observed yet. Staff are also monitoring oak leaf development because it is preferred to have 50% leaf development so that there is enough leaf surface area for the Btk to adhere to the foliage.
It’s been a slow start to the year with a limited number of inspections but I was able to find a few Monsters in Central Indiana this past week. A couple weeks ago I had the chance to go over to Cincinnati to an arborist meeting at Spring Grove Cemetery and Arboretum. While in attendance I was alerted to an invasive which I didn’t have much experience with, Lesser Celandine. Lesser Celandine is a spring ephemeral which shows up very early in the season and dies out by early spring. Usually this plant likes wet areas along streams but it appears that it will have no problem moving out into turf and wooded hillsides. It propagates by bulbils and its hypothesized that these can be moved by deer and squirrels. When I saw it at Spring Grove I was really taken back by just how dense a carpet of foliage it puts out and how it forms an almost complete monoculture in the understory. Later that same week while I was on a social media I spotted a picture of what I suspected to be Lesser Celandine taken by a friend and retired coworker and contributor to this publication, Scott Kinzie. I inquired where he took the photo and he gave me a location in Eagle Creek Park in Indianapolis. So after doing some ailanthus mapping last week with my coworker Ren Hall we decided to see what we could find and oh boy we found some.
For a more through write up on Lesser Celandine, visit Joe Boggs’ post on the Ohio State Blog.
A couple of other interesting things I’ve seen while out in about include the following.
The late start to spring-like weather has left many scrambling to protect delicate new growth from cold and freeze damage. Even on sunny days, it was often necessary to keep plants protected. Despite best efforts, I have still seen quite a bit so far this spring. It’s important to remember that even a normally hardy plant can succumb to cold damage if it has just released new growth or is grown in an environment that is generally not that cold.
Greenhouses have the advantage of having a more controlled environment, but the warmer temperatures means increased risk of pests. Thrips has been the main culprit of damage I’ve seen thus far.
