Indiana Department of Natural Resources sent this bulletin at 05/01/2018 07:52 AM EDT
Weekly Review for May 1, 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.
Having a background in plant nutrition sure came in handy this
week.During a greenhouse inspection,
the growers pointed out ivy geraniums that were showing a lot of burn on the
new leaves and growing tips.Geraniums
are the one thing this greenhouse excelled at, so it was curious.After searching some more, I noticed a
similar burn to a much lesser extent on a couple cultivars of seed
geraniums.I asked the grower if they
changed anything this year and it turns out a friend of theirs suggested that
they needed to add Epsom salts to their nutrient mix to help their
tomatoes.So they added it to everything.Turns out that ivy geraniums are more
susceptible to high electroconductivity (EC – a measure of soluble salts) than
other geraniums.Epsom salt is magnesium
sulfate, a soluble salt.In addition, magnesium
toxicity in geraniums can reduce calcium uptake.The symptoms of calcium deficiency?Necrosis of the newest leaf edges and buds… However, I have to add that the tomatoes have
never looked better!So here’s the
lesson.Plant production is all about
“dialing in” the growing conditions.If
you are going to try to improve production for one species, isolate those
changes from everything that is growing well.That way you don’t help one crop and wipe out another!
I also have to comment on Ken’s Photo 8 and Jared’s Photo 17.I saw tons of trees, especially fruit trees,
buried too deep today.Often times the
graft will be at soil level, but the root flair is 2-6” below that.Trees are often “socked in” so they stand
better without support in the nursery.While
it’s never good for the tree, the end buyer can go a long way toward improving the
survivability of the tree by getting the flair back up where it belongs.
I’m also seeing heavy freeze damage on apricots, plums, and
nectarines in nurseries.Often these
trees came from Oklahoma or Tennessee nurseries.They were too far into bud break, brought to
Indiana well before our last frost, and not given adequate protection.
I’ve been inspecting dealers in Allen County over the past
week.The main problem I saw was freeze
injury on a lot of plants.Other
findings include aphids feeding on the new growth of ‘Easy Elegance’ Rose,
boxwood mite damage on ‘Winter Gem’ boxwood and botrytis blight on
geranium.I also found an issue with
incorrect labeling where sweet bay magnolia was labeled as ‘Royal Star’
Magnolia.
Ken Cote (Nursery Inspector & Compliance Officer) - KCote@dnr.IN.gov
Trees are finally starting to break bud
in my area. We still had frost on Sunday morning with scattered locations being
below freezing. I have not seen any eastern tent caterpillar.
However, I did see boxwood psyllid feeding on boxwoods on a south facing
landscape bed. As boxwoods begin to grow, look for leaf cupping and a
wax-like material on leaves. I have not seen much boxwood leaf minor
feeding injury. Many boxwoods have severe winter injury and I have some
boxwoods on my property that do not appear to be recovering. Aphids were found on magic carpet Spirea. I found a small, white hard
scale on arborvitae at a garden center. I believe they may be minute
cypress scale (Carulaspis minima) or juniper scale (Carulaspis
juniperi). Both of these scale species essentially look the same in
the field, but minute cypress scale is said to be slightly smaller according to
the literature. Minute cypress scale is also more likely to be found on
arborvitae.
During last week’s report I complained
about plants that suffered severe winter injury on my property. However,
there are some plants that have done surprisingly well. Both of my
dwarf dawn redwoods were not harmed and my Peve Minaret bald cypress seems to
be budding out. Any plant with a small root system, suffered
the most damage, but my Chamaecyapris obtusa ‘Nana Lutea’ suffered no
winter injury this year despite being in an open area. Once established,
this plants seems to be pretty hardy. Sun scald seems to be more of an issue
than winter injury with this cultivar. I also have a Japanese snowbell
that is doing quite well. No serious injury that I can see.
I have not found many disease during the
last week. Botrytis still continues to be a problem on geraniums
and begonias. I am seeing cultural problems in many garden
centers. Plants are coming in with loose root balls and in many cases
plant are planted too deep in the pot. Garden centers are often
overwhelmed with shipments at this time of year and space is limited in garden
centers. Remember to keep plants spread out so disease problems do not
develop as the weather becomes warmer. It is better to have fewer
healthier plants than twice as many plants that are not sellable due to damage
caused by spacing issues.
Ren
Hall (Nursery Inspector & Compliance Officer) - RHall@dnr.IN.gov
I was out conducting nursery dealer inspections today in Boone
County. The main issues I was seeing over and over were freeze/frost damage and
drought stress.
At one dealer I saw significant frost injury on Weigela,
Hydrangea, Althea, Magnolia, Ninebark, Holly, Willow, Amur Maple, and many
other shrubs sitting out on the lot unprotected from the elements, resulting in
damage and dieback to the tender new shoots, leaves, and buds. The ‘Endless
Summer’ Hydrangeas were hit especially hard. This is a common issue we see at
dealers in early spring and especially with this year’s unseasonably cold
weather, inspectors have been seeing plenty of cold damage. To avoid damage to
plants on cold nights, cover plants with a tarp or sheet, or move them inside
(especially plants that are not winter hardy).
At all but one dealer that I inspected today, I also saw
significant drought stress and injury. At one dealer in particular this was an
issue, with a table of annuals and vegetables in flats and hanging baskets
cooking in the afternoon sun on hot asphalt.
I don’t have a lot to report. I found
some obscure scale on weeping cherry.
I also have some photos of Douglas fir
with Diplodia blight. I hadn’t realized that Doug fir was a host for Diplodia
and at first glance would have probably attributed the damage to freeze damage
unless it hadn’t been pointed out to me.
I have also been seeing a lot of winter
burn on southern Magnolias
The most interesting thing I continue to
find is root and propagation problems. I have found a number of containers
where I will see branches protruding from the soil (these are true branches not
suckers). Usually upon further investigation I find that when the material has
been stepped up it gets buried deeper than the original soil line. On occasion
I have been able to find plants where this has been done multiple times and it
has been buried several inches too deep. I’ve also found material that was being
girdled by various objects including twine to tie up the ball and nursery tags.
As well as having material being held to long in too small of a container.
This Arb was actually a B&B which I
assume would have been noticed upon planting (but it serves to illustrate what
I have been seeing).
This is a Japanese maple which was
starting to be girdled by the tag.
This was a 3.5-4 inch caliper red maple
in was I estimate to be a 20 gallon container.
