Answers to popular current questions from the Master Gardener Helpline
A link is made to those UVM Extension leaflets (EL,GD,etc.) available on the web. All
leaflets are available through mail order or in person from UVM Extension offices (see
Vermont Hardiness Zone Map (link to UVM Extension)
England Hardiness Zone Map (link to UConn)
POTATOES AND FERTILIZER
Application of manure may encourage potato scab problems. With heavy rains, supplemental
sidedressing may be needed, but no N should be applied after plants are 8-10 inches high.
To control potato scab, maintain the soil pH around 5.3 or plant scab-resistant varieties.
Sulfur can be used to acidify soil if necessary. If soil pH is much less than 5, a light
application of lime may be advisable. If you are adding large amounts of home-made manure
or compost, less fertilizer will be needed.
Well-rotted manure can meet N requirements. If growing hybrid varieties, increase all
fertilizer application rates by 50%. Nutrients are added after cutting to promote healthy
fern growth the following year. Do not remove ferns until the end of the growing season.
Boron deficiency may cause deformed fruit or uneven bud break. A foliar spray of 1.5
lb/100 gal water/acre of Solubor may alleviate these symptoms. Excess B may be toxic, so
apply soil or foliar B with care and only when need is indicated by soil or tissue test.
Blueberries have become a popular crop in
the home garden. They require an acid soil, so will benefit from added peat moss at
planting, and 2 oz. elemental sulfur sprinkled around each plant every two years. Pine
bark mulch makes a good weed control. Fertilizing can be done with a foliar feed of a
chelated iron product designed for acid-loving plants. There is a witch's broom condition
showing up on blueberries. It is caused by an unusual fungus, and produces numerous
swollen spongy shoots that have tiny leaves and no fruit. Fungicides are not effective,
the diseased plants must be eradicated. Pruning out the brooms will not control it, as the
whole plant is infected by the time it is noticed. The other host plant for this fungus is
the fir tree (Abies). Do not plant blueberries within 1200 feet of fir trees.
LAWNS LAWNS LAWNS
Consider replacing part of the lown with groundcovers. Great suggestions for groundcovers
in Vermont are in Leaflet OH55 http://www.uvm.edu/extension/publications/oh/oh55.htm
Here's a short course in lawn care:
Spread a half inch of compost on the lawn every year. Scratch and reseed bare spots. Raise
the mowing blade to 3 inch height. Leave clippings on the lawn unless they are too long or
too wet and lying in piles. Fertilize once a year in the fall. Test the soil, add lime in
the fall in amounts indicated by the soil test report to keep the pH optimal so nutrients
are available to the grass plants. Let the grass go dormant during a drought, it will come
back when the rains do. If you do all these things, your lawn will tolerate up to 12 grubs
per square foot, will crowd out weeds, and will have a cooled root system that goes deep.
Pesticides aimed at grubs are not effective in April, May, and June. The grubs are too
large, and the amount of chemical needed to kill them is much much more than if it were
applied at the proper time. Apply grub control in late July through August in the
Northeast. That is when the eggs are hatching and the larvae are small.
Milky spore needs grubs to maintain and spread the disease, so don't use chemical
pesticides with it.
There is an organic product made with kaolin, a fine clay, that can be sprayed on plants
to discourage the beetles from chewing on them. They find it incomfortable to walk on or
bite into. The whole plant, however, is then covered with a white powder and it may need
to be reapplied after a rain. Worth a try? Kind of ugly to look at.
The volcanoes are rising up around the trees and shrubbery again. Try to keep the mulch
several inches away from the trunks of trees and shrubs so the bark can stay dry and
impervious to insects and diseases. Keep the depth to 3-4 inches so the roots can breathe.
Trees use shallow roots, studies have shown. Planting a tree at the proper depth and then
burying it with mulch is inviting trouble, including accessory roots that grow into the
mulch and then can girdle the tree, leaving it weakened for the next wind storm to topple
it. Try for a bagel shape, not a volcano, when mulching trees.
Heads up for squash growers. Blossom end rot can be prevented by growing in well-drained
soil, watering deeply during dry periods of weather, especially in the heat of summer, and
mulching to maintain moisture. Avoid using a high ammonium fertilizer, which can burn the
roots. It also locks up the calcium in the soil.
STRAWBERRIES mulched with red plastic have
up to 90% more aromatic compounds than those mulched with black plastic. (From the
"Avant Gardener", Vol. 32, No. 11, Sept. 2002).
Dr. Pat Vittum, Turf Entomologist with the UMass Extension Turf Program, has developed
a list of possible sources of entomopathogenic nematodes for
white grub control. To read the complete message, please visit: http://www.umassturf.org/mangement_updates/management_updates.html
The UMass Extension Turf Program: http://www.umassturf.org
UMass Extension's Landscape, Nursery and Urban Forestry Program: www.UMassGreenInfo.org
TIMING IS EVERYTHING! Several common problems that show up later in the summer can be
prevented by proper timing of treatment, which means at budbreak in the spring.
APPLE SCAB is a fungus disease spread by
spores which are especially active during warm spring weather with high humidity. It
causes defoliation, reduced yields and blemished fruit. All apples are attacked, including
ornamental crabapples. Control is possible through planting of resistant varieties,
sanitation and/or fungicide application. Resistant varieties include Jonafree, Macfree,
Liberty, Freedom and Nova Easy-gro. If you insist upon growing McIntosh, Red Delicious,
Roma, or Cortland, be prepared to follow a strict fungicide spray schedule. The most
crucial time for spraying is from the time the green tips of the first leaves appear until
the fruit is set, usually from beginning of May to mid-June. Spray application should be
every 7 days during that period. Remember, fungicides work by providing a protective
coating to block out spores, not by killing spores. So sanitation, fall clean-up, etc., is
also needed. Also keep trees healthy by watering, fertilizing, and proper pruning. This
information and more is available on the Leaflet GD17,
which can be obtained by calling the Helpline.
VIBURNUM: If your viburnum has twisted,
curled, distorted and cupped foliage, it may be from the SNOWBALL
APHID. If so, add this shrub to your list of plants to be sprayed with
dormant oil. The eggs are on the twigs and buds and hatch along with the first buds
opening in the spring. If you are planning to plant viburnum, choose the resistant
'Viburnum tomentosum'. See leaflet EL176.
EUONYMUS CATERPILLAR: The larvae hatched
last summer and waited all winter under their eggshells for the spring to begin feeding
within a small web which expands as the colony grows. Break this web open with a stick and
let the birds feast on the larvae. If you have no birds, Bt or other organic insecticides
for defoliators will help, but break open the webbing first. See leaflet EL256.
There are some leaflets available to assist you to get ready for the gardening season.
GL's (Garden Leaflets) discussing timely subjects for the upcoming busy season can be
requested from the Master Gardener Program by calling the Helpline at 1-800-639-2230 or
(802)656-5421 and leaving a voice-mail with your request, your name and mailing address,
and any other questions you may have.
OH14 FORCING FLOWERING BRANCHES (http://www.uvm.edu/extension/publications/oh/oh14.htm)
and provides a handy chart of plant type, bloom color, when to cut and weeks to force.
Directions for successful forcing are also included.
GL9 COLD FRAMES/HOTBEDS includes
schematic drawings for construction of frames.
GL13 FROST PROTECTION for those who can't
wait until last frost to get something set out. Suggests which crops are best to start
early, and various products to use as cover against frost.
GL28 USING DORMANT SPRAYS TO CONTROL OVER-WINTERING PLANT
PESTS stresses the importance of timing when applying dormant sprays,
which is" before new growth begins in the spring or green tissue is visible, but
after buds start to swell". Consider dormant lime-sulfur spray if you have probelems
with aphids, mites and scale insects. Also used to control powdery mildew, rust and black
spot on dormant roses. Raspberry and blueberry cane blights can be reduced by lime-sulfur
applied jus before buds begin to break in the spring.
GL37 CONTROLLING TRANSPLANT HEIGHT has
some non-chemical tips on keeping those seedlings short and stocky.
USDA BULLETIN: HOW TO BUY LAWN SEED lists
the most frequently used grass seeds, explains their characteristics and what to look for
on the label.
Just a mention of SNOW FLEAS, which may
show up before this winter is finished. They usually appear as "thousands of little
black things jumping around in my front yard". They are not fleas at all, but
primitive insects named Collembola, commonly called springtails. Snow fleas ARE HARMELESS
and actually help break down leaf litter, etc., on the soil. They will not bother people
or pets, and will not get into the house, or contaminate foodstuff.
Think about ordering SOIL TEST KITS (see
phone numbers above) before things get really busy.
There are several leaflets of information available for helping to deal with problems
that can show up on houseplants at this time of year.
HOUSEPLANT PESTS EL 38
Lists insects that attack plants mostly by chewing and sucking, such as aphids, mealybugs,
and scale. Also spider mites. Controls discussed include prevention as well as
non-chemical means of removal.
FUNGUS GNATS EL50
Discusses fungus gnats, tiny black flies that thrive in any plant grown in a high organic
(i.e. peat-based) medium. They damage root systems as well as being a nuisance.
HOUSEPLANT PROBLEMS OH17
Provides a detailed and easy to read chart of symptoms and what the probable causes are.
An example would be leaves that turn brown at the tips or margins are suffering from over
or underwatering, too much or too little fertilizer, or low humidity (esp. in the house in
winter). Also included is a brief listing of common insect pest problems on houseplants.
On the lighter side:
STARTING SEEDLINGS INDOORS GL12
Here is all the information you need to be successful with seed-starting indoors.
PLANTING CALENDAR FOR VEGETABLES GL 5
Here is a listing of approximate dates for indoor seed-starting, using May 30 as the safe
date outdoors for sensitive crops.
These last two leaflets are not available from the internet, but can be requested
at no charge by calling the Master Gardener Helpline at 1-800-639-2230 or (802) 656-5421
any time and leaving a message with your name and address along with your request.
Helpline staff found these two useful articles on the VERMONT ENTOMOLOGICAL SOCIETY
- Introducing a new ladybird beetle to Vermont called Harmonia axyridis
- Black Widow Spiders (Latrodectus) in Vermont
WESTERN CONIFER SEED BUG has been turning
up indoors lately to spend the winter. They are smelly when squashed and can be a
nuisance, but do not chew on anything nor do they present a poisonous problem. They can be
vacuumed or swept up and disposed of. Spraying with a pesticide is only a last resort, and
no one wants pesticides in the house. Prevention of this invasion of bugs (also applies to
the ladybeetles and boxelder bugs) begins with making sure the house is well caulked
around windows and doors and any other openings for pipes, vents, etc. http://www.uri.edu/ce/factsheets/sheets/westconseedbug.html
BOXELDER BUG has been plaguing many
homeowners by coming inside homes to spend the winter. They are smelly, especially when
squashed, and a nuisance, but do not chew on anything nor do they present a poisonous
problem. They can be vacuumed or swept up and disposed of. Spraying with a pesticide is
only a last resort, and no one wants pesticides in the house. Prevention of this invasion
of bugs (also applies to the ladybeetles) begins with making sure the house is well
caulked around windows and doors and any other openings for pipes, vents, etc. Nearby
boxelder trees may have to be eliminated. Maple trees are also a favorite host of these
PUTTING THE GARDEN TO BED for the winter
is outlined on our factsheet number OH 03,
'Preparing the Garden for Winter'. Most important is clean-up of diseased plant material,
disposing of it off-site.Do not put it into the compost pile unless you can maintain a
very hot pile. An often forgotten but important cultural practice to prevent disease
problems in the garden is the cleaning of tomato stakes and/or cages, trellises, tools,
plastic supplies (row covers, hoops, jugs, etc.) with a solution of one part bleach to 9
parts water at fall clean-up to kill bacteria and fungi and not carry them over to the
next season. APPLE SCAB fungus remains on fallen leaves and fruit and these should be
cleaned out and disposed of to lessen the return of spores next spring.
BIRDSEED information excerpted from
"The Avant Gardener", Vol. 34, No. 10 (Horticultural Data Processors, Box 489,
New York, NY 10028) as follows: "Beware Birdseed:
One of the most common components of bird feed is black oil sunflower seed. It is valued
for its high-quality protein and as an oil source for avian diets. Plant
pathologists, however, have detected the overwintering form (sclerotia)of a
plant-pathogenic fungus in some commercial sunflower seed. 'Sclerotinia sclerotiorum' can
infect some 400 species of annuals, perennials, vegetables and woody plants. It causes a
disease called cottony rot, which has been documented as being on the increase for the
past several years. When birds discard infected seeds to the ground around the feeder, the
sclerotia can lay dormant for months or even years, then produce spores that will infect
plants. When plant pathologists at the Ohio Agricultural Research and Development Center
(Wooster, OH 44691) tested ten bags of commercial sunflower seed, five were found to
contain sclerotia of the fungus. Since there are no resistant sunflower varieties and no
fungicides to control the disease, commercial growers are being urged to rotate their
crops and monitor them for infection, and to practice double-screen cleaning plus gravity
screening to reduce infected seeds to the lowest possible levels." http://www.ext.nodak.edu/extpubs/plantsci/rowcrops/pp840w.htm
LAWNS: Fall fertilization of lawns should
have been accomplished by early September, but there is still time, right up to October,
to apply limestone. To be most efficient, a soil test should be done. Soil test kits may
be ordered from the Helpline at 1-800-639-2230 or 656-5421. The directions are all
included, and payment is sent with the soil sample. The alternative is to follow the rule
of thumb, which is to apply a nominal amount of lime if you haven't put any on in the last
GREEN MANURE: Be careful when buying rye
for green manure. There are 4 types of rye, and the one most often desired is ANNUAL
RYEGRASS. This a small grass that can be planted up to 3 weeks before first frost, will be
killed by the winter, and will leave a dead mat which can be turned into the soil in the
spring and can be planted into immediately. PERENNIAL RYEGRASS will die back in the winter
and then regrow in the spring, just like the lawn, which is where it is best used. WINTER
RYE is a grain crop that grows 4-5 feet tall, dies back in the winter and then regrows in
the spring. It can be tilled under when it is 10-12 inches high in the spring, but takes
several weeks to decompose enough for planting any garden crops. It is also difficult to
dig under by hand. SPRING RYE is a grain crop that is not common in the North.
The Helpline has been receiving calls about Blossom End
Rot on tomatoes. Here is the GD leaflet with information on it: http://www.uvm.edu/extension/publications/gardendisease/gd1.htm
Is it too late to use Merit to control grubs this year? Dr. Pat Vittum, Turf
Entomologist with the UMass Extension Turf Program, has provided some tips on how to make
the most of a Merit application. http://www.umassturf.org/updates/2002/15aug02.htm
Hornets and Wasps
The Helpline is receiving requests for information regarding bee and wasp problems, which
begin to become a problem now as the nests grow larger and the insects become more
aggressive. The Entomology Leaflet EL31 is an excellent resource for information. Recent
studies have shown that a 10% vinegar solution makes an effective weed killer, especially
on young weeds. You can make your own 10% solution by buying household vinegar (a 5%
solution) and boiling it down by half. Spray or wipe on with a sponge.
Anyone interested in starting a wildflower garden, meadow, patch, etc., should be getting
the soil ready this fall. An informative and comprehensive article covering all the
aspects of planting and maintaining a wildflower garden, "Planting a Wildflower
Garden" written by Master Gardener Judy Lochbruner, can be found in the articles
section of this website.
Time Sensitive Advice: Grub Control Must Be Done Now
by Marge Westphal, Vermont Master Gardener
If you are treating for lawn grubs and if you are using imidicloprid (MERIT or BAYER
SEASON-LONG GRUB CONTROL), it should be applied NOW, the first week of August. The window
closes after that, because it must be applied before the grubs hatch.
"GRUB-EX" product used to include imidicloprid, but is now registered with
halofenozide, which means it is effective on Japanese beetle only. If you have diazinon
left and want to use it up, it should be applied after eggs hatch, which is through
August in the Northeast. This chemical is more effective if applied now, while larvae are
small, rather than in the spring.
Milky spore disease is not effective north of Albany, New York.
For more details, refer to the "Grubs in the Lawn" section further down in the
Seasonal Tips posted 5/10/02.
Hydrogels, those sponge-like water retaining granules that are added to soil, may not
be as safe as previously thought. One researcher offers some concerns about their
I've received several reports from northern Vermont of moderate to heavy defoliation of
sugar maple by a small green looper called the Bruce Spanworm. Light numbers of the insect
seem to be widespread and common. Caterpillars may also be found on beech leaves. A pest
alert on the insect can be accessed at http://www.na.fs.fed.us/spfo/pubs/pest_al/bruce_spanworm/pa.htm.
Please let us know of any moderate to heavy infestations.
Ronald S. Kelley
Forest Insect & Disease Specialist
Dept. of Forests, Parks and Recreation
29 Sunset Dr. Suite 1
Morrisville, VT 05661-8331
TEL 802-888-5733 FAX 802-888-2432
- Fungus Problems Common Right Now:
- Oak leaf blister is a fungus that deforms
and puckers leaves. Treatment not usually necessary. Rake up and get rid of leaves in the
- Rust on hollyhock, raspberry, crabapples, hawthornes
is a fungus that can be minimized by applying fungicides when the leaves are just
emerging. For this year, make sure to clean up infected leaves this fall.
- Botrytis on peony will show up as
blackened leaves and stems. For this year, clip out and destroy infected areas. Clean
tools with alcohol. Next spring, apply fungicide when leaves are emerging from the ground.
- Apple scab affects leaves and fruit. For
this year, clean up all infected tissue, be ready next spring with orchard spray when the
- Fire blight
This bacterial disease can affect crabapples, apples, mountain ash, rose, pear and other
ornamental species. Most noticeable will be the appearance of dead terminal shoots of new
growth, which turn brown or black, the leaves droop downward, and the branch appears to
have been scorched by fire. The blight progresses downward on the branch and forms a
sunken dark brown to purplish canker from which frequently amber colored gum oozes. Fire
blight requires pruning out, starting well below the diseased area. Clean tools with
alcohol. Avoid excessive nitrogen fertilizers and plant resistant species. If you must,
spray a bacterial spray next spring just before leaf buds start to open.
- Cabbage Root Maggot
The fly lays its eggs at the base of cabbage family garden crops. When the eggs hatch, the
maggots burrow into the roots. Usually the first sign of damage occurs mid-June when
plants suddenly wilt during the heat of the day. Plants appear sickly and stunted, take on
a bluish cast, and eventually die. To control: 1. pull soil away from the plant , place a
heaping tablespoon of wood ashes around the stem and mix some wood ashes into the soil
around the plant; 2. a 6-8 inch flat circular collar of tar paper, foil, shingle,
plastic, etc., can prevent the flies from laying their eggs; 3. if seen, the small white
eggs can be removed. Cultural methods include rotating crops and removal of crop residues
in the fall as prevention of infestation.
This rainy weather has been perfect for wetting periods required by fungi that cause leaf
spots and blights like anthracnose in maple, ash, oak and sycamore. The only thing that
may keep infections light are the cooler temperatures that may slow the development of the
disease and the emergence of leaves. Here are a couple of links with more information on
the disease. No fungicides are usually warranted. http://www.uri.edu/ce/factsheets/sheets/anthractrees.html,
- SNOWBALL VIBURNUM APHID
There have been several inquiries about curling, distorted leaves in viburnam. These are a
result of earlier feeding injury from the snowball aphid. It is too late now to do
anything about it since the insects have left. More information is available from the EL
titled Snowball viburnam aphid (http://www.uvm.edu/extension/publications/el/el176.htm)
and homeowners should be ready next year when the buds break with something like Safer's
soap for organic or Malathion or sevin for non-organic prevention. Fungicides
are preventatives, and the label directions must be followed exactly to be effective.
- BACTERIAL BLIGHT ON LILAC
Several samples of lilac twigs have been seen with new growth stunted and brown, bark
black and moldy, some parts covered with a white fuzzy mold. Blossoms are brown and
unopened, leaves are blackened and wilted. The diseased portions should be pruned out well
below the affected areas, and the tools must be dipped into alcohol between each cut.
Remove all trimmings and destroy them, do not compost. If the infestation is serious or
widespread, be ready next Spring to start a fungicide program with a copper sulfate based
product at bud break, repeating every 7-10 days during wet weather.
- SPRING WEATHER AND APPLE CROP
The early warm days in April, followed by cold temperatures, has caused the apple trees to
bloom way before their normal May 15th bloomtime, resulting in an estimated 30%-50% loss
of crop. There has been damage to the king blossoms, the first to open, and even the
closed buds suffered damage to the anthers and pistils. Consequently, fertilization will
not take place and fruit will not form. Damage is found top to bottom in most trees.
Continued cold weather will reduce bee activity, resulting in even more loss due to
inadequate pollination during the period when blossoms are open.
To examine your tree's blossoms, cut open the flower longitudinally and note whether there
is any browning of the sex parts, which would indicate damage and loss of fruiting
Fruit set occurs in June, but there will be many spurs not fruiting in 2002. These will
then fruit in 2003, causing an overabundance of fruit that requires extra expenditure of
time and labor to thin so as to maintain quality.
- WORMS ON BURNING BUSH AND HYDRANGEA
Now is the time to check the succulent growing tips of these shrubs, looking for wrinkled,
folded and/or stuck together leaves with tiny eggs or webbing on the underside. These tips
are very tender and can be easily pinched out by hand now to prevent larval damage and
webbing that leads to indiscriminate spraying of pesticides later. Pinching out the tips
does not harm the plant, and even makes it bushier.
- GYPSY MOTH
The bellweather gypsy moth egg mass in South Burlington has hatched hundreds of tiny black
larvae. They are at the base of the tree and ready to climb, so wrap your tree trunks with
Tanglefoot now if you have this pest in your trees.
- Now is the time for dormant oil spray,
before the trees leaf out and temperatures are above 40 degrees F.
- Also, check those Home Orchard Spray labels for timing
your spraying before budbreak, to prevent the fungus and insect problems
you see later on.
- Get Ready: Pre-emergent treatment for crabgrass should
be applied two weeks before the last expected frost, and should be on by the time the
forsythia blossoms fall. There is an organic pre-emergent for crabgrass now available,
made from corn gluten.
- Indian meal moths in the house but you
have cleaned up your kitchen and put flour and cereals in cans and/or jars? Check your
birdseed! Don't store it inside the house.
- FYI: Proper diagnosis is important!
Found in the Helpline logs a classic example of why we don't spray or dust until
the problem is properly diagnosed: A person wrote in about several problems, including
gladiola leaves turning whitish, dahlia leaves turning yellow with brownish spots and also
losing perennial plants. Home gardener sprayed a fungicide and Sevin but the problems
seemed to continue. The Helpline requested plant samples. These samples showed that
two-spotted spider mites were affecting all the plants (mites loved our hot dry summer
last year) and a miticide was recommended. The fungicide previously applied was totally
inappropriate, and Sevin does not even list spider mites on the label.
- Vermont Vegetable and Berry Newsletter for April: Heirloom tomato
trial, GMO legume inoculants, transplanting pumpkins, corn borer biocontrol, Japanese
millet to suppress Rhizoc on potato http://www.uvm.edu/vtvegandberry/newsletter/04012002.html
- Q: I'd like to know what is recommended for spraying apple trees, especially as
an early dormant spray? I have a greening apple tree and I'd like to increase the
production of fruit, but am not sure what sprays to use.
A: There is a great deal of information available online on this subject, so rather than
typing it all, I will just mention these web sites which have good information for our
New England Apple Pest Management Guide http://orchard.uvm.edu/aim/9697neapmg/arthropod.html
UVM Extension publication "Spray Strategies" for general spraying tips.
Univ of RI general publication on home orchard spraying, which includes specific
information about apples http://www.uri.edu/ce/factsheets/sheets/fruitsprayguide.html#apple
And a good article about using horticultural oils may be found at http://www.rce.rutgers.edu/pubs/pdfs/fs866.pdf
- Q: I have a question about saving bulbs. My husband has been buying me a new
plant each week. (Tulips, daffodils, etc. in pots). I would like to save the bulbs for
planting in the fall. What is the best procedure for drying & storing them, or should
I plant them this spring when the ground thaws.
A: It is possible to save these bulbs although results are not always assured. You should
fertilize the plants with a high phosphorous houseplant fertilizer, keep them moist, and
keep them in a cool spot so that their leaves will stay green as long as possible. Then
plant them outdoors as soon as weather permits, so they can continue the ripening of the
foliage. Since the leaves are needed to form the bulb for the following year's bloom, it
is important not to remove them until they have died off naturally. If the leaves die off
naturally while in the pot and you seem to have what appear to be normal-looking bulbs,
you can just plant the bulbs outside in spring at the normal depth for planting (about
6" for large bulbs). Otherwise, plant them out, with the leaves, at the same depth as
they were in the pot, and remove the leaves only after they have naturally died off. In
either case you can then hope they will come up next year. Some of the paperwhite
narcissus are not hardy in our zone, so they will not survive, but some will.
- Q: We are being overrun with moles or voles. I've tried spray on repellents and
poison in the holes and they seem to enjoy both. Any tips on how to solve this problem?
A: It might be best to figure out what you have -- moles or voles. I suspect moles as
their activities with mounds and surface tunnels are more obvious than the voles. Voles
poison more easily as they more readily eat poison grains. Moles are insectivores and eat
grubs and such. For this reason, one way to reduce the mole population is to decrease the
numbers of white grubs in your lawn, if that is in fact a problem.
There is a UVM Extension Service publication available online on the subject of white
grubs at http://www.uvm.edu/extension/publications/el/el1.htm which gives information on
controlling moles from this angle.
You could also try trapping. There is a good description of the various kinds of
mechanical traps, plus information on mole life cycle and other methods of controlling
them at http://muextension.missouri.edu/xplor/agguides/wildlife/g09440.htm
This is an excellent information source. The traps are available locally at garden and
farm supply stores. They may also be caught in spring-type mousetraps baited with peanut
butter. I've personally used this technique with variable success. You have to find a main
exit hole, best to set 2 traps right at the entrance to the hole, then you must cover the
traps with something that will exclude light such as a bucket or flowerpot. This will also
keep pets and children away from the traps.
When you say you've used spray repellent, I'm assuming you used a castor oil product such
as Mole-Med, which will repel, but not kill the moles. It needs to be watered in and the
repellent effect will last up to 2 months, depending on rainfall. They will go elsewhere,
so there is an initial additional flurry of movement and tunneling. Perhaps the ground is
not yet sufficiently thawed for the product to have been absorbed enough to deter them, or
perhaps you are observing their attempts to get away. I noticed that there is a new
granular product to sprinkle the ground (which I think might be easier to use), available
at Gardens Alive (a mail order supplier) and perhaps Gardener's Supply and/or other places
I've heard of people running water into their holes with a hose, then standing by with a
shovel or other weapon to bop them as they come out the exit holes. Just another thought?
- LADYBUGS AND CLUSTER FLIES
Question: We recently moved to an old, old house in Waitsfield. I am
finding in the attic (which has skylights and windows on the sides) lots of ladybugs. They
are also coming around to the windows on the second floor now, especially on the windows
facing the south side of the house. I am also finding flies around too! What's the summer
to bring? Help! Are the lady bugs and flies bad to have around? What can I do to get rid
of them? If you have any suggestions, please let me know or whom to contact! Thanks for
Answer:Your problems with the lady bugs and flies are very common ones.
The flies are cluster flies. There is a UVM Extension publication on cluster flies
available at http://www.uvm.edu/extension/publications/el/el11.htm and from Rhode
Island at http://www.uri.edu/ce/factsheets/sheets/clusterfly.html. There are a
number of these publications but they have few suggestions for dealing with them once they
appear. From my own experience, I've found that if they are gathering at windows, they
will immediately fly outdoors if you open the windowsp; Also I've found it fairly
effective to vacuum them up. And here is a UVM Extension publication on ladybugs http://www.uvm.edu/extension/publications/el/el53.htm.
It is easier and more informative for you to use these links than for me to try to
synthesize and type an answer to you. I hope these will help. You are very welcome to
inquire again of the master gardener helpline, but I wanted you to be aware of a good
resource for finding UVM Extension Service publications. There is a search page for these
Marion -- volunteer master gardener
Now is a good time to think about preventing some of the vole damage similar to that which
was such a problem last winter. We are already receiving calls regarding vole activity in
perennial beds and fall planted garlic beds. Callers have left the leaves on the beds for
mulch, and have heavily mulched their garlic beds. Mulching should wait until the ground
is frozen, so as to discourage the critters from finding a warm home. If you have
shrubbery mulched, pull back the mulch, and replace after ground is frozen. Mouse traps
can be set with apple slices, or with peanut butter mixed with oatmeal, and set out on
fresh runs. Deep watering your shrubbery before the ground freezes is helpful to the
plants and may also discourage critters.
- GYPSY MOTHS
Before the snow flies, when you are taking Autumn walks, keep your eyes open for fuzzy
patches at the bases of trees. These are the egg masses of the Gypsy Moth. The egg masses
look like someone cut a patch from a camel hair coat and stuck it on the tree bark. The
female Gypsy Moth does not fly, so egg masses are low on trees. There they are also
covered by snow to survive the winter and hatch out next Spring when the serviceberry
blooms. It is easy to scrape off the egg mass now and crush it or put in soapy water.
- Some raspberry disease and pest
- The following is a link talking about spur blight
and fireblight in raspberries. Control
recommendations are given. http://www.extension.umn.edu/distribution/horticulture/DG1152.html
- Here is some info on cane and tip borers (EL13)
- Anything you can do to improve air circulation will help with the diseases.
- Applying lime sulfer in the spring is a good practice.
- Viburnum Leaf Beetle -The latest exotic pest to
by Margaret Skinner, Entomologist, UVM Entomolgy Research Laboratory
The viburnum leaf
beetle, Pyrrhalta viburni (Paykull), was detected in Vermont for the first time
in the fall of 2000 along the shore of Lake Champlain in Burlington. Originally from
Europe, it was found first in North America in 1947 in Ontario, Canada. It has been in
Maine, New York and New Hampshire for several years. This year heavy damage by this beetle
has been reported in several northern Vermont locations, and it has been sighted in six
different northern and central counties. Considering that viburnum is a favorite landscape
shrub, this pest could have a significant impact in this state. If left untreated, a bush
can be killed if it is heavily defoliated for two to three years.
The larva and adults of this insect feed on the leaf tissue between the veins so that
the leaves look skeletonized. They overwinter as eggs, which hatch in May. The larva are
very small and darkly colored when they first hatch. Early feeding damage looks like small
pin pricks or holes. As they mature larvae can range in color from brown to pale green
with dark brownish dots. By June the skeletonizing of the leaves is obvious. In June,
larvae drop off the leaves to pupate in the soil. Adult beetles emerge in late July and
continue to feed. They are brown and less than half an inch long. Females lay eggs from
late summer to the first frost. They make a hole in a small twig, and lay several eggs in
each hole, which is then covered with a mixture of chewed wood and excrement. Egg laying
holes can be found in a straight line on the underside of the current season's growth. One
female can lay up to 500 eggs per season.
This pest feeds on all species of Viburnum, including European highbush
cranberry (V. opulus), wayfaring tree (V. lantana), arrowwood (V.
dentatum), and American highbush cranberry (V. trilobum). Some species are
preferred more than others, but all of them are susceptible.
The simplest way to minimize the damage from this pest is to inspect your viburnum
bushes anytime after the eggs have been laid and before they hatch. In most areas of
Vermont that would be from late October until April. The egg masses appear as rows of
small bumps on the underside of the most current twigs. Any infested twigs should be
pruned and destroyed. Bushes should also be inspected in the spring to see if larvae are
present. If the infestation is small it should be possible to destroy these young larvae
by hand before heavy damage occurs. adults can also be picked off, but this is most
effective if done in the morning because in the warm afternoon they are apt to fly off
when the leaf is disturbed.
As a last resort, there are several insecticides that are effective against the
viburnum leaf beetle. control is most effective if applied against the larval stage.
Products containing pyrethrins are the least environmentally damaging and most effective
for controlling the larvae.
For more information about viburnum leaf beetle, contact Dr. Margaret Skinner at email@example.com or call 656-5440
POSTED 7/27/01: The weather
patterns have brought warm temperatures with rains which means perfect disease conditions!
Continue to look for:
- Tomato foliar diseases (GD18)
showing up on lower leaves first. Info is in leaflet and control info in the Brieflet.
Organic control is copper fungicides and Bravo for conventional control. These fungicides
will not cure the leafspots already on the plant but will protect new tissue if sprayed on
a weekly-10 day schedule. These diseases typically hit earlier varieties harder.
- Lilac leaf miner (EL 16)
browning and rolling leaves-look at the EL leaflet for info and control
- 2 spotted spider mites causing white
stippling and bronzing of several species including phlox, greenhouse tomatoes, etc. They
prefer hot dry weather. Try Safers soap but watch for phytotoxicity.
- Tomato hornworms should be showing
up-handpick and destroy.
- Look for imported cabbageworm larvae (EL63) on
the undersides of crucifer foliage. Control while small by handpicking or by spraying
Dipel. See EL leaflet for more info.
- Rust on peas and on sunflower lower
leaves. Spores are obvious on lower leaves with handlens. Use sulfur if severe.
- Colorado potato beetle-all lifestages
present! Crush eggs, handpick larvae and adults. Potatoes can withstand a fair amount of
feeding but they can multiply rapidly!
- Rapid browning and death of lawns can be a result of chinch
bug (EL191) or bluegrass billbug.
Check out EL leaflet on hairy chinch bug and how to sample for them, so homeowners can try
on their own.
- Apple maggot traps should be out now in
- Squash bugs (EL83)may
be causing wilting at the base of squash leaves. Check out the EL leaflet.
- Blossom end rot (GD1)
may be showing up on the first tomato fruits with a brown blossom end. Try to lessen water
fluctuation with mulching and watering. Typically, the next fruit are fine.
- new Armyworm leaflet (Adobe
- EL 56
- COMMON ARMYWORM ALERT (adapted from Brian Caldwell, Cornell Extension) Vegetable
growers, particularly those who grow rye, other small grains, or sweet corn, need to be
aware that there have been severe infestations of common armyworm this year in the
northeast, from NY to Maine. This pest sometimes blows up from the south and in most years
is not a problem. However, this year is evidently an exception, so keep a closer eye than
usual on your sweet corn plantings, and any vegetables near fields of rye or other small
grains. The pest is a caterpillar, and if you have an infestation you will see thousands
of them. They can be controlled with pesticides that are labeled for caterpillar pests on
your crop. Options for many crops would include Warrior, Larvin, Sevin, or Bt. Reports
indicate that Bt products containing the azawai strain are the most effective type of Bt
to use against armyworms.
- COMMON ARMYWORM --John Howell and Pam Westgate (from Ruth Hazzard's IPM Vegetable
Newsletter) There are numerous reports of common armyworm in turf and hay crops, in many
areas of the state. This insect also attacks corn and, occasionally, some other vegetables
especially peppers. The mature caterpillar is about 1 1/2 inches long, greenish yellow to
brown, with a dark stripe along each side. At this time it appears that the caterpillars
are full size and will likely pupate soon. Therefore,damage from this generation should
not continue much longer. These are heavy feeders on the leaves, in the whorl and in the
ear. Damaged leaves appear to have been shredded and this is characteristic of both the
common and fall armyworms. Larvae enter fruits of pepper and can cause extensive damage.
Typically, damage begins near the edge of a field as the caterpillars move in from
neighboring fields or grassy or weedy borders. This is likely to happen when they use up
their food supply and move on to new areas. Be particularly watchful in fields that border
hay. Available insecticides for corn include Warrior, Spin Tor, Larvin, Ambush and
Lannate. Apply in 75 to 100 gallons of water per acre. Make two applications five to seven
days apart when damage exceeds 15% in the whorl or pretassel stages. In peppers damage is
more likely to occur from fall armyworm, but a second generation of common armyworm is
possible. Orthene, Poounce, Spin Tor, Confirm and Lannate are labeled. Bacillus
thuringiensis, while available and effective on small larvae, is ineffective on the large
larvae that are causing the damage out there now. See the New England Vegetable Management
Guide and the label for more information. Growers may want to apply a treatment to the
edges of fields to intercept migrating caterpillars.
- Four-lined plant bug damage (EL148)
apparent on mints, daisies, hydrangea, basil, many ornamental flowers and herbs. The
angular leafspots look like a disease but they are feeding damage.
- Birch leaf miner (EL 2)
damage obvious on birches. Too late to control now. Do that next year when the mines are
first noticed. Keep up the vigor of the trees.
- Lilac leaf miner (EL 16)
injury should be obvious. Check out the leaflet. There is a leaf mining phase and a
leafrolling phase. Too late to control now.
- Armyworms (EL 56)
are stripping grass species (this includes sweet corn) in some areas. Hand pick or use
insecticide if severe and insects are still small, less than an inch.
- Tomato foliar fungus diseases although
gardeners will not be seeing leafspots yet, spraying for these diseases usually begins now
since we have accumulated enough degree days for the fungus to become active. Spray
fungicides now and repeat on a week to 10 day schedule for control. Organic options are
copper, otherwise, chorothalonil (Bravo). To lessen the disease, stake tomatoes to improve
- Found black leg on potato. This is a black
rot on the stem of potatoes that is gross and slimy. It is usually a hit or miss disease
and is caused by a bacteria. There is no control other than good cultural practices.
- Brown rot still showing up on stone
fruits. Too late to control with fungicides now. Causes blossom blight and gummosis on
stems of plants.
- Japanese beetles (EL 37)
out now. Use Rotenone or Sevin. Do not recommend traps.
- Colorado potato beetles (EL 65)
all life stages should be present. Handpick, kill eggs and control young larvae.
- Fruit drop may be apparent in apples due to plum curculio
97) or a normal phenomenon called June drop when the tree sacrifices extra fruit since
they cant ripen all the seeds produced.
- Still some scattered frost last week so
plant injury on succulent growing tips may be apparent.
- Slugs are going crazy with some of the wet
- Watch for striped cucumber beetles (EL 68)
and damage as new plants/seedlings emerge. Check out the EL leaflet on these beetles,
their damage and the Brieflet for Vegetable Insects and Diseases will have control
- Slime molds (GD
22) may be a nuisance in some wet areas on bark mulch
- With cool temps at night, cucurbits will tend to produce more female flowers that male.
If there are no males available, the flowers will not be pollinated and therefore no
- As peonies beging flowering one may see
botrytis or gray mold killing the tight flower buds if the weather is wet. Usually just
clipping out the infected buds and letting the next develop fine in drier weather is the
- There have been reports of aphids on new
succulent tissues. Try Safer's soap for an organic control.
- Diseases have been at a minimum this year compared to last year. Since we have had some
recent rain, more leaf spots on trees and
shrubs are showing up. Most of the time it is not necessary to control these with a
- There have been some calls about leaf tying catipillars.
The organic control would be to use Bt Dipel or handpick. The Dipel will not work if the
feeders are sawflies so if in doubt get an ID. the sawflies would not be associated with
any webbing, just voracious feeding.
- Rhododendren leaf samples have been coming
in with browned edges. Ann Hazelrigg, plant pathologist, has noted that no fungi or
insects were found, so the problem is suspected to be damage from the wet year last year.
Look for new growth to be healthy, clip out dead portions, fertilize with an acidic
fertilizer, and help out with watering if there is a dry spell this year. If no new
growth, the plants may be dead due to wet feet last summer.
- Pear thrips defoliation of maple has been
a problem in some areas of Vermont.
- Swarms of maple leaf cutters have been
noted at elevations of 1300 feet. (EL 34). These pests cause holes in foliaage. In large trees, control
is not warranted.
- Leafspots from apple scab (GD
17) and cedar apple rust (bright orange) are appearing on apple hosts, hawthornes,
- Hail injury from last week of May will
show up on newly developing fruits as scars on shoulders of blueberries, apples, etc.
- There is a possibility of an infestation of the viburnum
leaf beetle, Pyrrhalta viburni. It was found in Morrisville, VT,
this spring, and may be in the Grand Isle region. Please be on the lookout for it. For
more information, visit http://www.gov.on.ca/OMAFRA/english/crops/facts/vlb.htm. If you find
the larvae, pick them off and send some samples to the Helpline.
- We received, at the Helpline, some insect specimans that seem to be new to the area. A
Master Gardener from the Alburg area brought them, and said several folks are dealing with
the problem there. Margaret Skinner identified them as Lily
Leaf Beetles, and provided a website for further information. It is http://www.uri.edu/ce/factsheets/sheets/lilyleafbeetle.html.
These beetles are native to Europe, but have been in the Montreal area since 1945, and
first sighted in Cambridge, Mass., in 1992. They are bright red on the body, with black
legs, head, antennae, and undersurface. They are excellent fliers and hiders. They feed on
Lilium species, Fritillaria, Solomon's seal, bittersweet nightshade, potato, Nicotiana,
among others. However, they lay eggs and develop only on Lilium species and species of
Fritillaria. So be careful when sharing plants or transplanting in your own yard.
Hand-picking adults is recommended if you have only a few plants. Neem can be useful on
the first instar larvae to kill them, but only repels adults. It would have to be repeated
every five to seven days after egg hatch. There are studies being done with biological
controls. (posted 5/21/01)
- This is the time when the serviceberry (Amelanchier) is blooming, and that means also
that the Gypsy Moth eggs are hatching their
tiny larvae. If you see any of the egg masses that haven't hatched yet, they are bright
yellow to buff color, 3/4 to 1 1/2 inch ovals, found on the lower trunks of trees,
buildings, fences, etc. and should be scraped off and destroyed. See EL 55 for
all the details.
- Another insect problem that we get calls about every year is the Euonymus Caterpillar. This larva of the European spindle
ermine moth hatched last August already, and spent the winter in its eggshell on the twig
bark and in the bud axils. It begins feeding now in the Spring, within a small web, and
the web and the colony will expand as the summer progresses. By the time they are noticed,
the web is quite large and dense and must be shredded with a tool or with high pressure
water, and then a Bt insecticide can be sprayed on. See EL 256
for the full story.
- Moles are a hot topic again this Spring,
same as last Fall. The Helpline can suggest that the homeowner try mole traps, cats, and
stepping on the tunnels and mounds to flatten them. Studies have shown that moles eat
mostly earthworms, some grubs, and not the roots of the grass. They actually are aerating
the lawn, unsightlty as it may be. They are an important part of the food chain and only
live a year or two. Using insecticides on the lawn kills the earthworms as well as the
grubs, so the moles may go away (and maybe not), but so will birds you may be wanting to
have around to help eat insects. If insecticides are the choice, see EL 1,
White Grubs, and EL 37, Japanese Beetles, for in depth information and proper timing of
application to be effective.
- This is the information collected for the helpline volunteers and the Lake Friendly
committee by Judy Goodyear MG:
- CORN GLUTEN ( used as an organic pre-emergent) can be found:
1. Gardener's Supply - 25 lbs/$37 -Company name Fertrell, brand name Weedzstop
2. Agway - 5 lbs/$10.49
3. Four Seasons - no corn gluten
4. Depot Home and Garden - same as Gardener's Supply
All recommend 20 lbs./1000 sq. ft.
- NO P FERTILIZER - none of the above stores carry this but Oliver Seeds in Milton
(802-893-4628) formulates and distributes this in NH and Maine. Perhaps if there is enough
call for no P fertilizer, the stores will carry it. Oliver Gardener (owner of Four
Seasons) said that the company Osmocote also formulates and distributes a no P fertilizer.
- All of these stores carry fertilizers with N over 50% WIN.
- None of these stores emphasize soil testing before applying fertilizer.
- March is a good time to obtain soil test kits so
you are ready to use them when Spring finally does arrive. Call the Helpline at
(802)656-5421 or 1-800-639-2230 and we will send a kit out to you. All instructions are in
the kits, along with cost, which is currently $10.00 for a basic lawn or garden test. The
early bird gets the results back fastest.
- There have been some calls about carpenter ants in
homes. This can be a serious problem. There is a leaflet about carpenter ants, EL10. A
sample of insects should be sent to Vt Dept of Agriculture or the Helpline, and positive
identification made before other action is taken. Because of the damage possible,
contacting a professional exterminator is recommended.
- The time to prune crabapples and lilacs during dormancy is
upon us. For expert hands-on training, two opportunities are soon
available, both being held at the UVM Horticultural Research Farm.
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Last modified: July 02, 2003