Transcript Major Insect & Mite Pests of Perennials

Major Insects & Mites
That Attack Ohio
Landscape Perennials
Dr. David Shetlar (the BugDoc)
The Ohio State University
OARDC/OSU Extension
Columbus, OH
© D.J. Shetlar, 2005, all rights reserved
Major Insects & Mites
That Attack Ohio
Landscape Perennials
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Plant bugs, Aphids & Psyllids
Sawflies & Caterpillars
Twospotted spider mite
Leafminers
Slugs (not arthropods!)
“Bugs” & Aphids
On Perennials
 Fourlined plant bug - one generation.
• Most damage in May & early June.
• Prefers mint family.
 Aphids – many species, several
generations per season.
• Look for predators – be patient!
• Syringe (hose off with water).
Fourlined plant bug
(damage above), late instar
nymph (above right), and
adult (right).
Tarnished plant bugs also
damage various perennials
as well as several shrubs.
Tarnished plant bug
nymph (above), and
adult (right).
Other
Miscellaneous
Bugs
Many stink bug species
feed on seeds and
flowers.
Chrysanthemum lace
bugs are unique in that
they prefer leaf upper
surfaces!
Other sucking insects that
attack perennials include tree
hoppers (left) and leafhoppers
(below). The painted
sharpshooters (a kind of
leafhopper) cause puckering of
leaves. The nymphs (below)
run sideways.
Rudbeckia psyllids cause
disease like purple blotches
on the leaves of host plants.
The psyllid nymphs
and pupae look like
scales.
Most perennials have one
or two species of aphids
that may feed on them.
The goldenrod aphid
(above) feeds on a variety
of daisy and composite
flowers. The milkweed
aphid (right) feeds
exclusively on plants in the
milkweed family.
Generalized diagram of an aphid life cycle showing a species that alternates
asexual and sexual forms along with alternation of hosts.
Plant Bug & Aphid Control
(for homeowners)
Traditional
• Diazinon
X
• Dursban
X
• Sevin
• Orthene
X
• Malathion
• DiSyston
?
Still/Now Available
• Pyrethroids
(permethrin,
resmethrin,
esfenvalerate,
bifenthrin, cyfluthrin)
• Soaps & Oils
• Sevin, Malathion
Sawflies & Caterpillars
On Perennials
 Columbine sawfly – one generation
(May to June).
 Hollyhock sawfly – 3-4 generations.
 “Generalist” caterpillars – cabbage
looper, European corn borer, green
fruitworm.
 Stalk Borer & Iris Borer – not much
you can do other than remove!
Columbine sawflies can
completely defoliate
plants by the time they
are ready to flower.
Columbine sawflies hide on
the undersides of host
leaves during the day.
Though the larvae look like
caterpillars, they have more
than 5 pairs of prolegs on
the abdomen – a sawfly
characteristic.
Hollyhock sawfly larvae
skeletonize leaves and
the damage is often
mistaken for Japanese
beetle damage.
Larva (below)
Adults
look like
small
wasps or
flies.
Lysimachia sawfly larvae
are covered with a white
powdery material.
The violet sawfly
produces damage that
often looks like slug
damage – look on leaf
undersurfaces to
determine if the sawfly
larvae are hiding there.
The cabbage looper
may be found on a
variety of annual or
perennial flowers as
well as vegetable
crops.
Fruitworms
usually attack
fruit tree foliage,
but they may be
found on roses
and perennials.
The milkweed tiger
moth has a striking
caterpillar that feed on
all plants in the
milkweed family.
American painted lady
caterpillar feeding on
perennial.
Sawfly Insecticides
(for homeowners)
Traditional
• Dursban
X
• Diazinon
X
• Sevin
• Orthene
X
Still/Now Available
• Pyrethroids
(permethrin,
resmethrin,
esfenvalerate,
bifenthrin, cyfluthrin)
• Merit
• Sevin
• Soaps or Oils
Caterpillar Insecticides
(for homeowners)
Traditional
• Dursban
X
• Sevin
• Orthene
X
• Malathion
Still/Now Available
• Sevin
• Pyrethroids (permethrin,
resmethrin, esfenvalerate,
bifenthrin, cyfluthrin)
• Merit (imidachloprid)
• Bt
• Soaps or Oils
The iris borer overwinters in the egg stage attached to old
leaves. The eggs hatch in spring and the larvae burrow
down the leaves to the rhizomes. They continue feeding all
summer, nearly eating all the rhizome internal tissues. The
larvae drop out in August, pupate in the soil and the adult
moths emerge in October into November.
Iris Borer Insecticides
(for homeowners)
Traditional
• Dursban
X
• Lindane
X
• Cygon
X
(dimethoate)
• DiSyston
X
Still/Now Available
• ???
Twospotted Spider Mite
On Perennials
 Prefer hot-dry conditions.
 Females overwinter in mulch &
protected areas OFF THE PLANT.
 Often “reinstalled” on new bedding
plants.
 Often resistant to common miticides.
Twospotted spider mites can
completely web over the
foliage of their hosts.
Twospotted spider mite
eggs, nymphs and adults
generally reside on leaf
undersurfaces unless they
have completely covered
their host foliage.
Miticides
(for homeowners)
Traditional
• Kelthane
X
• Cygon
X
• Soaps & Oils
• Orthene
?
X
Still/Now Available
• Pyrethroids??
X
• Soaps or Oils
• DiSyston (Rose
Systemic Granules) ?
• Conserve (=Naturalite)
??
Coneflower flowergall
mites are eriophyids.
Eriophyids are often not
susceptible to regular
miticides.
Leafminers on Perennials
 Columbine leafminer(s) – several
species with multiple generations
per year - dipterous.
 Serpentine leafminers – several
species that attack Phlox,
hollyhocks and others - dipterous.
Columbine leafminer adults
(above left) feed by making
“pinholes” in leaves (left). Eggs
are inserted into leaves and the
larval maggots make winding
mines which may end in a large
blotch.
Leafminer Insecticides
(for homeowners)
Traditional
• Dursban
X
• Lindane
X
• Cygon
X
(dimethoate)
• DiSyston
?
X
• Orthene
• Neem
(azadirachtin)
Still/Now Available
• Pyrethroids
(permethrin,
resmethrin,
esfenvalerate,
bifenthrin, cyfluthrin)
• Merit ?
• Neem ?
• Conserve ?
• DiSyston ?
A half dozen species of
slugs can be found in
Ohio landscapes and
most will feed on the
leaves of plants while
others specialize on
feeding on fungi.
Garden snails are not
common in Ohio, but
they occasionally
become established
through recent plantings
of new plants. Most
can’t survive Ohio
winters.
Molluscicides
(for homeowners)
Traditional
• Metaldehyde
• Methiocarb
X
Still/Now Available
• Iron Phosphate
(Sluggo)
• Metaldehyde (Deadline)
Black Vine Weevil
On Perennials
 Not a common landscape pest of
perennials, mainly in container
production areas.
 One generation per year, females
lay eggs over long period of June
& July.
 Larvae overwinter in soil or pots.
Black vine weevils are
commonly called the Taxus
Weevil because this is one
of their favorite hosts.
Black vine weevil larvae look
like scarab white grubs, but
weevil larvae have no
obvious legs (right).
Black Vine Weevil
(adults only)
(for homeowners)
Traditional
Still/Now Available
• Dursban
• Pyrethroids (cyfluthrin,
X
resmethrin, bifenthrin)???
• Turcam
X
(professionals only) • Cygon & DiSyston?
• Orthene
X
NEW! Black Vine Weevil Management
Merit! (home owner product
available, apply to soil for
larval control, NOT mulch,
not for adults!)