GardenGateMagazine.com | GARDEN GATE 61
WEED WATCH
VIRIDESCENCE
The process by which the variegated
leaves of a plant revert to all-green.garden jargon
Q
Can you explain why
my lilies (Lilium spp.)
stopped blooming and why
my peony (Paeonia hybrid)
turned brown? Bob Moyer, NYA
It’s most likely botrytis, the
most common disease for lily
growers. This fungal disease affects
the stems, leaves and, in extreme
cases, the flowers and buds of lilies.
Botrytis is spread by spores located
on the undersides of the leaves, on
the ground and in garden debris.
The spores are spread by wind and
rain, and are encouraged by wet and
humid conditions. It begins as a small
white or brown spot on a leaf or bud
and grows into a larger brown spot
with a lighter center until it engulfs
the entire leaf and then the stem and
buds as you see in the photo above.
Once it starts, it moves like wildfire
through the lilies.
The damage can be held back or
avoided using a broad-spectrum
biofungicide registered for organic
use (follow directions for use).
Botrytis is also the most common
disease of peonies. On peonies af-
flicted with botrytis, the young shoots
rot off at ground level when they are
5 to 8 inches tall. The stems often
have a water-soaked appearance. The
leafy shoots wilt and fall over. The
spore-producing structures of the
fungus develop along the base of the
rotting stalks and survive in debris left
in the garden over the winter. In early
fall, cut down all old leaves and stalks
to ground level and destroy them.Q
How can I get rid of wire-
worms that keep eating my
potatoes? Martha Plank, ILA
You will need to thoroughly
loosen and break up the top 6 to
8 inches of soil in your potato beds.
This makes conditions unfavorable
to the egg-laying adult wireworms—
click beetles—and exposes them to
the elements and its natural enemies.
Common in home gardens across
North America, wireworms (up to
1½ inches long) are tough, slender
worms with shiny skin and three
pairs of legs just behind their head
as you see below. They are yellow to
brown-red in color and feed entirely
underground, attacking germinat-
ing seeds, roots, bulbs and tubers.
Damaged plants soon wilt and die.
If infestations are heavy, thin and
patchy crops may appear in the
garden and reseeding will most likely
be necessary.
Potatoes also make great wire-
worm traps. Cut one in half and run
a stick through the middle. Bury
it about an inch deep so the stick
stands straight up like a handle. Pull
the traps out after a day or two and
discard the wireworms.PHOTOS: Courtesy of Bob Moyer (lily); courtesy of Alton N. Sparks, Jr., University of Georgia, Bugwood.org (wireworm larvae); courtesy of Joseph Berger, Bugwood.org (click beetle)Crownvetch
Securigera variaWhat it looks like Crownvetch is an
attractive perennial that rapidly forms
large clumps from creeping stems
up to 6 feet long and underground
rhizomes up to 10 feet long. A single
plant may fully cover up to 100 square
feet within a four-year period. Pink-
white flowers are produced from late
spring to fall on long stalks in clover-
like clusters above leaflets arranged
in pairs. Flowers are followed by
crown-shaped seed pods. It forms a
tangled mass less than 2 feet tall.Where to find it Crownvetch
is a European species that was
introduced into North America in
the 1950s as a ground cover. It was
mainly planted along highways and
on embankments to control soil
erosion. However, it is now natural-
ized throughout the United States,
including fields and roadsides. This
aggressive exotic excludes native
plants by fully covering and shading
them out.How to get rid of it Small patches
of crownvetch can be pulled or dug
from the ground. The entire plant,
including all pieces of the stems, roots
and rhizomes, needs to be removed.
Repeated mowing can be effective.
For larger infestations, you may need
to apply a systemic herbicide like
Milestone® in the fall for the most
effective control.Wireworm
(larvae)Click beetleLily with
botrytisGG14960_61_QA.indd 61GG14960_61_QA.indd 61 6/28/2019 11:42:22 AM6/28/2019 11:42:22 AMGardenGateMagazine.com | GARDEN GATE 61WEED WATCH
VIRIDESCENCE
The process by which the variegated
leaves of a plant revert to all-green.garden jargon
Q
Can you explain why
my lilies (Lilium spp.)
stopped blooming and why
my peony (Paeonia hybrid)
turned brown? Bob Moyer, NYA
It’s most likely botrytis, the
most common disease for lily
growers. This fungal disease affects
the stems, leaves and, in extreme
cases, the flowers and buds of lilies.
Botrytis is spread by spores located
on the undersides of the leaves, on
the ground and in garden debris.
The spores are spread by wind and
rain, and are encouraged by wet and
humid conditions. It begins as a small
white or brown spot on a leaf or bud
and grows into a larger brown spot
with a lighter center until it engulfs
the entire leaf and then the stem and
buds as you see in the photo above.
Once it starts, it moves like wildfire
through the lilies.
The damage can be held back or
avoided using a broad-spectrum
biofungicide registered for organic
use (follow directions for use).
Botrytis is also the most common
disease of peonies. On peonies af-
flicted with botrytis, the young shoots
rot off at ground level when they are
5 to 8 inches tall. The stems often
have a water-soaked appearance. The
leafy shoots wilt and fall over. The
spore-producing structures of the
fungus develop along the base of the
rotting stalks and survive in debris left
in the garden over the winter. In early
fall, cut down all old leaves and stalks
to ground level and destroy them.Q
How can I get rid of wire-
worms that keep eating my
potatoes? Martha Plank, ILA
You will need to thoroughly
loosen and break up the top 6 to
8 inches of soil in your potato beds.
This makes conditions unfavorable
to the egg-laying adult wireworms—
click beetles—and exposes them to
the elements and its natural enemies.
Common in home gardens across
North America, wireworms (up to
1½ inches long) are tough, slender
worms with shiny skin and three
pairs of legs just behind their head
as you see below. They are yellow to
brown-red in color and feed entirely
underground, attacking germinat-
ing seeds, roots, bulbs and tubers.
Damaged plants soon wilt and die.
If infestations are heavy, thin and
patchy crops may appear in the
garden and reseeding will most likely
be necessary.
Potatoes also make great wire-
worm traps. Cut one in half and run
a stick through the middle. Bury
it about an inch deep so the stick
stands straight up like a handle. Pull
the traps out after a day or two and
discard the wireworms.PHOTOS: Courtesy of Bob Moyer (lily); courtesy of Alton N. Sparks, Jr., University of Georgia, Bugwood.org (wireworm larvae); courtesy of Joseph Berger, Bugwood.org (click beetle)
Crownvetch
Securigera variaWhat it looks likeCrownvetch is an
attractive perennial that rapidly forms
large clumps from creeping stems
up to 6 feet long and underground
rhizomes up to 10 feet long. A single
plant may fully cover up to 100 square
feet within a four-year period. Pink-
white flowers are produced from late
spring to fall on long stalks in clover-
like clusters above leaflets arranged
in pairs. Flowers are followed by
crown-shaped seed pods. It forms a
tangled mass less than 2 feet tall.Where to find it Crownvetch
is a European species that was
introduced into North America in
the 1950s as a ground cover. It was
mainly planted along highways and
on embankments to control soil
erosion. However, it is now natural-
ized throughout the United States,
including fields and roadsides. This
aggressive exotic excludes native
plants by fully covering and shading
them out.How to get rid of it Small patches
of crownvetch can be pulled or dug
from the ground. The entire plant,
including all pieces of the stems, roots
and rhizomes, needs to be removed.
Repeated mowing can be effective.
For larger infestations, you may need
to apply a systemic herbicide like
Milestone® in the fall for the most
effective control.Wireworm
(larvae)Click beetleLily with
botrytis