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Can
this azalea be saved? The petals are slimy and
it has expanding white or brown spots. Yechh! This is
azalea petal blight. It usually attacks the lower leaves first,
but it's only a day or two until the flowers collapse. Azalea
petal blight can affect various flowers but is most common in azaleas
and rhododendrons. It's a fungus that overwinters in dead
flowers and soil under the shrub. To get rid of it, pick the
infected flowers as soon as you notice the above conditions.
Clear away any debris under the shrub. You can help to prevent
it by not watering from above while the shrub is flowering and covering
the soil with a thick layer of mulch.
Prevent damping-off
fungal infection in new seedlings by planting in
well drained soil and maintaining good air circulation.
If a damping-off
fungal infection occurs, spray the seedlings and soil
surface with chamomile tea. To make, pour one cup boiling water
over one-fourth cup dried chamomile blossoms (grow your own or buy
wherever bulk herbs are sold). Let sit until cool, and strain into
a spray bottle. Chamomile has antifungal properties that create
virtual miracles in the greenhouse.
Bacterial
leaf spot affects cabbage, turnips, cauliflower and some
other veggies mainly when they're in the seedling stage. It
leaves small brown or purple spots on the leaves which eventually
turn yellow and fall off. The affected plants cannot be saved
and should be removed and destroyed immediately. To prevent,
rotate crops in a three year cycle.
Black rot
can affect any crucifer (cabbage, cauliflower, broccoli, turnip,etc.)
and at any growth stage. The initial symptoms of infection
are the presence of small, yellow-brown, V-shaped areas at the leaf
margins. As the lesions enlarge, the nearby veins turn black and
affected areas dry out and turn black or brown. A cross- section
of the stem will show a distinct ring of discolored or decayed tissue.
Root systems on infected plants are usually less extensive than
on healthy plants. The disease cycle of the black rot pathogen
starts in infected seed or crop residue. The bacteria are spread
to healthy plants by splashing water, mechanical spread or by insects.
Black rot is favored by wet weather and temperatures between 80-86o
F. Using disease-free seed and transplants are essential for
black rot control. Plant in areas where air circulation and soil
drainage are good. Fall tillage will hasten the decomposition of
infested crop residue and decrease pathogen populations. Rotate
your beds out of crucifers for three years for both disease control
and soil management.
Crown gall
is a bacterial disease that enters the plant through wounds.
Round rough galls up to several inches in diameter are formed, usually
near the soil. Warm weather and alkaline soil provide good
growing conditions for crown gall. Prune out all diseased
areas of the plant. Sterilize your tools with bleach after
each cut. Seriously infected plants should be removed and
destroyed. Don't put any new plants in the affected area for
a few years.
Fusarium wilt
is characterized by darkening veins, wilting and yellowing leaves
and stems and rotting roots. It's a fungal disease that can
affect various plants. The fungi live in the soil. Destroy
any affected plants and clear away debris. Prevent by rotating
on a minimum three year schedule and buying resistant cultivars.
Mosaic
can affect many different plants including flowers and vegetables.
The symptoms are mottled green and yellow foliage or veins, wrinkled
or curled leaves, banded stems and/or stunted growth. It's
often transmitted by aphids or leafhoppers. Destroy infected
plants. Buy certified disease-free plants or seeds.
Plant resistant cultivars. Clear away debris.
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