Prevention is the best remedy when it comes to dealing with most plant
diseases. Many diseases cannot be
effectively controlled once symptoms develop or become severe. Fall is a good time to launch your
preventative management program in the home orchard and garden. This includes a combination of strategies
involving sanitation, cultural practices, and seasonal spray applications.
Garden sanitation aims
to remove the source of future disease infections by means of a thorough clean
up program. Common fungus diseases like
peach leaf curl, brown rot, apple scab, camellia petal blight, and black spot
on roses will reappear the next season because the fungus spores survive over
winter in dead leaves, rotting or mummified fruit and other plant debris left
behind the previous Fall. Disease
pathogens can also survive in older mulching material laid out in previous
years. If a serious fungus infection
exists, such as Camellia Petal Blight, remove old mulch and replace with fresh
material. Grab a rake and get out into
the garden for a clean up day before first rainfall for best results. Dispose of any suspect plant debris.
Removal of diseased
plant tissues on the plant itself is your next line of defense. Prune out diseased foliage, twigs or
branches, hand pick blighted camellia blossoms as they appear and dispose of
these in the trash. Avoid unnecessary
pruning; pruning causes wounds, which can be entry sites for decay and disease
organisms. Sanitize pruning equipment to
avoid transmitting disease to healthy plants.
Avoid overhead irrigation
– splashing water spreads fungal spores and wet foliage promotes some foliar
and fruit diseases such as leaf spots, rusts, anthracnose, and brown rot.
Finally, follow up with
preventative applications of a fungicidal spray. This is an especially critical step in the
control of peach leaf curl and other recurring diseases. Synthetic and organically acceptable spray
materials are available to control certain plant pathogens, primarily fungi. Products such as Bordeaux mixture, sulfur,
fixed copper, and fungicidal soap sprays protect plants from pathogen
infection. These organically acceptable
fungicides generally only prevent the infection of healthy, spray-covered
tissue and do not act systemically to kill existing pathogens; therefore
repeated applications may be necessary during critical growing stages. Synthetic fungicides are often more
effective, easier to apply, and are less likely to damage susceptible plants;
some have systemic activity. Fungicides
require careful timing to be effective.
Consult a qualified nursery sales person to determine an appropriate
spray product for you. Wear protective
gear such as goggles and gloves, and use as directed on the product label.
Other Master Gardener
articles about specific disease pathogens:
·
Mildew
·
Root
Rot