CONTROLLING PEST AND DISEASE PROBLEMS-
Sometimes, despite your best efforts, pests and dis eases may attack
your flowers. The key to control ling these problems is spotting
them early. Take a few minutes as often as you can (daily is ideal;
weekly is okay too) to really look at your plants. If you spot insects
or damage, try to find out what caused it; correctly identifying
the problem will help you choose the most effective control. Some
of the most common problems, along with their causes and controls,
are covered below. Before try ing any control for pests, wait a
few days to see if the beneficial insects living in your garden
will take care of the problem for you. If pests are increasing after
a few days, then try a control measure.
Leaves or shoots are distorted
or discolored:
Aphids are small pear-shaped insects that come in many different
colors. They often cluster on buds, shoots, and leaf undersides
to feed on plant sap. Pinching off and destroying infested plant
parts is often an effective control. If pests get out of hand, buy
a commercial insecticidal soap spray and apply it according to the
label directions. Or mix up your own spray by adding 2 teaspoons
of liquid dish soap (not detergent) to 1 gallon of water. Spray
plants every 2 to 3 days for 2 weeks. Commercial neem sprays are
also quite effective. (Neem is an organic insecticide derived from
the seeds of the neem tree.)
Leaves are yellow or pale, often
with webbing on the undersides:
Spider mites are tiny (almost microscopic) pests that suck plant
sap. Pinching off infested parts and using insecticidal soap or
neem sprays (as discussed above) are effective against spider mites
as well as aphids.
Leaves have holes:
Caterpillars or slugs and snails could be at work here. Look for
silvery or shiny slime trails, which are signs of slugs and snails.
These pests like to hide in cool, damp places during the day, so
you may be able to trap them under upside-down fruit rinds set among
your plants. Check the traps each morning and remove and destroy
trapped pests. Some gardeners report good success with beer traps:
Sink a shallow container so the rim is flush with the soil surface,
and fill it with beer. Every few days, remove the drowned pests.
If a caterpillar is the culprit, you
may find it clinging to the underside of the leaf, or to a nearby
stem. Look carefully, since these pests often blend in well. If
you find the caterpillar, pick it off (use gloves if you're squeamish!)
and destroy it. If there are too many caterpillars to hand pick,
or if you can't find the culprit, try spraying plants with BT (Bacillus
thuringiensis). BT is a bacterium that is harmless to plants, pets,
or people but toxic to caterpillars. Mix the BT concentrate according
to package directions, and use a sprayer to thoroughly coat plants;
make sure you get the leaf under-sides too. Damage should stop within
2 to 3 days.
Leaves have white or gray spots:
Powdery mildew is one of the most common diseases that attacks flowers.
Roses, zinnias, and bee balm are common targets. To prevent problems,
snip out some stems to allow for good air circulation through the
clump. If only a few leaves are affected, try pinching them off
and spraying the rest of the plants with compost tea (see "Mulching,
Watering, and Weeding"). Besides giving plants a nutrient boost,
compost tea can help control some fungal diseases. If that doesn't
work, try a baking soda spray: Dissolve 1 teaspoon of baking soda
and a few drops of liquid dish soap in 2 quarts of warm water, and
spray all parts of the plant thoroughly.
If your plants don't match these symptoms,
look in gardening books or ask your local home or garden center
salespeople to help you identify the problem. Insecticidal soap
or neem-based sprays will control a wide variety of different pest
problems, and they may be all you need to deal with virtually all
pest problems. Pinching off and destroying disease-infected leaves,
then spraying plants with compost tea, will control many disease
problems. If plants look seriously diseased or insect infested,
remove and destroy them before the problem spreads to other plants.
