Description |
Controls |
|
Aphids
Often
called plant lice, these insects are up to 1/8 inch long and may
be green, red, black, or brown. Tender new growth and leaf
undersides are usually affected. Aphids suck the plant juices
causing yellow foliage and death. They secrete a sticky
"honeydew" that is deposited on leaf surfaces.
|
Minor
infestations can be treated by spraying or showering with water.
Severe infestations will need treatment with an insecticide safe
for houseplants.
See Insect Problems. |
Brown leaf tips
Look for
leaf edges that turn crispy and brown as if burned. New growth
is often affected, becoming brown and weak. Culprits are:
too high heat, too low humidity, allowing plants to dry out
between watering, cold or hot or dry drafts, or
over-fertilizing. |
You must
find the problem causing the browning, so: lower the
temperature, raise the humidity, stop the drafts, water more
evenly, and carefully follow fertilizer directions. Note:
some houseplants are sensitive to fluorides or other chemicals
in water. Simply trim off the browned leaf tips. |
Bud drop
Flower
buds drop off before flowering. Causes: too
high room temperatures, too low humidity, hot or cold or dry
drafts, uneven or insufficient watering, too much fertilizer, or
shock from being moved while in the bud stage. |
Determine
the problem and correct it. Lower the heat, increase the
humidity. eliminate drafts, water evenly, and don't move the
plant to new locations frivolously.
|
Failure
to bloom
Flowering
plants don't flower. Main reasons are: insufficient light
or too much high-nitrogen fertilizer. Some blooming houseplants
like poinsettias and Christmas or Easter cacti are dependent on
day length and must be shaded. See Holiday
Houseplants for information. |
Position plants in bright light - use supplemental grow lights for 14+
hours daily. Use only a low nitrogen fertilizer. Mist
daily to raise humidity high and keep soil moisture constant.
Follow re-blooming instructions for plants that are sensitive to
day length.
|
Fungus
Gnats
Clouds
of tiny black flies - smaller than fruit flies - swarm around
plants and on the soil surface. They suck the plant juices
damaging foliage and weakening the plant. They reproduce
quickly and will kill the plant if left untreated. |
Repeated
applications of a houseplant insecticide are required to
eliminate fungus gnats. You will have to treat the soil surface
too. Adding a 1/4" layer of sand to the soil surface
helps discourage them. Don't handle other plants that are not
infected to prevent spreading.
See Insect Problems.
|
Mealybugs
Mealybugs
are soft-bodied, 1/4-inch-long insects with a powdery coating of
white or beige. They look like little cotton balls clustered
under leaves or on shaded ones, or in stem crotches. They suck
plant juices and can severely weaken or kill plants.
|
Good
results can be had by daubing each insect with rubbing
alcohol. Use a cotton swab to apply. For severe
infestations, use repeated applications of a houseplant
insecticide.
See Insect Problems. |
Scales
Scale
insects are oval or round, 1/8 inch long, and have a shell-like
covering. They come in brown, black, gray, or white. Scales
leave a honeydew residue on leaves that is sticky and/or shiny.
They suck plant juices and can weaken and kill plants.
|
For
small infestations, remove them with soapy water. Serious
infestations will need repeat applications of a houseplant
insecticide.
See Insect Problems. |
Spider
mites
Spider
mites are so tiny they can barely be seen. You will notice
yellow flecks or speckling on the upper side of the leaves, an
overall dull look to the foliage, and fine webbing in severe
infestations. |
Proper
watering and high humidity are the best preventatives. Shower
plants weekly with plain, lukewarm water. For severe
infestations, use a houseplant pesticide that specifies it is
effective again spider mites.
See Insect Problems. |
Whiteflies
These
white insects rise in clouds off disturbed plants and look like
flying dandruff. They suck plant juices, yellowing foliage and
weakening plants. They reproduce quickly and will kill the plant
if left untreated. |
Repeated
applications of a houseplant insecticide are required to
eliminate whiteflies. Don't handle other plants that are not
infected to prevent spreading.
See Insect Problems. |
Wilt
This
can quickly kill a plant. The main causes are:
insufficient water, poor soil, high temperature, low humidity.
Water-logged or poorly drained soil can also rot plant roots
causing wilt. |
Lower temperature, water more often and more
evenly, raise the humidity, repot the plant or top dress with
fresh soil. Improve drainage and avoid overwatering or
watering too often. |
Yellowing
foliage
Yellowing
foliage that falls off can be caused by different problems: too
much/too little light, high room temperature, overwatering, poor
drainage, too much or too little fertilizer - or the wrong type,
air pollution. Some yellowing and leaf drop of older leaves is
normal. |
Correct
the problems that are causing the condition. Provide the correct
amount of light, lower room temperatures and raise humidity,
water evenly, fertilize correctly with the right fertilizer for
the plant, and ensure good air circulation and fresh air. |