Jusect Enemies of Your Houseplants 
Aphis Mealybug Mite Red Spider Scale 
In a greenhouse where the temperatures are regulated ac- 
cording to the needs of each crop, insect pests are kept to 
a minimum by syringing the plants, chemically spraying 
them at regular intervals, or through the use of aerosols. 
However, when the plant's environment is changed to the 
drier and warmer conditions of the home, danger of infesta- 
tion increases. Fortunately, the variety of insects commonly 
found attacking houseplants is not large. 
APHIS: These Plant Lice are small, soft-bodied, green or 
black sucking insects about 1/8” in size. They usually occur 
in clusters at the soft growing parts of plants. With long 
legs they can move around freely, and appear to stand on 
their heads while sucking plant juices. They multiply rap- 
idly but are easy to control. 
Aphis are seen less on tropical houseplants and favor the 
cooler growing group of porch plants such as Ivy, Pelargo- 
nium, fast growing vines, Chrysanthemums, Fatshedera, 
also Dieffenbachias, Gardenias and ferns. 
CONTROL: key #2, 3, 6, 9 
MEALYBUGS: Slow-moving pinkish white soft-bodied in- 
sects equipped with many leg-like filaments. They are 
covered with a powdery waxy substance which tends to 
prevent penetration.of insecticides to their bodies. The 
young which emerge from cottony masses are easier to kill. 
Found usually on the undersides of the leaves and in their 
axils, they live by sucking sap which causes sickly foliage, 
and bud drop on flowering plants. Mealybugs infest many 
houseplants including Saintpaulias, Dieffenbachias, Dra- 
caenas, Gardenias, Cissus, ferns, Syngonium, Philodendron. 
CONTROL: key #1, 3, 4", 5, 6, 7 
MITE: Microscopic eight-legged, oval arachnoids, nearly 
transparent, and less than 1/100 of an inch in size. The 
Broad mite moves rapidly, the Cyclamen mite slowly. The 
Cyclamen mite prefers to suck in the newly forming leaves 
and buds of plants where they are difficult to reach, 
crippling the growing tips. It feeds preferably on African 
Violets, Ivy, Cissus, Begonias, Episcias and other Gesne- 
riads where extra effort must be made to force insecticide 
through the shielding hairs of the plant. Broad mite which 
feeds on the more exposed underside of leaves, is more 
easily controlled and is found on Ivies, Cissus, Vitis, Fats- 
hedera, Aralias. CONTROL: key #6, 8, 9 
RED SPIDER: A tiny mite which can be seen with a hand 
lens. They thrive where the air is hot and dry, and usually 
live on the underside of leaves where they spin webs if 
allowed to remain. These tiny eight-legged creatures, 
usually red or brown, will produce new generations rapidly, 
from transparent eggs the size of a pin point. Red spiders 
when sucking the sap from the leaf, injure the plant tissue 
which causes speckling and discoloration to the leaf sur- 
face. They attack such plants as Ivy, Araucarias, Aspidis- 
tras, Marantas and Red Dracaenas. 
CONTROL: key #3, 6, 7*, 8 
6 
SCALE: A small sucking, turtle-shaped and mostly station- 
ary insect of great variety. Their color may be tan, brown, 
black or white, and their shape oval, oblong or circular. 
Their shield-like appearance is nothing more than a waxy 
coat which covers the indistinct body of the insect. This 
shell of the adult scale protects them from most contact 
insecticides, and is therefore difficult to dislodge. The 
young however are vulnerable while they move around. 
With plants having hard foliage, a soft sponge, brush or 
rag dipped in an insecticide can kill the young, while dis- 
lodging the adults sheltering them. 
Typical host of scale are Palms, Ferns, Aralia, Ficus, Citrus, 
Ivy, Oleander, Cactus, Pandanus, Orchids and Bromeliads. 
CONTROL: key #4, 6, 7 
SUGGESTED CONTROLS 
Commercial growers have access to some very potent in- 
secticides such as Parathion, TEPP and other phospates but 
these are not approved for public use by the Dept. of Agri- 
culture because they are dangerous to human life and 
warm blooded animals. 
For this reason, this Key includes only remedies which are 
being used in the home. 
1. Spray or dip of Nicotine Sulphate (Blackleaf 40), (1 tea- 
spoon) and Summer White Oil (2 tablespoons) per gal. 
of water. Use oil with caution; see #7. 
2. Spray with Nicotine Sulphate (1 teaspoon) and soap 
flakes (2 level tablespoons) to a gal. of warm water. 
3. Forceful syringing with water every 3 to 4 days, es- 
pecially the underside of the leaves; best done in sink 
or bath tub. 
4. DDT emulsion (do not use on ferns and certain succu- 
lents). Because it will not kill Red Spider, the popula- 
tion of these may increase if DDT is used alone 
continuously. 
(4*: DDT will kill the young and unprotected Mealy- 
bugs but not the adults.) 
5. Touch insects or nests with toothpick tipped with cotton, 
or an artists brush, dipped in Alcohol or ether (nail 
polish remover). (Alcohol may burn tender Gesneriads). 
6. Spray or dip of Rotenone and monolaurate (spreader) 
preparation, such as NNOR or TEC. 
7. Spray or dip of Summer White Oil emulsion, such as 
Volck with water. Use with caution at weakest concen- 
tration recommended and not more than once a month. 
It is best suited to leathery foliage which will not burn 
easily. Apply at relatively warm temperature, 70-80° 
and not in direct sunlight. After a few hours, syringe 
plant with water to remove any excess oil since satura- 
tion of foliage with oil, especially at low temperature 
will burn or cause leaf-drop. (7*: Do not use on Ges- 
neriads). 
8. Mite Controls: New Miticides are Aramite, Dimite and 
Ovotran (these may cause leaf burn on some plants and 
should be tested on a small scale). 
Fumigating with mothballs (Paradichlorobenzine), used 
with the plants in a confined space such as an inverted 
box. 
Submerging the top of the plant in water for 15 minutes 
at 110°F. and keeping it there will kill mites without 
harm to the plant. 
Broad mite can be eliminated by dusting with fine 
dusting sulphur, but the temperature must be a warm 
70-80° to be effective, preferably in the sun if the plant 
allows it. 
9. Spray or dust of Benzine-hexachloride in refined form 
such as Lindane. (Prolonged use may cause leaf drop.) 
