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Aphids (Homoptera Aphididae) also known as plant lice are tiny (1/8″) soft bodied, oval to pear shape insects that come in green, pink, red, brown, black or dusty gray. The woolly apple aphid has a fluffy white cottony coating that closely resembles a mealybug. They congregate in groups and feed on the plant juices of young leaves, succulent tip growth and flower buds causing curling, stunted and distorted leaves. Infested leaves can wilt in bright sunlight and turn yellow/brown. The whole plant can turn pale yellow and stop growing. For infestation, the check new growth, stems and underside of leaves. Root aphids attack plant roots and display similar symptoms.
Aphids excrete honeydew which attracts ants and is the perfect medium for black, sooty mold fungus. In addition, they can also transmit incurable viral diseases. Most damage occurs when temperatures are 65-80 degrees.

They develop from an egg to adult but give birth to mature insects and reproduce rapidly.
Each adult aphid can produce 80 offspring within a week. Some mature adults have wings and fly infecting other plants.

Aphid control: A strong water spray will wash them off the plant, repeat at least 3 times. Handpicking, by squeezing the bugs between your fingers will help reduce the population. Yellow sticky traps will attract and control aphids. Homemade sprays such as garlic spray and hot pepper spray will repel the insect. Garlic spray: Mix 1/2 cup of finely chopped garlic cloves with 1 pint of water, strain and spray. Hot pepper spray: Mix 1/2 cup of finely chopped or ground hot peppers in 1 pint of water, strain and spray. Use gloves to protect your skin.
If that doesn’t work use insecticidal soap every 3-5 days for two weeks. Do not use insecticidal soap on gardenias.A stronger alternative is pyrethrum/ alcohol spray: combine 1 TBS alcohol to 1 pint of pyrethrum. The solution should have direct contact with the aphids to be effective. Other chemical remedies such as Neem are available. Be sure to follow label directions for safe application on specific plants.

Natural predators such as ladybugs, parasitic wasps, syphrid fly larvae and green lacewing larvae are biological controls that feed on aphids. They reduce the population and can eliminate the need for treatment when present. Aphids are also susceptible to fungal disease in humid weather. Look for reddish or brown, shriveled dead aphids

Can spider mites kill or harm my houseplant? How often/long should I treat the plant for?

Spider mites penetrate the leaf surface and remove the cell content. The result of spider mite infestation are tiny dots or stippling that give the leaves a bronze, chlorotic, grayish mottled look. Eventually the leaves will start to turn yellow/brown along the veins and drop. The foliage starts to wilt and general health of the plant declines. In severe infections you will also see fine webbing on the plant.

To test for spider mites, take a white sheet of paper, place it on the underside side of the leaves and tap on the leaf. If you see tiny pindots moving on the paper, then you have spider mites. Isolate your plant from all others because they reproduce rapidly (50-200 eggs in 7-14 days depending on temperature) and spread easily. If the plant is heavily infested then it should be discarded. It can be a difficult insect to control.

To control the infestation, spray the plant with insecticidal soap every 3-5 days for two weeks. Be sure to thoroughly spray the plant getting the underside of the leaves. If insecticidal soap does not do the trick try Neem oil. An alcohol solution made of 4 parts of water to 3 parts of rubbing alcohol with a squirt of dish detergent can also work as a contact spray. Spider mites love the hot, dry environment that is indoors during the winter and will attack plants that are stressed and weakened due to poor environmental conditions.
Increased humidity around the plant and washing the plant repeatedly with a forceful spray will knock off the mites and eggs which will help curtail the problem effectively but not eliminate it.

A note about insecticidal soap: A study at (ifas.ufl.edu) has found that some plants are sensitive to insecticidal soap causing phytotoxicity. The plant will show symptoms of yellow/brown spotting, burned tips, yellow or brown scorching leaf edges. Some plants sensitive to insecticidal soap are ; gardenia, lantana, nasturtium, Easter lilies(when forming buds) , maidenhair fern and crown of thorns. In this case use a miticide for houseplants. Follow manufacturer label and be sure it is safe to use indoors.