Aphids                          Spider Mites and eggs

One of the biggest challenges with plant care is insect control. Once you have an insect presence on your houseplants it can very quickly become an out of control infestation. The best way to avoid an infestation is prevention, early detection and prompt adequate treatment. The most common way for insects to gain entry to your home is by hitching a ride on new plants, where they may be hidden in crevices, or there may be one or two microscopic eggs attached to the underside of a leaf. For this reason it is recommended to keep new plants separated from other resident houseplants for 3-4 weeks, during which time any lurking insect problems have ample time to become apparent. Isolating plants does not mean you need to keep them in a separate room. A distance of 10 ft or so is sufficient to keep a minor insect problem from moving from one plant to another, because insects seldom seek new host plants when they are satisfied with the one they have.

The insects that are most commonly found on houseplants cause damage to the plant by feeding on plant juices. It does not take long for a moderately sized insect population to damage a plant beyond it’s ability to recover. Plants that had more than half of their leaves damaged by insects are often not worth saving. However, if the plant can be propagated from a stem cutting and you find a stem that appears insect free, you can try rooting the cutting. This is often the best way to retain a beloved plant that has been ravaged by insects.

The types of insects most commonly found on houseplants are Aphids, mealybugs, Scale, Fungus Gnats and Spider Mites. Most of these insects produce 'honeydew'. 'Honeydew' is a thick, clear, sticky liquid that is produced by insects as waste. Honeydew can be found on leaves and surfaces under and around the infested plant. 'Sooty Mold', a black mold that looks like soot, can often be found growing on honeydew.

~ Aphids are small, soft bodied insects that are easily recognized by their pear shaped body. Most species of Aphids are green but some are brown, red or black. Adult Aphids can be winged or wingless. Aphids are easily controlled by most insecticidal soap sprays and chemical pesticides.

~ Mealybugs are soft-bodied, oval shaped, scale like insects with many legs. Mealybugs are covered by a sticky, white, cottony looking substance that extends out from it's body like short filaments. Mealybugs can be a problem to get rid of because the cottony substance often protects the insect from pesticides. The best way to get rid of Mealybugs is to pick them off with a cotton swab dipped in alcohol. Be sure to check all little crevices, folds and grooves on both the leaves and stems. Also check the pot and the area immediate surrounding the pot (such as a window sill) as well as the plant for eggs.

~ Fungus Gnats are little flying insects often seen flying around plants. They usually stay near the surface of the soil or under the leaves of plants unless disturbed. The larvae are tiny and worm like and live in the soil. Fungus Gnats are more an annoyance than a threat to the health of the plants infested with them. Fungus Gnats are hard to get rid of. The key to controlling Fungus Gnats is to kill the larvae since adult Fungus Gnats have a short life span (2-3 days). The absolute best way to get rid of them is to release beneficial nematodes into the soil that will seek out and kill the Fungus Gnat larvae. Another, more practical way of controlling Fungus Gnat larvae is to drench the soil with a 2% solution of malathion. If you don't like using such a toxic chemical pesticide in the soil there are a couple non toxic ways to control the larvae. One way is to place a slice of raw potato into the soil. The larvae will be attracted to the potato slice and will crawl inside of it. Simply throw the potato slice away and replace it with a fresh slice every day until there is no more sign of Fungus Gnat presence. A good way to get rid of the adult Fungus Gnats is to place a bowl or cup of water with a few drops of dishwashing liquid mixed into it next to your plants. The adults will be attracted to it. Change the soapy water everyday.

~ Scale insects are black, brown or tan, somewhat flat, oval shaped insects that are covered by a hard shell. Adult scales are stationary. Immature scales (called crawlers) emerge from eggs deposited under the adult females protective shell. Once crawlers establish a feeding site, they begin to secrete the hardened covering over their body. Adult Scale are a problem to control because their shell protects them from pesticides. Pesticides and soap sprays are only effective on crawlers. If there are only a few Scales, they can be picked off by hand. Check the plant every few days, picking off any scales you find. Like Mealybugs, Scale are often found in crevices, folds and creases on both the plant's leaves and stems. By far the best way to control Scale is by using a systemic insecticide. In cases of a heavy infestation, a systemic is the only effective means of control.

~ Spider Mites are tiny, spider like mites that can barely been seen with the naked eye. The most common Spider Mite is the Two-spotted Spider Mite, they have soft pear shaped bodies with 2 dark spots on their backs. The most visible sign of a Spider Mite presence is webbing on the undersides of leaves and between stems, however, webbing indicates a high population of Spider Mites. Although Spider Mites are very hard to see with the naked eye, their eggs can usually been seen easily, grouped together on the undersides of leaves. Spider Mites are very difficult to get rid of or control. Often they are resistant to chemical pesticides and many insecticides do not work for Spider Mites. If you are going to use a commercial pesticide be sure that it is listed on the label that the product is effective for Spider Mites.

The first step in getting rid of spider mites (and most crawling insects) is to spray the leaves, especially the undersides, with a strong spray of water. This will wash off as many of the insects as possible. Since Spider Mites are often resistant to most chemical pesticides it is best to use an insecticidal soap spray. Another good thing to use is pesticides made with neem oil. Be sure to cover all leaf surfaces completely. Repeat treatment every 5-7 days until there is no sign of Spider Mite presence.

There are several different types of commercial pesticides available. There are traditional chemical pesticides, insecticidal soap sprays and systemic pesticides. Always check the label of any pesticide you are thinking about using to make sure that the insect you want to get rid of is listed on the label. Also, as a general rule, always look for 'Houseplants' somewhere on the label of any product they want to use on houseplants.

~ Insecticidal soaps are usually the best to use on houseplants. They are effective and not as toxic as most commercial chemical pesticides and are safe around children and pets once it is dry. Insecticidal soap products are also the safest products for plants since most don't contain harsh, toxic chemicals. Insecticidal soap works by disrupting the insect's cell membranes and destroying the insect's protective coating, causing it to dehydrate and die.

You can use a commercial insecticidal soap spray or you can make your own insecticidal soap spray. It is best to make homemade insecticidal soap using soap that contains no perfumes, dyes, moisturizers or deodorants. Never use liquid hand soap, such as Soft Soap, to make insecticidal soap spray.  A lot of people commonly use dishwashing liquid to make insecticidal soap spray, but dishwashing liquid contains a lot of perfumes, dyes and degreasers that can be harmful to plants. What I recommend doing is getting a small bar (or cutting a sizable chunk off of a larger bar) of a 'pure' soap, such as Ivory. Cut the bar (or chunk) into several small pieces, put them in a small amount of water and allow them to 'melt'. You now have a concentrate that can easily be mixed with an additional amount of water to make an insecticidal soap spray. Here is a good recipe for homemade insecticidal soap that I have had good results with;

Mix 4 TBSP of the soap concentrate (or 1 TBSP of dishwashing liquid) and 1/2 TBSP of vegetable oil into 2 quarts ( 8 cups) of lukewarm water. You can also use this recipe without the vegetable oil for most insects. I usually only add the vegetable oil for heavy populations of spider mites.

The drawback to insecticidal soap sprays is there is no lasting effect and you may have to repeat treatment several times.

To be effective, all leaf surfaces, especially the underside, needs to be wetted thoroughly with the insecticidal soap. Sometimes with soft leafed plants, such as African Violets, or small dense plants, it is best to use the insecticidal soap as a dip rather than a spray.

~ Of the commercial chemical pesticides the one being used most these days is products containing Imidacloprid. Imidacloprid is not as toxic as most traditional pesticides and just as effective. However, it is still a toxic pesticide.

Pesticide products made with Neem oil are effective on most insects, including Spider Mites, and a lot less toxic than other chemical pesticides. Neem oil also has anti-fungal benefits, which is why most ' 3 in 1' products are made with neem oil. Neem oil is safe to use on most plants.

No matter what type of spray pesticide you use, always spray a ' test leaf' before spraying the entire plant with any pesticide product. Wait at least 24 hours then check the test leaf, if there is no damage to the test leaf then continue to treat the rest of the plant.

Please note that all types of Ferns are very sensitive to all kinds of soaps and chemical pesticides. The only safe way to control insects/mites on ferns is to wash the plant thoroughly with a strong spray of plain, tepid water about every other day until there is no sign of insect presence.

~ A systemic insecticide is a insecticide that works by getting absorbed into the plant and distributed throughout all parts the plant. When an insect feeds on the plant it is poisoned. Systemic insecticides are especially good for severe infestations or reoccurring insect problems. There are two forms of systemic insecticides, one is a granule that gets mixed into the soil and is taken up into the plant by the roots. This form of systemic takes time to take effect, often 5-10 days. The other form is spray systemics. This form of systemic is sprayed onto the plant's leaves and is absorbed into the plant. This form works like a spray insecticide, killing insects on contact, then works as a systemic for lasting control.

The most important part of insect control is early detection. A few insects on a plant is much easier to get rid of than an infestation of hundreds on several plants. Check plants often for any sign of insect presence and if found, act quickly. Keep affected plants away from other plants to prevent the insects from spreading to other plants. Keeping plants clean by spraying plants with water about once a month will not only wash away dust and dirt but also any insects that may have found their way into your home, preventing them from evolving into an out of control infestation.

Plants that are healthy are much less susceptible to infestations of insects. Always follow good cultural practices. Warm and dry conditions commonly found in most homes are ideal conditions for some insects such as Spider Mites. Misting plants regularly may help.