Pest Control

Having a beautiful sustainable garden in San Diego also involves the identification, control, and eradication of common pests that can cause harm to your lawn & plants.  Below is a list of common pests that can cause problems in your yard if left unmanaged.

White Flies

whiteflyWhiteflies are tiny, sap-sucking insects that are frequently abundant in vegetable and ornamental plantings. Whiteflies usually occur in groups on the undersides of leaves.  They excrete sticky honeydew and cause yellowing or death of leaves.  They can be found on over 80 plant species including avocado, citrus, hibiscus, xylosma, houseplants, and most vegetables.

Whitefly control is difficult and complex, as they rapidly gain resistance to chemical pesticides.  Insecticidal soaps can have some success in eliminating these nuisances, if combined with an active program of removing infected leaves and branches, and thoroughly washing down the affected parts of the plant.  Some companion plants have been proven to repel and/or trap whiteflies if incorporated into your garden.  These include calendula (marigolds), nasturtiums, mint and basil.

Snails / Slugs

snaildamageSnails and slugs can be a big nuisance in most San Diego gardens and landscapes.  Both slugs and snails love moist dark places and feed on all varieties of plant material. On plants they chew irregular holes with smooth edges in leaves and flowers and leave a shiny mucous trail behind. There are several approaches to controlling snails. These include hand picking the snails, trapping them, and using pesticides.

Hand picking the snails can be effective, but you will have to do this regularly over a long period of time. The most common chemical used to control snails and slugs is metaldehyde. This is the active ingredient in most molluscides including Slug and Snail Death and Sluggo. Unfortunately, metaldehyde is highly toxic to other animals, including dogs and cats so if you have pets, you should avoid using these chemicals. A much safer chemical solution to snails is iron phosphate.  Another way to control snails is to use copper flashing as a barrier around plants you want to protect. When they try to cross the barrier they will receive a small electric shock, which will keep them from crossing the barrier. 

Aphids

aphidsAphids or “plant lice” may infest almost any plant. Aphids are soft-bodied pear-shaped insects generally less than 1/8 inch long and usually green in color but many are black, brown, pink, yellow, blue, or white.  They are more commonly found on camellia, crape myrtle, gardenia, hibiscus, oleander, palms, roses, as well as most annuals. Aphids cause damage by sucking the plant juices.

However, their ability to transmit plant viruses may be more harmful than any direct feeding damage. Aphids also excrete large amounts of honeydew, which provides an excellent medium for the growth of a black fungus called “sooty mold.” Besides being unattractive, sooty mold may interfere with photosynthesis and hinder plant growth. Usually aphids are not difficult to control with insecticides. For control, apply an effective insecticide or insecticidal soap if aphids are beginning to damage the plants. Be especially careful to cover the undersides of the leaves and all parts of the twigs thoroughly. Continue to inspect the plants periodically especially new growth and re-apply an insecticide if plants become infested again.

Mealy Bugs

mealybugsMealy bugs are cottony-looking insects that suck the fluids from leaves and stems, robbing plants of essential nutrients. Mealy bugs feed on all parts of the plant, but especially on tender new growth. Identify mealy bugs by looking on the undersides of leaves and around leaf joints.

These insects look like small (1/10 to 1/8 of an inch) balls of cotton. Mealy bug-damaged plants look withered and sickly and may have sticky sap on the leaves and stems.  The easiest way to control mealy bugs is by hosing off the affected parts of the plants with a strong stream of water.  If this doesn’t work, insecticidal soap can be used to spray on the undersides of the plant leaves.

Spider Mites

spidermitesSpider mites are common plant pests. Symptoms of injury include flecking, discoloration (bronzing) and scorching of leaves. Injury can lead to leaf loss and even plant death. Periodic hosing of plants with a strong spray of water can physically remove and kill many mites, as well as remove the dust that collects on foliage. Chemical control of spider mites generally involves pesticides that are specifically developed for spider mite control (miticides). Few insecticides are effective for spider mites and many even aggravate problems.

Beneficial Insects

If you are opposed to using any insecticides in your garden, predatory insects can also be a useful way to control pests.  Ladybugs, praying mantis, parasitic wasps, predatory beetles and beneficial nematodes are examples of insects that feed on aphids, mealy bugs, spider mites and whiteflies. Ladybugs are one of the most effective beneficial insects for your garden and are available for purchase at most lawn and garden centers.

Lawn Insects

Contrary to popular belief, insects are not a common cause of lawn damage in San Diego.  More often, poor lawn care, improper watering or fertilization or dog urine can cause lawn damage resembling that of insects.  Grubs, chinch bugs, and webworms can be an issue under certain conditions but are not frequent.  Proper identification of the problem is suggested before taking any action with chemical applications.

Gophers

Many people who live near canyons in San Diego have a problem with gophers digging holes in their yards. These critters can be a nuisance to get rid of. Although it is not recommended, you can try poisoning them with the use of bait applicators. Trapping them can also be somehwat effective. Another suggestion is the use of battery-operated devices that emit a high-frequency sound into the ground which deter the rodents away. One such product is the Sonic Gopher Control.

If gophers continue to be a nuisance to your lawn, we have had success installing chicken-wire like material under new sod installations that prevents the gophers from reaching the surface of the new lawn.