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Integrated Pest Management

Insect Pests

Weed Control

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Caterpillar Management What: Caterpillars are particularly active in the early spring.  Fortunately, many spring Caterpillars will become excellent food for hungry baby birds.  Other Caterpillars will become gorgeous butterflies. Threat Level: Mild Consider letting the infestation run its course.  Native trees and other well-adapted plants that will not suffer long-term harm. Treatment Category Effectiveness Notes Strong Spray of Water Mechanical Control Fair A strong spray of water will send caterpillar eggs and the Caterpillars themselves off your treasured plant temporarily.  This gives the birds and other predators a chance to catch up with the population and keep them down to reasonable numbers. Bacillus Thurengensis (Bt) Chemical (Bacterial Extract) High Bt works by disrupting the digestive systems of caterpillars. It does not negatively impact other insects or wildlife.  However, it must be applied regularly so that it is eaten by the Caterpillars  It will wash off in rain. Insect-Killing Soap Chemical (Organic Control) Fair Insect-killing soaps act on many insect pests and on beneficial insects.  The soap harms insects by disrupting their outer protective layers. It does not harm other wildlife.

Aphids What: Aphids are easy to spot if you have identified them once.  They are only 1/16  to 1/8 of an inch in size. At first glance, they appear to be tiny bumps often found all over new flower buds or on newly-sprouted plants. They reproduce very quickly and feed by sucking sap from plants. Aphids leave behind a sticky "honeydew." Sometimes ants protect them from predators in order to harvest the honeydew. Threat Level: Mild. Aphids are annoying, but rarely fatal. Natural predators will often catch up with them.  Help the process along with some of the steps listed below if they seem to be overwhelming a favorite plant. Treatment Category Effectiveness Notes Strong Spray of Water Mechanical Control Fair A strong spray of water all around the buds and other badly-infested areas. This will dislodge the aphids. Most effective if repeated every two days. Predators such as Ladybugs Biological Control Fair; but give time for ladybugs to find the aphids It is possible to buy ladybugs and other predatory insects at local nurseries. There is no harm in releasing them in your garden. The easiest method is to allow small infestations to attract naturally found predators. Insect-Killing Soap Chemical (Organic Control) Fair These act on many soft-bodied insect pests and on beneficial insects. The soap harms insects by disrupting their outer protective layers. It does not harm other wildlife. Oils such as Neem and Canola Organic Chemical Fair Spray directly on affected areas to suffocate insect pests in their early stages. Neem and Canola also have insecticidal properties. Follow label instructions to prevent injury to tender ornamental plants. Pyrethrin Products Organic Chemical High Pyrethins are derived from chrysanthemum plants.  They are often combined with other products to counteract natural defenses of insects against them. They have short-term impact on insects with low impact on mammals. Permethrins are non-organic cousins that are synthetically enhanced to have a higher toxicity to insects and more stability for longer impact.

Snails and Slugs What: The slimy trails left by these two pests are their hallmark. They can generally be discouraged through the use of baits, or physically removing them at night when they are active. Threat Level: Serious on non-native plants. Snails and slugs are not usually a problem on native or well-adapted plants. However, they will destroy tender and well-watered annuals like pansies. If you see them getting started, control them with the steps below. Treatment Category Effectiveness Notes Beer or Other Traps Mechanical Control Excellent Place small containers of beer or apple cider near affected plants. Slugs and snails fall into traps. Copper Barrier Tape Mechanical Control Mixed Results; May Discourage Attacks Use copper stripping around planters to prevent slugs and snails from getting to non-native plants.

Spider Mites What: Tiny spider mites thrive on heat and dry weather. This makes them a problem during San Antonio summers. The symptoms include leaves that turn brown and curl under with many yellow specks. There may also be a fine webbing under leaves. Threat Level: Serious if you see damage. You should not expect to eliminate spider mites, but to discourage them from overwhelming plants. A healthy native or well-adapted plant will rarely show any signs of spider mite stress. Try the steps below early when they start to appear. Treatment Category Effectiveness Notes Strong Spray of Water Mechanical Control Fair A strong spray of water of water directed on underside of leaves every two days keeps spider mites from getting out of hand. Insecticidal Soaps & Horticultural Oils Chemical(Organic Control) Fair Spray these products up at leaves from underneath for maximum effectiveness. Natural Predators; Lacewing Larvae and Predacious Mites Biological Fair If you avoid overuse of broad spectrum insecticides you will have some natural predators to help control spider mites. Removal of Badly Infested Plant Material Cultural Practice Fair If a plant seems overrun with spider mites, consider removing the plant. Established perennials will grow back after infested growth is removed.

Galls What: Galls are formed by insect or fungus using leaves as hosts. leaves with galls will look somewhat deformed, but will still have good color and vigor. The plants are not caused any long-term harm from galls. They will disappear eventually. No treatment is recommended. Threat Level: None. The galls do not cause any long term harm. Treatment Category Effectiveness Notes NONE Needed Good Garden Practice High Galls will disappear. No treatment is needed.

Insect Scale What: These are tiny, sucking insects that are most often found on the underside of leaves. They can look like natural bumps and do not seem to move. Threat Level: Low for native or well-adapted plants. High for houseplants or tropicals. Treatment Category Effectiveness Notes Remove Affected Part of Plant Early in Infestation Mechanical Fair Consider discarding highly-infested individual plants from garden. Prune badly-infested parts of larger plants and discard in trash. Dormant Oil Organic Chemical High Dormant oil can be used during winter months only. It helps to suffocate scale insects. Horticultural Oils; Canola and Neem Organic Chemical High Spray directly on affected areas to suffocate insect pests in their early stages. Neem and Canola also have insecticidal properties. Follow label instructions to prevent injury to tender ornamental plants.