Gardening: What to do when you need to take action

Eileen Ward

Last week I discussed the use of integrated pest management in the yard. These methods allow you to have a healthy garden and lawn yet use less pesticides, fungicides, herbicides and fertilizer. Less is the key word here as we live in a semi tropical climate and insects, diseases, weeds and nutritional deficiencies are a constant that cannot be avoided entirely.

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Following are methods to help you decide what to do when you need to take action.

Pests of ornamentals are grouped according to the way they damage plants.

Insects with piercing-sucking mouthparts

They have beak-like mouthparts used for piercing the plant tissue and sucking plant juices. Examples: scales, aphids, whiteflies, mealybugs, thrips and lacebugs.

Foliage feeding Insects

They feed on the leaves, flowers or roots. Examples: caterpillars, beetles, grasshoppers.

Spider mites

These pests are not insects but closely related to spiders and scorpions. They suck plant juices with piercing sucking mouthparts.


These are small larvae of flies, beetles or moths that tunnel between leaf surfaces.


These are either the larvae of moths or beetles which bore into twigs and trunks of plants.

Speckling of lower dusty leaves with black spots, micro webs and loss of green color indicate the presence of spider mites.

Spider mite damage.

If a population of pests gets out of control use a garden hose and direct a strong spray of water at the stems and undersides of leaves of the plant to lower the pest population.

If you do have to spray, try to use the less toxic products such as insecticidal soap. Or Neem insecticide, a derivative of the neem tree, which acts as a reproductive and feeding inhibitor/disrupter, growth regulator. Pyrethrins from crysanthemums will paralyze and kill insects. Another product line uses potassium salts of fatty acids which penetrates the outer shell of soft bodied insect pests causing dehydration and death within hours. Oils which smother the insects. And Bacillus thuringiensis, Dipel or Thuricide, a natural bacterium for control of moth or butterfly larvae when they ingest the leaves.

  • Insecticides may be required to control pests when they reach damaging levels on the plants. Before using a chemical insecticide, you should consider the following points.
  • Select the right material. Only use an insecticide that is recommended to control the target pest and is safe on the host plant.
  • Use the right amount. Too little won’t control the pest and too much may injure the plant. Read the label for the correct dosage rate.
  • Apply it the right way. Thorough coverage of leaves, especially the underside, twigs and branches are essential. The insecticide must reach the area where the pest is feeding. Use of a spreader sticker will aid in the pesticide adhering to and penetrating the leaves for better coverage and control.

Systemic insecticides are absorbed by the host plant and trans-located throughout the tissues which makes the plant toxic to certain mite and insect pests for up to six weeks or as much as six months. They can be taken up by the roots when applied in granular form or absorbed by foliage or stems using sprays or injections. Systemic insecticides are effective in controlling sucking pests and mites. Most do not give satisfactory control of chewing insects. An example of a systemic insecticide is Merit.

Malathion is effective for controlling sucking insects. Sevin controls a wide range of chewing insects. Kelthane controls mites. Lindane, now no longer available, was for borers and leafminers. You will have to search for a new product for these insects. Read labels to identify which plants these sprays can be safely used on.

Phytotoxicity, or plant injury, can be caused by certain pesticides on ceratin plants. The degree of injury can be affected by conditions like temperature, humidity and other environmental factors. It is best to apply pesticides during the cooler part of the day. Plants are less likely to be injured when protected by partial shade as opposed to being in direct sun. Some materials can injure plants that are stressed for moisture. Plants should be well watered a day or two in advance of being treated with insecticides. Above all else remember to read the label.

If you use a professional spray company, you should ask them about an IPM program which would include scouting services and applying pesticides only as needed. Often you will be paying for knowledge not chemicals. Don’t allow routine blanket sprays in your yard. And be prepared to pay for their time even if they don’t spray any chemicals during the visit.

The largest benefit to using less chemicals in your yard is that the beneficial insect populations will flourish and reduce future populations of the insect pests that cause damage, which in turn reduces the need to use any chemicals in your yard. Other benefits include less exposure to the chemicals for users, homeowners and maintenance personnel. Reduced exposure to fish and wildlife. Reduced pollution to our water, air and soil so that we all benefit from a cleaner environment. We should all do our part to achieve that.

Eileen and Peter Ward have owned a landscape and lawn maintenance company for 35 years. Eileen can be reached at or 239-394-1413.