MANAGING AROID PESTS

Identification comes first. Everything else follows from knowing exactly what you are treating — and then choosing the insecticide or miticide least harmful to the environment and to beneficial insects, especially on plants that spend any time outside.

Pest management in ornamentals is a wide field, and there are many ways to build an integrated pest management (IPM) protocol. These guides cover one part of it — the insecticidal approach — in enough depth to act on.

1. 01Ornamental plants only. Not to be used on anything you intend to eat.
2. 02Some of the insecticides mentioned are indoor-use only, because they are not pollinator-friendly. Those are marked with the rose flag wherever they appear.
3. 03These pages describe the insecticidal approach — one component of an IPM protocol, not a substitute for one. Cultural controls, biological controls and quarantine sit outside their scope.
4. 04The label is the legal document. Rates, intervals, protective equipment and site restrictions printed on the product override anything written here.

Systemic

Absorbed into the plant through the roots or the leaves, then moved through the rest of it. Typically gives long-term residual protection.

Translaminar

The spray solution penetrates leaf tissue and forms a reservoir of active ingredient inside the leaf, giving residual protection. It moves from the top side of a treated leaf to the underside — but unlike a systemic, it is not carried to other parts of the plant.

Contact

Works only where the spray lands. Nothing moves into the leaf or the plant, so coverage — undersides, leaf axils, stems — is the whole job, and there is no residual protection afterwards.

Control

Reducing the population to zero or near zero.

Suppress

Reducing numbers enough to keep the pest from killing the plant, without eradicating it.

Insecticidal soap

Real soap, made from fat and lye, carrying the potassium salts of fatty acids that do the insecticidal work. Dr. Bronner’s and Safer are two examples.

1. 01Identify the pest before buying anything. The eight guides above start there for a reason — the wrong identification wastes the treatment and selects for resistance at the same time.
2. 02Match the product to where the pest actually lives. Leaf undersides, leaf axils, growing points, soil — that is what decides between a contact spray, a translaminar and a systemic.
3. 03Treat on the pest’s timetable, not yours. Most need repeat applications spaced to catch the eggs that hatch after the first round.
4. 04Rotate modes of action between rounds. Repeating one chemistry is how a resistant population gets selected — and mites are quick about it.
5. 05Re-inspect after each round, and know which outcome you are after — control or suppress (see §04). They call for different amounts of chemistry.