Plant Health: Inspect, Isolate, and Respond

Inspect systematically

Examine leaf tops and undersides, stems, crowns, soil surface, drainage holes, and roots when warranted. Record when symptoms began and whether they affect old growth, new growth, one side, or the whole plant.

Separate new or suspect plants

Keep new arrivals and plants with unexplained symptoms away from the collection while observing them. Clean hands and tools between plants.

Separate causes

Pests, infection, root damage, nutrient problems, light injury, temperature stress, and incorrect watering can look alike. Check the growing conditions and roots before assuming a disease.

Use the least disruptive response

Correct light, drainage, watering, crowding, and sanitation first. Remove badly damaged material with clean tools. Use a pesticide only when the pest is identified, the site and plant appear on the label, and nonchemical steps are insufficient.

The label is the law

Read and follow the complete pesticide label. Never exceed the rate, combine products without directions, or apply a product to an unlisted plant or setting. Protect people, pets, pollinators, and water.

When to discard

Discard a plant when a serious contagious problem cannot be contained, treatment would endanger the collection, or the plant is too damaged to recover. Bag infectious material; do not compost it unless authoritative guidance says it is safe.

Sources

• Purdue Plant and Pest Diagnostic Laboratory
• U.S. Environmental Protection Agency — Pesticide labels