Plant pest and disease control

A landscape’s ability to withstand pests and disease is mostly a function of plant health: when material is well-watered and well-fed, its natural defenses ward off or limit most infestations. Under stress — usually too wet or too dry — those defenses fail. That is why our pest and disease control starts with the irrigation system and ends with targeted treatment.

The pests we watch for

• Aphids — the broadest-spectrum infestation, attacking hibiscus, daylilies, jacaranda and London plane; they defoliate and leave sooty mold and honeydew in their wake.
• Giant whitefly — larger than common whitefly and harder to treat, it smothers foliage in a sticky web-like substance; hibiscus, Fatsia japonica and Tupidanthus calyptratus are the usual hosts.
• Lerp psyllid — a eucalyptus specialist (chiefly Blue Gum) that causes massive defoliation and honeydew staining; the main stage runs May–June through November.
• Chlorosis — yellowing from iron and other nutrients locked out by saturated soils; corrected with pH adjustment and drainage.
• Phytophthora root rot — the serious one; treatable with moisture management and fungicide injection. See arbor care →

Spray or inject? Both, used deliberately

Traditional spray applications deliver a contact knockdown at lower cost — ideal when populations must be reduced quickly. Trunk injection with a systemic such as Merit penetrates the vascular system, killing the initial infestation and protecting the tree from reinfestation later in the year — best timed for March–April, at the start of sap flow. Injection typically costs two to three times more than spraying, so we recommend it where the tree’s value justifies it.

Early detection, continual control

Anticipating emergence and treating with residual controls — or treating the moment an outbreak appears — is the key to containing any infestation. Pest and disease monitoring is built into every weekly maintenance visit, and project supervisors report exposure and options before problems spread.