Pest Management Guidelines

Various methods are available for managing pests of houseplants. The pest, number of plants infested, size of the planting, and inclination of the owner will determine what methods are best. Table 6 lists some registered pesticides for houseplants (see Tables 2 and 3 for toxicity information).

Many of the pesticides available for use on houseplants are formulated in ready-to-use pressurized cans or as pump sprays. Make sure the product you choose is labeled for use indoors and on houseplants. Other formulations may cause plant injury (phytotoxicity) or plant death. All pesticides labeled for use on houseplants should be applied outdoors.

Plant spikes containing insecticides may also be available. Be sure to follow label directions carefully: amount to use, how to water, storing unused spikes, precautionary statements, and hazards to humans. Wash hands thoroughly with soap and water after handling, or better yet, wear disposable gloves and discard after use.

For a general description of some common insects and diseases on houseplants and for information on nonpesticidal management of houseplant pests and diseases, see Part I, Cultural Methods.

Consider removing infected leaves or discarding infested plants rather than treating with a toxic substance. Most chemical pesticides are effective at protecting plants against disease but cannot “cure” existing infections. If houseplants need to be sprayed, remove them from the living space for treatment. If weather allows, take the plants out of doors or into a garage to make the application. Bring plants back indoors when dry.

Note: Check all pesticide labels carefully. Products may not be registered on all varieties or may not be tested on all rare or unusual varieties. If the host and pest are not listed on the label, do not use the pesticide.

Fungus gnats may breed in any moist soil that is high in organic matter. If they are a problem in houseplant soil, B.t. var. israelensis (Gnatrol, Knox-out Gnats) may be used to control them.

Table 6 Houseplant pesticide guidelines
Plant	Pest/Disease	Some recommended pesticides for management
African violet	Botrytis blight (gray mold)	Apply Bacillus subtilis or thiophanate-methyl once following cultural plant sanitation practices. Under greenhouse conditions apply Mycostop.
	Powdery mildew	Apply myclobutanil, Bacillus subtilis, neem oil, thiophanate-methyl, jojoba oil, or Lilly Miller RTU -MPF per label directions.
	Cyclamen mites	None. Discard infested plant. Isolate new plants for three to four months before placing in your collection.
	Mealybug	Insecticidal soap, neem, resmethrin, or pyrethrins plus soap are registered.
	Root mealybug	Apply insecticidal soap using drench treatment as specified on label.
Asparagus fern	Aphids	Spray with insecticidal soap, horticultural oil, neem, or resmethrin.
Begonia	*Bacterial leaf spot (Xanthomonas* sp.)**	Apply Bacillus subtilis per label directions.
	Botrytis blight (gray mold)	Apply Bacillus subtilis or Cleary's 3336F. Under greenhouse conditions apply Mycostop.
	Powdery mildew	Apply myclobutanil, Bacillus subtilis, neem oil, thiophanate-methyl, jojoba oil, or Lilly Miller RTU-MPF per label directions.
	Aphids	Treat with insecticidal soap, or neem.
Whitefly	Mealybug	Treat with insecticidal soap, neem, or resmethrin.
Whitefly	Whitefly	Treat with insecticidal soap, neem, or resmethrin. Good coverage of leaf undersides is important for control. Repeat sprays may be needed.
Citrus	Scale	Use insecticidal soap or pyrethrins plus soap . Treat the crawler stage (the young insect that emerges from the egg and “crawls” to a feeding site).
	Spider mites	Apply insecticidal soap or pyrethrins plus soap. Good coverage of leaf undersides is important for control. Repeat sprays may be needed.
	Whitefly	Use insecticidal soap, pyrethrins plus soap or neem. Good coverage of leaf undersides is important for control. Repeat applications may be needed.
Coleus	Mealybug	Spray with insecticidal soap, pyrethrins plus soap, neem, or resmethrin.
	Whitefly	Spray with insecticidal soap, pyrethrins plus soap, neem, or resmethrin. Good coverage of leaf undersides is important for control. Repeat sprays may be needed.
Croton	Mealybug	Treat with insecticidal soap, pyrethrins plus soap or neem.
Dieffenbachia	Spider mites	Treat with horticultural oil, pyrethrins plus soap or resmethrin. Good coverage of leaf undersides is important for control. Repeat sprays may be needed.
Dracaena	Mealybug	Treat with horticultural oil, insecticidal soap, pyrethrins plus soap or resmethrin.
	Spider mites	Use insecticidal soap, pyrethrins plus soap or resmethrin. Good coverage of leaf undersides is important for control. Repeat sprays may be needed.
False aralia	Scale	Insecticidal soap, pyrethrins plus soap or resmethrin may be used when crawlers are active.
	Spider mites	Use insecticidal soap, pyrethrins plus soap, resmethrin, or tetramethrin sprays. Good coverage of leaf undersides is important for control. Repeat sprays may be needed.
Ferns	Anthracnose	Apply Milstop or Remedy if needed.
	Scale	Treat with insecticidal soap, horticultural oil, or resmethrin. Check all pesticide labels carefully. Product may not be registered on all varieties or may not be tested on all rare or unusual varieties. If host and pest are not listed on the label, do not use the pesticide.
Fuchsia	Botrytis blight

Pest Management Guidelines A Cornell Cooperative Extension Publication	New York Pest Management Guidelines
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