Weevil
2 host plants
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Weevils are small beetles with a characteristic long snout and measure roughly three-eighths inch long. Adult weevils chew notches from leaf margins of pieris and other host plants. Larvae feed in the soil and on roots. Light feeding is cosmetic; heavy infestations cause leaf yellowing and weak branch growth on ornamentals in western Washington gardens.
Remove and destroy infested plant material in early summer when adults are actively feeding. Spray neem oil or insecticidal soap on foliage when weevils are visible. Maintain plant vigor through regular irrigation and avoid excessive nitrogen fertilizer, which stimulates soft growth attractive to weevils. Most populations are self-limiting due to natural parasitoid activity.
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Cultural Controls
- biological control beneficial nematodes-Nematodes, such as Heterorhabditis spp.
- and Steinernema spp., have shown some effectiveness in controlling larvae when applied as label directs, as a drench in the fall.
- Nematodes must be placed in the root zone where weevil larvae are present.
- See also: Entomopathogenic Nematodes Management-cultural control Cultivating soil in April-May can eliminate overwintering larvae before planting.
- Use a cereal cover crop, as small grains are not a host for root...