Fletcher Scale (Parthenolecanium fletcheri)
GDD Window (base 50): 600-1200
Overview:
- Adults are 2-4mm in diameter, dome-shaped soft scales, brown to tan in color, and usually found on twigs and stems
- Nymphs are oval, flat, and yellowish amber crawlers which remain on the same plant all season
- Females begin laying eggs under their bodies in late May, which hatch in June
- Overwinter as second stage instars
- One generation per year
- Produces honeydew which grows sooty mold
- Causes yellowing leaves and reduced plant vigor, as well as premature needle and leaf drop
- Host plants: arborvitae, yew, juniper, hemlock
Management:
Cultural Practices:
- Natural predators: lady beetles, parasitic wasps
- Monitor populations and remove scales manually
- Reduce plant stress
- Prune heavily infested branches
Materials:
- Contact insecticides:
- Pyrethroids [3]: –thrins
- Carbamates [1A]: carbaryl
- Systemic insecticides:
- Neonicotinoids [4A]: imidacloprid, dinotefuran
- Avermectins [6]: abamectin
- Organophosphates [1B]: acephate (translaminar)
- Considerations:
- Will harm non-target species
- Spray during crawler stage
Biorationals:
- horticultural oil
- insecticidal soap
- Neonic: acetamiprid
- IGRS:
- Buprofezin [16] (IGR)
- Pyriproxyfen [7C] (IGR)
Resources:
Some Key Soft Scale Pests in the Landscape – PPA
Landscape Pest Notes for Late June 2023 – PPA
Disclaimer – Materials do not cover all possible control scenarios and are intended for licensed professionals. Tradenames do not imply endorsement and are used as examples. You must strictly follow the label for each compound prior to use. Rutgers is not responsible form is used materials or damages thereof. The label is the law. Labels will provide detailed information on use and restrictions. Additionally, application intervals, compatibility, surfactant use, PHI, PPE, important and other key information is described in detail. Always discuss treatments with your local agents. Note: Neonicotinoids can only be legally applied in commercial agriculture settings by licensed applicators. Guidelines and recommendations made in this presentation are specific to the state of New Jersey.