Psyllobora vigintimaculata
(Say, 1824)
Twenty-spotted Lady Beetle, Twenty-spotted Ladybird
A small North American lady beetle distinguished by its white with dark, orange, or bicolored spots. Unlike most lady beetles that prey on aphids, this feeds on powdery mildew fungi. It has been proposed as a agent for fungal plant .
Pronunciation
How to pronounce Psyllobora vigintimaculata: /ˌsɪl.oʊˈbɔː.rə ˌvaɪ.dʒɪn.tiˈmæk.jəˌleɪ.tə/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Distinguished from the fourteen-spotted lady beetle (Propylea quatuordecimpunctata) and Asian lady beetle (Harmonia axyridis) by its unique spot pattern, particularly the 'M'-shaped pronotal markings and white-based coloration. The combination of small size, white , and distinctive pronotal pattern is diagnostic for this in North America.
Images
Appearance
Body length 1.75–3.0 mm. White with dark, orange, or bicolored spots. Pronotum bears four or five distinctive dark spots arranged in an 'M' shape.
Habitat
Urban and natural landscapes with powdery mildew-infected vegetation. Documented on more than 25 plant across 13 in California alone.
Distribution
North America, from Newfoundland to Alaska in the north, south to Virginia, Tennessee, and Louisiana, west to southern California.
Seasonality
Active from late February through mid-December in California; exact timing varies with local conditions.
Diet
Obligate consumer of powdery mildew fungi (Erysiphales). Uses olfactory cues to locate infected plants.
Life Cycle
Four larval instars followed by . First instar: white oval body with small thoracic hairs. Second instar: darker with stripe, lightening with subsequent . Fourth instar attaches to leaf or petiole to molt. Pupae emerge with wing pads and black spots. Development from to : approximately 32 days at 20°C, 20 days at 25°C under laboratory conditions.
Behavior
Aggregates in response to powdery mildew , showing a positive to severity. Nocturnally active at lights.
Ecological Role
Specialized mycophagous of powdery mildews, with potential as a agent for fungal plant .
Human Relevance
Proposed as alternative to for powdery mildew control in agriculture and horticulture. May serve as an indicator of powdery mildew presence in managed systems.
Similar Taxa
- Propylea quatuordecimpunctataFourteen-spotted lady beetle; differs in spot number and lacks white base color
- Harmonia axyridisAsian lady beetle; larger, more variable in coloration, lacks distinctive 'M'-shaped pronotal pattern