Pulvinaria vitis

(Linnaeus, 1758)

Cottony Grape Scale, Cottony Scale

Pulvinaria vitis is a thelytokous cottony insect native to Europe, now established across much of the Northern Hemisphere and beyond. It is a pest of grape and peach, with females on bark and producing large ovisacs containing thousands of in spring. The exhibits distinctive discontinuous growth and feeding patterns, with three nymphal instars and limited mobility after the first moult.

Pulvinaria vitis by (c) Kathy Warburton, some rights reserved (CC BY), uploaded by Kathy Warburton. Used under a CC-BY license.

2023 05 20 Pulvinaria vitis by Ralf Huber. Used under a CC BY-SA 4.0 license.

2023 05 20 Pulvinaria vitis 2 by Ralf Huber. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Pulvinaria vitis: /pʊl.vɪˈnaː.rɪ.a ˈvɪ.tɪs/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other Pulvinaria by association with Vitis and Prunus, thelytokous , and . The white felt-like ovisac produced in mid-May is characteristic. Specific morphological characters for separation from would require examination of microscopic features not detailed in available sources.

Images

Appearance

females are covered by a cottony, felt-like ovisac secreted from submarginal glands. The ovisac is white and encloses the . The body beneath is partly grown and flattened when . Newly emerged nymphs () are small, mobile, and phototactic.

Habitat

Orchards and vineyards; specifically on bark, leaves, and twigs of plants. occurs on bark of host trees.

Distribution

Native to Europe; introduced to North America prior to 1897. Present in Georgia, Russia, Israel, United States, United Kingdom, Ukraine, Turkmenistan, Turkey, Tajikistan, Switzerland, Sweden, Spain, Sardinia, Germany, Canada, China, Corsica, Crete, Denmark, Romania, Bulgaria, Czech Republic, Greece, Hungary, Iran, Ireland, Italy, Jordan, Japan, France, New Zealand, Portugal, Finland, Norway, Brazil, Netherlands, Morocco, Mongolia, Moldova, Luxembourg, Latvia, Kazakhstan, Algeria, Argentina, Armenia, Austria, Malta, Poland, and Australia.

Seasonality

females overwinter on bark. laid mid-May when temperatures reach 14°C or higher. Egg hatch occurs after approximately 200 day degrees above 10°C. Nymphal development continues through summer; third moult at 56–93 days post-hatching. Activity ceases in late August to early September.

Diet

Phloem sap; on twigs, stylets penetrate to xylem and destroy cambium in feeding area.

Host Associations

Vitis vinifera - Grapevine; primary giving rise to specific epithet
Prunus persica - Peach; significant economic in Ontario orchards

Life Cycle

(one per year). Partly grown female overwinters on bark. (~4,000 per female on peach) laid in mid-May within white felt-like ovisac. Egg hatch after ~200 day degrees above 10°C. Three nymphal instars: first moult at 12–18 days, second at 28–36 days, third at 56–93 days post-hatching. At , only and appendages are shed.

Behavior

Newly emerged nymphs are phototactic and photokinetic. Wind disperses at any active stage, especially early . Movement on plant is frequent until first moult, continuing sporadically through summer and early fall except during late August–early September. Feeding is discontinuous with periods of days without feeding. Limited from leaves to bark occurs; only small percentage of scales successfully reach bark from leaves.

Ecological Role

Herbivorous pest of cultivated fruit crops. Feeding damages phloem, xylem, and cambium tissues. Potential prey for and , though suppressed by orchard applications.

Human Relevance

Economic pest of grape and peach orchards. Managed through spray programs, which suppress natural enemy . potential exists but is often unrealized due to chemical management practices.

Similar Taxa

Pulvinaria aurantiiCongeneric cottony with similar ovisac structure; distinguished by preferences and geographic distribution
Parthenolecanium corniAnother Coccidae on stone fruits; lacks the characteristic cottony ovisac of Pulvinaria

More Details

Temperature-dependent development

development and hatching are strongly temperature-dependent. Hatching rate increases with temperature, though no close correlation exists between hatching rate and average daily temperature during the hatching period.

Population density limitation

For given environmental conditions, there appears to be a maximum number of nymphs that can establish per unit area of , suggesting -dependent settlement limitations.