Pinyonia

Gagné, 1970

Pinyon Spindle Gall Midge

Species Guides

1

Pinyonia is a of gall midges in the Cecidomyiidae. The genus contains at least one described , P. edulicola, which forms spindle-shaped galls on pinyon pine needles. These insects are small flies that induce abnormal plant growth through larval feeding activity.

Pronunciation

How to pronounce Pinyonia: //pɪˈjoʊniə//

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Identification

are tiny flies, approximately 1 mm in length, typical of gall midges. The is distinguished by its specific gall : spindle-shaped swellings on pinyon pine needles. Galls contain 5–40 larvae and cause affected needles to yellow and drop prematurely.

Habitat

Associated with pinyon pine (Pinus edulis) in urban and natural settings. Found in Colorado, particularly in residential areas and forests where trees occur.

Distribution

Colorado, USA. Records from Fort Collins and Colorado Springs.

Seasonality

emerge mid-June to mid-July. Larvae pupate in late spring following year of gall formation.

Diet

Larvae feed within galls on pinyon pine needle tissue. Specific feeding mechanism involves inducing plant tissue growth that surrounds and nourishes developing larvae.

Host Associations

  • Pinus edulis - gall inductionPinyon pine; sole known . Females lay in developing needles mid-summer. Galls form at needle base.

Life Cycle

Females lay in developing pinyon pine needles mid-summer. Larvae hatch and crawl to needle base, where feeding induces gall formation. Five to forty larvae occupy each gall, feeding and growing within. occurs in late spring of following year. emerge mid-June to mid-July. Infested needles drop 5–7 years prematurely.

Ecological Role

Gall formation causes premature needle drop, potentially leading to substantial defoliation and tree weakening. Heavy may increase vulnerability to secondary pests such as Pinyon Pine Beetles (Ips confusus). Serves as for Platygaster sp. (Hymenoptera: Platygasteridae), with observed parasitization rate approximately 1.7%.

Human Relevance

Considered a pest of ornamental and landscape pinyon pines in urban Colorado. Heavy cause aesthetic damage and tree stress. Chemical control trials have been conducted; effectiveness depends on proper timing, rate, and application method. Carbofuran, dimethoate, and oxydemeton-methyl showed significant reduction in infestation levels in 1982 trials.

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