Decatomidea cooki

Prodecatoma phytophaga

Eurytomidae

Prodecatoma

Parthenocissus quinquefolia

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Vitis labrusca

Prodecatoma cooki

Decatomidea cooki

Vitis sp.

Fruit and bud galls
Reared from grape seeds.

Key to American Insect Galls

Decatomidea cooki How.

Vitis
Fruit and Bud Galls
Shriveled berries and enlarged seed, summer

Plant Galls and Gall Makers

Prodecatoma cooki 

There are two species of grape seed chalcid. Prodecatoma cooki is widespread but rare within its geographic range, with reports from Canada to Venezuela. There is no mention of Evoxysoma vitis in the scientific literature since 1924. It has disappeared. 

Grape seed chalcid was found damaging ‘Concord’ grapes, Vitis labrusca and Virginia creeper, Parthenocissus quinquefolia in a back yard home garden setting in Montrose, Colorado (Montrose County) in 2011. 

A search of literature published on grape seed chalcid reveals two species of seed chalcids that attack grapes. Evoxysoma vitis (Saunders) was originally described in Saunders 1869, with life history observations in Crosby 1909a & b. Crosby 1909a describes a second species of seed infesting chalcid, Prodecatoma phytophaga, from Virginia creeper. Gahan (1924) recorded the first account of P. phytophaga feeding on grapes. He recognized that there were actually two distinct species of chalcid that fed on vitaceae seeds. His mention of E. vitis is the last mention of this insect in non-taxonomic scientific publications. He recognized synonymy of P. phytophaga and Decatomidea cooki (Howard) in his 1951 publication and renamed the species to Prodecatoma cooki (Howard). Adlert documents P. cooki in Florida grapes in two 1973 publications. It has been reported from Canada, several US states, Venezuela (Cermeli 1973) and Mexico (Cortez-Madrigal et al. 2012).

Prodecatoma cooki (Howard) in Western Colorado