Diplolepis nebulosa

Diplolepis polita

Diplolepis nebulosa

Mature galls are spherical, averaging 5.0–7.0 mm in diameter, spineless and on the abaxial leaf surface. They occur singly or in rows. They are most common on short R woodsii on dry exposed prairie. Immature galls are green to light brown with scaly, thick walls and a prominent depression distal to the point of attachment. Mature galls are pale brown and the depression is less prominent. Walls are thin and easily crushed between fingers. Larvae feed over the entire chamber surface. Adults removed from cold storage take an average of 26.3 days to emerge and are present in the field from mid-May to mid-June. Immature galls are found from early July to mid-August. Both immature and maturing galls appear together suggesting a lengthy period of gall initiation. Periclistus are found in 66.6% of the galls by mid-season and are major source of inducer mortality. 

Diplolepis polita

Galls of D. polita (fig. 3) are monothalamous, spherical, 3.5 to 5.0 millimeters in diameter, clothed with weak spines and formed on the adaxial surface of leaflets. Immature galls are yellowish-green, but mature galls are often bright red. They usually occur in clusters with several galls per leaflet. They are found only on Rosa acicularis Lindl. in forested regions of Alta. and Sask. growing in partly shaded habitats. Walls of mature galls are thin (about 1 millimeter) and easily crushed with fingers. The larvae feed over the entire chamber surface. Adults removed from cold storage take an average of 26.8 days to emerge (fig. 9) and are present in the field in early May with the first galls present by about May 20. Periclistus take an average of 23.4 days to emerge after cold storage. Periclistus are found in about 71 percent of the galls by mid-season (table 1) and are the major source of inducer mortality. Galls are mature and on the ground by mid-August. 

Role of Periclistus (Hymenoptera: Cynipidae) Inquilines in Leaf Galls of Diplolepis (Hymenoptera: Cynipidae) on Wild Roses in Canada