Oviposition and development of two plantain pests, Scopula rubraria and Epyaxa rosearia (Lepidoptera: geometridae)

Two native Geometrid moths, Scopula rubraria and Epyaxa rosearia, have emerged as major pests of of narrow-leaved plantain as this forage plant has grown in popularity in summer-dry regions of New Zealand. As little was known of the species, laboratory studies were undertaken to gain greater understanding of their biology and development. Both species have a strong preference for ovipositing on hairy rather than smooth foliage, and are therefore likely to target young leaves. S. rubraria has five instars, while E. rosearia have five or six, with the latter more prevalent at 18oC and below. S. rubraria had a lower temperature threshold of 13.3oC for egg hatch compared with 6.3oC for E. rosearia, but a lower degree day requirement of 459 compatred with 1117 to complete development. The results suggest both species would start hatching in late spring and have three generations by mid-autumn.