Biology: Usually thought of as apple, peach and plum pest but also on blueberry, huckleberry, grape, persimmon and cherry (Milholland & Meyer 1984). One of the most potentially damaging pests during the petal fall period. Life cycle covered in apple section. Adults become active when average daily temperatures near 10-15oC (50-60oF) for 3-4 2 or more consecutive days and high temperatures are 24oC (75oF) for 2 or more consecutive days (Milholland & Meyer 1984). Often active when early varieties beginning to bloom (Marucci 1966). Female oviposits in fruit, leaving crescent-shaped scar. Larvae develop in fruit, over about a 2-week period. Infested berries turn blue prematurely, often dropping to ground before uninfested berries turn blue. A few late-maturing larvae may reach market (Marucci 1966). Most of the adults produced enter diapause, but a few mate and produce a second generation (Mampe & Neunzig 1967). Reissig et al. (1998) reported that injury progressed faster and ended earlier in smaller apple trees than larger trees, probably because of differences in tree architecture; this may relate also to a relatively small host plant as blueberry.

Monitoring: Shake branches over a sheet. Examine fruit for fresh injury, especially on borders adjacent to woodlands.

Control: Two applications of a contact insecticide usually necessary (Milholland & Meyer 1984); first when adults begin to return to field; second timed to end of migration period, when max. temps. reach 32oC (90oF) (Milholland & Meyer 1984). Guthion and Imidan are very effective.

Additional Reading:

• Mampe, C. D. and H. H. Neunzig.  1967.  The biology, parasitism, and population sampling of the plum curculio on blueberry in North Carolina.  J. Econ. Entomol. 60: 807-812.
• Reissig W. H., J. P. Nyrop and R. Straub. 1998. Oviposition model for timing insecticide sprays against plum curculio (Coleoptera : Curculionidae) in New York State. Environ. Entomol. 27: 1053-1061.