Balsam Fir Sawfly

In Newfoundland, Canada, female sawflies lay their eggs in late September or early October using their saw-like ovipositor into foliage of the current year or foliage of the previous year. The different strains of N. abietis are known to differ in host plant oviposition preference. Months later, around June or mid-July, the eggs hatch and the larvae feed immediately on needles of the balsam fir. The larvae prefer to eat 2 or 3-year-old balsam fir foliage and will rarely feed on foliage of the current year. The development of male and female sawfly vary slightly. Females can have five or six instars whereas males only have five instars. Secondly, females take slightly longer than males to complete their development. A female's developmental period lasts 35 days whereas males complete their development within 30 days. Male and female sawflies spin a cocoon during their last-instar larva, they pupate inside, and adults emerge from the cocoon within 2–3 weeks. Account differs concerning whether N. abietis will spin its cocoon on the foliage or in the ground.