The metallic, blue-black adults are now aggregating and will soon seek out protected winter quarters where they will spend the winter. The striped alder sawfly larvae could also be found on alder in July and August but were more common on birch. Although we have received a number of reports of ant activity, none have so far been as spectacular as in past seasons. See also fall insects . Although known infestations of this serious pest remain limited to the NY city and Chicago areas, we urge you to keep an eye open for it.
Early detection is the key.
To aid you in this process we are enclosing a wallet-sized identification guide. Additional copies are available upon request. The recent expansion of gout phase populations on Christmas tree stock and of the woolly trunk phase in scattered forest stands across the state raises concerns that the problem may be expanding its range and impact, especially as the climate moderates. It bears watching as control may be difficult. Although birch leafminer populations, especially those of Profenusa thomsoni , were up this season, it was the larvae of the striped alder sawfly that produced the most notable impact.