HWA Phenology Project

HWA Phenology in New York

Monitoring HWA phenology is an important component of our biocontrol program. In addition to teaching us more about how HWA behaves in New York across climate, topography, and temperature gradients, tracking the timing of HWA’s major life stages is essential for timing biocontrol releases at sites around the state. The HWA Phenology Project is a collaboration between NYSHI and the National Phenology Network that focuses on collecting community scientist data to improve NYSHI research efforts and plan for biocontrol releases.

Our HWA Phenology Project is part of the New York Phenology Project which tracks phenology for many native and non-native species throughout the state to investigate the effects of climate change and urbanization on the plants and pollinators all around us.

Our HWA Phenology Project

NYSHI’s HWA Phenology Project involves monitoring HWA in the field to watch the timing of two major life stages: (1) aestivation break, when HWA begins to develop following the period of summer dormancy and (2) HWA egg laying. Fall phenology (aestivation break) helps us schedule releases of Laricobius beetles and spring phenology (egg laying) helps us schedule releases of Leucopis silver flies.

To track the timing of these HWA life stages, we rely on Nature’s Notebook, the data tracking system of the National Phenology Network. The Nature’s Notebook smartphone app allows community scientists to easily collect data in the field and contribute to a statewide phenology map for HWA.

HWA Phenology Project volunteers choose a stand of infested hemlock trees and monitor HWA in the stand each week during the months of September-November and April-June. We offer trainings to individual phenology volunteers who are interested in tracking the timing of HWA’s major life stages. In order to learn more about the program and sign up to be a NYSHI Phenology Project volunteer, enter your name and email below:

Learn more about Nature’s Notebook and sign up to track HWA phenology:

Learn more about HWA Phenology

What to Look For: Fall Phenology

Using a Hand Lens

Using a hand lens or magnifying glass at 7x or 10x magnification, you’ll be looking for HWA’s shift from inactive nymph to active adult. Inactive nymphs (right, top) will appear like tiny black sesame seeds with a thin halo of white wool near the base of hemlock needles. Active adults (right, bottom) will show signs of development including increased size,  a greyish segmented appearance, and wool accumulation. Data from observations will help determine if HWA has broken aestivation at your survey site.

Using a Dissecting Microscope
If you have access to a dissecting scope, you’ll take samples from the field and look for HWA’s shift from inactive nymph to post-dormant nymph to active adult. Using a dissecting scope will allow you to more accurately pinpoint the timing of aestivation break compared to using a simple hand lens in the field. Either observation will provide us with the data we need.

What to Look For: Spring Phenology

In the spring you will watch for active adult HWA to begin laying eggs. Eggs will appear orangey-gold to yellow. HWA typically begin laying eggs at the end of March and the beginning of April, signaling the time for spring biocontrol releases to begin. Egg laying continues through the spring into the early summer when HWA’s second generation lays its eggs.

Phenology Project Resources

Nature’s Notebook uses specific language to describe HWA’s life stages. You can use our HWA Phenophase Photo Guide for reference.

If you would like to collect HWA phenology data without using a smartphone, you may also print and hard copy HWA phenology datasheet to record observations. Email completed and scanned datasheets to Charlotte Malmborg at cm933@cornell.edu. Be sure to include a note in your email describing the amount of time spent surveying, which helps us report on volunteer efforts accurately. Your volunteer hours help our research stay funded!

We have also created a helpful HWA Phenology Diagram to help visualize HWA’s life cycle and understand the Nature’s Notebook life stages definitions. You can download and print your own copy, or see it below: