Biological Calendars: Phenology and Growing Degree-Days for Monitoring Pest Management in Ohio Dan Herms Department of Entomology The Ohio State University Ohio Agricultural Research and Development Center Wooster

High biodiversity in landscapes and nurseries creates IPM challenges

Development rates of plants and insects are temperature dependent.

Limitations of Degree-Day Models: Insect response to temperature is not linear. Lower temperature threshold known for very few species. Measured temperatures not the same as those experienced by the pest. Degree-days are cumbersome to track. Multiple, optimized models not practical for large pest complexes.

Because both plant and insect development is temperature-dependent, phenological events of plants can also be used to track degree-days… and predict pest development.

Hypothesis: the flowering sequence of ornamental plants can be used as a biological calendar to predict pest activity and schedule pest management appointments.

The hypothesis was tested in Secrest Arboretum by monitoring over the past 7 years: 1.The phenology of 45 key arthropod pests of ornamental plants (e.g. egg hatch, adult emergence). 2. The flowering sequence of 75 taxa of woody ornamental plants. Secrest Arboretum, OARDC

First bloom: date first flower on the plant opens to reveal pistils and / or stamens. Full bloom: date 95% of flowers have opened (e.g. 1 out of 20 buds remains closed). Key Phenological Events

The flowering sequence of plants can be used as a biological calendar to track degree-days and schedule pest management appointments. S. Gage, Michigan State Univ. D.G. Nielsen, Ohio State Univ.

Phenological Sequence for Secrest Arboretum Species Event Degree-Days Red Maplefirst bloom 45 Eastern Tent Caterpillaregg hatch 92 Eastern Redbudfirst bloom197 Gypsy Mothegg hatch203 Snowdrift Crabapplefirst bloom214 Birch Leafmineradult emergence231 Common Lilacfirst bloom238 Pine Needle Scaleegg hatch301 Vanhoutte Spireafirst bloom309 Lilac Boreradult emergence336 Black Cherryfirst bloom376 Euonymus Scaleegg hatch463 Black Locustfirst bloom503 Bronze Birch Boreradult emergence519 Mountain-laurelfirst bloom565 Juniper Scaleegg hatch579 Littleleaf Lindenfirst bloom878 Japanese Beetleadult emergence966

Key premise: phenological sequence remains constant from year-to-year.

How accurate is a sequence that was developed in another region?

Generalized Degree-Day Model for 120 organisms: Method:Modified sine wave Starting date:January 1 Base temp: 50°F

Seven years of data reveals systematic bias across years in the accuracy of the generalized model. However, the phenological sequence remains highly constant from year-to-year.

Biological Calendar for Predicting Foxtail Emergence Cardina et al Weed Science 55: More accurate than optimized degree-day models, calendar days, and WeedCast.

The OSU Phenology Garden Network Coordinators: Denise Ellsworth OSU Extension, Summit County Dan Herms Dept. of Entomology, OSU / OARDC

The concept: a state-wide network of identical gardens to quantify geographic patterns of phenological and climatic variation across Ohio.

Objective: create a standardized biological calendar Research: document short-term phenological and weather variation; long-term climate change. Outreach: predict pest emergence / fine-tune timing recommendations. Science Literacy: increase public awareness / involvement with “the world’s oldest science”. Education: provide infrastructure for experimentation and demonstration projects.

The Biological Calendar Species First Bloom (DD50) Star Magnolia 83 Forsythia 86 PJM Rhododendron 147 Koreanspice Viburnum 185 Coralburst Crabapple 217 Common Lilac 234 Vanhoutte Spirea 309 Redosier Dogwood 326 Miss Kim Lilac 423 Bush Cinquefoil 445 Red Prince Weigela 446 Arrowwood Viburnum 534 Bumald Spirea 624 Elderberry 707 Oakleaf Hydrangea 835 Rose-of-Sharon1347

Additional applications: Butterfly garden and phenology (when do monarchs return?) Bird / wildflower / mushroom phenology (when should I look for trilliums; hunt for morels?) Weed phenology (forsythia and crabgrass?) Frost-free dates (Vanhoutte Spirea?) Planting dates (forsythia and radish; lilac and beans?) Plant propagation (when to take cuttings?) Others?

Velocity of Phenological Wave: 16 km / day for Forsythia; 9 km / day for Lilac

Number of degree-days required for first bloom of ‘Miss Kim’ lilac decreased as latitude increased

The National Phenology Network Coordinator: Dr. Mark Schwartz University of Wisconsin Milwaukee

The National Phenology Network Coordinator: Dr. Mark Schwartz University of Wisconsin Milwaukee

Facilitate collection and dissemination of plant phenological data across the US Support research on interactions between plants and lower atmosphere, and long- term impacts of climate change. National Phenology Network Mission

NPN: Lilac Observations Syringa chinensis 'Red Rothomagensis'

Lilac Phenological Observations: 1. First leaf 2. 95% leaf 3. First bloom 4. Full bloom 5. End bloom