Biological Calendars:Phenology and Growing Degree-Days for Monitoring

Pest Management in Ohio

Dan Herms

Department of EntomologyThe Ohio State University

Ohio Agricultural Research and Development CenterWooster

herms.2@osu.edu

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. G

age, Michigan S

tate Univ. D.G. Nielsen, Ohio State Univ.

Phenological Sequence for Secrest Arboretum

Species Event Degree-Days

Red Maple first bloom 45Eastern Tent Caterpillar egg hatch 92Eastern Redbud first bloom 197Gypsy Moth egg hatch 203Snowdrift Crabapple first bloom 214Birch Leafminer adult emergence 231Common Lilac first bloom 238Pine Needle Scale egg hatch 301Vanhoutte Spirea first bloom 309Lilac Borer adult emergence 336Black Cherry first bloom 376Euonymus Scale egg hatch 463Black Locust first bloom 503Bronze Birch Borer adult emergence 519Mountain-laurel first bloom 565Juniper Scale egg hatch 579Littleleaf Linden first bloom 878Japanese Beetle adult emergence 966

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 1Base temp: 50°F

http://www.oardc.ohio-state.edu/gdd

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 EmergenceCardina et al. 2007. Weed Science 55:455-464

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 toquantify geographic patterns of phenological and climaticvariation 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 83Forsythia 86 PJM Rhododendron 147Koreanspice Viburnum 185Coralburst Crabapple 217Common Lilac 234Vanhoutte Spirea 309Redosier Dogwood 326Miss Kim Lilac 423Bush Cinquefoil 445 Red Prince Weigela 446Arrowwood Viburnum 534Bumald Spirea 624Elderberry 707Oakleaf Hydrangea 835Rose-of-Sharon 1347

www.phenology.osu.edu

www.phenology.osu.edu

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

www.uwm.edu/Dept/Geography/npn

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