Using Degree-Day Tools To Improve Pest Management: Dont get caught off-guard!

Transcription

1 Using Degree-Day Tools To Improve Pest Management: Dont get caught off-guard! Len Coop, IPPC, OSU Corvallis Jan 25, 2012 You fell asleep, didn't you?

2 Topics for today's session: Degree-day/phenology concepts Some features of the IPPC "Online weather data and degree-days" website at uspest.org/wea Development and use of specific models example applications

3 Typical IPM questions/decision tools: "Who?" and "What?" Identification keys, diagnostic guides, management guides "When?" Phenology models (crops, insects, weeds), Risk models (plant diseases) "If?" Economic thresholds, crop loss models, sampling calculators, other decision tools "Where?" GIS, precision agriculture

4 Typical IPM questions/decision tools: "Who?" and "What?" Identification keys, diagnostic guides, management guides "When?" Phenology models (crops, insects, weeds), Risk models (plant diseases) "If?" Economic thresholds, crop loss models, sampling calculators, other decision tools "Where?" GIS, precision agriculture

5 Typical IPM questions/decision tools: "Who?" and "What?" Identification keys, diagnostic guides, management guides "When?" Phenology models (crops, insects, weeds), Risk models (plant diseases) "If?" Economic thresholds, crop loss models, sampling calculators, other decision tools "Where?" GIS, precision agriculture

6 "If?" Economic thresholds: do numbers of pests justify treatment? "Where?" GIS, precision agriculture Typical IPM questions/decision tools:

7 What to know about degree-days: Insects have complex life cycles Eggs Larvae Pupae (most) Adults -Timing of all stages is *typically* predictable using degree-days, which are a two dimensional heat unit of development for cold blooded organisms

8 Phenology and degree-day concepts Heat unit concepts and examples first published by Reaumur (1736), modern refs. in Arnold (1959, 1960) Degree-day models in common use for timing of sampling and management events in agriculture; a cornerstone of IPM

9 Phenology: the study of periodic phenomena in their relations to each other, as climatic and weather changes to plant life (from Torre-Bueno 1 st ed.)

10 Degree-day calculations method varies: Simplest: (daily max + min)/2 low threshold How fast are they going? Single triangle compared with typical daily fluctuation

11 Phenology and degree-day concepts Different organisms have different lower thresholds for development. Examples include: Plants: ca. 30 to 45 F Wheat: 32 Corn: 50 Insects: ca. 38 to 55 F Aphid: 38 Leafrollers: Codling moth, spotted wing Drosophila: 50 Lygus bug, stink bug: Bees: can generate their own heat in the hive (with limits)

12 Types of degree-days Used for insects, plants, plant diseases, other uses Simple average: daily max + min/2 - lower threshold (ignores any upper threshold) Growing degree-days for corn: use simple avg but subst lower threshold in place of min (if min is lower), subst upper threshold in place of max (if max is higher) Growing degree-days for cereals: same as simple average Single and double triangle: simple geometric formulae (the latter uses tonights min for second half of today) Single and double sine curve: more complex trig. formulae Actual degree-days: computed in real time ex. once/minute Degree-hours: require hourly data Fireblight degree-days: 4-day running degree-day total Heating and Cooling degree-days: used by the power industry

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14 Degree-day Models: A bit more detail

15 Degree-day Concepts Assume that developmental rate is linearly related to temperature above a lower threshold (Tlow) Work best in temperate regions for populations that have relatively few, non-overlapping generations DD models often require a "biofix" - biological monitoring event used to initialize the model (biofix = starting date that the user inputs)

16 Days Developing degree-day models from lab studies 200 Temperature vs. development time Development time (days) Temperature (F)

17 Rate (1/days) Degree-day models: from lab studies Temperature versus development Temperature (F) Development time (days) Rate (1/days)

18 Rate (1/days) Degree-day models: x-intercept method (Arnold 1959) Temperature versus development 1/slope = 1/ = 920 ~ DD requirement x-intercept ~ Tlow = 37 F Temperature (F) Development time (days) Rate (1/days)

19 Weather and Degree-day Concepts 1)Degree-day models: accumulate a daily "heat unit index" (DD total) until some event is expected (e. g. egg hatch) Eggs start developing: 0 DDs cumulative: 20 daily: o(avg) - 50 o(threshold) =20 DD Eggs hatch: 152 cumulative DDs

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21 DD model example - corn earworm, Helicoverpa zea

22 Corn earworm model output - summary, daily report

23 Corn earworm -degree-days and event labels

24 Missing data algorithm simple: nearest date averaging

25 Corn earworm - graph of date vs. degree-days

26 Weather and Pest/Disease Models Over 18 Disease risk/hourly driven models Over 73 DD/phenology models available

27 Weather and Pest/Disease Models

28 Example multi-regional Disease Alert Map integrating real-time observed and forecast weather data into one disease index: Forecast fire blight risk model available at the IPPC website Other Disease Alert Maps include: Tomato-potato late blight, Tomcast DSV, Soybean rust, also animated movies are available for each of these.

29 Prism Interpolated Degree-Days New for Google Maps interface

30 What is Climate Mapping? The process of interpolating climate statistics at irregularlyspaced station locations to a regular grid Geospatial Climatology The study of the spatial patterns of climate on the earth s surface and their causes

31 Degree-day map example for US: Brown Marmorated Stink Bug

32 Summary Points: Degree-day/phenology models can help in timing of sampling and treatment based on weather trends IPPC uspest.org/wea has evolved as a hybrid for support of State, Regional, and National needs MyPest Home Page now integrates numerous models and weather in one place Degree-day maps can help show how timing varies over local and regional scales

33 Degree-days: a tool for decision support, not another tool we can store in the tool shed

34 Using Degree-Day Tools To Improve Pest Management: Questions? Len Coop, IPPC, OSU Corvallis Jan 25, 2012 Are you ready for the quiz now?