Integrated
Plant Protection Center at Oregon State
University


ONLINE IPM WEATHER DATA and DEGREE-DAYS

CURRENT CONDITIONS

note Disclaimer


6/1/98
Completely revised from May 26 update

Cool wet trend impacts
From May 8th through May 30, we had unseasonably cool wet weather, with 5.2 inches of rainfall (Corvallis) which has had many impacts on insect crop and disease development. In fact, in Western Oregon, we have averaged only 2.9 (Medford) to 3.4 (Corvallis) degree-days per day (50F base; normal is 6.9 for this period, last year 12.6 for this period). Compared to last year, we have had only one-quarter as many degree days over the last 22 days. The forecasts show faint hope on whether we have broken out of this cool wet pattern. Try the Oregon Climate Service or The Weather Channel for the latest forecasts.

In the Willamette and Hood River Valleys and The Dalles, we are still 20-50 degree-days warmer than "Normal" (compare the deviations from normal map for May 30 vs May 7), but we lost the lead that had developed during the first part of March and May (see graph below). Also note that at a lower threshold of 41F, we are well past 200 degree-days cooler than normal in most of southern and far-eastern Oregon (we are off the scale in fact!).

graph

Cumulative Degree-Day comparison created using JAVA degree-day calculator

With temperatures seldom reaching the lower '60's, insects and diseases that have a lower threshold of 50 have not been developing at their normal rate. Even though we are still 20 degree-days higher than normal, the last 3 weeks were key for many species, and they are now behind schedule. These include the codling moth, obliquebanded leafroller, san jose scale, cabbage looper, black cutworm, spider mites, predator mites, and most other predators and parasites.

Catches in pheromone traps have been low. The moths which emerged in April and May are mostly still around, waiting for it to warm up. Once it does, traps should show very high numbers for a while.


Individual Pest Model Predictions (selected)

note: forecasts are made using actual 5-day forecasts followed by historical normals

Western cherry fruit Fly - BIOFIX March 1
**** revised 6-5-98 ****
Willamette Valley - First emergence was predicted May 31, first eggs on fruit predicted June 7, and first hatch predicted on June 12
The Dalles (warmest locations) - First emergence was predicted May 6, first eggs on fruit May 13, first hatch May 19, peak egglaying May 28, 100% emergence June 1, and first pupation predicted on June 5
Hood River (lower valley) - First emergence predicted on May 28, first eggs June 4, and first hatch June 9

Codling moth
**** revised 6-5-98 ****
Medford - BIOFIX Apr 21; 3% egg hatch predicted June 1; 20% egg hatch predicted June 10
Corvallis/Eugene - BIOFIX Apr 30; 3% egg hatch predicted June 10
Hood River (lower valley) - BIOFIX Apr 24; 3% egg hatch predicted on May 31; 20% egg hatch predicted June 10

Obliquebanded leafroller [Hazelnuts]
**** revised 6-5-98 ****
McMinnville - 5% moth catch in pheromone traps predicted June 7, and first egglaying predicted on June 15
Hood River - 5% moth catch in pheromone traps predicted June 7, and first egglaying predicted on June 15
Corvallis - 5% moth catch in pheromone traps predicted June 12, and first egglaying predicted on June 20

Orange tortrix
**** revised 6-5-98 ****
Forest Grove - Peak egglaying predicted May 8; peak egg hatch is predicted May 30

McMinnville - Peak egglaying predicted May 11; peak egg hatch is predicted June 1

Corvallis - Peak egglaying predicted May 17; peak egg hatch is predicted June 6

Strawberry root weevil
**** revised 6-5-98 ****
Corvallis - Currently teneral adults and pupae in soil; Peak adult emergence predicted June 18
Madras - Currently large larvae and pupae in soil; Peak adult emergence predicted June 26

European pine shoot moth
**** revised 6-5-98 ****
McMinnville - First moth catch in pheromone traps predicted May 30; 50% catch predicted June 16
Corvallis - First moth catch in pheromone traps predicted May 29; 50% catch predicted June 15

San Jose scale
**** subject to revision within a few days; awaiting more accurate BIOFIX dates - currently using a default of March 15 ****
Corvallis - While first crawlers are normally expected the first week in June, preliminary predictions set June 15 as the date for first crawler emergence


Disclaimer: No claims are made as to the correctness or appropriateness of this information for your particular needs. No specific pest control products are intended for endorsement or use. This responsibility rests solely with the people who interpret and implement information from this and other sources. Use all predictive information with caution - errors occur, and predictive models do not replace the need for proper monitoring in the field. If you observe conditions that differ substantially from model predictions, please contact us to determine if the model inputs were incorrect, if the model functioning or weather data are in error, or if the model is inappropriate for your conditions.

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This project funded in part by a grant from the USDA-Western Regional IPM program.

On-line since April 5, 1996
Last updated June 1, 1998
Contact Len Coop at coopl@bcc.orst.edu if you have any questions about this information.