By Becky Wiepz and Dan Kielar
Sampling for foliar nutrient tests should be done soon for the most accurate results. 50 leaves from the middle of this year’s growth is the recommended sample size.
| Date 8/14 | 2020 | 2021 | 2022 | 2023 | 2024 | 20-year avg. |
| Base 50 | 1584 | 1636 | 1480 | 1575.5 | 1625.5 | 1588 |
GDD50 continues to be approximately 3-5 days ahead of the 20-year average.
Apples
The current dry spell means many apple varieties will need irrigation as fruit is sizing up and approaching harvest.
Now is a good time for summer pruning and planning any stop drop applications for varieties like Honeycrisp.
Insects
Wooly Apple Aphid (WAA) populations are increasing in orchards with dense canopies. The wet conditions are ideal for WAA development, and we will likely see continued pressure from this pest.
Codling Moth populations continues to be very large this year. It appears we’ve started second generation.
Apple Maggot have emerged and flight has started. Insecticides applications should start in your orchard 7-10 days after flies are caught on yellow sticky boards or immediately if they are caught on red spheres.
Leaf Hoppers and Oblique Banded Leaf Rollers are still being caught in some blocks. San Jose Scale will soon start their second generation, so scout for crawlers in any blocks that had high pressure in the past.
Japanese Beetles are present in large numbers throughout the county.
Disease
Blocks with good initial control are experiencing very low Apple Scab pressure and growers can stretch their applications out to every 10-14 days.
Powdery Mildew pressure seems to be decreasing with very few new strikes being detected.
Fireblight strikes may still appear in your orchards throughout the season, be sure to prune them out promptly. This article from Leslie Holland has more information on the latest recommendations for removing Fireblight strikes. Remember that Strep is not an effective tool for managing shoot blight.
Summer disease complex (Sooty Blotch and Flyspeck) may need controls to go out soon. Check the NEWA model to monitor pressure in your area. Save shorter PHI products for closer to harvest for managing late season rots.
Cherries
Harvest is now complete in all blocks!
Hedging and post harvest sprays are now due.
Insects
European Red Mite counts should be done in August to protect leaves as we move into the fall. Use of pyrethroids can cause ERM to flare, especially in dry weather conditions.
Post harvest sprays are not recommended for Spotted Wing Drosophila. Allowing populations to grow after harvest helps to prevent insecticide resistance from developing.
Disease
Cherry Leaf Spot is still active in some orchards and one or two post harvest sprays may be warranted.
GRAPES
Grapes on the station are approaching Veraison.
Insect pressure continues to be high, particularly with Japanese Beetles. Monitor your vineyards to assess activity and plan management.