Dry Weather and Extreme Temperatures
Posted: June 27, 2012
by Win Cowgill, Rutgers University Extension Agricultural Agent
Reprinted from Rutgers Plant and Pest Advisory Newsletter, with edits by Tara Baugher
Irrigation and Avoiding Spray Injury
We are expecting dry weather until the weekend. Many orchard soils are getting dry. Keep your irrigation on this week. It is essential with trickle irrigation not to lose your subsoil moisture and replace what the trees are using on a weekly basis. New trees should be watered 2 to 3 times a week. Beginning this weekend the forecast is for extreme temperatures for 5+ days in the 90s. Make sure to get your cover sprays (for BMSB) and Ethephon for return bloom on before then. Mike Fargione, extension educator, Cornell warns “Be aware of the danger of applying spray materials under hot, slow drying conditions. To limit damage, avoid applying sulfur and any kind of salt, including calcium sprays, until the weather cools a bit. Also limit the number of products, particularly adjuvants (including oil) that you add to the tank at any one time.”
Apple Return Bloom
Continue your weekly Ethephon or NAA sprays but do not apply during or prior to extreme temperatures. Ethephon applied over 85 degrees F or if temperatures rise above 85 degrees F up to 3 days after application can be problematic. Caution: Ethephon applications at high temperatures and high rates can de-fruit trees; temperatures over 85 degrees F can cause severe fruit drop.