Practical Implications of Early- and Mid-Summer Water Stress
Mike Basedow, Tree Fruit Specialist
Eastern New York Commercial Horticulture
The sunnier weather we experienced in June 2022 should have been good for photosynthesis and resulted in greater production of carbohydrates to support fruit growth compared to other years, unless the hotter temperatures and lack of rainfall in late June/early July 2022 in portions of Eastern New York have induced water stress in the plant. This is the kind of situation where even with irrigation apples don't always size that well. We think it is because the high temps and high evaporative demands with the rather high hydraulic resistance of apple roots, we get some significant stresses even with wet soil. The following Figure 1, modified from Mark O'Connell and Ian Goodwin in Australia, shows that increased afternoon vapor pressure deficit (VPD) creates greater stress in the plant. In a study we did with fruit growth monitors we found the fruit started to expand about 2 pm each day but with afternoon VPD's of 3 kPa even with irrigation the trees still experience stress and fruit growth is reduced.
Practical Implications of Early- and Mid-Summer Water Stress (pdf; 279KB)

Upcoming Events
Capital Region Orchard Twilight Meeting
August 11, 2026
Rexford, NY
Join the ENYCHP and Cornell scientists on August 11 for the Capital Region Orchard Twilight meeting in Saratoga! We will be touring Bowman Orchards and reviewing seasonal recommendations for pests and diseases for apples, plums, and berries, as well discussing crop insurance.
NYSDEC Pesticide Applicator Recertification Credits: 1.25 in categories 22, 1A, & 10. Refreshments will be provided.
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Champlain Valley Orchard Storage Meeting
August 26, 2026
Chazy, NY
Join various experts from Cornell and Cooperative Extension at an orchard storage meeting for the Champlain Valley in Chazy from 1 to 4PM on August 26th. Free to attend, however we do ask that you register ahead so we know how many people to expect.
