Northern Michigan FruitNet 2002
Weekly Update
James E. Nugent      Gary E. Thornton       William M. Klein
NW Michigan Horticultural Research Station
Michigan State University

June 4, 2002

WEATHER

For the first week since mid-April, temperatures were not below normal. Rainfall occurred at trace levels or more on 7 of the last 8 days of May. Evaporation exceeded rainfall by only 1.28 inches, for this growing season to date.

GROWTH STAGES

Apple: Red Delicious—mid petal fall
Pear: Bartlett – fruit set
Sweet Cherry: Napoleon – 11 mm fruit
Tart Cherry: Montmorency – shuck split
Plum: European type – shuck split
Grapes: Chardonnay – 1"-3" shoots

COMMODITY REPORTS

Cherries: Both tart and sweet cherry crops look shorter than already anticipated, due to repeated freezes and poor pollination conditions this spring. Bacterial canker has been severe in some blocks of sweet cherries and plums, resulting in significant levels of spur death. Cherry leaf spot lesions are present on the oldest full sized leaves in many tart cherry blocks. This will not cause significant defoliation, but will provide abundant inoculum for secondary infection. Check tarts at this time for the presence of leaf spot. The first catches of American plum borer were reported this past week, averaging six per trap. Plum curculio were active this past week, but no stings have been reported so far. Any stone fruits that are out of the shuck are susceptible at this time to plum curculio. Orchards with crops should maintain a tight schedule, as plum curculio may be traveling further than in the past to seek out fruit for egg laying. 

Apples: Last week we had back-to-back heavy infection periods for apple scab and cherry leaf spot throughout NW Michigan. Late in the week growers should have protected apples for fireblight, as the warm temperatures increased the numbers of bacteria. Forecasts predict that temperatures will be warm enough late this week for strep sprays to be considered again. Codling moth trap catches are just beginning. They averaged one per trap at the NWMHRS. Spotted tentiform leafminer averaged 138 per trap. European red mites are active, and some are above threshold, but with rapidly expanding leaves those populations are likely to be diluted to below threshold levels. June beetles and cutworms have been reported and activity will increase with warmer temperatures later in the week.

Please send any comments or suggestions regarding this site to: 

Bill Klein, kleinw@pilot.msu.edu
Last Revised: 6-04-02