February 25, 2018

Appendix A: Grape Phenology

APPENDIX A:  The following grape diagram is an amended version of the original “Modified E-L system for identifying major and intermediate grapevine growth stages” [Coombe, B. and Dry, P. (eds.). 2004. Viticulture 1 Resources. Winetitles. Adelaide, Australia.]. 

The original document outlines 39 growth stages.  Modifications were made for pest management purposes only.

Pictures provided by E. C. Burkness and T. L. Galvan, University of Minnesota

Stage: Dormant

Diseases: Anthracnose (control at this stage is imperative)

Stage: Wooly Bud

Insects: Grape flea beetle

Stage: Bud Burst

Insects: Grape flea beetle, Climbing cutworms, Apple twig borer

Diseases: Phomopsis

Stage: 1st Leaf Separated

Insects: Grape flea beetle

Diseases: Phomopsis

Stage: Inflorescence Swelling

Insects: Grape flea beetle

Diseases: Black rot, Powdery mildew, Downy mildew, Phomopsis

Stage: 14 leaves separated, caps starting to loosen

Insects: Grape flea beetle

Diseases: Black rot, Powdery mildew, Downy mildew, Phomopsis

Stage: Flowering-50% caps off

Insects: Japanese beetle

Diseases: Botrytis, Black rot, Powdery mildew, Downy mildew, Phomopsis

Stage: Fruit Set

Insects: Japanese beetle

Diseases: Botrytis, Black rot, Powdery mildew, Downy mildew, Phomopsis

Stage: Berries BB Sized

Insects: Japanese beetle

*Diseases: Powdery mildew, Downy mildew

Stage: Berries Pea-Sized

Insects: Grape berry moth, Japanese Beetle

Diseases: Powdery mildew, Downy mildew

Stage: Berries Touching

Insects: Grape berry moth, Japanese beetle

Diseases: Botrytis, Powdery mildew, Downy mildew

Stage: Veraison

Insects: Grape berry moth

Diseases: Botrytis, Powdery mildew, Downy mildew

Stage: Harvest

Insects: Grape berry moth, Multicolored Asian lady beetle, Yellowjacket, Bumble flower beetle

Diseases: Botrytis, Powdery mildew, Downy mildew

*Berries become resistant to black rot, downy mildew, and powdery mildew 3-4 weeks after bloom; however, the rachis and leaves are still susceptible to infection by powdery mildew and downy mildew.

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