Grape phenology and GDD accumulation

May 25, 2015 by Marilyn Odneal

GDD base 50 accumulated since April 1 = 567 (Tuesday, May 26 – system down on Monday) http://agebb.missouri.edu/weather/reports/gddTable.asp

Phenology stages according to the Modified E-L system
http://door.uwex.edu/files/2010/10/ModifiedEichhornLorennzsystem.pdf

N Norton E-L Stage 18 14 leaves separated; flower caps still in place but cap color fading from green.

MVEC Delaware E-L Stage 25 80% caps off.

MVEC Valvin Muscat E-L Stage 18-19 14 – 16 leaves separated; flower caps still in place, but cap color fading from green and beginning of flowering (first flower caps loosening).

MVEC Sunbelt E-L Stage 27 Setting; young berries enlarging (>2mm diam.), bunch at right angles to stem.

MVEC Chambourcin E-L Stage 15-18 8-14 leaves separated; shoots elongating rapidly, single flowers in compact groups to inflorescence well developed, single flowers separated, flower caps still in place but cap color fading from green.

W Catawba E-L Stage 23-26 17-20 50% caps off = flowering, 80% caps off, cap fall complete.

R Vidal Blanc E-L Stage 17-18 12-14 leaves separated, inflorescence well developed, single flowers separated, flower caps still in place but cap color fading from green.

R Seyval Blanc E-L Stage 23 17-20 leaves separated, 50% flower caps off (= flowering).

R Catawba E-L Stage 26 Cap fall complete.

F Vignoles E-L Stage 15 8 leaves separated, shoot elongating rapidly; single flowers in compact groups.

Chardonel E-L Stage 17-23 12 to 17-20 leaves separated, inflorescence well developed, single flowers separated, flower caps still in place but cap color fading from green, about 16 leaves separated; beginning of flowering, 10 – 50 % cap fall.

F Traminette E-L Stage 17-18 12-14 leaves separated, inflorescence well developed, single flowers separated, flower caps still in place but cap color fading from green.

F Cayuga White E-L Stage 23 17-20 leaves separated, 50% flower caps off (= flowering).

D Concord E-L Stage 26 Cap fall complete.

D Vivant E-L Stage 20-21 10 – 30% caps off.

D Mars E-L Stage 19-20 About 16 leaves separated, beginning of flowering to 10% caps off.