University of Maryland Extension


Evaluating Grape Samples For Ripeness

Timely Viticulture - Pre-Harvest
It is critical to properly monitor and assess the fruit characteristics and maturity to make the appropriate management, harvesting, and winemaking decisions to produce the best quality grapes and wine possible from each specific vintage. A previous Timely Viticulture on Crop Development Sampling...

Crop Development Sampling

Timely Viticulture - Pre-Harvest
It is critical to properly monitor and assess fruit maturity characteristics to make the appropriate management, harvesting, and winemaking decisions to produce the best quality grapes and wine possible. The first step to assessing ripeness and quality is to take a proper sample that best...

Pre-Harvest Disease Management and Late Season Bunch Rots

Timely Viticulture Timeline-Pre-Harvest
Many vineyards are approaching or already within 30 days of the anticipated harvest date for early wine grape varieties. During this window, grape berries are becoming very susceptible to a variety of late-season rots, such as ripe rot, sour rot, Botrytis bunch rot, and other “secondary-fungi”...

Disease Management - Botrytis

Timely Viticulture - Bloom and Pre-harvest
Botrytis is a major disease threat as harvest approaches. Botrytis cinerea is a fungus that affects many plant species, especially wine grapes, where it is commonly known as Botrytis bunch rot or gray mold. Botrytis basics Grape flowers are considered the “gateway” for Botrytis infections, but the...

Crop Estimation

Timely Viticulture - Mid Season
Experienced growers often say that they were caught by surprise that their crop was either much less than or much greater than they anticipated or their average. Many growers do not use a formal method of estimating their crop yield - what appears on the vine is what is harvested. An important role...

Downy Mildew Management

Timely Viticulture Timeline Post Bloom
Downy mildew is now a year-long challenge for grape growers in the East. Downy mildew is often difficult to manage because it requires specific weather conditions to become a serious threat, but it can develop into an epidemic very quickly in favorable weather. Downy Mildew Basics The downy mildew...

Canopy Management - Shoot Thinning and Positioning

Timely Viticulture Timeline Pre-Bloom
Managing excessive vine vigor is one the greatest battles in Eastern viticulture and this problem is exacerbated in seasons with high rainfall and warm spring temperatures. Many vigorous varieties and variety/rootstock combinations are quickly beginning to increase in shoot length. Obviously there...

Early Season Insect Management: Flea Beetles

Timely Viticulture: Pre Bloom
Identification and Biology Grape Flea beetles, Altica spp. (Coleoptera: Chrysomelidae), are small (4-5 mm), oval shaped, metallic blue-purple beetles that jump when disturbed. Grape flea beetles overwinter as adults and become active on warm April days when grape buds begin to swell. Adult beetles...

Avoiding Injury to Grapes From Off Target Herbicide Exposure

Timely Viticulture - Pre-Bloom
Over the past few years there have been quite few cases in Maryland of injury to grapevines from herbicides that were sprayed to control weeds before planting crops on adjacent or nearby fields. Damage has ranged from some minimal leaf distortion through severe damage, crop loss, and vine death...

Final Pruning, Pre-emergence Herbicides, and Planting New Vines

Timely Viticulture Timeline - Dormant
Final Pruning Most have finished or already finished pruning. Remember, if you have a site where there is a history or severe risk of bud damage from late frosts with early budding varieties (such as ‘Chardonnay’), it is best to prune those last as this will help to delay bud break. You can also...


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