- Author: Stephen J. Vasquez
- Author: Matthew W. Fidelibus
Low temperatures experienced during the winter do not usually damage dormant grapevines in the San Joaquin Valley. However, succulent green shoots are much more sensitive to low temperatures, so spring frost damage is serious concern. Damage from spring frost can vary within and between vineyards. Some factors that determine the extent and severity of frost damage include vineyard location, stage of shoot growth, the minimum temperature reached, and the duration of time that the tissues are at or below critical temperatures (Table 1). A mild frost shortly after budbreak may only damage a few leaf cells, causing necrotic (brown to black) spots (Fig. 1, inset) which will appear to be unevenly distributed throughout the leaf blade or...
- Author: Marcia Wood
- Contributor: Stephen J. Vasquez
Grapes like DOVine, Selma Pete, Sweet Scarlet and Scarlet Royal likely would not exist were it not for ARS scientists’ expertise with a laboratory technique known as “embryo rescue.” The technology “allows us to use two seedless grape plants as parents for new, seedless offspring,” says grape breeder David W. Ramming with USDA Agricultural Research Service (ARS) at Parlier,...
- Author: Stephen J. Vasquez
After 38 years, David Ramming has retired from the USDA Agricultural Research Service (ARS)-Parlier, California, where he bred grapes for California’s raisin and fresh market industries. Starting in 1975, he replaced...
- Author: Dennis O'Brien
- Contributor: Stephen J. Vasquez
Combating USDA's Top-ranked Invasive Insect
First detected in the United States a decade ago, the brown marmorated stink bug (BMSB) is now in at least 39 states, is wreaking havoc in homes and gardens, and is a major economic threat to vineyards, orchards, garden vegetables and row crops. It's no wonder the U.S. Department of Agriculture (USDA) ranks this pest as its top "invasive insect of interest."
But help may be on the way: USDA scientists at the Agricultural Research Service (ARS) Invasive Insect Biocontrol and Behavior Laboratory in Beltsville, Md., are searching for ways to control the stink bug by deciphering its...
- Author: Stephen J. Vasquez
At a recent meeting held at UC Davis titled “Current Issues in Vineyard Health”, a newly-discovered viral disease being expressed in California’s vineyards was discussed. Currently named ‘Red Blotch Disease’, its symptoms distinguish it from leafroll virus expression, as does its PCR fingerprint. Presently, the most complete information available on the disease can be found in a brochure developed by Jim Wolpert, Viticulture Extension Specialist, UC Davis and Mysore Sudarshana, Plant Pathologist, USDA-ARS, UC...
