(NVR) - A recent study about controlling the dreaded Pierce’s disease is starting to get a lot of attention by grapegrowers in the Napa Valley.

This research was conducted at Texas A&M University and the study is titled “Control of Pierce’s Disease by Phage.” It was published in the June 2015 issue of the journal PLOS ONE. It is significant to the wine industry in its battle with Xylella fastidiosa, the cause of Pierce’s disease.

Xylella fastidiosa is a bacterium (in the class Gammaproteobacteria) carried by leafhoppers that suck on the woody xylem of plants. When the insect inserts its proboscis into the vine, the vine becomes infected with the bacterium. As the colony of bacteria multiplies in the vascular system or woody tissue of the plant, it obstructs the ability of the xylem to transmit moisture and nutrients to the leaves. They, in turn, begin to wilt. Often the bright red and orange autumn colors seen in spotty sections of vineyards are actually the result of a Pierce’s disease infection.

Until recently the only means of controlling Pierce’s Disease was to remove the infected vine and to spray vineyards with insecticides to kill the leafhoppers that carry the disease. At UC Davis, plant pathologists have been attempting to genetically engineer new root stocks that are resistant to the bacterium. (Chardonnay and pinot noir vines are said to be particularly vulnerable to the disease, while muscadine grapes — Vitis rotundifolia — are said to have a natural resistance.) Unfortunately, genetic engineering is not considered a viable strategy for the wine industry, as genetically modified grapes create havoc with the vinicultural labeling of vintages as defined by the ATF.

The Texas A&M study documented in the PLOS ONE journal is novel in the authors’ use of bacteriophages to control and reduce infections of Xylella fastidiosa.

A phage is a virus that infects and replicates within a bacterium. Phages, according to the authors, are the most abundant and ubiquitous genetic entity on earth. “Besides ubiquity, two major properties of phages, specificity and exponential propagation, make them attractive as antibacterial agents.”