A recent article by Western FarmPress highlighted the sobering fact that the fight against Xylella fastidiosa (Pierce’s Disease) is a long one.
In Temecula, California, thousands of acres of vines have been rogued because of glassy-winged sharpshooter transmitting Pierce’s Disease, and this was the trigger for the Sharpshooter Areawide Management Program in the San Joaquin Valley, which continues today.
Beth Stone-Smith, California Assistant State Plant Health Director, USDA APHIS, said that when she started with the program more than 20 years ago, scientists never thought they would be holding the line this long. And now, they don’t have the option of giving up.
With the current lack of control measures for the vector over large agricultural areas, the program aims to slow the natural spread of the sharpshooter vector, and its artificial spread via nursery plants that might carry egg masses on the underside of leaves.
The glassy-winged sharpshooter is well-adjusted to areas where food sources are available year round, and therefore, at best, the program is aimed at suppression rather than eradication due to the range of available hosts.
The glassy-winged sharpshooter is a larger and stronger flier than native vectors, which has seen Pierce’s disease spread further throughout vineyards, and feeding not just limited to a vine’s soft tissues, but also the bark.
What can we learn in Australia?
Prevention and preparedness are key. We need to be vigilant in keeping Xylella out of the country. We need a good grasp of native insects that could vector the disease if it was to be imported.
We need to monitor for symptoms and report anything unusual to the Exotic Plant Pest Hotline on 1800 084 881 so it can be assessed quickly.
Fast facts
- Xylella fastidiosa is the number one unwanted plant pest for Australia and a High Priority Pest for the wine industry
- Is a bacterium which affects the xylem of plants where it blocks the movement of water, dehydrating the plant and causing death within a couple of years
- Known as Pierce’s Disease in grapevines and by other names in other host plants
- The disease causes significant environmental and economic impacts across more than 550 commercial and ornamental plant species, including grapevines
- Spread occurs either through the movement of infected plant material or by the xylella bacterium being transmitted into a host plant by a sap sucking insect
- Some plant species can be infected with xylella but not show any symptoms or significant effects
- Xylella fastidiosa was originally detected in the Americas but is also now found in Europe, Taiwan, Israel, Iran and the Caribbean
- No treatments are currently available to cure diseased plants in the field
- It does not impact human health but general plant symptoms include scorched leaves, browning and loss of leaves, stunted shoots, reduced fruit size over time, dieback and plant death