Xylophilus ampelinus

Xylophilus ampelinus is a bacterial species that is known to cause the plant disease known as black dead arm in grapevines. This disease is a significant concern for viticulturists worldwide due to its potential to severely impact grape yield and quality.

Taxonomy

The bacterium belongs to the genus Xylophilus, within the family Xanthomonadaceae. It is a Gram-negative, rod-shaped bacterium. The species name ampelinus refers to its association with grapevines (ampelos is the Greek word for vine).

Pathogenicity

Xylophilus ampelinus is a pathogen that primarily affects grapevines, causing a disease known as black dead arm. The bacterium enters the plant through wounds, often those caused by pruning or harvesting. Once inside the plant, it produces toxins that cause necrosis of the vine tissues, leading to the characteristic blackening and death of the affected arm.

Symptoms and Diagnosis

The initial symptoms of infection by Xylophilus ampelinus include wilting and yellowing of the leaves, followed by necrosis of the affected vine arm. As the disease progresses, the arm turns black and dies, hence the name black dead arm. Diagnosis is typically based on these symptoms, along with laboratory testing to confirm the presence of the bacterium.

Management and Control

Management of Xylophilus ampelinus involves a combination of cultural practices and chemical treatments. Cultural practices include regular pruning to remove infected material and prevent the spread of the bacterium. Chemical treatments, such as the application of copper-based fungicides, can also be effective in controlling the disease.

Impact

The impact of Xylophilus ampelinus on grape production can be significant. The disease can reduce both the yield and quality of the grapes, leading to economic losses for grape growers. It is therefore a major concern in viticulture.

See Also

• Grape diseases
• Viticulture
• Xanthomonadaceae