Bacterial wilt of turfgrass
| Xanthomonas campestris pv. graminis | |
|---|---|
| Scientific classification | |
| Domain: | Bacteria |
| Phylum: | Proteobacteria |
| Class: | Gammaproteobacteria |
| Order: | Xanthomonadales |
| Family: | Xanthomonadaceae |
| Genus: | Xanthomonas |
| Species: | Xanthomonas campestris |
| Variety: | X. c. pv. graminis |
| Trinomial name | |
|
Xanthomonas campestris pv. graminis |
|
Bacterial wilt of turfgrass is the only known bacterial disease of turf. The causal agent is the Gram negative bacterium Xanthomonas campestris pv. graminis. The first case of bacterial wilt of turf was reported in a cultivar of creeping bentgrass known as Toronto or C-15, which is found throughout the midwestern United States. Until the causal agent was identified in 1984, the disease was referred to simply as C-15 decline. This disease is almost exclusively found on putting greens at golf courses where extensive mowing creates wounds in the grass which the pathogen uses in order to enter the host and cause disease.
Creeping bentgrass (Agrostis stolonifera) and annual bluegrasses (Poa annua) are the makeup of most putting greens, as well as the preferred hosts of this pathogen. Specifically, Toronto (C-15), Seaside, and Nemisilla are the cultivars of creeping bentgrass most commonly affected. The bacteria enter the plant host and interfere with water and nutrient flow, causing the plant to look drought stressed and to take on a blueish-purple color. Additionally, symptoms of bacterial wilt of turf grass include yellow leaf spots, tan or brown spots, water soaked lesions, elongated yellow leaves and shriveling of aforementioned blue or dark green leaves.Since putting greens are not a pure stand of turf, some grass blades may be resistant to the bacterium and thus remain unharmed while the surrounding turf dies, rendering the putting surface inconsistent and unsightly, especially at high-end golf courses.
The bacterium overwinters in diseased plants and thatch and is disseminated by water through rain splash, or mechanically by mowers, hoses, other gardening equipment, and golf shoes. The pathogen can also be present in the host at planting in infected sprigs, sod, or plugs. Unlike fungi, bacterial plant pathogens are unable to wound or mechanically probe plant hosts on their own. Instead, these pathogens enter through wounds inflicted on plants through verticutting, cultivation, sand, or through natural openings such as stomates and hydathodes. Once they have successfully entered and colonized the plant host, bacterial plant pathogens commandeer the nutrient and water supplies of plant cells to aid their own reproduction. In a study conducted by Zhou et al. (2013), the time between inoculation and wilt of host plants was found to depend heavily on temperature, with higher temperatures resulting in more rapid host decline. The researchers report the time between inoculation and wilting of host plants to be between 9–42 days. Bacteria can also spread to the roots of nearby plants underground. Within the plant host itself, bacteria spread by multiplying through binary fission and taking over more and more of the host by simply increasing their numbers.
...
Wikipedia