Modus operandi of bacterial wilt uncovered
scientists at the Indian Institute of Spices Research (iisr) in Kozhikode have found how bacterial wilt attacks ginger (Zingiber officinale), an important cash crop. Caused by a family of pathogens called Ralstonia solanacearum, the disease spreads quickly and can cause total crop loss. It is one of the major causes of ginger crop damage.
India is the largest producer of ginger in the world, accounting for 70 per cent of the global output. Almost 180,000 tonnes of ginger is grown annually, mostly by small farmers in Kerala, Karnataka, the seven north-eastern states and certain pockets of Maharashtra, Tamil Nadu and Andhra Pradesh. The spice is exported to more than 50 countries.
iisr scientists found R solanacearum colonises vascular cells (that transport water and minerals) where it multiplies and blocks supply of water and nutrients to the part of the plant above the ground. The plant dies ultimately.
R solanacearum is a large family, sub-divided into five classes or biovars. Two of these -- biovar 3 and biovar 4 -- are widely prevalent in India. iisr scientists conducted molecular studies and found the class of R solanacearum responsible for causing havoc with the ginger crop is biovar 3, though biovar 4 was also present on the affected plants. Till date, the genetic diversity of this pathogen in India was not known, say Aundy Kumar and others in a paper in the December 10 issue of Current Science (Vol 82, No 11).
The researchers also found the same strains of R solanacearum cause devastation in different parts of the country. This led them to conclude it spreads through the ginger rhizome (underground stem used to propagate the plant). Unsuspecting farmers carry the rhizomes from an affected area to a different geographical location for planting. More often than not, the rhizome also carries the pathogen, which thrives once the rhizome is planted. "Even a healthy looking plant from an affected field invariably carries the pathogen," observes Kumar.
Besides ginger, the dreaded disease affects more than 450 types of food crops including chilli, tomato and potato, belonging to 50 families of plants.
We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.
.png)
Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.