Overview
Ralstonia solanacearum is a soil-borne, Gram-negative bacterium that causes bacterial wilt across a very wide host range, including tomato, potato, pepper, eggplant and many other plants. It is considered one of the most important and destructive bacterial plant pathogens worldwide, and in potato is also known as the cause of brown rot.
Symptoms
The bacterium invades the roots and colonises the plant's water-conducting vascular system, causing rapid, often irreversible wilting of leaves and shoots while they remain green. A milky bacterial ooze streams from cut infected stems placed in water — a classic diagnostic sign.
How it spreads
Warm temperatures and moist soils favour the disease. The bacterium survives in soil, water and plant debris and spreads through irrigation water, soil movement, tools and infected planting material, which makes it very hard to eradicate once present.
The control challenge
Its soil-borne, systemic nature makes bacterial wilt extremely difficult to control with conventional chemistry, and there is no reliable curative treatment. Management leans on resistant varieties, sanitation and crop rotation — leaving a clear gap for new biological research.
Bacterial wilt is an additional target category within the scope of Exacta's platform. Bacteriophages that target Ralstonia are an active area of international research; for Exacta this is a research area of interest, described here as a development area rather than a commercially available product.