Acrocalymma vine decline

The disease known as Acrocalymma vine decline is caused by the fungus Acrocalymma vagum. It is a vascular pathogen that disrupts the internal water-conducting system of plants, leading to severe physiological stress and a rapid decline in plant health.

The primary host for this pathogen is the watermelon. The fungus attacks the root and crown areas, eventually colonizing the vascular tissues, which prevents the uptake of water and essential nutrients from the soil to the upper parts of the vine.

Symptoms typically start with localized wilting of vines, often appearing first during the warmest parts of the day. As the disease progresses, the foliage yellows and dries out, and a cross-section of the crown or rootstock reveals significant vascular browning. Unlike other wilt diseases, this progression can be relatively swift under optimal environmental conditions.

The development of the fungus is highly dependent on environmental conditions, particularly high soil moisture and warm temperatures. The pathogen is soil-borne, meaning it survives well in the soil on infected plant debris for several growing seasons, making it a persistent threat in continuous cropping systems.

Management and prevention focus on reducing inoculum pressure in the field. Essential practices include implementing a rigorous crop rotation schedule, ensuring excellent field drainage to prevent water stagnation, and sanitizing farming tools to avoid physical spread. In severe cases, the use of targeted systemic fungicides may be required to protect the crop during its vulnerable stages of development.