Echinosteliales

Echinosteliales is an order of myxomycetes, commonly referred to as slime molds, that can occasionally be found associated with agricultural crops. While these organisms are generally saprotrophic, they are often encountered by agronomists as they colonize the surface of plants, causing minor stress and potentially complicating plant physiological processes.

The biological agents are microorganisms that form a plasmodium during their vegetative phase. This mass moves across the plant surface, feeding on microorganisms such as bacteria and yeasts. The damage occurs primarily because the plasmodium and subsequent fruiting bodies can physically interfere with photosynthesis and stomatal gas exchange, weakening the host plant.

These organisms primarily affect plants grown in high-humidity environments, such as greenhouses or nurseries. Typical host plants include leafy greens, seedling vegetables, and certain ornamental species. The presence of decaying organic matter at the base of the plants serves as a primary source for the colonization of these slime molds.

Symptoms of infestation are identified by the presence of minute, stalked sporangia that appear as a fine dusting on the foliage or stems. These structures can be translucent, white, or brownish. The plant may show signs of yellowing or wilting, and in severe cases, the slime may promote the development of opportunistic pathogenic fungi or bacteria.

Prevention and management rely heavily on cultural practices. Since Echinosteliales thrive in stagnant, damp environments, the most effective protection involves ensuring proper air circulation and strictly controlling humidity levels. Removing debris, maintaining sanitation within the growing facility, and avoiding surface water accumulation are essential steps to keep the population of these organisms at negligible levels.