Crazy top of cereals

The disease known as crazy top of cereals is caused by the oomycete Sclerophthora macrospora. This soil-borne pathogen acts as a systemic parasite, infecting plants early in their development and disrupting the normal growth patterns of the cereal host throughout its lifecycle.

Host plants include a wide range of cereals such as wheat, barley, maize, oats, and various wild grasses. The pathogen is particularly devastating because it affects the reproductive organs, preventing seed set and resulting in significant yield losses for farmers in affected fields.

Symptoms are distinct and often referred to as "crazy top" due to the proliferation of leaves within the inflorescence, creating a distorted, bushy appearance. Infected plants exhibit extreme stunting, thickened leaves, and excessive tillering, with the entire structure of the panicle or spike being replaced by leaf-like, vegetative tissue.

The development of Sclerophthora macrospora is highly dependent on environmental conditions, particularly water saturation. The pathogen releases zoospores that thrive in flooded or waterlogged soils, making fields with poor drainage highly susceptible to severe infection outbreaks during wet seasons.

Effective management strategies focus on preventing water accumulation through land leveling and improved drainage systems. Crop rotation is essential to reduce soil inoculum levels. Additionally, seed treatments with systemic fungicides targeting oomycetes can help provide protection during the critical early growth stages of the crop.