Protected polyhouse gerbera (Gerbera jamesonii) cultivation faces severe stem and flower losses from moisture-loving soil fungi and foliar pathogens, notably Crown / Foot Rot (Phytophthora cryptogea / Pythium spp.), Powdery Mildew (Golovinomyces cichoracearum), and Botrytis Blight (Botrytis cinerea). Phytophthora attacks the crown at the soil line, causing sudden plant collapse, while Botrytis forms small brown spots on ray florets, ruining cut flower quality. Applying Bacillus subtilis as a crown drench, root dip, or weekly foliar spray creates a dense biological barrier over crown tissues and flower surfaces. The bacteria produce cyclic lipopeptides (surfactin, iturin, fengycin) that inhibit fungal spore germination and stop hyphal colonization in crown vascular channels.

Beyond disease control, Bacillus subtilis functions as a key plant growth-promoting rhizobacterium (PGPR) in high-value floriculture crops. It solubilizes fixed soil phosphorus, mobilizes iron via siderophore production, and secretes natural growth regulators that encourage crown division and root health. Stronger root systems support erect, thick flower stalks, vibrant ray floret coloration, and continuous flower flushing. Regular application ensures clean, residue-free cut gerberas with extended post-harvest vase life.

Importance of Bacillus subtilis in Gerbera Cultivation

Gerbera is a long-duration flowering crop that requires a healthy and active root system throughout its production cycle. Strong roots are essential for continuous nutrient uptake, regular flower initiation, and production of premium export-quality blooms.

Bacillus subtilis rapidly colonizes the rhizosphere and competes with harmful fungi and bacteria for nutrients and space. It also produces natural antimicrobial compounds that suppress disease-causing pathogens while encouraging beneficial microbial populations.

Healthy roots support vigorous vegetative growth, stronger flowering stems, larger flowers, and improved vase life.