Nectaries as Entry Sites for Aspergillus flavus in Developing Cotton Bolls

Area of Science:

• Agricultural Science
• Plant Pathology
• Mycology

Background:

• Aspergillus flavus infection in cotton can lead to significant yield and quality losses.
• Understanding the critical infection window is crucial for developing effective management strategies.

Purpose of the Study:

• To determine the susceptibility of cotton flowers and bolls to Aspergillus flavus infection at different developmental stages.
• To identify the optimal timing for preventing fungal contamination in cotton seeds.

Main Methods:

• Cotton flowers were tagged at the start of flowering and inoculated with Aspergillus flavus spores at various days post-anthesis.
• Bolls were harvested at maturity, and seeds were assessed for fungal presence and infection levels.
• Statistical analysis was performed to compare infection rates between inoculated and control groups.

Main Results:

• Inoculation up to 25 days post-anthesis resulted in significantly higher seed infection rates compared to controls.
• Inoculation after 25 days post-anthesis showed no significant difference in infection rates compared to uninoculated controls.
• A sharp decline in fungal infectivity was observed after 25 days post-anthesis.

Conclusions:

• Cotton susceptibility to Aspergillus flavus infection decreases significantly after 25 days post-anthesis.
• Physical or biochemical changes in the developing boll or plant likely contribute to this reduced susceptibility.
• Management strategies targeting early-season flowering may be most effective in preventing Aspergillus flavus seed contamination.