Development of a rapid methodology for biological efficacy assessment in banana plantations: application to reduced dosages of contact fungicide for Black Leaf Streak Disease (BLSD) control.

BACKGROUND

Black sigatoka is the main disease of banana crop production and it is usually controlled by using either systemic or contact fungicides through spray applications. Biological efficacy is typically assessed on a whole cropping cycle with a natural infestation and periodical spray applications. Developing a faster methodology for the biological efficacy assessment of a contact fungicide offers promising perspectives for the test of current and new fungicides or application techniques.

RESULTS

The methodology is based on the time of occurrence of the first BLSD symptoms. The artificial infestation protocol was optimized by multiplying the infestation spots and by covering the infested plants. Biological efficacy tests were based on a single spray application after infestation combining three mancozeb dose reductions and two nozzle types. Results demonstrated that dosage reduction of 50% of mancozeb rated dosage gave a significant efficacy independently from the nozzle type with a reduction of the number of lesions up to 55 % compared to control plants.

CONCLUSIONS

The infestation method provides a rapid and significant infestation level. The further comparison of spray settings and fungicide doses was made possible. This methodology will be tested at plantation scale on a longer time period covering the whole crop cycle. This article is protected by copyright. All rights reserved.