In-vitro Biocontrol of Sugarcane Stem Borer (Eldana saccharina Walker) with Essential Oils from Aromatic Plants

Study Design and Objectives: Sugar cane production is threatened by the devastating action of the larval populations of Eldana saccharina Walker. Faced with this situation, the search for sustainable control solutions is a major challenge for sugar producers. This study contributes to the control of the larval populations of the pest through the use of formulations based on essential oils of local aromatic plants.

Methodology: Bioassays on the survival of the larvae were therefore conducted in the laboratory at the Sucrivoire site in Zuénoula. The larvae obtained from the eggs, incubated for 5 days were reared on a nutritional medium and then transferred to empty dishes after one week. Essential oils from the hydrodistillation of three aromatic plants (Cymbopogon citratus, Ocimum gratissimum and Zingiber officinale) were used. Five concentrations of these essential oils (1000, 2000, 4000, 8000 and 10000-ppm) were tested by direct contact on batches of 10 larvae for a total of 30 larvae/concentration. Dead larvae were counted daily and the mortality rate was calculated after 24, 48 and 72 hours of exposure.

Results: As early as 24 hours, larval mortality was significant (P<0.001) from 2000-ppm for Cymbopogon citratus and Ocimum gratissimum essential oils. They caused larval mortality of 63.33 and 80% respectively. Zingiber officinale induced a significant mortality of 80% from 4000-ppm. After 72 hours of exposure of the larvae to the essential oils, the mortality rate increased significantly with the concentration (P<0.001). The lowest lethal concentrations for 50 and 90% (841.77 and 1905.06 ppm, respectively) were obtained with the essential oil of Ocimum gratissimum.

Conclusion: The use of essential oils of Cymbopogon citratus, Ocimum gratissimum and Zingiber officinale can help to control Eldana saccharina Walker larval borers for better sugarcane production.