Impact of Almond Oil, Amla Oil and Coconut Oil on the Growth and Virulence of Entomopathogenic Strains against Bactrocera Zonata Maggots

Abstract

Fruit flies, particularly Bactrocera zonata, are significant pests causing major agricultural losses. Chemical control methods result in pesticide residues, making alternative strategies essential. This study examines the impact of almond, amla, and coconut oils on the growth and virulence of entomopathogenic fungi (EPF) against B. zonata larvae. Objectives: To evaluate the effects of almond, amla, and coconut oils on the efficacy of nine EPF strains in controlling B. zonata larvae by assessing spore germination rates, lethal concentrations (LC50 and LC90), and lethal times (LT50 and LT90). Methods: The study was conducted at the University of Agriculture Faisalabad. Infested fruits were collected from citrus and guava orchards on campus. EPF strains were cultured on ¼ SDAY media with the three oils at seven concentrations (5%-35%) in IPM Laboratory of Department of Entomology UAF. Spore germination, LC50, LC90, LT50, and LT90 values were assessed in the lab. Results: Metarhizium pinghaense (MBC709), Lecanicillium attenuatum (MBC807), and Isaria farinose (MBC389) showed significant responses to oils and concentrations. Metarhizium aniopliae (F52) exhibited the highest virulence with the lowest LC50 (5.11×10^10 cfu/ml) and LC90 (3.26×10^13 cfu/ml) values after 3 days. Conclusions: Metarhizium aniopliae (F52) showed the highest virulence, followed by Isaria javanica (MBC524) and Beauveria brongniartii (MBC397). Beauveria brongniartii (MBC397) had the shortest LT50, indicating the highest mortality rate. This study highlights the potential of using EPF strains with oils for effective B. zonata management, offering a promising integrated pest management strategy.