A novel approach of nanoemulsion formulations of metarhizium anisopliae to control Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae) in Malaysia
In this article, we provided current information on developing, use of new nano bio-insecticide of Metarhizium anisopliae as components of integrated pest management strategies for control of RPW. The effect of Agnique PG9116 at 1% concentration gave 87.5% germination while at 5% surfactant Emereen1604 gave 70% conidia germination. Sunflower and glycerin gave 49.13 and 44.13% growth rate at 1% concentration, respectively. Palm oil at 5% concentration showed a 56.88% growth rate. At 10% concentration of oils, soy bean and glycerin gave 48.63 and 45.38% growth rate, respectively. Four ternary phase diagram systems were constructed. All the formulations were stable under centrifuge, storage at 26±1°C, and 54±1°C for two weeks. Three formulations were in the range below ˂100 nm sizes, indicating that the formulations were in the category of the nanoemulsion. The zeta potential of the formulations ranged between -7.22 to -39.06 mV, the surface tension ranged from 32.03 to 37.90 mN m‑1, and the viscosity ranged from 2.40 to 28.8 mPas. The formulation coded as E1604 gave the LT50 of 4.90 days while the water suspension gave LT50 of 6 days. On adults, the LT50 was 2.20 days while the water suspension was 5 days. The E1604 recorded 100% cumulative mortality after 6 and 4 days on larvae and adults, respectively. Effect of oil nano-formulations on the conidia germination on the cuticle of R. ferrugineus was also observed, and after 20 h, the E1604 showed 55% germination compared to water suspension of 49.8%. The formulation E1604 showed the most extended germ tube of 41.34 µm and full penetration while the water suspension gave 5.28 µm length of a germ tube. The oil nano-emulsion of M. anisopliae conidia shows good potential for the sustainable control of both adults and larvae of R. ferrugineus.
Abdulqader, A.Z., Omar, D.B., Awang, R.M., Ahmed, A.M., Ali, Q., Islam, Y. and Saleem, M.H. (2023). A novel approach of nanoemulsion formulations of metarhizium anisopliae to control Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae) in Malaysia. Acta Hortic. 1371, 121-138
nanoemulsion, M. anisopliae, R. ferrugineus, conidia, SEM