Nematicidal effectivity of neem oil, castor oil, and pyrethroids toward foliar nematode (Aphelenchoides fragariae) mortality

Abstract

The nematicidal activity of neem oil, castor oil, and pyrethroids (deltamethrin and λ-cyhalothrin) was assessed in triplicate toward A. fragariae mortality in vitro. Carbamate carbosulfan was used as a comparative chemical. All chemicals tested have a contact poison activity for nematodes. About 25 to 50 nematode vermiforms consisting of larvae and adults were soaked in 0.0%, 0.5%, 1.0%, 1.5%, and 2.0% of botanical oils and pyrethroids solutions for 1 hour, and the dead nematode was then counted under 100x magnification of a compound microscope. The results showed that the mortality rate of A. fragariae that was exposed to neem oil, castor oil, deltamethrin, λ-cyhalothrin, and carbosulfan solution with several concentration levels was significantly higher when compared to the mortality rate in the water (P < 0.05). On 1.0% concentration, neem oil was more effective in killing the nematode (84.85% mortality) than castor oil (36.52% mortality), and deltamethrin was more effective (74.27% mortality) than λ-cyhalothrin (54.19% mortality. LC50 of neem oil was 0,680 μlml−1, deltamethrin was 0.517 μlml−1, and carbosulfan was 0.545 μlml−1. The regression equation for neem oil is y = 60.295x with R2 = 0.9551, while for deltamethrin is y = 42.499x + 21.066 with R2= 0.8709.