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.

Interplay of plant pathogens and host defenses: Unveiling the mechanisms and strategies for crop protection

“…Traditional method: The application of neem and castor oil can repel and reduce the feeding of nematodes (Djiwanti et al, 2024). Soil solarization involves shielding the soil with transparent plastic during the warmest months of the year to increase the soil temperature and kill nematodes and other soil-borne pests.…”