Bioefficacy evaluation of chalcone derivatives against infecting rice, L.

A series of chalcones () were synthesized, characterized (using IR and 1H NMR techniques), and evaluated with an objective to manage rice root-knot nematode (RRKN) () both under pluronic gel and field conditions. Out of these fourteen compounds, 1-(4-fluoro-phenyl)-3-phenyl-propenone () and 1,3-diphenyl-propenone () showed promising and dose dependent activity at 10, 20, and 40 mg L. A significant reduction in penetration of second stage juveniles (Js) in rice roots was observed in compounds (9.5-12.0 Js/plant) and (10.5-13.4 Js/plant) compared to control plants (PB1121) (13.5-23.6 Js/plant) in pluronic gel study. The results of field trials indicated that , showed significantly ( ≤ 0.05) better plant growth on 28 days after sowing (DAS) compared to . Both and reduced gall formation significantly than carbofuran 3 G @1 kg a.i./ha. However, lower concentrations were less effective in field in reducing the gall formation. Also, a significant reduction in the number of galls was observed when soil was drenched with @ 40 mg L. However, root dipping was not as effective as soil drenching. The study revealed that both the chalcones have the potential for effective management of RRKN in fields, and can be a better alternative to carbofuran.