Use of aqueous plant extracts to reduce profenofos residues in the leaf of mustard (Brassica juncea L.) and suppression of the grasshopper population

Abstract

Profenofos is an active ingredient from the organophosphate group which residue is often found in various fresh and processed vegetable products. This study aimed to assess the use of aqueous plant extracts of Sapindus rarak seeds, Luffa acutangula peel and Centella asiatica leaves to reduce profenofos residues in leaf of mustard and to evaluate their performance in suppressing the grasshopper populations. S. rarak seeds, L. acutangula peels and C. asiatica leaves were dried and filtered using a 100 mesh sieve. A total of 30 gm samples of each ingredient were mixed with 1000 ml of water and blended at 800 rpm, then filtered using 100 mesh sieve before use. The field experiment was performed by spraying profenofos pesticide with a concentration of 3 ml l-1 at a dose of 30 ml per plant. Two days after the profenofos application, the plants were sprayed with the aqueous plant extracts. Twenty-four hrs aqueous plant extracts application, pesticide residues were detected by the UPLC-MS/MS machine. The phytotoxicity test results showed that the use of aqueous plant extracts at a dose of 30 ml per plant did not cause any phytotoxic symptoms. Furthermore, in the field experiment, the control plants showed a residual value of 2407.62 ng g-1. Results of UPLC-MS/MS showed that the residual value of profenofos in PL treatment (aqueous extract of S. rarak seeds) was 1502.05 ng g-1, the recorded residual value in the PP treatment (aqueous extract of C. asiatica leaves) was 1316.27 ng g-1 and the residual value in the PG treatment (aqueous extract of L. acutangula peels) was 660.71 ng g-1. In the treated plants, the residual value decreased from 37.48% to 72.55%. Furthermore, the number of grasshoppers after the PL treatment decreased and was significantly different from the control. This study provides new information that aqueous plant extracts can reduce the residue of profenofos and suppress the population of grasshoppers in the mustard leaf.