Residues of Imidacloprid and Mycolbutanil in on grape and soil under field conditions

Abstract EN

Persistence Vs degradation behavior of insecti-cide imidacloprid (35% SC) and fungicide myclobu-tanil (24% EC) in/on grape (leaves and fruits) and surrounding soil under canopy were investigated under field conditions.

Leaves, fruits and soil sam-ples were collected at 2 hours to 21 days after ap-plication at the recommended rate.

QuEChERS method was used for extraction and clean-up and analyzed using HPLC and GC for imidacloprid and myclobutanil, respectively .The initial residue de-posits, degradation percentages and/or, the pa-rameters (RL50 and RL90) and Pre Harvest Intervals (PHIs) of the targeted pesticides were the criteria of concern.

Results revealed that, grape leaves re-tained higher initial amounts than fruits by about 5.0 7 and 1.34 times for imidacloprid and myclobu-tanil, respectively.

As for RL50, RL90 and PHIs val-ues, imidacloprid showed 4.12 ,13.42 and 21.95 days and 5.13 ,13.41 and 11.96 days on grape leaves and fruit, respectively.

The corresponding calculated values were 4.71, 9.38 and 16.31days and 1.97, 9.14 and 14.90 days for myclobutanil on the same targeted samples, respectively.

In addi-tion, the grape fruits could be consumed safely after 12 and 15 days of treatment with imidacloprid and myclobutanil, respectively.

On the other hand , results indicated that the residue half life (RL50) values for the same targeted pesticides in soil were 11.56 and 15.74 days, respectively.

In gen-eral, myclobutanil residues in soil recorded higher persistence levels than higher imidacloprid and on the contrary it showed less persistence in/on grape leaves and fruits.