Multiphoton-ionization fast-conductance (MPI-FC) was directly applied for detection of photoionization currents originated from pesticide traces irradiated by UV-laser. The principal methodology required for direct screening of pesticide traces deposited on various vegetational specimens was addressed. This approach was exemplified with 1,2,3,4,5,6-hexachlorocyclohexane and 3-amino-1,2,4-triazole, which are frequently found in agriculture-related industries. The range of pesticide concentrations covered was from 0.001 ng/mL to 1 mg/mL, and all measurements were carried out under ambient conditions. Our target vegetation substrates were sampled from the outdoors: grass, plant, and/or tree leaves. Neither material purification nor laborious extraction routines were utilized; thus employing MPI-FC for in situ/on-line monitoring of pesticide-contaminated vegetation is feasible.