Screening, Quantification, and Integrated Pest Management based Mitigation of Pesticide Residues in Major Fruits and Vegetables of Punjab (Pakistan)

In the current study 5 fruits (mango, apple, citrus, guava, and banana) and vegetables (Ladyfinger, Brinjal, Cocumber, Cauliflower and Tomato) from 5 major cities of Punjab were collected and analyzed for residues against 8 pesticides used to control insect pests. Samples were prepared using QuECHERS extraction and clean-up technique followed by solid phase extraction (SPE). The results revealed that among all analyzed samples 63.35% were contaminated with different pesticides and 36.65% samples were contamination free. Among the contaminated samples 38.04% showed residue values above maximum residue limits (MRL) specified by Codex Alimentarius Commission or the European Union. Mango was quantified with maximum number of contaminated samples (74.25%) and minimum number of contamination free samples (25.75%) among which 47.81% exceeded MRL followed by apple with 68.5% contaminated and 33.94% exceeding MRL among contaminated samples respectively. Banana fruit was determined with least residues among selected fruits, where 51.75% samples were contaminated, 48.25% with no residues and 33.33% exceeded determined MRL values. Fruit (mango) with the highest number of contaminated samples, was selected for the application of pesticide residue mitigation modules (PRMM-1, 2, 3, 4) in comparison to control. Orchard with PRMM-2 showed maximum reduction (90.79%) in pest population followed by PRMM-1 which accounted for 83.61% reduction in pest population. Module-3 reduced the pest population up-to
75.78% followed by PRMM-4 which reduced the population to 72.18% over control. Overall PRMM-2 (cultural + mechanical + attract and kill methods + insecticide) showed maximum pest reduction. This module performed 18.61% better against chemical method in terms of pest population reduction; while PRMM-1(cultural + mechanical + attract and kill methods) pest reduction was 11.43% over chemical control. Maximum marketable yield was recorded in PRMM-2 which surpassed control by 25.29%; while found minimum (11.47%) in PRMM-4 over control. Analytical analysis of the samples collected from PRMM-4 orchard; 75% samples were contaminated with pesticide residues while 41.66% samples exceeded MRL values of Codex Alimentarius Commission. In case PRMM-3, 66.66% samples were contaminated while only 33.33% exceeded MRL values which is 8.34% less than PRMM-4. While PRMM-1 showed 25% contamination and 8.33% above the limits of MRL and 16.66% were exceeding MRL from total 33.33% contaminated samples in PRMM-2. In total, 41.67% less samples were contaminated with residues in PRMM-2 over PRMM-4 while 50% samples in case of PRMM-1. In the case of control treatment 8.33% samples were determined with pesticide residues while no sample surpassed the limits. Finally cost benefit ratio (CBR) was compared for all the modules and PRMM-2 resulted in 1:64.69 followed by PRMM-1 (1:54.75), PRMM-3 (1:30.27) and PRMM-4 (1:21.40). In the case of vegetables, the highest contamination with insecticide residues was observed in samples of cucumber (59.53%). Therefore, cucumber was selected for the IPM modules for mitigation of pesticides residues as it showed highest contaminated
samples with highest concentration of residues. Four IPM modules were formulated and labeled as Less Pesticides Residue Modules (LPRMs) including LPRM-1, LPRM-2, LPRM 3 and LPRM-4 in comparison to control. Application of LPRM-4 (IPM + soft insecticides) showed maximum pest reduction (91.54%), followed by pest reduction in LPRM-1 (IPM+GF-120) (84.02%), LPRM-2 (cultural+Mechanical+ physical+ foliar application of imidacloprid+ methyl euginol + Spinosad) (78.31%) LPRM-4 (convention practices) (71.29%). Residues analysis of samples collected from different LPRMs demonstrated that
approximately 58.25% samples were contaminated with insecticides residues in LPRM-3 where 43.75% samples were above MRL limits. In the case of LPRM-2, 29.17% samples were contaminated while 17.6% samples exceeded MRL limits. In the case of LPRM-1, 19.78% samples were contaminated and 12.49% samples above MRL limits. In LPRM-4 almost 10.42% samples were contaminated and only 6.42% samples were above the MRL limits. The results of present research indicate that LPRM-4 proved effective and economical for pest management and mitigation of pesticides residues and hence can be recommended for implementation in cucurbit vegetables. Results of current study provided a glimpse of the pesticides residues contamination status of fruits in Pakistan and urgency of the curtailment of some excessively applied and potentially persistent pesticides is highlighted. The study also proposed more extensive investigation of all the food commodities to device/generate a better policy making and consumer awareness.