Methyl Eugenol (Parapheromone) Trapping System on Diversity of Fruit Flies and Influence of Weather Parameters on Trap Catches in Mango and Guava Cropping Systems

Studies on species diversity and influence of weather parameters on methyl eugenol (parapheromone) trap catches were carried out in mango and guava orchards at Coimbatore and Dindigul Districts of Tamil Nadu from Standard Meteorological Week (SMW) 16th to SMW 25th. Species diversity indices were calculated, and the methyl eugenol trap catches were correlated with the weather parameters. The results revealed that four fruit fly species viz., Oriental fruit fly, Bactrocera dorsalis (Hendel), Guava fruit fly, B. correcta (Bezii), B. caryeae (Kapoor), and Peach fruit fly, B. zonata (Saunders), were attracted to the parapheromone methyl eugenol traps. Among them the population of B. dorsalis was higher in both mango and guava orchards of Coimbatore and Dindigul Districts. The highest species diversity indices for fruit flies viz., Shannon H’ (0.936) and Simpsons D’ (0.593), evenness (0.468), and richness (0.482) were observed in guava orchard located in Coimbatore District, and the minimum diversity indices Shannon H’ (0.254), Simpsons D’ (0.921), evenness (0.160), and richness (0.291), were observed in mango orchard located in Dindigul District. The maximum number of fruit flies were trapped in 19th SMW in mango orchards in both Districts 134 and 145 flies/three traps, respectively. In Coimbatore District’s guava orchard and Dindigul District's mango orchard, trap catches revealed a significant positive correlation with rainfall. The subsequent weather parameters like max. temperature, min. temperature, wind speed, and relative humidity, were either positively or negatively correlated with trap catches in mango and guava orchards. In multiple regression analysis, the maximum predictability was seen in mango orchard (75.54%) located in Coimbatore District and the minimum (66.68%) in mango orchard located in Dindigul District.