Efficacy of lure mixtures in baited traps to attract different fruit fly species in guava and vegetable fields

Abstract

Fruit flies (Diptera: Tephritidae) are major pests of fruits and vegetables worldwide. We measured the efficacy of attractive lure mixtures in baited traps on naturally-occurring fruit flies in commercial mosaic guava and vegetables fields in Pakistan. We tested three mixtures (methyl-eugenol [ME] and cue lure [CL]; GF-120 and methyl eugenol; and GF-120 and cue lure) in eleven ratios: 0:100, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, 90:10, and 100:0. We recorded three fruit fly species: Bactrocera zonata was the most abundant in baited traps, followed by Bactrocera dorsalis, while Zeugodacus cucurbitae was significantly less attracted to baited traps. We also found that the most attractive mixture and ratio varied among species: B. dorsalis was most attracted by 40CL:60ME, while B. zonata was most and equally attracted by 100ME, 10CL:90ME, 20CL:80ME, 30CL:70ME, and 40CL:60ME. Finally, Z. cucurbitae was most attracted by 10CL:90ME, which resulted in the highest total number of flies counted in 10CL:90ME-baited traps. Mixtures with GF-120 were less attractive to all three species. Our results suggest that lure mixtures in baited traps influence the attraction of fruit flies in a species-specific way. This needs to be considered in the integrated pest management of multiple species of fruit flies simultaneously. If Bactrocera species are most damaging and abundant, a 40CL:60ME mixture in baited traps will likely be most effective to reduce pest abundance and crop damage. However, if Z. cucurbitae is the main pest target causing most crop damage and yield loss, 10CL:90ME-baited traps will be a more effective in their monitoring and management.

Keywords: 2-dimethoxybenzene-carboxylate; 4-(p-acetoxyphenyl)-2-butanone; 4-allyl-1; GF-120; Tephritidae; cue lure; methyl eugenol.

Figure 1

Weekly mean (± SE) number of fruit flies collected in traps baited with the three different mixtures and eleven different ratios: (A) B. dorsalis; (B) B. zonata; (C) Z. cucurbitae. In each panel, different letters show significant differences between ratios from the same mixture and between different mixtures ( Tables S1-3 ); letters are colored following their corresponding mixture. Data points without letters were not included in the comparisons. ‘ME’: methyl eugenol; ‘CL’: cue lure (4-(p-acetoxyphenyl)-2-butanone); ‘GF’: GF120 (insecticide).

Figure 2

Comparison of mean number of flies caught weekly between species among the most efficient mixtures and ratios for each species. Different letters with the same font show significant differences between treatments for each species (reported from Figure 1 ). ‘ME’: methyl eugenol; ‘CL’: cue lure (4-allyl-1,2-dimethoxybenzene-carboxylate); ‘GF’: GF120 (insecticide).