BACKGROUND

Under the family Tephritidae, Bactrocera zonata (Saunders) is a serious pest, attacking fruits and vegetables causing large quantitative and qualitative damages throughout the world. Fruit flies require proteinaceous food for sexual maturation and egg development. Therefore, food bait attractants are frequently utilized for fruit fly detection, monitoring, mass trapping, and control. Using a Y-shape olfactometer (behavioral tests), we selected the best synthetic proteinaceous food bait attractants to volatiles identified by fruit fly antennae. The responses of B. zonata adults, male and female, to some ammonium compounds (ammonium acetate (AA), trimethylamine (TMA), and putrescine) that were mixed with certain food attractants were evaluated under laboratory conditions. Using flies ranging in age from 5 to 30 days, possible mixtures were discovered that might be useful in developing fruit fly attractants for both males and females. So, four base baits were developed by mixing protein hydrolysate with jaggery, papaya powder, kachri powder, potassium hydroxide (KOH), and guava pulp. Finally, thirty-two (32) synthetic blends were developed when the above four base baits were mixed with synthetic attractants.

RESULTS

The olfactometer bioassay indicated that protein hydrolysate and jaggery-based baits were effective in attracting both male and female flies throughout their adult lives when combined with AA + putrescine (Bait 6) and AA + TMA + putrescine (Bait 8). Similarly, protein hydrolysate + guava pulp-based baits combined with AA + putrescine (Bait 6) and AA + TMA + putrescine (Bait 8) was effective in attracting both male and female flies from 5 to 30 days of age. The pH of all 32 synthetic blends was measured and ranged from 4.77 to 11.35.

CONCLUSIONS

According to our observation, the variation in pH may be due to differences in chemical composition between the attractants and food constituents. The pH of protein bait attractants may be an important factor in the attraction efficiency of B. zonata males and females.