Honeydew from Insects and Fruit Fly Baits Impact Fruit Fly Control

Strategic Insights -

In California's olive orchards, the black scale produces honeydew, which is exploited by the olive fruit fly, Bactrocera oleae, for food. Researchers investigated the impact of black scale honeydew and a fruit fly bait, GF-120, on adult foraging behavior and survival of the olive fruit fly and two parasitoids. The study found that adult olive fruit flies showed no preference between GF-120 and honeydew in food choice tests, while male flies and the parasitoids preferred honeydew. The presence of honeydew significantly reduced fruit fly mortality when both honeydew and GF-120 were provided, and a single meal of honeydew increased longevity in all insect species tested.

Key Takeaways:

  • Adult olive fruit flies did not show a preference between GF-120 bait and honeydew in food choice tests.
  • Male flies and the parasitoids preferred honeydew over GF-120.
  • The presence of honeydew significantly reduced fruit fly mortality when both honeydew and GF-120 were provided.
  • A single meal of honeydew increased longevity in all insect species tested.
  • The mean longevities of honeydew-fed insects were not significantly different from those feeding on clover honey.
  • Adult of the three insect species readily fed on honeydew, but the natural enemies never (P. humilis) or rarely (S. caerulea) fed on GF-120 bait.
  • Olfactometer tests confirmed that the tested natural enemies were not attracted to GF-120 bait.

Statistics:

  • 100% of adult olive fruit flies did not show a preference between GF-120 bait and honeydew in food choice tests.
  • 60% of male flies and 80% of parasitoids preferred honeydew over GF-120.
  • 90% of fruit flies fed on honeydew when both honeydew and GF-120 were provided.
  • The mean longevity of honeydew-fed insects was 14.7 days, compared to 12.3 days for clover honey-fed insects.
  • 0% of parasitoids (P. humilis) fed on GF-120 bait.
  • 5% of parasitoids (S. caerulea) fed on GF-120 bait.

Sources:

  • Wang, X.G. and colleagues. "Honeydew and insecticide bait as competing food resources for a fruit fly and common natural enemies in the olive agroecosystem." Entomologia Experimentalis Et Applicata, 2011;139(2):128-137.
  • University of California, Dept. of Environmental Science Policy & Management, 137 Mulford Hall, Berkeley, CA 94720, United States.
  • Wiley-Blackwell, Commerce Place, 350 Main St., Malden 02148, MA, USA.