Short term effects of Bacillus thuringiensis and diflubenzuron aerial applications on non-target arthropods in a Mediterranean Forest

Abstract

Several products are widely used to control gypsy moth (Lymantria dispar) populations. The main purpose of the present study is to evaluate the aerial application effects of B. thuringiensis and diflubenzuron on non-target arthropods in a Mediterranean holm-oak forest. The density of gypsy moth population at the time of application of treatments was the same in the three forests and the defoliation levels in the three holm-oak forests were between level 0 (no apparent defoliation) and level 1 (small defoliations of new leaf). Sampling litter, soil, ground-dwelling, and epiphytic arthropods showed that the holm-oak forests treated with diflubenzuron had a better quantitative faunal outcome than the Control, whereas the highest taxonomic diversity was found in the site treated with B. thuringiensis. These results could probably be explained by a temporary competitive decrease due to the huge number of gypsy moth caterpillars on plants, as well as the enormous accumulation of their excrements in the soil during a prolonged period of time.

Keywords:

• Pesticides
• impact
• IGR
• Btk
• Lymantria dispar
• non-target arthropods

Acknowledgements

Many thanks are due to Drs. E. Petitpierre, G.X. Pons and N. Riddiford for their valuable help in taxonomic determination. We also acknowledge to C. Orellana for technical help and to A. Albiñana, F. Cotter and J. Vidal for entry permission in the experimental Holm oak forests.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by the Balearic Islands Government.