Epitrix similaris and Epitrix cucumeris in Portugal: damage patterns in potato and suitability of potential host plants for reproduction

Abstract

The potato flea beetle species Epitrix similaris and Epitrix cucumeris were identified in mainland Portugal in 2009. This was the first finding of the species E. similaris in the EPPO region, and the first report of the species E. cucumeris, established in the Atlantic Islands of Azores (Portugal) for three decades, in the mainland EPPO zone. Preliminary information on the damage patterns caused by E. similaris and E. cucumeris on potato and their host plant preferences is provided. Leaf feeding by the adults causes the characteristic shot‐hole pattern common to flea beetles. The larvae of both species develop on the root system and cause damage to the tubers. In field experiments, tuber damage by E. similaris presented three patterns: superficial tracks (serpentines), black splinters, and shallow holes. In the laboratory E. cucumeris was observed to be able to feed on very small immature tubers, causing serpentines and holes as well. However, in some cases it developed exclusively on roots. The adults of both Epitrix species hardly fed and reproduced on sweet pepper plants but fed and reproduced on the remaining five solanaceous plants tested (aubergine, Datura stramonium, tomato, potato and Solanum nigrum). E. similaris produced a much higher number of progeny on potato and on S. nigrum than on the other host plants. E. cucumeris produced more offspring on S. nigrum than on the other host‐plants.