Evidence of antibiosis resistance of four strawberry cultivars against Duponchelia fovealis (Lepidoptera: Crambidae)

Abstract

European pepper moth, Duponchelia fovealis (Lepidoptera: Crambidae), is an invasive polyphagous pest that causes economic losses in strawberry production. This study assessed the preference and performance of D. fovealis on four strawberry cultivars (Albion, Aromas, Portola, and San Andreas) and an artificial diet to determine resistance mechanisms against this pest. Duponchelia fovealis completed its life cycle on the four strawberry cultivars, with differences in development time and reproduction. Larval stage was longer on ‘Albion’ (27.00 ± 0.37 days). The lowest pupal weights were recorded for males on ‘San Andreas’ (24.3 ± 0.4 mg) and for females on ‘Portola’ (27.3 ± 0.4 mg). The shortest longevity of females was observed on ‘Aromas’ (11.14 ± 1.44 days). The net reproductive rates of D. fovealis were lower on ‘Albion’ (150.2 ± 4.8), ‘Aromas’ (178.0 ± 16.3) and ‘Portola’ (164.5 ± 13.2) when compared to the artificial diet (206.8 ± 14.0). Approximately a third of the larvae fed with strawberry leaves had an additional instar (sixth instar), whereas those fed on the artificial diet only had five instars. The highest foliar consumption was observed on ‘Albion’ (6.37 ± 0.82%). In a no-choice test, oviposition was reduced in ‘Albion’ (7.83 ± 1.85 eggs/leaf), which had the highest number of glandular trichomes (28.87 ± 1.99 trichomes per 1.7 mm2 of leaf). Evidence of antibiosis resistance was observed in the Albion, Aromas, and Portola strawberry cultivars (longer egg-adult development time, lower pupal weights and an additional larval instar), while evidence of antixenosis could not be confirmed. This is the first report of host plant resistance to D. fovealis in four strawberry cultivars.