Effect of temperature and host plant species on the juvenile development of Euscelis ohausi (Hemiptera: Cicadellidae), a potential insect-vector of plant pathogens

Abstract: Euscelis (Hemiptera: Cicadellidae) is an economically important genus of the Deltocephalinae subfamily containing vectors of agricultural plant pathogens. In Greece, Euscelis species are widely distributed and abundant; particularly on the island of Crete, Euscelis ohausi has been recorded in high populations on the herbaceous cover in olive groves. To understand the effects of temperature and host plant species on biological parameters of E. ohausi, juvenile development and survival were studied at 15, 20, 25, 30 and 33 °C on oat and at 25 °C on vetch plants. Temperature affected both the developmental time and survival of E. ohausi. The shortest egg incubation period was recorded at 30 °C and the longest at 15 °C, whereas the highest percentage of nymphal hatchability was recorded at 25 °C and the lowest at 30 °C. The shortest developmental period was recorded at 30 °C and the longest at 15 °C. The lowest nymphal survival rate was 25 % at 33 °C, while in the other temperatures it was above 60 %. Shorter nymphal developmental time was recorded on oat compared to vetch plants, however, no differences were recorded in survival percentages at 25 °C. According to the linear model, the lowest temperature developmental threshold from egg to adult was 7 °C. The assessment of the factors impacting juvenile development and survival is important for understanding the biology and phenology of E. ohausi.