Survival, fecundity, and body mass of Amplicephalus curtulus influenced by ‘Candidatus Phytoplasma ulmi’ (16SrV‐A) infection

The leafhopper Amplicephalus curtulus Linnavuori & DeLong (Hemiptera: Cicadellidae) can transmit ‘Candidatus Phytoplasma ulmi’ (16SrV-A) from a native Chilean shrub, Ugni molinae Turcz. (Myrtaceae), to ryegrasses. A recent study showed that this phytoplasma reduced the total protein content and the activity of detoxifying enzymes in A. curtulus, which could also affect its vector fitness. This study evaluated the effect of ‘Ca. Phytoplasma ulmi’ on the longevity, fecundity, and body mass of A. curtulus. Both females and males were exposed to ‘Ca. Phytoplasma ulmi’-infected plants for 96 h, whereas a control group remained unexposed. Quartiles from adult emergence to 75% (t75), 50% (t50), and 25% (t25) survival rates were determined for each leafhopper survival distribution. The dry weight was also established at the end of the experiment. The adult lifespan of phytoplasma-infected males and females was significantly lower than that of the uninfected leafhoppers in quartile survival distributions t50 and t25. The phytoplasma-infected males and females lived 3 and 4 weeks less than uninfected ones in the last quartile, respectively. Fecundity was established by number of nymphs per female (in four periods) in phytoplasma-infected and uninfected assays. In general, the weekly pattern of the number of nymphs per phytoplasma-infected female was lower than that of uninfected leafhoppers; it was 37% lower at the end of the experiment. Phytoplasma-infected females weighed significantly less (11%) than uninfected individuals. Phytoplasma-infected males weighed 8% less than uninfected ones, but this difference was not significant. Our data indicated that ‘Ca. Phytoplasma ulmi’ negatively affected the fitness of A. curtulus, and nymphs produced by phytoplasma-infected females varied over time, which may influence the disease dynamics in nature or in field crops.