Cicadella viridis (Linnaeus, 1758)

Hasbroucq, Séverine, Casarin, Noemi, Czwienczek, Ewelina, Bragard, Claude & Grégoire, Jean-Claude, 2020, Distribution, adult phenology and life history traits of potential insect vectors of Xylella fastidiosa in Belgium, Belgian Journal of Entomology 92, pp. 1-21 : 10-12

Cicadella viridis

Distribution in Belgium

It was found in all the ecological regions of the country ( Fig. 4 ). We collected it in 28 sites out of 36.

10

Adult phenology

Adults were found from May to December ( Fig. 5 ). We collected them in higher number from June to September, mostly in humid meadows but also along roads and in dry meadows, on a large range of plants but mostly on Juncus spp. ( Table 4 ).

Oviposition, egg winter diapause and voltinism

Oviposition was observed in slits inside Juncus stems. The eggs overwinter and there is no diapause.

Immature development

Under outdoor conditions, development of the first generation started in late April and ended in mid-June ( Fig. 6A ). There are five instars and nymphs are mobile, without spittle protection. The cephalic capsule measures between 0,5–1,6 mm according to nymphal instar. Immature development lasts from 49 to 62 days. The adults appeared between June 6 and 19 ( Fig. 6A ).

Under controlled conditions, immature development lasted 21–27 days. The last 5 th instar nymphs appeared after 25 days ( Fig. 6B ).

Local abundance in the field

37 oviposition slits were measured and the eggs therein were counted. The slits were 3 to 8 mm long (mean: 5,9 ± 1, 1 mm) and contained a mean number of 10,3 ± 2, 4 eggs. There was a linear relationship between the slits' length and the eggs they contained (y=1,7662x; R 2 =0,7177; p<<0.001), corresponding to 1.8 eggs/mm in the slits. 32% to 83% of the Juncus stems in the samples contained eggs. Extrapolating from the mean length of oviposition slits in each sample and from the linear relationship between slit length and egg load, we estimated that there were ca 500 to 3,300 eggs in the samples, corresponding to a density of 6,000 to 37,000 eggs per m 2 ( Table 5 ) .

Parasitism by the egg-parasitoid Anagrus incarnatus ( Hymenoptera , Mymaridae )

Parasitism rates varied from 3.48% to 11.77% in the samples, with an average of 6.67% ( Table 6 ).

Figures

Fig. 4. Distribution map for Cicadella viridis in Belgium. Data: RBINS; Observations.be (2010-2016); our own samplings (2016-2017).

Fig. 5. Phenology of adult Cicadella viridis in Belgium. Data: RBINS; Observations.be (2005-2017); our own samplings (2016-2017).

Fig. 6A. Immature development of Cicadella viridis under outdoor conditions (Ixelles, Belgium, 2016. Fig. 6B. Immature development of Cicadella viridis under controlled conditions (21.5°C; D:L= 9:15).