Life cycle, population dynamics

Empoasca vitis performs 2 to 4 generations on the vine depending on the regions and climates considered. The hibernation takes place at the stage of female adults fertilized outside of the vineyard, on evergreen trees such as conifers, wild roses, brambles.

• In the spring , the females adult reach the vineyard plots where they begin to lay eggs at the end of April under the veins of the leaves.

• The eggs will give rise to neonate larvae ( first stage L1 larvae) which will hatch after 5 to 10 days from mid-May in general. The larvae will develop during 3 to 4 weeks before giving adults (2nd flight) during the second decade of June. Strong migrations (emigrations and immigrations between the vineyard plots and the wooded environment) can take place, explaining in some cases the absence of intergenerational link for a given plot.

• The 2nd generation will start at the beginning of July and will continue until the beginning of August, when we will observe, in particular in Bordeaux, a 3rd generation which will overlap with the previous one. In this case, it will be difficult to distinguish them because of the concordance of all stages of development of the life cycle.

• From September, adults will gradually migrate to winter refuges.
  
  
  
• Synoptic of Empoasca vitis development on vines (figure 3)