Impact of Jacobiascalybica’sattacks on the physiology of the vine leaf.

Abstract

During the inventory undertaken in Algeria on the vine, the green leafhopper proved to be a new bio aggressor on this crop. Indeed, the first observations on vines date back to July 2002 and renewed in 2003 and 2004 [4], in the vineyards of the Western Mitija where the insect has spread rapidly throughout the country ([6]; [7]; First data JacobiascaLybica ( Bergevin&Zanon ) (Homoptera , Jassidae ) on Vine in Algeria; [8]). Jacobiascalybicaresponsible of the grillure on the vine leaves, generates considerable damages on the leaf after each attack. Given the climate change,These studies were made during the wine-making campaigns on 2013, 2014 and 2015 and having for objectives of: · Consolidate the searches undertaken during the wine-making campaign in 2007, on the fluctuation in the populations of the green leafhopper, responsible of the grillure but this time on the grape varieties of local product not imported one and observe the effect of the climate change on this harmful. · Determine the influence of the vigour of stocks and their sensibilities to this insect. · Demonstrate the effect of the attacks of this devastator on the limb physiology. These studies were conducted through the seasonal evolution of the green leafhopper on the vine variety: cinsaut, grenache and carignan by accounting larvas on the young and old leaves of the same vine variety studied by using the similar attractive traps to the sexual traps type INRA. They are established by a plastic shelter in the shape of tent, at the bottom there is a sticky sheet. The shelter is of bright yellow color. This technic permits to trap the green adults of leafhopper by chromatic attraction. The samplings were made once a week during three wine-producing campaigns, on 2013, 2014 and 2015 by making a periodic enumeration of larvas and adults. They were been realized in Hadjout, the Metidja and Mascara (west of Algeria). This study showed the succession of four peaks from May to September in Hadjout on the carignan wine which pilosity on the lower face of the limb has compared with cinsault and Grenache. Indeed the numbers of the green leafhopper on carignan especially in second generation exceed widely the recommended threshold. Moreover, it would seem that thelest vigorous vine to this leafhopper: Carignan accuse a strong depigmentation of the limb 50% followed with 40% and 10% respectively by Grenache and cinsault. However, no presence was revealed on the same vines of Mascara with 0% for all vignard. These studies allowed us to conclude that the populations evolution of the green leafhoppers depends of several factors such as the temperature, vigor of the vineand hairiness of its limbus.