The detection of green leafhopper pests in vineyard has put wine growers on alert at a key moment of the grape season, just a few weeks after harvesting time begins. Several official bodies have warned of the substantial increase of mobile forms of green leafhopper in vineyard, as high population scenarios have appeared in which it is foreseeable to exceed the treatment thresholds.
In Spain, the Department of Plant Protection of the Generalitat Valenciana (Valencia) has issued warnings to producers in the central area of the province. The same occurs with the Network of Alert and Phytosanitary Information of the Junta de Andalucía as several spots have been detected in the province of Malaga. In Toledo, ASAJA has also confirmed the presence of this pest in vineyards in the district of Méntrida and La Torre de Esteban Hambrán. In these areas, caution is even greater after the devastating plague that farmers suffered last crop.
Green leafhopper in vineyard results in an insect between 2 and 3 mm in length. It is placed on the underside of leaves and is used to fly at the slightest movement. Green leafhopper attacks the nerves of leaves, as it feeds on the plant sap. Its effect is extremely detrimental because it stops the vegetative development and, consequently, the fruit ripening. Visually, the most evident consequence is the marginal desiccation of leaves, which turn yellow.
The most intense presence of green leafhopper in vineyard usually occurs during summer because of high temperatures, warm and dry weather conditions. Economic losses for growers can be significant because the effects can be extended in the post-attack season, with a possible decrease in sprout vigor and crop yield.
Treatments for green leafhopper in vineyard
The scenario caused by the proliferation of green leafhopper in vineyard (Empoasca vitis Goethe) in Spain has also occurred in Europe, as a substantial increase in the population of cicadellidae has been observed in recent years. Seipasa has produced Pirecris®, a natural biopesticide showing an excellent performance in the control of several species of cicadellidae in vineyard.
The active ingredient of Pirecris® guarantees its efficacy and knock-down effect. In addition, the formulation of a high technology product has allowed Seipasa to obtain the product, guaranteeing a ‘green’ profile based on a plant matrix that enhances the action.
Pirecris® efficacy against the green leafhopper has been tested through more than 18 field trials conducted in several countries. One of them is the one carried out in the south of France during the summer of 2014. For this trial, a complete randomized block with 4 repetitions and 5 treatments was unfolded: an untreated control, Pirecris at 3 different doses (1; 1.5 and 2l / ha) and a reference chemical pyrethroid (0.125 l / ha). Two applications (A and B) were performed: the first one, on July 2014 and the second 7 days later. The number of larvae in 50 inner leaves was evaluated at 3 and 7 days after each application.
As shown in figure 1, the first application of Pirecris® significantly reduced E.vitis populations. These populations were lower than the ones in the control treatment for all doses tested.
Figure 1.- Evolution of the number of E.vitis larvae found in 50 leaves. A: first application; B: second application. Samples made at 0, 3 and 7 days after each application.
Green leafhopper populations remained low in all treatments with Pirecris during subsequent samplings, especially after the second application. The results are similar to those obtained by the reference treatment. The efficacies obtained in this trial were high (about 90%), especially with the medium and high doses (1.5 and 2 l / ha), surpassing those obtained by the reference pyrethroid (see figure 2).
Figure 2.- Evaluation of the Abbott efficacy of Pirecris and the reference pyrethroids against E.vitis in vineyard corresponding to samples taken at 0, 3 and 7 days after each application.
The results prove that Pirecris® is a solid and efficient alternative for the treatment of the green leafhopper in the vineyard. This solution, 100% natural and free of chemical residues, is fully aligned with the needs of producers and consumers towards a rational, sustainable and environmentally friendly agriculture.