Field effectiveness of pheromone-based mating disruption to control the vine mealybug, Planococcus ficus (Hemiptera: Pseudococcidae): results from Italy

Pheromone-based mating disruption (MD) has been tested on a wide range of insects of agricultural importance. The successful results obtained on a relevant number of pest species boosted its wide-scale employ, with a growing number of commercial products currently available to farmers. Nowadays, the vine mealybug (VMB), Planococcus ficus (Hemiptera: pseudococcidae), is recognized as one of the main insect pests damaging vineyards. The harmfulness of VMB is due to phloem ingestion, resulting in degeneration of plants, decreased vigour, early defoliation, reduced bunch quality and decreased organoleptic characteristics of the obtained wine. This species produces a large amount of honeydew and wax, which serves as a substrate for sooty molt growing that reduces photosynthetic activity in leaves. Besides, VMB can transmit the grapevine leaf roll-associated virus and increasesthe risk of ochratoxin A contamination. A major challenge in vineyard IPM is reducing the amount of broad-spectrum insecticides currently used to manage insect pest populations, with special reference to moths, such as Lobesia botrana, and mealybugs. The chemical ecology of P. ficus has been extensively studied, with the identification of its sex pheromone in 2001 by Hinkens and co-authors, followed by the description of the site of pheromone emission in 2012. The effective employment of the pheromone main component, lavandulyl senecioate, for MD purposes was reported in 2006 and 2014 by Walton and colleagues and by Cocco and co-workers, respectively. In this scenario, little is still known about the optimization of MD programs against P. ficus. Herein, field research aimed at the successful management of VMB was recently carried out both on table grape and grapevine in various Italian regions. We focused on the potential impact of different amounts of pheromone (respectively 54, 72 and 90 g/ha) per hectare on VMB mating and thus VMB infestation levels. This was achieved by deploying per hectare respectively 300, 400 and 500 Isonet® PF reservoir dispensers, each dispenser containing 180 mg of racemic lavandulyl senecioate, and by assessing the effectiveness of the three different rates in reducing VMB infestation levels in comparison to control vineyards. Results pointed out that all three tested dispenser rates and thus amounts of pheromone per hectare were effective in reducing the percentage of VMB infested bunches as well as the number of VMB per bunch, with significant differences over the untreated control