Mating disruption field trials to control the vine mealybug Planococcus ficus
Abstract: A mating disruption experiment against the vine mealybug, Planococcus ficus, wascarried out during 2008 in 3 commercial vineyards in northwestern Sardinia. Within eachvineyard, 2 adjacent plots of variable size (0.2, 0.4, and 0.5ha, respectively) were established asmating disruption and control plot. Plastic dispensers (Suterra Inc., USA) with 100mg each of thesynthetic sex pheromone were deployed in mid-May, before the first flight of adult males, at arate of 625 dispensers per hectare. The effectiveness of the mating disruption technique wasevaluated by comparing the number of males captured in pheromone traps, the leaf populationdensity, the percentage of ovipositing females, and the crop damage. Male flights were monitoredwith traps baited with 0.01mg of the sex pheromone. The percentage of females with ovisacs andtheir fecundity were estimated by collecting adult females after each peak male flight and rearingthem individually under laboratory conditions. The mealybug density was assessed from June toSeptember by counting every 2 weeks nymph and female mealybugs on basal leaves of 20-30vines per plot. The crop damage was evaluated at harvest by assessing the percentage of damagedbunches on the same vines. In all the vineyards, the number of males captured in matingdisruption plots was lower by far than in control plots, while the percentage of females withovisac was significantly different only in the first generation. Females collected from the fieldafter the first male flight produced more eggs than those collected after the second and thirdflight, with no significant difference between treatments. The density of mealybugs on leaves inmating disruption plots was lower than that in control plots, but the difference was notsignificant. Also, the percentage of damaged bunches at harvest did not differ betweentreatments. Mating disruption experiments to control the vine mealybug produced mixed results.This could be due to the limited size of experimental plots and/or the suspected parthenogeneticreproduction of Sardinian populations of P. ficus.