Development of a Mating Disruption Program for a Mealybug, Planococcus ficus, in Vineyards

Abstract

The vine mealybug (VMB), Planococcus ficus (Hemiptera: Pseudococcidae), is a key insect pest of vineyards, and improvements in sustainable control of this pest are needed to meet increasing consumer demand for organically farmed products. One promising option is mating disruption. In a series of experiments conducted from 2004 to 2007, we tested the effects of mating disruption on trap captures of Pl. ficus males in pheromone-baited traps, on Pl. ficus numbers and age structure on vines, and on damage to grape clusters. From 2004 to 2005, the effects of dispenser load (mg active ingredient per dispenser) were also assessed, and dispensers were compared to a flowable formulation. Across all trials, mating disruption consistently reduced pheromone trap captures and often reduced mealybug numbers on vines and/or crop damage, regardless of the pheromone dose that was applied. Reductions in Pl. ficus densities in mating disruption plots were not accompanied by clear effects on mealybug population age structure; however, production of non-viable ovisacs by unmated females may have obscured differences in proportional representation of ovisacs. Pheromone trap captures were never lowered to zero (often called trap shut down), possibly because trials were conducted in vineyards with unusually high Pl. ficus densities. Trap-capture patterns in both treated and control plots commonly began low in April–May, increased in mid-July or August, and often decreased in September–October when post-harvest insecticides were applied. During the four-year trial, the release rate from plastic sachet dispensers was improved by industry cooperators as pheromone was released too quickly (2004) or not completely released during the season (2005–2006). The flowable formulation performed slightly better than dispensers at the same application dose. Results over all years suggest season-long coverage or late-season coverage may be as or more important than dose per hectare. Development of a dispenser with optimized season-long pheromone emission or targeted seasonal periods should be a future goal.

Mating Disruption of Pseudococcus calceolariae (Maskell) (Hemiptera, Pseudococcidae) in Fruit Crops

“…Previously, studies showing the usefulness of this technique as a control tool for a mealybug species have been carried out only for Pl. ficus in grapes [ 15 , 34 , 35 , 37 , 38 ], leading to commercial formulations. Our results showed that in MD plots “trap shutdown” occurred, as male captures in pheromone traps were reduced by 97% to 100% in both fruit crops one to two months after the applications in two seasons.…”

“…The pheromone doses used in this study (6.32 and 9.45 g/ha of the stereoisomeric pheromone mixture) were much lower than those used in studies with Pl. ficus , which found effects with 62.5 and 93.8 g/ha [ 35 ]; 93 g/ha [ 36 ]; 54 to 90 g/ha [ 38 ] and 20.0 to 61.7 g/ha [ 15 ]. When lower doses were tested, such as 4.15 and 8.3 g/ha, male trap captures were similar in the MD and control treatment [ 15 ].…”

“…ficus , which found effects with 62.5 and 93.8 g/ha [ 35 ]; 93 g/ha [ 36 ]; 54 to 90 g/ha [ 38 ] and 20.0 to 61.7 g/ha [ 15 ]. When lower doses were tested, such as 4.15 and 8.3 g/ha, male trap captures were similar in the MD and control treatment [ 15 ]. In our study with P. calceolariae , with ten times less pheromone than other studies with Pl.…”

“…Successful cases of mating disruption have also been reported in other insect orders such as the Oriental beetle ( Anomala orientalis (Waterhouse)) and Prionus californicus Motschulsky, both Coleoptera [ 2 , 10 , 11 , 12 ]. Only two commercial formulations of MD have been developed so far for Hemiptera, one against the California red scale, Aonidiella aurantii (Maskell) (Diaspididae), the other for the vine mealybug, Planococcus ficus Signoret (Pseudococcidae) [ 3 , 13 , 14 , 15 ].…”

“…ficus , given its great economic importance as a key pest in several crops, particularly grapes. Its sex pheromone was first described by Hinkens et al [ 18 ], and later monitoring methods [ 33 , 34 ] and mating disruption studies were developed [ 15 , 34 , 35 , 36 , 37 , 38 ]; it is the first mealybug species for which the successful use of MD has been reported. An additional case of successful application of MD for a mealybug species has been reported for Planococcus kraunhiae (Kuwana) in Japanese persimmon orchards [ 39 ].…”