Analysis of spatio-temporal Bactrocera oleae (Diptera, Tephritidae) infestation distributions obtained from a large-scale monitoring network and its importance to IPM

Bactrocera oleae is the key-pest considered in the “Olive-oil quality improvement project” in Tuscany (Italy). In this region, a network of 286 representative farms has been created in 2002 for monitoring weekly olive fruit-fly infestations, and the obtained data have been used in advising farmers on B. oleae control. The field observations were made by the regional extension service, and data have been collected from an internet-based monitoring network implemented in the Landscape Entomology Laboratory (LELab) of Scuola Superiore Sant’Anna. In this paper, we rely on the Geographic Positioning System (GPS) to locate the monitoring farms and make use of farm-specific information to analyze the regional spatial pattern of B. oleae infestions. Data analysis has been performed with Arcview 8.2, and we used variograms to model autocorrelations between sample points and cross-validation to identify the most reliable index. We consider the utility of Geographic Information System for spatial analysis at the landscape (or large) scale and kriging technique to interpolate between sample points. The resultant map can be used to predict the beginning of B. oleae infestations

The Cuticular Hydrocarbons of Dasineura Oleae Show Differences Between Sex, Adult Age and Mating Status

: In insects, cuticular lipids prevent water loss and act as semiochemicals. Because of their ecological function, the profile change across the insects' sex and development offers insight into insect biology and possible tools for pest management. Here, the first work on cecidomyiid cuticular extracts is proposed considering Dasineura oleae (Diptera: Cecidomyiidae) males and females at different adult ages (0-12 h, 12-24 h, 24-36 h) and distinct sexual conditions (virgin and mated). A set of 49 compounds were recorded (12 alkanes, 1 monomethyl alkane, 11 fatty acids, 4 esters, 1 aldehyde, 1 allylbenzene, 1 amine, 1 flavonoid, 1 ketone, 1 phenol, 1 steradiene, 1 sterol, 1 terpene, 1 triterpene and 11 unknown compounds), and 18 of them showed significant differences between groups. Among alkanes, hexacosane (nC26) exhibited a decreasing trend from the youngest to the oldest females, while pentacosane (nC25) and nonacosane (nC29) showed a decreasing trend from 0 to 12 h to 12-24 h virgin females. In addition, nonadecane (nC19) was significantly more abundant in the youngest males compared to older males and females. The alkanes nC25, nC26 and nC29 have been reported to be age-related also in other dipterans, while nC19 has been described as gender-specific chemical cue for platygastrid parasitoids. Further behavioural trials and analyses are required to assign the specific ecological roles to the characterized compounds. Our results may contribute to develop new low-impact control strategies relying on the manipulation of D. oleae's chemical communication (e.g. disruption of mating or species recognition). HIGHLIGHTS: • Cuticular hydrocarbons are often involved in dipteran intraspecific communication. • We explored the cuticular profile of D. oleae at different age, sex, mating condition. • Five alkanes and one mono-methyl alkane showed differences among groups. • Linoleic acid is the most abundant compound in virgins, absent in mated insects. • Eleven compounds disappear in mated insects, but were present in all virgins

First observations on the parasitoid complex and on the biology of Dasineura oleae during an outbreak in Tuscany, Italy

Dasineura oleae (Angelini) (Diptera Cecidomyiidae) was generally considered as a minor pest in Italy, but in 2013 an outbreak of this species was registered in the South - West of Tuscany. In the current work, we investigated several aspects of D. oleae outbreak in Tuscany: the life cycle, the pest status, variations in the infestation rate due to the first generation of 2018 and the role of parasitoids in this pest control. We observed that in 2017 D. oleae had one generation in Spring and one generation in Autumn. Our results proved that the infestation rate increased after the occurrence of D. oleae first generation of 2018 and also that D. oleae infestation rate differs across the outbreak area. Parasitism was lacking in most of the monitored sites, however where parasitization was present, a negative correlation between parasitism rate and infestation rate was evidenced. We detected three new species for Italy as parasitoids of D. oleae: Platygaster demades Walker, Platygaster oleae Szelenyi (Hymenoptera Platygastridae) and Mesopolobus aspilus (Walker) (Hymenoptera Pteromalidae)