Search

Helicoverpa armigera is a polyphagous and globally distributed pest. In Italy, this species causes severe damage on processing tomato. We compared the efficacy of mating disruption with a standard integrated pest management strategy (IPM) in a two-year experiment carried out in Northern Italy. Mating disruption registered a very high suppression of male captures (&gt, 95%) in both growing seasons. Geostatistical analysis of trap catches was shown to be a useful tool to estimate the efficacy of the technique through representation of the spatial pattern of captures. Lower fruit damage was recorded in mating disruption than in the untreated control plots, with a variable efficacy depending on season and sampling date. Mating disruption showed a higher efficacy than standard IPM in controlling H. armigera infestation in the second season experiment. Mating disruption showed the potential to optimize the H. armigera control. Geostatistical maps were suitable to draw the pheromone drift out of the pheromone-treated area in order to evaluate the efficacy of the technique and to detect the weak points in a pheromone treated field. Mating disruption and standard IPM against H. armigera were demonstrated to be only partially effective in comparison with the untreated plots because both strategies were not able to fully avoid fruit damage.

Within agroecosystems, the presence along the year of ladybirds is a crucial factor for aphids biological control. In the urban environment, this becomes exacerbated due to stricter regulations against use of pesticides. The demonstrative garden of the agricultural faculty of Bologna University is located in the urban environment, and consists in about 0.3 ha composed by more than 400 plots. The garden hosts more than 350 plant species, including forage, industrial, and horticultural crops, herbs and cereals. In order to assess the presence and preferred hosts of aphidifagous ladybirds within the demonstrative garden, weekly visual samplings in each of the 400 plots were conducted between March and September 2015. This included monitoring of presence and abundance of Coccinella septempunctata (the most important native and wild lady beetle species in Italy). Adult ladybirds were observed in the garden across the whole season, and abundance was greater in Triticum spp., Brassica spp., Prunus persica and Asclepias syriaca. Accordingly, a possible set of plants with scalar flowering enabling to guarantee the year-round presence of ladybirds in the urban garden is presented.

Females of the pine sawfly Neodiprion sertifer (Hymenoptera Diprionidae) usually avoid Pinus pinea trees as host plants. In contrast, this sawfly species is highly attracted by P. sylvestris and P. nigra trees. Here, we investigated which pine volatiles might mediate this behavior by in situ sampling experiments and olfactometer laboratory tests. Volatiles emitted from P. pinea, P. sylvestris, and P. nigra foliage were sampled by solid-phase microextraction (SPME). Analysis of these volatiles by coupled gaschromatography/ mass spectrometry revealed that the relative amounts of the compounds emitted by the three species were significantly different. A discriminant analysis showed that the amounts of limonene and myrcene significantly contributed to the species-specific volatile patterns. Pinus pinea emitted higher relative amounts of limonene than the other pine species. Pinus sylvestris emitted the highest relative amounts of myrcene. When testing the response of N. sertifer females to these pine terpenoids in an olfactometer bioassay, a low amount of limonene was attractive, while a repellent effect was evident when higher amounts were used. The sawfly females showed no significant olfactory response to myrcene. These data suggest that low relative amounts of limonene have a significant function in attracting N. sertifer females, while high amounts might contribute to avoidance of a tree.

Classical biological control is generallyunderstood as an environmentally safe practiceof insect pest management. However, questionshave been raised about possible negativeeffects for native species. As part of a riskassessment study a semi-field trial was carriedout in northern Italy in order to compare theoverwintering of the native species Propylea quatuordecimpunctata (L.) and Adalia bipunctata (L.) (Coleoptera:Coccinellidae) with the exotic Harmoniaaxyridis (Pallas) (Coleoptera: Coccinellidae).All the experiments were carried out from April1998 to April 2001. Harmonia axyridis wasable to overwinter successfully in northernItaly. Fecundity, oviposition rate, longevityand rate of increase of overwintering femaleswere calculated and the phenology of the threespecies was studied. Harmonia axyridisoverwintering mortality (31.9%) was lower incomparison with mortality of native species(68.9% for P. quatuordecimpunctata and61.3% for A. bipunctata). As aconsequence, post-overwintering rate ofincrease of the exotic species was higher.Longevity of overwintered females was similaramong the species. Mean fecundity of H. axyridis (783.8 eggs per female) was slightlyhigher than A. bipunctata (720.2 eggs perfemale), and much higher than P. quatuordecimpunctata (193.7 eggs per female). H. axyridis and A. bipunctatacompleted four generations and P. quatuordecimpunctata three generations in a year. The results show that H. axyridisappears to posses a high potential for establishment in Italy.

The influence of four constant temperatures (15, 20, 25, and 30°C) on development time and survivorship of Liriomyza trifolii (Burgess) and Liriomyza huidobrensis (Blanchard) was studied in laboratory experiments. L. huidobrensis required more time for embryonic development at 25 and 30°C, and less time at 15°C, compared with L. trifolii; at 20°C there were no differences between the two species. Larval development time for L. huidobrensis was longer than for L. trifolii at 20, 25, and 30°C. At 15°C no differences were detected. Pupal development of L. huidobrensis was always faster at 15, 20, and 25°C than that of L. trifolii. Total preimaginal development time was quicker at 15 and 20°C in L. huidobrensis than in L. trifolii; at 25°C no significant differences were found. Highest survival of L. trifolii (68%) occurred at 20°C, while that of L. huidobrensis (61%) occurred at 15°C. At 30°C no adults of L. huidobrensis emerged. The estimated lower threshold temperatures for egg, larva, pupa and total development of L. huidobrensis ranged between 7.3 and 8.1°C, and they were always lower than L. trifolii thresholds, which ranged between 9.9 and 10.7°C. The Logan model was used to describe the relationship between development rate and temperature. The quantification of development times presented in this study, combined with fecundity under different temperatures, could be incorporated into a phenological model that will aid in predicting population charges of leafminers.

As part of an environmental risk assessment study of exotic natural enemies used in inundative biological control, life-history characteristics of Harmonia axyridis (Pallas), Hippodamia variegata (Goeze) and Adalia bipunctata (L.) (Col., Coccinellidae) were quantified under laboratory conditions at 25°C on Myzus persicae (Sulzer) as prey. Comparative studies showed significant differences among pre-adult development times: H. axyridis developed slower ( = 19.8 days) than H. variegata ( = 18.1 days) and A. bipunctata ( = 18.4 days). Differences were also evident in the duration of egg, larval and pupal stages. No measurable differences among the three species were found for fecundity, oviposition rate and adult longevity. Harmonia axyridis exhibited the longest pre-oviposition ( = 7.4 days) and interoviposition ( = 3.6 days) periods and the shortest oviposition period ( = 13.7 days). The Bieri model was used to describe age-specific fecundity for the three species of coccinellids. The intrinsic rate of increase (rm), net reproductive rate (R0) and mean generation time (T) were higher for H. variegata (rm = 0.114, R0 = 52.75, T = 41.88 days) than for H. axyridis (rm = 0.089, R0 = 26.27, T = 38.81 days) or A. bipunctata (rm = 0.081, R0 = 18.49, T = 40.06 days). Our findings show that the biological traits of H. axyridis do not seem to be factors that may contribute to the invasiveness of this coccinellid.