Land use influences the abundance and diversity of soil arthropods. The evaluation of the impact of different management strategies on soil quality is increasingly sought, and the determination of community structures of edaphic fauna can represent an efficient tool. In the area of Langhe (Piedmont, Italy), eight vineyards characterized for physical and chemical properties (soil texture, soil pH, total organic carbon, total nitrogen, calcium carbonate) were selected. We evaluated the effect of two types of crop management, organic and integrated pest management (IPM), on abundance and biodiversity of microarthropods living at the soil surface. Soil sampling was carried out in winter 2011 and spring 2012. All specimens were counted and determined up to the order level. The biodiversity analysis was performed using ecological indexes (taxa richness, dominance, Shannon–Wiener, Buzas and Gibson's evenness, Margalef, equitability, Berger–Parker), and the biological soil quality was assessed with the BSQ-ar index. The mesofauna abundance was affected by both the type of management and sampling time. On the whole, a higher abundance was in organic vineyards (N = 1981) than in IPM ones (N = 1062). The analysis performed by ecological indexes showed quite a high level of biodiversity in this environment, particularly in May 2012. Furthermore, the BSQ-ar values registered were similar to those obtained in preserved soils.

Tomato plants have their leaves, petioles and stems covered with glandular trichomes that protect the plant against two-spotted spider mites and many other herbivorous arthropods, but also hinder searching by phytoseiid mites and other natural enemies of these herbivores. This trichome cover creates competitor-free and enemy-free space for the tomato russet mite (TRM) Aculops lycopersici (Acari: Eriophyidae), being so minute that it can seek refuge and feed inbetween the glandular trichomes on tomato cultivars currently used in practice. Indeed, several species of predatory mites tested for biological control of TRM have been reported to feed and reproduce when offered TRM as prey in laboratory experiments, yet in practice these predator species appeared to be unable to prevent TRM outbreaks. Using the phytoseiid mite, Amblydromalus limonicus, we found exactly the same, but also obtained evidence for successful establishment of a population of this predatory mite on whole plants that had been previously infested with TRM. This successful establishment may be explained by our observation that the defensive barrier of glandular plant trichomes is literally dropped some time after TRM infestation of the tomato plants: the glandular trichome heads first rapidly develop a brownish discoloration after which they dry out and fall over onto the plant surface. Wherever TRM triggered this response, predatory mites were able to successfully establish a population. Nevertheless, biological control was still unsuccessful because trichome deterioration in TRM-infested areas takes a couple of days to take effect and because it is not a systemic response in the plant, thereby enabling TRM to seek temporary refuge from predation in pest-free trichome-dense areas which continue to be formed while the plant grows. We formulate a hypothesis unifying these observations into one framework with an explicit set of assumptions and predictions to be tested in future experiments.

Leptoglossus occidentalis Heidemann (Heteroptera, Coreidae), the western conifer seed bug, is a serious conifer seed pest in North America; after its accidental introduction in Italy, it has spread to several European countries. In Central Italy, severe seed loss was recorded in stone pine forests (Pinus pinea). Classical biological control against L. occidentalis was evaluated by performing laboratory tests on Gryon pennsylvanicum (Ashmead), the most important hymenopteran egg parasitoid of the pest in North America, to acquire biological and demographical parameters. Tests were performed in climatic chambers using glass tubes to house specimens at 26±1°C, 75±5% RH and 16:8 L:D and supplying honey drops as food for adults. G. pennsylvanicum reared on eggs of L. occidentalis has a high fecundity rate (144.55 eggs/female) and 90% of the total number of eggs are laid in the first two weeks of oviposition. Mean oviposition period is 23days. Parasitoid females live a mean of 40days, and longevity is higher in host deprived females. The intrinsic rate of increase (rm) was calculated to be 0.206. Mean sex ratio throughout a female’s life span was 70.42% females, though at the start of oviposition it was over 87% females. Adults survived only four days without honey as food, but up to 50days with food; water did not influence longevity. Females lived significantly longer than males. Fecundity was negatively affected by duration of host deprivation, nevertheless, host-deprived females retained the ability to parasitize host eggs, and without a substantial sex ratio change in offspring. On the whole, G. pennsylvanicum shows potential for use in classical biological control against L. occidentalis. Several factors contribute to its suitability for biological control like high reproductive rate, high sex ratio, long-lived adults, and the ability to maintain reproductive potential during periods of host deprivation with a no substantial change in the sex ratio.

Biological control of spider mites (Acari: Tetranychidae) under dry conditions is a serious problem, which cannot be solved with the currently available strains of predatory mites (Acari: Phytoseiidae). However, there is considerable intraspecific variability in the degree of adaptation to low humidity, allowing the screening for a drought-resistant strain. Due to its plasticity in biological and ecological traits Neoseiulus californicus qualified as a suitable species for strain screening. Egg hatchability, juvenile survival and oviposition rate of eight N. californicus strains were evaluated at three or four humidity levels (ranging from 64.0 to 75.6% r.h. at 25 °C). Strains came from Hérault/France (FR), Tuscany/Italy (FL), Valencia/Spain (SP), La Cruz/Chile (CH), Sicily/Italy (SI), and California/USA (C-BOKU, C-ISZA, CARO). Pronounced intraspecific variation of the traits evaluated at 64.0% r.h. served as a basis to rank the strains and to determine three distinct groups. In the first group (SP, FL, C-ISZA) egg and juvenile survival probability was nearly zero. The second group (FR, CH, C-ARO) was characterized by low egg survival probability (0.14-0.18), but high survival probability of mobile juveniles (0.69-0.82). Strains of the third group had the highest egg and juvenile survival probabilities among the strains evaluated: 0.37 and 0.83 (SI), and 0.38 and 0.96 (C-BOKU), respectively. We conclude that the strains of the latter group are the most promising ones with respect to spider mite control under relatively dry conditions

The nature of the damage caused by eriophyoid mites and the assessment of yield losses still require detailed studies if appropriate control and risk mitigation strategies are to be planned. The economic importance of eriophyoid mites is increasing worldwide and a lot of species have reached a permanent pest status in certain crops, while others represent a quarantine threat for several countries. Due to their relevant role in Europe and elsewhere, three eriophyoid mites that have been frequently reported in recent research, are here considered as case studies: two of them (the apple rust mite, Aculus schlechtendali, and the grape rust mite, Calepitrimerus vitis) colonise temperate fruits, while one (the tomato russet mite, Aculops lycopersici) affects vegetables. The damage assessment related to the apple rust mite has been evaluated on different apple varieties with implications for pest control. Some factors affecting the spread and economic importance of the grape rust mite have been identified. The complexity and difficulty in controlling the tomato russet mite by chemicals enhances the interest in biological control agents. Considerations on interactions between eriophyoids and host plants (e.g. resistance, varietal susceptibility), on pest management regimes (e.g. impact of fungicides, resistance to acaricides, perspectives on biological control) are presented.