•The non-target effects of biological control agents are currently poorly known.•Entomopathogenic fungi and nematodes were tested against Popillia japonica.•A Before-After Control-Impact experiment ...was conducted to evaluate soil biota.•An indigenous nematode showed the strongest effect in decreasing P. japonica larvae.•No negative effect on non-target soil biota was found.
Biological and integrated pest control are key assets to environmentally friendly management of cropland. Use of entomopathogens against target pests is common, yet the effects of such released organisms on native, non-target invertebrates are currently poorly known. This is particularly true for relatively inconspicuous components of agroecosystems such as soil biological biota. Popillia japonica, a polyphagous alien invasive scarab beetle native to Japan, is now present in Europe where huge efforts are being conducted to control the pest and slow its spread. In particular, entomopathogenic nematodes and fungi have been used for larval control. Here we test the effects of those agents on both P. japonica larvae and non-target soil biota by comparing soil arthropod assemblages before and after treatment of field plots in an irrigated perennial meadow.
Application of an indigenous strain of the nematode Heterorhabditis bacteriophora resulted in significant reduction in numbers of P. japonica larvae. In contrast, an indigenous strain of the entomopathogenic fungus Metarhizium robertsii failed to provide significant control. We found no evident effect on non-target edaphic arthropods under either treatment in comparison to untreated control plots. Some taxa, namely Collembola and Acarina, showed a disproportionate increase in treated plots, suggesting that some changes may occur in the long term, at least in particular arthropod groups. Our results suggest the selected strain of H. bacteriophora is an excellent candidate for managing P. japonica larvae with minimal adverse impact on non-target species and ecosystem functioning.
is a free-living, pseudoparasitic, necromenic, and parasitic nematode, depending on the host. This species feeds mainly on bacteria present in decaying organic matter, soil, and other substrates; ...however, in its parasitic form, it can colonize some species of snails. Moreover, the presence of
has also been detected in birds and mammals, including humans.
In 2021–2023, during monitoring of the palm borer
in Central Italy,
emerged from dead larvae of this alien invasive moth and was extracted from palm fibres of
in three independent sites. The nematode was identified by morphological and morphometric analyses. Molecular analyses using SSU and LSU gene fragments were used to confirm the identification and to perform Bayesian reconstruction of the phylogeny. Each sampling site showed a unique haplotype.
Concerning the pathogenicity of this nematode against insects, the test performed on
larvae did not show any entomopathogenic effect. This is the first time that
was found associated with
and this recurrent association was discussed.
Saffron is one of the most precious spices in the world. It is derived from the dried stigmas of the
L. flowers. This plant is triploid sterile and propagated by corms. As a subterranean organ, the ...corm can come into contact with different nematodes. In this contribution
was reported for the first time in Italy. It was found associated with
corms and characterized based on morphological and morphometrical characteristics for this species. The identification was confirmed using molecular analyses. Moreover, a review of nematodes associated with
worldwide is also provided.
The natural presence of entomopathogenic nematodes (EPNs) has been investigated in the Piedmont region (Northern Italy) in areas infested by the Japanese beetle Popillia japonica. Thirty-nine out of ...155 soil samples (25.2%) were positive for EPNs. Most of the samples contained only steinermatids (92.3%), 5.1% contained heterorhabditids, and one sample (2.6%) contained both genera. All the recovered isolates were identified at species level both morphologically and molecularly. Steinernema carpocapsae was the most abundant and it was mainly distributed in open habitats, such as perennial meadows, uncultivated soils, and cropland, characterized by sandy loam soil texture and acidic pH. Steinernema feltiae has been found associated mainly with closed habitats such as coniferous and deciduous woodland, characterized by sandy loam-texture and extremely acidic soil. The three isolates of Heterorhabditis bacteriophora were collected only in open habitats (perennial meadows and uncultivated fields) characterized by strongly acidic soils with sandy loam texture. The virulence of all EPN natural strains was evaluated by laboratory assays against P. japonica third-instar larvae collected during two different periods of the year (spring, autumn). The results showed that larval mortality was higher for pre-wintering larvae than post-wintering ones. The five more promising EPN isolates were tested in the semi-field assay in which H. bacteriophora natural strains have been shown to be more efficient in controlling P. japonica grubs. All of these results are finally discussed considering the use of these natural EPNs as biological control agents against P. japonica, within an eco-friendly perspective of management.
The olive fruit fly
is one of the most serious and economically damaging insects worldwide, affecting the quality and quantity of both olive oil and table olives. Laboratory bioassays were conducted ...for the first time to evaluate the susceptibility of
pupae to two entomopathogenic nematodes (EPN) species,
and
. The nematodes tested caused pupal mortality of 62.5% and 40.6%, respectively. The most noteworthy result was obtained with
which was able to infect 21.9% of the emerged adults. Since this tephritid fly spent several months in the soil as pupa, the use of EPNs could be a promising method to control this pest.
Soil invertebrates represent almost a quarter of the total diversity of living organisms and their activity affects the entire soil ecological process. The choice of adequate thinning systems may ...differently affect soil nematode and microarthropod biodiversity in artificial black pinewoods. In this work, the results of the impact of different thinnings on the structure of nematode and microarthropod communities was reported. In a short-term experiment, thinning from below and selective thinning were compared to unmanaged stands to provide indications at the regional scale in central Italy. Soil nematode and microarthropod biodiversity was explored by examining community structure, assessing biodiversity. The interaction between environmental variables (crown volume, Photosynthetically Active Radiation, soil texture, soil temperature, and moisture) with taxa abundance of nematodes and microarthropods were also reported. The results indicated that the effects of thinning practices were temporary and varied between years. Soil nematode community shifted during the first and third years of thinning managements only in the Pratomagno site, while soil microarthropod community shifted in both sites only in the second year. The total nematode abundance was minimally affected by thinning practices, while the nematode community composition showed a decrease of omnivores and predators in the first years. Soil indicators showed inconsistent results. In microarthropods, mites and collembola were the least affected by thinning in terms of abundance and species biodiversity, while eu-edaphic taxa of Chilopoda, Diplopoda, and Pauropoda were not influenced by thinning, hemi-edaphic and epi-edaphic taxa of Coleoptera, Diptera, Hymenoptera, Tysanoptera, and Hemiptera were negatively affected. Soil indicators such as Shannon-Weiner and Simpson indices and soil biological quality (QBS-ar) improved in thinning from below in both sites. Soil temperature and moisture were the main driving factors in affecting soil nematode and microarthropods communities. Thinning from below probably allowed a more rapid recovery than selective thinning.
Meloidogyne graminicola is one of the most harmful organisms in rice cultivation throughout the world. This pest was detected for the first time in mainland Europe (Northern Italy) in 2016 and was ...subsequently added to the EPPO Alert List. To date, few methods are available for the control of M. graminicola and new solutions are required. In 2019, field trials using rice plants as trap crops were performed in a Lombardy region rice field where five plots for three different management approaches were staked out: (i) Uncultivated; (ii) Treated: three separate cycles of rice production where plants were sown and destroyed each time at the second leaf stage; (iii) Control: rice was sown and left to grow until the end of the three cycles in treated plots. The results showed that in the treated plots, the nematode density and the root gall index were lower than for the other two management approaches. Moreover, the plant population density and rice plant growth were higher than the uncultivated and control plots. In conclusion, the use of the trap crop technique for the control of M. graminicola gave good results and thus it could be a new phytosanitary measure to control this pest in rice crop areas.
A new species of mermithid nematode,
Hexamermis popilliae
n. sp. (Nematoda: Mermithidae) is described from the Japanese beetle
Popillia japonica
Newman in Italy, an area of new introduction for this ...invasive pest. The combination of the following characters separates
H. popilliae
from other members of the genus
Hexamermis
Steiner, 1924: adult head obtuse; amphidial pouches slightly posterior to lateral head papillae in female but adjacent to lateral head papillae in males; amphidial openings large, well developed; amphidial pouches elliptical in females and oblong in males; cuticular vulvar cone well developed, vulvar lips greatly reduced or lacking, vagina curved at tip where meeting uteri, without reverse bend (not S-shaped), spicules slightly curved, with a slight bend in the basal portion, approximately equal to body width at cloaca. This is the first record of a species of
Hexamermis
parasitizing the Japanese beetle
Popillia japonica
. The only previous mention of mermithid nematodes from
P. japonica
was an undescribed species of
Psammomermis
in North America.
Hexamermis popilliae
will be evaluated as a potential biological control agent in an integrated control program of the Japanese beetle in Italy.
Biological invasions are a global threat to biodiversity. Since the spread of invasive alien plants may have many impacts, an integrated approach, assessing effects across various ecosystem ...components, is needed for a correct understanding of the invasion process and its consequences. The nitrogen-fixing tree Robinia pseudoacacia (black locust) is a major invasive species worldwide and is used in forestry production. While its effects on plant communities and soils are well known, there have been few studies on soil fauna and microbes.
We investigated the impacts of the tree on several ecosystem components, using a multi-trophic approach to combine evidence of soil chemical properties and soil microbial, nematode, microarthropod and plant communities. We sampled soil and vegetation in managed forests, comparing those dominated by black locust with native deciduous oak stands.
We found qualitative and quantitative changes in all components analysed, such as the well-known soil nitrification and acidification in stands invaded by black locust. Bacterial richness was the only component favoured by the invasion. On the contrary, abundance and richness of microarthropods, richness of nematodes, and richness and diversity of plant communities decreased significantly in invaded stands. The invasion process caused a compositional shift in all studied biotic communities and in relationships between the different ecosystem components.
We obtained clear insights into the effects of invasion of managed native forests by black locust. Our data confirms that the alien species transforms several ecosystem components, modifying the plant-soil community and affecting biodiversity at different levels. Correct management of this aggressive invader in temperate forests is urgently required.
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•We analysed the impacts of Robinia pseudoacacia invasion.•We analysed impacts on soil chemical properties, plant and soil biotic communities.•We found qualitative and quantitative changes in all components analysed.•We detected soil nitrification and acidification in stands invaded by black locust.•Changes (mostly biodiversity reduction) were observed in biotic communities.
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•The natural occurrence of entomopathogenic fungi (EPF) was investigated in Piedmont.•Eighty-three out of 155 soil samples were positive for EPF presence.•Most of the isolates (94%) ...belonged to the genus Metarhizium.•M. robertsii 17/T02 showed high efficacy against P. japonica larvae in the lab tests.
The natural occurrence of entomopathogenic fungi (EPF) was investigated along the Ticino River (Ticino River Natural Park, Novara Province, Piedmont, Italy), at the center of the area of the first settlement of the invasive alien pest Popillia japonica. Using Zimmermann’s “Galleria bait method”, EPF were successfully isolated from 83 out of 155 soil samples from different habitats (perennial, cultivated, or uncultivated meadows, woodlands, and riverbanks). Sequencing of the 5’ end of the Translation Elongation Factor 1 alfa (5’-TEF) region allowed the assignment of 94% of the isolates to Metarhizium spp., while 8% and 7% were assigned to Beauveria spp. and Paecilomyces spp., respectively. Four Metarhizium species were identified: Metarhizium robertsii was the most common one (61.5% of the isolates), followed by M. brunneum (24.4%), M. lepidiotae (9%), and M. guizhouense (5.1%). Microsatellite marker analysis of the Metarhizium isolates revealed the presence of 27 different genotypes, i.e., 10 genotypes among M. robertsii, 8 among M. brunneum, 5 among M. lepidiotae, and 4 among M. guizhouense. Metarhizium brunneum appeared to be associated with woodlands and more acid soils, while the other species showed no clear association with a particular habitat. Laboratory virulence tests against P. japonica 3rd instar larvae allowed the identification of one M. robertsii isolate that showed efficacy as high as 80.3%. The importance of this kind of study in the frame of eco-friendly microbiological control is discussed.
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