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A drastic reduction in the use of chemicals and pesticides in agriculture requires new sustainable biocontrol strategies to restrain pathogen multiplication and virulence in plants. VIROPLANT is a EU-funded research project whose primary objective is to propose viruses as potential biocontrol agents of some specific plant diseases spread in Europe. As a first step, RNAseq was applied to characterize the virosphere of Scaphoideus titanus, vector of Flavescence dorée phytoplasma, Frankliniella occidentalis and Thrips tabaci, vectors of Tomato spotted wilt virus and Onion yellow spot virus, respectively. Populations of S. titanus were collected from Italy, France, Switzerland, Hungary, and the USA. All European samples presented the same unclassified dsRNA virus and a previously uncharacterized densovirus. A new iflavirus was occasionally found in some Italian and French insects. The USA samples were richer in viral biodiversity, as members of the families Bunyaviridae, Nodaviridae, Partitiviridae, Reoviridae and Permutotetraviridae were identified. Samples of F. occidentalis and T. tabaci were collected from seven Italian regions and from two laboratory populations from the USA. Overall, full-length genomes of more than 40 new viral species were assembled. Among them, a densovirus and a mesonivirus were highly prevalent in F. occidentalis, while a virga-like and a dimarhabdovirus were present in all the T. tabaci samples. Some of the identified viruses will be selected to measure their effects on insect fitness parameters and transmission efficiency. The most promising one for each pathosystem will be used to promote virus-induced gene silencing and interfere with gene expression of the host.

The present study aimed at surveying weed species in the banana tree (Musa sp.) intercropping with assai (Euterpe precatoria). The experiment was performed using a randomized complete block design with six treatments (monocultures and intercropping) and four replications. The weed species were identified and quantified, enabling the calculation of phytosociological parameters. The soil cover and the dry mass of the weeds were evaluated. In general, Mollugo verticillata is one of the main species found in the essay. The E. precatoria palm monoculture showed a greater diversity of weed species and individuals and dry mass of the aerial part. Areas with banana monoculture or under a banana intercropping with E. precatoria palm in different planting arrangements displayed the same amount of dry matter of the aerial part and similar soil cover levels. O presente estudo objetivou levantar espécies de plantas daninhas na bananeira (Musa sp.) consorciada com açaizeiro (Euterpe precatoria). O experimento foi conduzido em delineamento em blocos ao acaso, com seis tratamentos (monocultivos e consórcios) e quatro repetições. As espécies de plantas daninhas foram identificadas e quantificadas, possibilitando o cálculo de parâmetros fitossociológicos. A cobertura do solo e a massa seca das plantas daninhas foram avaliadas. Em geral, Mollugo verticillata foi uma das principais espécies encontradas no ensaio. A monocultura de E. precatoria apresentou maior diversidade de espécies de plantas daninhas e indivíduos, assim como maior massa seca da parte aérea. Áreas com monocultivo de bananeira ou consorciada com E. precatoria em diferentes arranjos de plantio apresentaram a mesma quantidade de matéria seca da parte aérea de plantas daninhas e níveis de cobertura do solo semelhantes. Made available in DSpace on 2019-12-03T00:37:07Z (GMT). No. of bitstreams: 1 26913.pdf: 447681 bytes, checksum: e54f924ac278e875e00af92f769c988b (MD5) Previous issue date: 2019

O conhecimento prévio de plantas daninhas que ocorrem em áreas de produção é importante para entrar com medida de controle adequada e eficiente. Assim, o objetivo deste trabalho foi realizar levantamento fitossociológico de plantas daninhas em áreas de cultivo de banana em diferentes espaçamentos de plantio nas condições climáticas do estado do Acre. O levantamento foi feito em três espaçamentos de plantio, os quais foram denominados áreas de cultivo, com 720 m2 cada, sendo assim disposto: área 1 - espaçamento de 3 x 3 m (1.111 plantas ha-1 ); área 2 - espaçamento de 3 x 2 m (1.666 plantas ha-1 ), e; área 3 - espaçamento de 4 x 2 x 2 m (1.666 plantas ha-1). Em cada área de cultivo, um quadrado de 0,5 x 0,5 m foi lançado 12 vezes ao acaso, onde se fez a identificação e quantificação das plantas daninhas, permitindo calcular os parâmetros fitossociológicos. A massa seca da parte área das plantas daninhas também foi avaliada, a qual foi estimada em kg ha-1. O espaçamento menos adensado (área 1) apresentou maior quantidade de massa seca em relação às demais e o maior número de espécies. As espécies importantes variaram conforme os espaçamentos de plantio avaliados, sendo que as principais foram: Paspalum maritimum, Paspalum paniculatum e Mollugo verticillata para área 1; Mollugo verticillata para a área 2; e Digitaria sanguinalis para a área 3. O índice de similaridade foi alto entre todas as áreas de cultivo, com semelhança acima de 70%. Previous knowledge of weeds occurring in production areas is important to enter with adequate and efficient control measures. Thus, the objective of this work was to carry out a phytosociological survey of weeds in banana cultivation areas at different planting spacings in the climatic conditions of the state of Acre. The survey was done in three planting spacings, which were denominated cultivation areas, with 720 m2 each, being arranged as follows: area 1 - spacing of 3 x 3 m (1.111 plants ha-1); area 2 - 3 x 2 m spacing (1.666 plants ha-1), and; area 3 - spacing of 4 x 2 x 2 m (1.666 plants ha-1). In each cultivation area, a square of 0,5 x 0,5 m was launched 12 times at random, where weed identification and quantification was performed, allowing the calculation of phytosociological parameters. The dry mass of the weed area was also evaluated, which was estimated in kg ha-1 . The less densified spacing (area 1) presented a greater amount of dry mass in relation to the others and the greater number of species. The major species were: Paspalum maritimum, Paspalum paniculatum and Mollugo verticillata for area 1; Mollugo verticillata to area 2; and Digitaria sanguinalis for area 3. The similarity index was high among all cultivated areas, with similarity above 70%. Made available in DSpace on 2018-05-15T00:39:14Z (GMT). No. of bitstreams: 1 26616.pdf: 623786 bytes, checksum: 2e7fa71f7a056f942d9ef452b8e0ed53 (MD5) Previous issue date: 2018-05-14

One of the negative consequences of globalization is the increased introduction of exotic pests into new areas. Italy, in particular, is at high risk of introduction, because of its geographical position and climate, which allows the settlement of (even subtropical) exotic species. In this context, native natural enemies may play a major role in the biological control of exotic species. The mechanisms involved in adaptation processes, which are crucial in studies of biological invasions, are only partially known. A joint effort by researchers operating in Italy and abroad is needed to deeply investigate this phenomenon and to develop appropriate strategies for sustainable control of exotic species. The present work illustrates the objectives and preliminary results of the project “Insects and globalization: sustainable control of exotic species in agro-forestry ecosystems (GEISCA)” focused on control of exotic species by native entomophagous insects. The overall goal of the project is to gain, at the end of three years, useful knowledge on the development of appropriate procedures for sustainable control of target pest species.

Made available in DSpace on 2022-04-29T07:35:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 Groundnut ringspot virus (GRSV) is a tospovirus species transmitted in a circulative propagative manner by several thrips species. Traditionally, GRSV is detected by enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR), so this paper describes a rapid diagnostic system for the reliable detection of GRSV in plants and individual thrips by real-time RT-PCR. Watermelon GRSV infected leaves and fruits, and individual thrips (Frankliniella schultzei) collected from flowers on infected watermelons were used in the test. We designed a GRSV TaqMan assay to efficiently detect GRSV in all samples. The method had high specificity and could distinguish GRSV from the other tospovirus species, like Tomato spotted wilt virus (TSWV), Tomato chlorotic spot virus (TCSV) and Zucchini lethal chlorosis virus (ZLCV). The test will help us to collect epidemiological data for GRSV in plants and thrips worldwide. Department of Plant Protection Faculdade de Ciências Agronômicas Universidade Estadual de São Paulo, Rua Dr. José Barbosa de Barros 1780 Dipartimento di Scienze Agrarie Forestali e Alimentari ULF Entomologia Generale e Applicata University of Turin, Largo Paolo Braccini 2 Istituto per la Protezione Sostenibile delle Piante C.N.R, Strada delle Cacce 73 Department of Plant Protection Faculdade de Ciências Agronômicas Universidade Estadual de São Paulo, Rua Dr. José Barbosa de Barros 1780

Sunn pest (or cereal bug) (Heteroptera: Pentatomidae and Scutelleridae) infestations of wheat, Triticum aestivum L., in the grain filling stage have the potential to adversely affect the quality of harvested grain for bread making. In the absence of resistant wheat cultivars, producers must rely on chemical control to protect their crop from sunn pest infestations. To implement an efficient environment friendly control strategy, there is a need to pinpoint the relationships between the timing of the bug attack and gluten degradation. Recent outbreaks of Eurygaster maura (L.) in northwestern Italy have increased the local concern toward this problem. A 3-yr study was carried out by caging plants of two bread wheat cultivars, characterized by different seed texture and bread-making quality, and introducing adults of E. maura in four periods corresponding to different grain filling stages: heading, early milk-ripe, milk-ripe, and late milk-ripe. The degree of bread-making quality depletion was assessed by analytical and biochemical methods and related to the attack period. Using analysis of variance, significant differences were found in the quality traits of kernels attacked by E. maura in different grain filling stages, the maximum damage occurring with bug feeding at the late milk-ripe stage. Biochemical investigations on gluten confirmed analytical results; in grain samples infested at the late milk-ripe stage, SDS gel electrophoresis revealed the degradation of some components of the high-molecular-weight glutenins, and high-performance liquid chromatography analyses showed a breakdown of the first peak of the insoluble fraction, mainly containing polymeric proteins highly related to dough strength.

Tomato spotted wilt virus (TSWV) (Tospovirus, Bunyaviridae) is one of the most agronomically important viruses worldwide. The virus is transmitted between plants by insects in the genera Thrips and Frankliniella (Thysanoptera, Thripidae), in a propagative mode. Lack of reverse genetic systems hampers the functional analysis of TSWV genome, but thanks to the selective pressure of the Tsw resistance gene in pepper, we obtained a number of TSWV isolates, carrying a deletion in the NSs coding region. Such deletions caused a recovery phenotype on Capsicum spp. and Datura stramonium, linked to lack of suppression of silencing activity for the resulting truncated NSs, but in N. benthamiana some of the NSs recovery isolates accumulated to wild type level. We show that Frankliniella occidentalis, its most efficient vector, fails to transmit TSWV coding for truncated NSs protein. Quantitative RT-PCR and immuno-staining of individual insects detected the mutant virus in 2nd-instar larvae and adults, demonstrating that insects can acquire and accumulate NSs-defective mutants. Nevertheless adults carried a significantly lower viral load, showing for the first time a specific role of NSs in maintaining a high titer of virus in adult thrips. Sequence analyses of reassortant isolates revealed a strict association of lack of transmission to the mutation in the NSs-coding sequence.

In this study we analysed the ability of individual thrips to transmit Tomato spotted wilt virus (TSWV) in a population of Frankliniella occidentalis over their lifespan as adults (about 10 days). In three experiments a total of 636 thrips were individually tested for their transmission capacity through leaf disc assays using four inoculation access periods (IAPs). Almost half of the transmitting thrips maintained the capacity to infect leaf discs in each of the four IAPs, confirming the persistent propagative nature of the transmission modality. Nevertheless, a relevant number of thrips (9.25% of transmitter thrips) was able to transmit in the early phases of their adult life (for the first two IAPs), but did not transmit the virus for the remainder of their lifetime. We compared the virus titer of these individuals at the end of the fourth IAP with that of individuals that maintained transmission ability in the four IAPs and showed a statistically significant difference. This difference could be evidence for recovery from TSWV infection in individual thrips.

In 2004, infections of Blueberry scorch virus (BlScV) were detected for the fi rst time outside North America on Vaccinium corymbosum (Ericaceae) in Piedmont (NW Italy). Since 2009, however, virus was found also in Trentino on V. corymbosum and on a new host species: V. ashei. Overall, four infected fi elds in Piedmont and three in Trentino were identifi ed. Molecular analysis on the two strains, from Piedmont and from Trentino, showed two distinct epidemics are now present in Italy: the Piedmont isolates belong to a BlScV strain similar to isolates from the East Coast of Canada and the US, whereas the Trentino isolates are very similar to an American strain from Washington State on the West Coast of the US. In its area of origin, the virus is transmitted by Ericaphis scammelli (Hemiptera: Aphididae) in a non-persistent fashion. In 2005-2010, fi eld surveys were carried out to monitor aphid populations in seriously infected highbush blueberry crops in Piedmont. Moreover, experiments were set up to evaluate aphid transmission ability in laboratory and fi eld trials. E. scammelli was the predominant aphid species in the investigated highbush blueberry crops with population levels varying in relation to the locality and the year. However, in transmission trials, E. scammelli proved not to be a very effi cient vector of BlScV.