The genetic diversity of Bemisia tabaci was investigated in Southern Italy using the mitochondrial cytochrome oxidase I (COI) gene as molecular marker and sampling whiteflies on cultivated plants, weeds and bushes. Phylogenetic analysis of COI sequences and restriction analysis of COI amplicons were used to genotype whitefly populations. A PCR-RFLP method based on digestion with the endonuclease ApoI was set up to identify the B. tabaci genetic variants so far recorded from the Mediterranean region. In general, biotype Q populations were most frequently collected (76.0% of all sampled populations). In greenhouse districts, 87.0% sampled populations were identified as biotype Q, and 13.0% were assigned to biotype B. Outside the greenhouse districts, the biotype B was never collected, whilst biotype Q populations were found on weeds and on plants cultivated in family gardens in different environments, also located in interior plains or in mountain areas distant from intensive cultivations of whitefly host plants. A new genetic variant unrelated to B and Q biotypes, which was named Ru, was collected on Rubus ulmifolius and grapevine. Phylogenetic analysis of COI sequences shown that Ru haplotypes form a wellsupported clade sister to the clade including the Asian/ Australian major genetic groups and the Italy major genetic group. The closest relative of the Ru clade (10.7% pairwise genetic distance) was the Italy group, with this latter so far including only the haplotypes of the T biotype. These results were discussed in the light of the recent B. tabaci species concept.

Q2 invasion seems to have been favoured by the agroecological conditions of southern Italy and by the female-biased sex ratio. Endosymbionts may have a role in Q2 invasiveness, acting as sex-ratio manipulators (e.g. Rickettsia) and possibly by benefiting the host fitness.

The nucleotide sequence of the putative coat protein open reading frame of seven previously uncharacterized AMV strains from Italy and France was determined and aligned with comparable sequences of other AMV strains (425 L, 425 M, YSMV, S, VRU, 15/64 and Da). The data set of AMV sequences was used to determine phylogenetic relationships by both a stochastic (stationary Markov model) and a deterministic method (maximum-parsimony) of analysis. The topology of the trees obtained with the two methods was essentially the same showing that all AMV strains clustered in two monophyletic groups. Close clustering of Italian strains in subgroup I and of French strains in subgroup II seems to suggests the effect of geographic distinctiveness of evolutionary dynamics of these AMV strains. This separation did not correlate with differences in host range or symptoms (necrotic or non necrotic) induced in tomato but rather it reflected variations in the amino acid sequence of their CP, which might be related to structural properties of virus particles. A simple and rapid procedure based on the reverse transcriptase-polymerase chain reaction (RT-PCR) followed by ezymatic digestion (RFLP) was developed to identify and classify AMV isolates into the two subgroups. The method applied to a number of other AMV isolates from Italy and France supported their division in two distinct subgroups. This RT-PCR RFLP method may be useful way to investigate the dynamics of AMV populations in nature.

Resistance against both Potato virus Y (PVY) and Tobacco etch virus (TEV) was identified in the wild tomato relative Lycopersicon hirsutum PI247087. Analysis of the segregation ratio in F(2)/F(3) and BC(1) interspecific progenies indicated that a single recessive gene, or two very tightly linked recessive loci, are involved in resistance to both potyviruses. This locus was named pot-1. Using amplified fragment length polymorphism markers and a set of L. hirsutum introgression lines, pot-1 was mapped to the short arm of tomato chromosome 3, in the vicinity of the recessive py-1 locus for resistance to corky root rot. Because of the occurrence of phenotypically similar genes in pepper ( Capsicum spp.), the comparative genetics of resistance to potyviruses between tomato and pepper was investigated. Unlike most of the comparative genetic studies on resistance genes, pot-1 was tightly flanked by the same restriction fragment length polymorphism (RFLP) markers than the pvr2/pvr5 locus for resistance to PVY and TEV from pepper. These results may indicate that recessive resistance genes against potyviruses evolve less rapidly than the majority of the dominant genes cloned so far, and consequently may belong to a different family of resistance genes.

Tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus (family Geminiviridae) identified for the first time in 1995 in Asia, from where it spread into several countries of the Mediterranean basin. ToLCNDV was found in Spain in 2012, and subsequently in Tunisia and Italy. The first outbreak in Italy occurred at the end of 2015 in Trapani province (Sicily) on zucchini squashes. Then in 2016, ToLCNDV was found in infected zucchini plants in Campania, Lazio and Sardinia regions, and in 2017 in Calabria. This study addressed the dispersion and genetic diversity of ToLCNDV isolates in Italy. A total of 1400 plants were analysed. Phylogenetic analysis showed low variability among the Italian isolates, probably as a consequence of the recent introduction and rapid spread of this virus in Italy. Two statistically significant clusters were reported: one grouping only Italian isolates and the other grouping Italian, Spanish, Tunisian and Moroccan isolates. Furthermore, the highest incidence of ToLCNDV was observed in Sicily, although the disease also appears to be critical in other Italian regions. In this work, a high efficiency of ToLCNDV mechanical transmission into Cucurbita pepo, Cucumis melo inodorus and Cucumis melo cantalupensis has been demonstrated. The rapid spread of ToLCNDV in the Mediterranean basin represents a threat for horticultural production, thus it is very important to develop suitable crop management practices, applying genetic resistance strategies and more restrictive phytosanitary measures.

Perennial wall-rocket (Diplotaxis tenuifolia (L.) D.C.) is a herbaceous plant belonging to the Brassicaceae with a cosmopolitan distribution. Traditionally harvested as a spontaneous herb, today it is a crop species of increasing importance after the diffusion of the ready-to-use salads in the vegetable retail markets. Besides relevance as a food crop, its consumption is prompted by consideration in the traditional medicine of several peoples in the native areas of the Mediterranean and western Asia based on recognized health beneficial effects. In fact, the leaves have notable nutritional properties related to their contents of glucosinolates and some antioxidant compounds, such as vitamin C and flavonoids, which entitle their dietary inclusion for the prevention of cancer and cardiovascular diseases. This paper provides an overview on aspects concerning the biology, crop management, nutritional properties, industrial processing and uses of perennial wall-rocket.

Cyantraniliprole is a novel insecticide for control of multiple chewing and sucking insect pest species including the sweetpotato whitefly Bemisia tabaci (Gennadius), which is one of the most important polyphagous pests in tropical, subtropical, and Mediterranean regions. This study aims to evaluate the effects of cyantraniliprole on the probing behavior of B. tabaci on tomato. Electrical penetration graph data indicated that on plants treated with cyantraniliprole (foliar application), adult whiteflies of the genetic variant Q2 were not able to reach the phloem and consequently did not perform the activities represented by E1 and E2 waveforms, i.e., phloem salivation (during which inoculation of geminiviruses occurs) and phloem sap ingestion (during which geminiviruses are acquired by the whiteflies), respectively. The complete failure of B. tabaci biotype Q adults to feed from the phloem of tomato plants treated with cyantraniliprole could be explained by rapid cessation of ingestion because of the mode of action of this insecticide. Overall, these findings indicated that cyantraniliprole might represent a useful new tool for producers to protect tomato plants from damage by B. tabaci.

Tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus affecting tomato cultivation on the Indian subcontinent. Recently, however, a new strain of the virus, named ToLCNDV-ES, has spread to Mediterranean countries such as Spain, Italy, and Tunisia, and occurred in Cucurbita crops, causing economic damage. Although ToLCNDV is spread by the sweet potato whitefly (Bemisia tabaci), like other begomoviruses, it has not been clear how ToLCNDV suddenly spread from the Indian subcontinent to the Mediterranean region. In 2017, ToLCNDV was diagnosed in young seedlings germinated naturally from fruits fallen in the prior year on a farm located in Giugliano in Campania, Naples, Italy, suggesting a possible role of the seeds in vertical transmission of the virus. Because sweet potato whiteflies were widespread naturally in that region, it was necessary to verify that in an artificial insect vector-free condition. Seeds were harvested from two ToLCNDV-infected zucchini squash cultivars in Naples in 2017 and 2018 to examine whether ToLCNDV can be transmitted from zucchini squash seeds to young plants. Viral DNA was amplified from these seeds and 1- to 3-week-old seedlings germinated from them with a ToLCNDV-specific primer set. According to PCR results, viral contamination was confirmed from all harvested seeds and dissemination was proven from 61.36% of tested seedling samples. Mechanical transmission from seed-borne virus-infected seedlings to healthy zucchini squash plants was also succesful, demonstrating that seedlings from ToLCNDV-infected seeds did act as inoculum. This is the first report demonstrating that ToLCNDV is a seed-transmissible virus in zucchini squash plants in Italy.