Evaluation of phenolic compounds in virgin olive oil by direct injection in high-performance liquid chromatography with fluorometric detection

Hydrophilic phenols are the most abundant natural antioxidants of virgin olive oil (VOO), in which tocopherols and carotenes are also present. The prevalent classes of hydrophilic phenols found in VOO are phenyl alcohols, phenolic acids, secoiridoids such as the dialdehydic form of decarboxymethyl elenolic acid linked to (3,4-dihydroxyphenyl)ethanol or (p-hydroxypheny1)ethanol (3,4-DHPEA-EDA or p-HPEA-EDA) and an isomer of the oleuropein aglycon (3,4-DHPEA-EA), lignans such as (+)-1-acetoxypinoresinol and (+)-pinoresinol, and flavonoids. A new method for the analysis of VOO hydrophilic phenols by direct injection in high-performance liquid chromatography (HPLC) with the use of a fluorescence detector (FLD) has been proposed and compared with the traditional liquid-liquid extraction technique followed by the HPLC analysis utilizing a diode array detector (DAD) and a FLD. Results show that the most important classes of phenolic compounds occurring in VOO can be evaluated using HPLC direct injection. The efficiency of the new method, as compared to the liquid-liquid extraction, was higher to quantify phenyl alcohols, lignans, and 3,4-DHPEA-EA and lower for the evaluation of 3,4-DHPEA-EDA and p-HPEA-EDA.     

Treatment of cereal products with a tailored preparation of trichoderma enzymes increases the amount of soluble dietary fiber

Nutritionists recommend increasing the intake of soluble dietary fiber (SDF), which is very low in most cereal-based products. Conversion of insoluble DF (IDF) into SDF can be achieved by chemical treatments, but this affects the sensorial properties of the products. In this study, the possibility of getting a substantial increase of SDF from cereal products using a tailored preparation of Trichoderma enzymes is reported. Enzymes were produced cultivating Trichoderma using durum wheat fiber (DWF) and barley spent grain (BSG) as unique carbon sources. Many Trichoderma strains were screened, and the hydrolysis conditions able to increase by enzymatic treatment the amount of SDF in DWF and BSG were determined. Results demonstrate in both products that it is possible to triple the amount of SDF without a marked decrease of total DF. The enzymatic treatment also causes the release of hydroxycinnamic acids, mainly ferulic acid, that are linked to the polysaccharides chains. This increases the free phenolic concentration, the water-soluble antioxidant activity, and, in turn, the phenol compounds bioavailability.     

Review of <Emphasis Type="Italic">Coenosia attenuata</Emphasis> Stein and its first record as a predator of important greenhouse pests in Turkey

Greenhouses in Turkey under integrated pest management can be colonized by a high number predatory flies of the species Coenosia attenuata Stein, 1903 (Muscidae: Coenosia Meigen, 1826). Studies have shown that Coenosia predators do not simply colonize greenhouses from the outside for short periods but instead they are able to complete their developmental cycle in the greenhouse soil and can become established there for a long period of time. C. attenuata is indigenous to the Palaeotropical region. Its prey spectrum includes whiteflies, black fungus gnats and leaf-mining flies. Studies of the natural occurrence of these predaceous flies in greenhouses led to a recognition of the significance of this complex of beneficials for the control of important greenhouse pests. They can build up effective populations under greenhouse conditions, and as non-specific predators can feed on a variety of pest groups and on innocuous species.     

Feeding potential of <Emphasis Type="Italic">Cryptolaemus montrouzieri</Emphasis> against the mealybug <Emphasis Type="Italic">Phenacoccus solenopsis</Emphasis>

Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is an exotic species native to the USA, damaging cotton and other plant families. The feeding potential of different development stages of Cryptolaemus montrouzieri Mulsant, a biological control agent against mealybugs, was investigated on different development stages of P. solenopsis. Fourth instar grubs and adults of C. montrouzieri were the most voracious feeders on different instars of mealybug. The number of 1^st instar nymphs of mealybug consumed by 1^st, 2^nd, 3^rd and 4^th instar larvae and adult beetles of C. montrouzieri was 15.56, 41.01, 125.38, 162.69 and 1613.81, respectively. The respective numbers of 2^nd and 3^rd instar nymphs of mealybug consumed were 11.15 and 1.80, 26.35 and 6.36, 73.66 and 13.32, 76.04 and 21.16, 787.95 and 114.66. The corresponding figures for adult female mealybugs were 0.94, 3.23, 8.47, 12.71 and 73.40, respectively. The results indicate that C. montrouzieri has the potential to be exploited as a biocontrol agent in North India; inoculative releases of 4^th instar larvae and adults may provide instant control of P. solenopsis. Field experiments should be conducted to determine the efficiency of the ladybird on this mealybug.     

Advanced lentil lines screened for resistance to <Emphasis Type="BoldItalic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="BoldItalic">lentis</Emphasis> under greenhouse and field conditions

Fusarium oxysporum f. sp. lentis is the most important pathogen of lentil plants, and most areas under lentil cultivation are reported to have a fusarium wilt disease background. The plants are infected in the seedling stage and later stages of their development. Fusarium wilt disease, which has appeared at high incidence rates during recent years, has caused sharp drops in the yield, especially in Moghan, in the northwest of Iran. Forty-five isolates of the pathogen were collected from different regions of the country with two isolates from ICARDA in the summer of 2008 and identified using Nelson’s key. The pathogenicity of the collected isolates was studied on a sensitive line (ILL 4605) under greenhouse conditions and significant differences in pathogenicity were found among them. The most pathogenic isolates from three provinces, East Azerbaijan (EA 30), Ardebil (Ar 3) and Khorasan (Kh 45), were selected and used in screening of 55 developed lines under greenhouse and field conditions. In the greenhouse, test plants were inoculated by immersing root tips in spore suspension and sowing seeds in pre-infested pot soil. Field tests were carried out in a naturally highly infested farm. At all stages, the plant response to the disease was based on the percentage of dead plants. Cluster analyses of the greenhouse and field data led to the selection of three lines (81S15, FLIP2007-42 L and FLIP2009-18 L) that were resistant under greenhouse and field conditions.     

<Emphasis Type="Italic">Cucurbit aphid-borne yellows virus</Emphasis> in Egypt

During 2010, yellowing symptoms were frequently observed in cultivated squash fields in Egypt. A total of 717 symptomatic squash leaf samples were collected from four regions where squash cultivation is of economic importance for the country: Kafrelsheikh, El-Behira, El-Sharkia and El-Ismailia. Serological analysis showed that 95.6% of the symptomatic squash samples were infected by Cucurbit aphid-borne yellows virus (CABYV), and visual estimation of the incidence of yellowing symptoms suggested a very high incidence of CABYV in the fields. Twelve CABYV isolates were characterized by sequencing two regions of the viral genome, open reading frame (ORF) 3 and ORFs 4/5. Overall, Egyptian isolates were very similar among them, and had higher similarity values with a French than with a Chinese isolate. The average nucleotide diversity for ORF 3 was significantly higher than for the other two regions, indicating that variability is not evenly distributed along the viral genome. The ratios between nucleotide diversity values in non-synonymous (d _N ) and synonymous (d _S) positions (d _N /d _S) for each ORF showed that the three ORFs are evolving under different pressures, although predominantly under purifying selection. Phylogenetic analyses revealed that these Egyptian isolates, with only one exception, shared the same clade with a French isolate. Moreover, these analyses suggested that Egyptian isolates belong to the Mediterranean group described previously.     

Existence of different physiological forms within genetically diverse strains of <Emphasis Type="Italic">Ampelomyces quisqualis</Emphasis>

Powdery mildew fungi are parasitized by strains of the genetically distinct Ampelomyces quisqualis. To investigate whether differences in the phylogeny and other cultural, morphological and physiological characteristics of these different strains are related to differences in their geographic origins or the host species from which they were isolated, several A. quisqualis strains isolated from different species of Erysiphaceae collected in different countries and possessing different ITS rDNA sequences were selected and characterized. The results revealed some significant variation among the selected strains, which provides evidence for the existence of different physiological forms within the A. quisqualis species. Two groups that display differential growth on artificial media were identified. These groups also differ in the morphology of their mycelium, but not in the morphology of their pycnidia and conidia. Temperature greatly affected the in vitro growth of the A. quisqualis strains and growth rate was closely correlated to colony color. Differences in the conidial germination of distinct strains were observed during the recognition phase of the parasitic relationship. The germination of each of the investigated strains was greatly stimulated by all of the examined powdery mildew species and not only by the conidia of their original hosts. An Italian strain isolated from grapevine in the Trentino Alto-Adige region was identified as the strain that germinates the most quickly in the presence of powdery mildew conidia. Phylogenetic analysis revealed that these A. quisqualis strains can be classified into five different genetic groups, which generally correlate with the fungal host of origin and morphological and growth characteristics.     

Susceptibility of cocooned pupae and adults of the parasitoid <Emphasis Type="Italic">Microplitis mediator</Emphasis> to selected insecticides

The braconid parasitoid Microplitis mediator (Haliday) is a key natural enemy of the cabbage moth, Mamestra brassicae (L.), in Europe. In the context of an Integrated Pest Management approach, the use of selective insecticides is essential for the conservation of naturally occurring beneficial arthropods. The present laboratory study investigated the side effects of six insecticides applied at recommended field rates on adults and cocooned pupae of M. mediator. Male and female parasitoids were paired in drum cells contaminated with dry residues of insecticides. Besides lethal effects after 24 h, parasitization capacity and longevity of the surviving parasitoids was evaluated. Lethal effects on cocooned pupae were also investigated by assessing adult emergence from treated cocoons. Pirimicarb caused 100% adult mortality after 24 h, whereas the other tested insecticides caused no direct toxic effects. However, sub-lethal effects in terms of reduced parasitization activity, percentage of parasitism or female longevity were found for flonicamid, pymetrozine, spinosad and thiacloprid. Spirotetramat shortened only male longevity. Adult emergence from treated cocoons was reduced only by flonicamid and pymetrozine.     

Black nightshade (<Emphasis Type="Italic">Solanum nigrum</Emphasis>) emergence and development is affected by seed density and burial depth

Black nightshade (Solanum nigrum L.) is a troublesome weed worldwide, affecting a large number of crops. As weed development is affected by a variety of factors, advanced knowledge on the plant’s biological and ecological qualities can support favorable management strategies. Seed density is an ecological factor affecting emergence and early growth of many weed species. For that reason, the current study characterizes and quantifies the seed density impact on black nightshade seedling-emergence and early growth, and the interaction between seed density and burial depth on these growth parameters. Greenhouse studies conducted in 2005, 2006 and 2010 examined black nightshade seed densities of 1, 5, 10, 25 and 50 seeds per pot, buried at, 1, 2, 3, 4 and 5 cm. Impact of seed density on weed emergence and growth was characterized by number of emerged plants and leaves, followed by biomass measurements. Seed density had no impact on emergence at the tested burial depths. There was a strong logistic relationship (P < 0.001, and R ²  > 0.97) between time and emergence, and a strong linear relationship (P < 0.002 and R ²  > 0.86) between time and number of leaves produced in all depths and seed densities. A negative relationship was observed between seed density and plant development and growth rate. Results of this study extend the knowledge on black nightshade biology and support decision-making concerning rational weed management.     

Identification of <Emphasis Type="Italic">Pythium tracheiphilum</Emphasis> as the causal agent of vascular necrosis of endive (<Emphasis Type="Italic">Cichorium endivia</Emphasis>) in Spain

Pythium isolates were recovered from endive plants (Cichorium endivia) showing vascular necrosis collected from commercial fields located in Castellón province (eastern Spain). They were identified as Pythium tracheiphilum on the basis of their phenotypical and molecular profile. Pathogenicity tests conducted with two P. tracheiphilum isolates, obtained from endive and lettuce (Lactuca sativa), respectively, in this region, confirmed that both isolates were pathogenic to endive, with no significant differences in virulence between them. This is the first report of vascular necrosis caused by P. tracheiphilum on endive in Spain.