In field control of Botrytis cinerea by synergistic action of a fungicide and organic sanitizer

A new Integrated Pest Management program based on the combination of synthetic pesticide with a GRAS(generally recognized as safe)-classified sanitizer for the control of Botrytis cinerea in field conditions was described. The aim behind this research was to determine whether the use of this mixture would enhance the efficiency of pesticides while decreasing the recommended dose. Naturally infected tomato plants, grown in the greenhouse, were treated with two commonly used fungicides SWITCH(Syngenta, Switzerland) and SIGNUM(BASF, Germany) each alone or combined with a commercially available organic sanitizer PERACLEAN?5(Evonik Industries, Germany). A total of 27 treatments were tested consisting of three concentrations of synthetic fungicide(×1, ×1/2 and ×1/4 of the recommended dose) either applied separately or combined with three concentrations of the tested sanitizer(0.5, 1 and 1.5%). The control efficacy achieved by the fungicides applied alone ranged between 0 and 66.7% while all fungicide-sanitizer mixtures resulted in up to 70% control of grey mould. The treatment that provides the maximum control of B. cinerea was the result mixture of ×1/4 of the recommended concentration of SWITCH(15 g L~(–1)) with 0.5% of PERACLEAN~?5. This combination suppressed 85% of grey mold infections while decreasing the usually used amount of this pesticide by 75%, reducing therefore the well known negative impacts of chemical pesticides on environment and consumers health.     

Comparative biocatalytic degradation of Kraft prehydrolysate phenolic fermentation inhibitors using bacteria-derived laccase

Wood Science and Technology - Kraft prehydrolysate contains fermentable sugars and other organic compounds such as furans, phenolic compounds and acids, which are toxic to the fermentation...     

Identification of resistance to <Emphasis Type="Italic">Bemisia tabaci</Emphasis> Genn. in closely related wild relatives of cultivated tomato based on trichome type analysis and choice and no-choice assays

The sweetpotato whitefly, Bemisia tabaci Genn., is a major pest of tomato (Solanum lycopersicum) and other crops throughout the tropics and subtropics. The objectives of this study were to characterize 255 accessions of S. galapagense, S. cheesmaniae and S. pimpinellifolium for trichome types, and to evaluate selected accessions with high densities of glandular trichomes for resistance to whitefly. Twenty-two accessions classified as either sparse or abundant for type IV trichomes were selected and evaluated for numbers of adults, eggs, nymphs, and puparium of whitefly in choice bioassays, for adult mortality and egg numbers in no-choice bioassays, and for densities of type I, IV, V, and VI trichomes. The highest whitefly resistance was detected in S. galapagense accessions VI063177 and VI037239 based on choice and no-choice bioassays. In addition, we found high levels of whitefly resistance in S. cheesmaniae accession VI037240 based on the choice bioassay and in S. pimpinellifolium accession VI030462 based on the no-choice bioassay. Whitefly resistance in VI037240 and VI030462 is noteworthy because these species are closely related to cultivated tomato and introgression of whitefly resistance should be relatively straightforward. High densities of type IV trichomes and low densities of type V trichomes were associated with reduced numbers of whitefly adults, nymphs, puparium, and eggs in the choice bioassay and with high adult whitefly mortality in the no-choice bioassay. Preliminary trichome analysis followed by choice and no-choice assays facilitated rapid identification of whitefly-resistant accessions from a large pool of candidates of different species.     

Characterization and photodegradation mechanism of three Algerian wood species

Aging is the irreversible change of mechanical, physical, and chemical properties of materials; the main objective of this work was to study the photochemical degradation and structural changes of three major Algerian wood species. For this, we evaluated the photodegradation mechanism for Maritime Pine (Pinus pinaster), zeen oak (Quercus canariensis), and afares oak (Quercus afares) by accelerated aging in a Xenon test chamber. Degradation of the samples was established by an initial color change (after 30 h exposure), followed by roughening and cracking (120 h exposure) as translated by scanning electron microscopy and Fourier transform infrared spectroscopy. The discoloration of irradiated wood samples was primarily related to the decomposition of lignin which is the key structure in wood photodegradation. As expected, a decrease in mechanical properties was observed; for all samples, the modulus of elasticity decreased after aging, indicating that the wood specimens loss some of their stiffness.     

Improving productivity and nutrients uptake of wheat plants using Moringa oleifera leaf extract in sandy soil

A field experiment was conducted on a sandy soil at Salhia El-Gdida, Al Sharqia government, Egypt, to study the effect of Moringa leaf extract on yield and nutrient uptake of wheat plants (Triticum aestivum cv.). Foliar spraying of Moringa leaf extract was done at 40, 70, and 90 days after planting at a rate of 0%, 1%, 2%, 3%, and 4%. Treatments of Moringa extract significantly increased straw and grain yield, biological yield, 1000 grain weight, yield efficiency, protein content, and nutrient uptake as compared to untreated plants in the both seasons. The highest values of straw and grain yield, quality yield, and nutrient uptake by plants were obtained with 4% of Moringa extract, while the lowest values were obtained with untreated plants. Also, the highest percentage increase in grain yield of 71% and 88% was recorded from the treatment 4% of Moringa extract in first and second seasons, respectively.     

Interactive effect of salinity and silver nanoparticles on photosynthetic and biochemical parameters of wheat

The present study investigated the influence of seed priming with silver nanoparticles (Ag NPs), 0, 2, 5 and 10 mM, on growth and biochemical parameters of wheat (Triticum aestivum L.) under salt stress. As expected, 150 mM of NaCl decreased the shoot fresh and dry weights and chlorophyll contents and increased the catalase (CAT) and peroxidase (POD) activities. Salinity enhanced the concentration of proline, soluble sugars, malondialdehyde and hydrogen peroxide. Seed priming with Ag NPs increased the shoot fresh and dry weight of normal and salt-stressed plants. Lower concentration of Ag NPs decreased the total soluble sugars and proline contents, while the higher Ag NPs levels increased these contents compared to the control. The combined application of Ag NPs and salt stress increased the soluble sugars and proline contents, while it decreased CAT activity and increased POD activity compared to the respective Ag NPs treatments alone. Overall, our results demonstrated that Ag NPs enhanced the salt tolerance in wheat, but the long-term response of Ag NPs under salt stress needs further investigation.     

Molecular and experimental evidence of multi-resistance of <Emphasis Type="Italic">Cercospora beticola</Emphasis> field populations to MBC,DMI and QoI fungicides

Binucleate Rhizoctonia (BNR) spp. isolates were collected from taro (Colocasia esculenta (L.) Schott) and ginger (Zingiber officinale (Willd.) Roscoe) (Yunnanxiaojiang cv.) in Yunnan province. These Yunnan (YN) isolates did not anastomose with any of the tester isolates of the known AGs of binucleate Rhizoctonia spp. The growth of YN cultures on PDA was appressed, mealy and matlike after 4 days of incubation, then turned white brown, producing brown to dark brown, irregularly shaped sclerotia were embedded in the PDA medium after 14 days. All attempts to induce basidiospore production were unsuccessful, but the length and sequence of the internal transcribed spacer (ITS1 + 5.8S rDNA + ITS2) regions of 5.8S rDNA from the YN isolates were identical in length and sequence to isolates of all the other AGs of binucleate Rhizoctonia /Ceratobasidium spp. The sequences of 5.8S rDNA-ITS from the YN isolates were unique among AGs of BNR. The YN isolates had sequence similarities of 94% with isolates of AG Fb and P, 93% with AG E, 91% with AG R, 79–94% with AG S, and 74–87% with AG A, Ba, Bb, Bo, C, DI, DII, DIII, Fa, G, H, I, K, L, O, and Q. Four isolates of AG YN caused minor virulence (lesions ≦1mm²⁾ to ginger or taro in growth chamber studies. It was concluded that the YN isolates belong to a new anastomosis group AG-V of the Ceratobasidium spp..     

Phytosynthesis of Silver Nanoparticles using Leaf Extracts from <Emphasis Type="Italic">Ocimum basilicum</Emphasis> and <Emphasis Type="Italic">Mangifira indica </Emphasis>and their Effect on some Biochemical Attributes of <Emphasis Type="Italic">Triticum aestivum</Emphasis>

In this investigation, leaf extracts of Ocimum basilicum and Mangifira indica were used as reducing agents for biosynthesis of silver nanoparticles (AgNPs). The biosynthesized AgNPs were authorized by UV-vis spectrophotometry and X?ray diffraction (XRD) analysis. AgNPs were obtained after 5?min of reaction at 80^oC. The formation of AgNPs was confirmed by the presence of absorption peaks at 439?nm using extract from O. basilicum and at 442.5?nm from M. indica. X?ray spectra showed strong peaks for the crystalline Ag. Shape and size of the biosynthesized AgNPs were studied using high resolution transmission electron microscope (HR-TEM). Size of the produced AgNPs was found to be 9–35?nm. Effect of the synthesized nanosilver was then investigated on some biochemical attributes of wheat plant (Triticum aestivum cultivar saka 92). The growth parameters such as shoot lengths, fresh and dry weight of shoot, chlorophyll, carbohydrate and protein contents in shoot of wheat plant were investigated. Application of AgNPs synthesized from Ocimum basilicum and from Mangifira indica at the concentrations of 20,40?ppm showed an increase in shoot length, fresh and dry weight of shoot, chlorophyll, total carbohydrate and protein content in shoot of wheat plants, beyond these concentrations an inhibitory effects were shown.     

Characterization of a unique copper resistance gene cluster in <Emphasis Type="Italic">Xanthomonas campestris</Emphasis> pv. <Emphasis Type="Italic">campestris</Emphasis> isolated in Trinidad,West Indies

Whole genome sequencing of a copper resistant (Cu^R) black rot strain of Xanthomonas campestris pv. campestris (Xcc) isolated from a broccoli plant in Trinidad revealed a unique operon for copper resistance. The cop genes of strain Xcc-BrA1 were determined to be present on a 160 to 180 kb plasmid shown to be non-conjugative with other xanthomonads. While nucleotide comparison of a putative 8.0 Kbp copLABMGF gene cluster identified in Xcc-BrA1 genome did not reveal any homologous region with other known Cu^R Xanthomonas strains from diverse origins, the comparison of the translated amino acid sequence indicated similarity with X. citri, X. c. pv. citrumelonis and X. vesicatoria Cop proteins. Cloning of the copLAB gene cluster from Xcc-BrA1 conferred copper resistance to other copper-sensitive xanthomonads. Although Xcc-BrA1 harbors copLAB genes with similar sizes and organization and is able to grow on Cu-amended medium as other Cu^R xanthomonads, the phylogenetic analysis of nucleotide sequences indicates that the cop cluster in Xcc-BrA1 is unique and distantly related to other copLAB genes from Xanthomonas and Stenotrophomonas. The origin of copper resistance genes in Xcc-BrA1 is likely a result of horizontal gene acquisition from a still unknown phylloplane cohabitant. The findings of this study have implications for the management of crop diseases caused by Cu^R xanthomonads. Future studies could focus on and determining the distribution, overall importance and appropriate control measures for strains harbouring these unique genes.