Characterization of antibiosis to the redbanded stink bug Piezodorus guildinii (Hemiptera: Pentatomidae) in soybean entries

Stink bugs are among the major pests of soybean [Glycine max (L.) Merrill] worldwide. Piezodorus guildinii [Westwood] (Hemiptera: Pentatomidae) is one of the predominant pest species, causing more severe damage in many regions than other stink bugs. Its attack reduces yield and quality of the beans. Plant resistance is a valuable strategy in integrated pest management that can reduce insect populations below economic injury level. Here, we report the resistance of 17 soybean entries to P. guildinii. PI 229358, PI 274454, L1-1-01, “IAC 19,” PI 171451, PI 227687, “IAC 100,” IAC 78-2318, PI 274453, and IAC 74-2832 caused high nymphal mortality (greater than 90 %), indicating the expression of antibiosis. “IAC 100,” IAC 74-2832, PI 274453, and “IAC 24” also increased the length of the nymphal stage of P. guildinii, showing the same mechanism of resistance. Our findings may be useful for breeding programs that focus on the resistance of soybeans to insects.     

Plant-derived essential oils affecting settlement and oviposition of Bemisia tabaci (Genn.) biotype B on tomato

The silverleaf whitefly Bemisia tabaci (Genn.) biotype B (Hemiptera: Aleyrodidae) is an economically important pest of tomatoes Solanum lycopersicum (L.), causing irregular ripening on fruits and transmitting several plant pathogenic geminiviruses. The management of this pest is commonly based on repetitive spraying with synthetic pesticides, causing serious environmental damages and increase of resistance by insect population. In the present study, essential oils from the leaves of Artemisia camphorata Vill., Ageratum conyzoides L., Foeniculum vulgare Mill., Lippia alba (Mill.) N. E. Br., Plectranthus neochilus Schltr., and Tagetes erecta L. were investigated for their possible repellent and oviposition-deterrent effects against B. tabaci biotype B on tomato. In a multi-choice assay, P. neochilus essential oil was the most active repellent and oviposition deterrent. Essential oils of A. conyzoides and T. erecta significantly deterred the female B. tabaci biotype B from laying eggs on treated tomato leaflets compared with the control. (E)-Caryophyllene (30.67 %) and the monoterpenes α-pinene (15.02 %) and α-thujene (11.70 %) were identified as the major constituents of the essential oil of P. neochilus. Our findings demonstrated the potential of essential oil of P. neochilus and other oils in the reduction of settlement and oviposition of B. tabaci biotype B on tomato.     

Granulomatous meningoencephalitis due to toxoplasma gondii in a black-headed night monkey (Aotus nigriceps)

This report describes toxoplasmosis infection in a black-headed night monkey (Aotus nigriceps) from the Zoological Park of the Federal University of Mato Grosso, Brazil. The animal was submitted alive to the Veterinary Hospital of the Federal University of Mato Grosso presenting neurologic clinical signs. There were no improvements on the animal's clinical condition after treatment, so it was euthanized. At necropsy, the most significant gross lesions observed were hemorrhages diffusely scattered throughout the cerebral hemispheres. Histologic findings were characterized by nonsuppurative encephalitis and mild multifocal necrotizing nonsuppurative myocarditis. Groups of tachyzoites and cysts were observed surrounding the inflamed areas of cerebral parenchyma. Sections of the brain were submitted for immunohistochemistry examination for Toxoplasma gondii and Neospora caninum and also for polymerase chain reaction (PCR) to determine the presence of Toxoplasma gondii. The samples were positive for Toxoplasma gondii by PCR; however, cross reactivity was observed between Toxoplasma gondii and Neospora caninum antibodies. These findings were consistent with a toxoplasmosis infection in this animal.     

Genetic gain and correlations among traits for stink bug resistance in soybeans

An experiment was carried out at the State University of Londrina School Farm in a randomized complete blocks design with three replications; the plots underwent natural stink bug attacks to check correlations existing among agronomic traits and stink bug damage in 33 F₈ pure lines soybean. The seed size trait was measured by the weight of a hundred seeds (WHS) and the percentage of stink bug damage seeds (PDS) was measured by staining the seeds with tetrazolium at 0.01%. Seeds were considered damaged with at least one puncture and or with marks characteristic of stink bug. The phenotypic and genotypic correlations between the WHS and the PDS seeds were positive, being 0.51 and 0.67 ± 0.19, respectively. The relationship between the visual pod width (VPW) and PDS was also significant, being 0.41 and 0.54 ± 0.19 for phenotypic and genotypic correlations, respectively. Thus the breeder can select lines for stink bug resistance indirectly either by WHS or VPW. These two traits are very easy to assess when compared with the assessment of PDS damage, allowing the use of larger populations. However, in this case, the genetic gains by selection were smaller than those obtained by direct selection, but even so they were considered noteworthy. The VPW may be an efficient way of selection in large populations for stink bug resistance. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ureaplasma diversum as a cause of pustular vulvovaginitis in bovine females in Vale Guapore,Mato Grosso State,Brazil

Ureaplasma diversum has been associated with various reproductive problems in cattle that include granular vulvovaginitis, weak calves, and abortion. This study was conducted in a beef herd situated in the Middle-West region of Brazil, and the objectives were to verify the presence of U. diversum and to elucidate its possible relationships with independent variables in this bovine herd population. A total of 134 vaginal mucous swabs were taken for polymerase chain reaction (PCR). Of these, 51 (38 %) were PCR positive for U. diversum. Of the 58 heifers with vulvovaginal lesions characterized by hyperemia, granulated lesions, and edema distributed throughout the vulvar mucosa, 37 (64 %) were U. diversum positive; of the 76 heifers without reproductive lesions, 14 (18 %) were U. diversum positive. All tested samples were negative for bovine herpesvirus 1 (BoHV-1). Multivariate logistic regression revealed that the following two variables were significantly associated with the presence of U. diversum: the presence of vulvar lesions (p?=?0.001) and the presence of a progesterone (P4) device (p?=?0.001). These findings indicate that U. diversum should be considered a pathogen that is associated with pustular vulvovaginitis in heifers from the Mato Grosso state and that additional studies of the risk factors associated with intravaginal P4 device transmission should be performed.     

Agronomic and molecular characterization of gamma ray induced banana (<Emphasis Type="Italic">Musa</Emphasis> sp.) mutants using a multivariate statistical algorithm

Bananas are tropical fruits grown worldwide playing a key role in market trade and especially used as main food source for low income populations. In Brazil, bananas are mainly consumed in natura, occupying the second largest internal market. Nevertheless, this crop presents low availability of productive commercial varieties with good agronomic characteristics. A strategy undertaken to solve this problem is the development of new cultivars through conventional genetic breeding methods. However, this strategy presents some obstacles such as female sterility and low number of seeds. In order to overcome these shortcomings, use of mutation induction aiming the selection of mutants with desirable agronomic characteristics seems to have great potential for developing new cultivars. The objective of the present work was to evaluate the genetic variability in putative banana ‘Pacovan’ (AAB genome, subgroup Prata Type) mutants submitted to gamma ray irradiation, using a set of agronomical and molecular data (ISSR markers). The distance between the putative ‘Pacovan’ mutants varied from 0.26 to 0.64 with cophenetic correlation coefficient of 0.7669. Four mutants were selected based on best agronomical characteristics and height. This data also shows that there is variability that can be explored after the irradiation of ‘Pacovan’ banana mutants, which can be used in the genetic breeding program of banana aiming to develop short new varieties that also present good agronomic characteristics. This is the first attempt to use combined data in order to evaluate the genetic variability in putative banana mutants.     

Correction to: Search for reservoirs of ‘Candidatus Liberibacter solanacearum’ and mollicutes in weeds associated with carrot and celery crops

European Journal of Plant Pathology -     

Efficiency of soil-applied 67Zn-enriched fertiliser across three consecutive crops

A very small amount of applied zinc (Zn) is taken up by crops, resulting in low recovery by plants. Adding elemental sulphur to zinc oxide (ZnO) fertiliser could improve Zn solubilisation and exert a higher residual effect on crops than soluble Zn sources. We produced an isotopically labelled Zn-elemental sulphur fertiliser and evaluated its performance in comparison to traditional Zn sources during sequential crop cultivation. Three ⁶⁷Zn-labelled fertilisers, ZnO, zinc sulphate (ZnSO₄), and ZnO co-granulated with elemental sulphur (ZnOS⁰), were soil applied, and their contributions to the uptake of Zn by three consecutive crops, wheat, ryegrass, and corn, were assessed in a 294-d pot experiment. The contributions of Zn fertilisers followed the order:ZnSO₄ > ZnO=ZnOS⁰. The relative contributions of Zn fertilisers were lower in the first crop than in the subsequent crops. The overall recovery of applied Zn by the three crops was higher for ZnSO₄ than for ZnO and ZnOS⁰, reaching 1.56%, 0.45%, and 0.33% of the applied Zn, respectively. Zinc recovery by plants was very low, regardless of the source of Zn. Adding elemental sulphur to ZnO did not increase its effectiveness up to 294 d after application. Fertiliser contribution was higher for the subsequent crops than for the initial crop, indicating the importance of assessing the residual effects of Zn fertilisers.     

Absorption and Toxicity of Copper and Zinc in Bean Plants Cultivated in Soil Treated with Chicken Manure

The interaction between copper, zinc, and chicken manure, whenadded to soil, was studied in a greenhouse setting. Coppersulfate and of zinc chloride at concentrations of 0.5 to 2.0mmol kg^-1 were added separately to pots containing 3.0 kgof dystrophic dark red latosoil (LEd) plus 1,0% (m/m) pH 4.2chicken manure. IAPAR 57 beans were used as test plant andcultivated in the experimental soils for 30 days. Plant growthin terms of dry weight and the concentrations of copper and zincin the aerial part of the plants were determined. Bean plantingswere repeated four times, at four-month intervals. A 20%decrease in dry weight was observed when amounts of copper orzinc equal to or geater than 1.0 or 2.0 mmol kg^-1, respectively, were applied to the soil over an average of fourplantings. For these concentrations, the average amount of metalfound in the plant was 13.4 mg kg^-1 for copper and 224.8 mgkg^-1 for zinc. Chlorosis of the leaves in the bean plantswas also observed. The copper and zinc concentrations in thetreated soil were determined using different extractants. Amongthe solutions evaluated for the extraction of available zinc,1.0 M ammonium acetate, pH 4.8, showed a better correlation withthe metal concentration in the plant. As for copper, the bestcorrelation was found with the Mehlich-1 extractant.