Influência de cultivares de batata-doce resistentes e suscetíveis a Euscepes postfasciatus fairmaire (Coleoptera: Curculionidae) sobre o parasitismo, sobrevivência e a biologia de Catolaccus grandis burks (Hymenoptera: Pteromalidae)

The influence of four resistant and two susceptible genotypes of sweet potato to Euscepes postfasciatus Fairmaire on parasitism and biology of Catolaccus grandis Burks were evaluated under laboratory conditions. Six sweet potato roots of each genotype were infested with E. postfasciatus adults during 40 days. After this period the larvae were taken, weighted and encapsulated in parafilm. Five larvae were offered in free choice and no choice tests to C. grandis pregnant females for 12h. Five replications were used. The parasitized larvae and the eggs of the parasitoid were counted. Three daily observations were made to determine the developmental time of phases and parasitoid survival. C. grandis females can distinguish E. postfasciatus larvae reared on susceptible and resistant roots, prefering to parasitize larvae reared on susceptible roots. C. grandis survival was higher when the parasitoid was reared on larvae originated from susceptible roots and the number of emerged females was higher on larvae reared on hosts originated from susceptible roots.

Putative pyrophosphate phosphofructose 1-kinase genes identified in sugarcane may be getting energy from pyrophosphate

Pyrophosphate-dependent phosphofructokinase (PPi-PFK) has been detected in several types of plant cells, but the gene has not been reported in sugar cane. Using Citrux paradixi PPi-PFK gene (AF095520 and AF095521) sequences to search the sugar cane EST database, we have identified both the α and β subunits of this enzyme. The deduced amino acid sequences showed 76 and 80% similarity with the corresponding α and β subunits of C. paradisi. A high degree of similarity was also observed among the PFK β subunits when the alignment of the sugar cane sequences was compared to those of Ricinus communis and Solanum tuberosum, it appears that α and β are two distinct subunits; they were found at different concentrations in several sugar cane tissues. It remains to be determined if the different gene expression levels have some physiological importance and how they affect sucrose synthesis, export, and storage in vacuoles. A comparison between the amino acid sequences of β PFKs from a variety of organisms allowed us to identify the two critical Asp residues typical of this enzyme's activity site and the other binding sites; these residues are tightly conserved in all members of this protein family. Apparently, there are catalytic residues on the β subunit of the pyrophosphate-dependent enzyme.

Development of a supercritical fluid extraction method for simultaneous determination of organophosphorus, organohalogen, organonitrogen and pyretroids pesticides in fruit and vegetables and its comparison with a conventional method by GC-ECD and GC-MS

The aim of this paper was to apply a multiresidue method using Supercritical Fluid Extraction (SFE) and capillary gas chromatography with electron capture and mass spectrometry detections in the analysis of the levels of pesticide residues in fruits and vegetables. Single laboratory validation of both solid-liquid and supercritical fluid extraction methods was carried out for 32 compounds selected from four pesticide classes (organochlorine, organonitrogen, organophosphorus and pyretroid) in blank and fortified samples of fresh lettuce, potato, apple and tomato. Recoveries for the majority of pesticides from fortified samples at fortification level of 0.04-0.10 mg kg -1 ranged 74-96% for both methods and confirmation of pesticide identity was performed by gas-chromatography-mass spectrometry in a selected-ion monitoring mode. Both methods showed good limits of detection (less 0.01 mg kg-1, depending on the pesticide and matrix) and the SFE method minimized environmental concerns, time, and laboratory work. ©2005 Sociedade Brasileira de Química.

Espectro de agentes etiológicos associados a surtos de doenças transmitidas por alimentos em núcleos receptores turísticos de três regiões geográficas do Estado de São Paulo

Foodborne and waterborne diseases are spread by the consumption of food or water contaminated with bacteria and/or their toxins, viruses, parasites or chemicals. The aim of the research reported here was to establish the spectrum of etiologic agents of foodborne outbreaks at 15 tourist resorts in three geographic regions of the State of Sao Paulo (Brazil). The study was based on the cases reported to the Epidemic Surveillance Center (CVE) of the Public Health Authority of the State of São Paulo (SES), from 2002 to 2005. The tourist centers were chosen at random in three regions of the state (Capital, Interior and Coast) and offered the following attractions: events, agribusiness, cultural history, shopping, town center, gastronomy, health and leisure, sun and sea. Among the bacteria, the results showed that Salmonella spp. were most frequently associated with outbreaks, followed by Shigella spp., enterotoxigenic Escherichia coli, Staphylococcus aureus, Clostridium perfringens, Bacillus cereus and Campylobacter spp. Viruses (Rotavirus and Hepatitis A) played a part in many of the cases, while the frequency of parasites and worm infestations was low in the foodborne disease outbreaks at these resorts. The mixed foods (rice, beans, liver, potatoes, barbecue, juice), fish and poultry were the three commonest vehicles implicated in the outbreaks.

Caracterización y clasificación de la red hidrográfica de la cuenca del río Bobo, departamento de Nariño - Colombia

The object of this work was to make a morphometric characterization of the Bobo river watershed in the Nariño department in Colombia. A map was created from topographical maps (1:25.000 scale) using the drainage network and the limit of each 2nd order microbasin as database. Dimensional, drainage network and relief morphometric parameters were evaluated for a later hy-drological study. The drainage area was 224.97 km2, having a 71.31 km perimeter. The Bobo river watershed is considered to be 6th order and has 176 2nd order drainage channels, 34 3rd order drainage channels, 9 4th order drainage channels and 3 5th order drainage channels. Average drainage density is 3.71km/km2, reflecting its high density, having strong, dissected geological formation. The area has a typical Andean land-use pattern, having native wooded vegetation, traditional transitory potato and vegetable growing predominating.

Mutagenic activity of glycoallkaloids from Solanum palinacanthum dunal (Solanaceae) found in the Brazilian cerrado

Solanaceous plants are widely distributed around the world and they are traditionally used as drugs for the treatment of cancer and herpes, and include familiar foods such as potato, tomato and eggplant and some berries popular in Brazil. As part of a program of research on pharmacologically active new molecules, the aim in this study was to assess the mutagenic effects of Solanum palinacanthum, known popularly as joá. The crude 95% ethanol extract and purified solamargine obtained from the fruits of S. palinacanthum Dunal were investigated by the Ames test, using the Salmonella typhimurium strains TA98, TA97a, TA100 and TA102 as test organisms, with and without metabolic activation. The concentrations tested ranged from 0.07 to 15.0 mg/plate for the crude ethanolic extract and from 1.25 to 5.0 mg/plate for the solamargine. The results showed a mutagenic effect of both the extract and the solamargine in the TA98 strain (without metabolic activation). The present study showed the potential mutagenicity and suggests confirming this effect in other models, before recommending their indiscriminate consumption by the population.

Optimal moment to change pressure regulator and sprayer kit on center pivot irrigation machines: application to a study case

A theoretical model developed by the authors for determining the optimal moment to substitute sprayer and pressure regulator kit on a center pivot irrigating potatoes and beans has been applied. The methodology compares the sum of the costs due to additional consumption of water and energy, maintenance and labor, as well as yield losses associated to areas with deficit or over irrigation to the costs due to buy and install a new sprinkling set on the pivot. The results showed that for a reduction of 3.07% of the Hermann and Hein’s Uniformity Coefficient (UCh), the substitution of the sprinkling module on the pivot is justified when potatoes and beans are cultivated.

Adubação nitrogenada e critérios de amostragem foliar para a cultura da batata

The present study aimed to determine which leave will be displayed and the time of collection of this leave. The treatments consisted on five doses of nitrogen, four times for collection sampling and three types of leaves, arranged in a randomized block design with three repetitions, totalizing one hundred and forty-four experimental units. The leaves collections took place every fifteen days at thirty, forty-five, sixty and seventy five days after budbreak (DAB), collecting the laminated / compound young leaf (first leave), newly mature (second leave) and the mature leave (third leave) from the set of terminal leaflets. For this was installed an experiment with the culture of potato (cv. Atlantic), in Barretos/SP, the period of march the june of 2010. According to this data collected in this study, the best time for collecting the leaves is at 30 days after the budbreak of the potato cultivation containing nitrogen concentrations in the leaves minus heterogeneous of plants from a fraction to another and with values R2 = 0.98 being higher to the all times of harvests. To the diagnostic leaf, the highest determination coefficient was observed in the newly mature (second leaf) with R2 = 0.98. It can be observed that the highest levels of nitrogen were found on the first leaf (39.01 kg-1). Nevertheless, the values were very heterogeneous and did not fit the curve being the second leave (newly mature) the one that best represents the nutritional status of the plant. Therefore the recommendation for nutritional diagnosis will collect the recently matured leaves (2nd leaf) 30 days after budbreak.

Microstructure of ceramics TiO2 obtained by protein consolidation

Porous ceramics can be produced by adding starch (corn, potato) and protein (animal or vegetable) to raw material as pore forming element. In this study, titanium dioxide ceramics were formed by vegetable protein consolidation. Soybean was chosen as the binding agent and pore forming. The samples, which were produced in cylindrical shape, had the following processing: material mixture, gelling, drying, pre-sintering and sintering. Heated platinum microscopy were performed by using suspensions with different compositions in order to verify protein gelling capacity and better know the temperature in which this process occurs. The samples were characterized by apparent porosity and roughness measurement. Besides, imaging by light microscopy was also performed in order to determine the sample morphology and porosity. © (2012) Trans Tech Publications, Switzerland.

Rhizoctonia solani GA-3PT es el principal patógeno asociado con el chancro del tallo y la sarna negra de la papa en Colombia

Stem canker and black scurf diseases of potatoes are caused by the basidiomycetous fungus Tanatephorus cucumeris (ana-morphic species complex Rhizoctonia solani). Tese diseases have worldwide distribution wherever potato is grown but their etiology varies depending on the predominance of distinct R. solani anastomosis groups (AGs) in a particular area. Within the species complex, several AGs have been associated with stem canker or black scurf diseases, including AG-1, AG-2-1, AG-2-2, AG-3, AG-4, AG-5 and AG-9. Tis article reports on the most comprehensive population-based study, providing evidence on the distribution of R. solani AGs in Colombian potato fields. A total of 433 isolates were sampled from the main potato cropping areas in Colombia from 2005 to 2009. Isolates were assigned to AGs by conventional PCR assays using specific primers for AG-3, sequencing of the ITS-rDNA and hyphal interactions. Most of the isolates evaluated were assigned to AG-3PT (88.45%), and a few to AG-2-1 (2.54%). Te remaining isolates were binucleate Rhizoctonia (AG-A, E, and I). Pathogenicity tests on the stems and roots of different plant species, including the potato, showed that AG-3PT affects the stems of solanaceous plants. In other plant species, damage was severe in the roots, but not the stems. AG-2-1 caused stem canker of Solanum tuberosum cv. Capiro and in R. raphanistrum and B. campestris subsp. Rapa plantlets and root rot in other plants. Te results of our study indicated that R. solani AG-3PT was the principal pathogen associated with potato stem canker and black scurf diseases of potatoes in Colombia.

Adubação de cobertura na batata-doce com doses combinadas de nitrogênio e potássio

Balanced fertilizations with N and K often increase the performance of crops, however, when there is absence of one of these nutrients in poor soils, can reduce crop response to fertilization with the other. The objective of this work was to evaluate the productivity of sweet-potato, the amount of sweetpotato without quality, and leaf nutrients analysis, of sweet-potato crop fertilized with N and K. The trial was conducted in farming for commercial production, in Presidente Prudente, São Paulo State, during February-June 2007, in a dystrophic Ultisol of medium texture. The experimental design was a randomized complete block design, with four replications, on factorial 4 x 4: levels of 0, 30, 60 and 120 kg N ha-1 (urea source) combined with levels of 0, 30, 60 and 120 kg K2O ha-1 (KCl source), applied to 39 days after planting of the crop. The sweet-potato is responsive to topdressing application with nitrogen and potassium, however, the greatest increases in productivity occur when doses of N and K are combined. Fertilization with N and K not increase the amount of sweet-potato without quality marketing. The highest increase in productivity of sweet-potato is reached with topdressing combined with 100 kg N ha-1 plus 120 kg K2O ha-1.

Eficiência de utilização de nutrientes por cultivares de batata

The use of cultivars efficient in nutrient use is essential to increase yield and reduce production costs. The objective of this study was to evaluate absorption and nutrients use efficiency on five potato cultivars. The experiment was conduced in Itaí, São Paulo State, Brazil, in winter cropping season of 2008 on Oxisol. The experimental design was randomized blocks with split-plots and four replications. Plots comprised the five potato cultivars and subplots were established by sampling times, performed at planting and every seven days after emergence. At 97 DAP was calculated the nutrients use efficiency for dry matter production and at 122 DAP were calculated the nutrients use efficiency for fresh tuber and tuber dry matter yield. Mondial and Asterix cultivars showed greater dry matter production, higher fresh tubers yield and nutrients accumulation. Nutrients use efficiency for total dry matter and tubers dry matter, was similar among cultivars, but Ágata was more efficient in nutrients use efficiency for fresh tubers yield.

Avaliação in vitro de diferentes métodos de análises de fungitoxicidade de óleos essenciais

Environmental problems caused by synthetic fungicides have increased the search for alternative methods of control of plant diseases. The objective was to evaluate the effect of essential oil of citronella grass, on the fungus Rhizoctonia solani, in different methods of in vitro fungitoxicity. We used a randomized design in a factorial design with four replications, where the factors were composed of four methods for assessing the in vitro fungitoxicity of the essential oil of citronella grass (essential oil diluted in Tween 80 (0.5%) and embedded in the culture medium PDA (potato dextrose agar) still melting, essential oil diluted in Tween 80 (0.5%) and distributed on the surface of the PDA; oil essential diluted in Tween 80 (0.5%) and distributed on filter paper attached to the inner surface of the lid of the Petri dish, pure essential oil and distributed on the surface of the culture medium, and control) and five evaluation periods (2, 4, 6, 8 and 10 days of incubation). Was used 0.25μL mL-1 of citronella oil in all treatments. Of the treatments evaluated the use of pure oil distributed on the surface of the culture medium was more effective in reducing the mycelial diameter in all evaluations. In this method the rate of mycelial growth was 9,02 mm day-1, reaching in last evaluation 79,77 mm.

Sensibilidade de stenocarpella macrospora a fungicidas

The application of fungicides in the aerial organs is control strategy to macrospora spot caused by fungus Stenocarpella macrospora. The objective of this study was to determine the sensitivity of S. macrospora to fungicides by inhibition of mycelial growth (MG) and conidial germination (CG). It was eval uated 12 fungicides belonging to the chemical groups of the benzimidazoles, triazoles and strobilurins, six concentrations and two isolates of the fungus (SC and MT). The fungicides were diluted in sterile distilled water and added to the culture medium of potato dextrose agar (mycelium) and water-agar (spore) after sterilization. The percentage of inhibition of MC and CG was calculed in comparison with control, estimating of 50% inhibitory concentration (IC50). The fungicides tested were effective in inhibiting the MC. The IC50 was less than 1 ppm for all fungicides. There was no difference between isolates. The inhibition of CG had higher fungitoxicity strobilurins, and the IC50 was between 0.0035 and 0.03 ppm, and the isolated SC showed the higher sensitivity to the fungicides. The IC50 values obtained for fungicides and specific S. macrospora will be useful in monitoring the sensitivity of the fungus, especially in regions with intense demand for fungicides in corn.

Fusarium solani f. sp. passiflorae: A new forma specialis causing collar rot in yellow passion fruit

The aim of this study was to characterize a Fusarium population obtained from yellow passion fruit (YPF) with collar rot using pathogenicity, morphocultural characteristics and molecular tests. Pathogenicity and disease severity were assessed in six plant species: YPF, zucchini, tomato, bean, soya bean and cucumber. Potato dextrose agar medium (PDA) was used to determine mycelial growth at five temperatures (15-35°C). The colour produced by isolates was also determined on PDA at 25°C. Synthetic nutrient agar medium was used to evaluate: (i) type of mycelium and phialides; (ii) size, shape and number of septa from conidia; and (iii) production of chlamydospores and perithecia. Molecular tests consisted of sequencing the ITS-5·8S rDNA region and elongation factor 1α (EF-1α) gene. The isolates caused large lesions on YPF, zucchini and tomato, with YPF having the highest mean disease severity and being the only one that showed wilt symptoms and death of the plant. Thus the isolates showed host specificity. Maximum mycelial growth occurred at 25°C and the predominant colour was bluish-white. The isolates produced long phialides, dense aerial mycelium, oval microconidia with a mean size of 9·5 × 2·6 μm, macroconidia of 32·7 × 3·4 μm with 3·3 septa, and chlamydospores; only one isolate lacked perithecia. Phylogenetic trees of the ITS region and EF-1α gene showed that isolates from YPF formed a distinct group within the F. solani group and the formae speciales of F. solani. It is proposed to name all isolates from YPF as F. solani f. sp. passiflorae. © 2013 British Society for Plant Pathology.