Activity of benomyl for control of postbloom fruit drop of citrus caused by Colletotrichum acutatum

Postbloom fruit drop (PFD) of citrus caused by Colletotrichum acutatum produces orange-brown lesions on petals and induces the abscission of young fruitlets and the retention of the calyces. Despite the fact that C. acutatum is not highly sensitive to benomyl in culture, this fungicide provides good control of the disease under field conditions. This study was undertaken to determine the effect of benomyl on various stages of disease development to understand the basis for its effectiveness in the field. We found that benomyl at 1.0 μg/ml reduced colony area of C. acutatum by about 75% and completely inhibited growth of C. gloeosporioides. Benomyl did not prevent conidial germination even at 100 μg/ml, but reduced germ tube elongation at 10 and 100 μg/ml. When benomyl was applied to flower clusters on screen-house-grown plants before inoculation, disease severity was greatly reduced. Applications at 24 and 48 h, but not at 72 h, after inoculation reduced PFD severity. Application of benomyl to symptomatic petals not bearing conidia did not prevent or reduce production of inoculum. Application to petals bearing conidia reduced viability of these fungal propagules by only about 50%. The viability of appressoria on mature leaves was not affected by benomyl application. Even when appressoria on mature leaves were stimulated to germinate by treatment with flower extracts, subsequent application of benomyl did not reduce propagule numbers below original levels. Benomyl appears to act by preventing infection and early development of the fungus in petals. However, once symptoms have developed, this fungicide has only minimal effects on further disease development and spread.

Benomyl sensitivity of isolates of Colletotrichum acutatum and C. gloeosporioides from citrus

Postbloom fruit drop (PFD) of citrus, caused by Colletotrichum acutatum, produces orange-brown lesions on petals and results in premature fruit drop and the retention of calyces. C. gloeosporioides is common in groves and causes postharvest anthracnose on fruit. Both diseases are controlled effectively by the fungicide benomyl in research fields and commercial orchards. Highly sensitive and resistant isolates of C. gloeosporioides were found, whereas all isolates of C. acutatum tested were moderately resistant. In preliminary studies conducted in vitro with three isolates of each, mycelial growth of sensitive isolates of C. gloeosporioides was inhibited completely by benomyl (Benlate 50 WP) at 1.0 μg/ml, whereas resistant isolates grew well at 10 μg/ml. Growth of all isolates of C. acutatum was inhibited by about 55% at 0.1 μg/ml and by 80% at 1.0 μg/ml. Spore germination of C. acutatum was inhibited more at 0.1 μg/ml than at 1.0 μg/ml or higher concentrations. In all, 20 isolates of C. acutatum from 17 groves and 20 isolates of C. gloeosporioides from 7 groves were collected from locations with different histories of benomyl usage in São Paulo, Brazil, and Florida, United States. Benomyl at 1.0 μ.g/ml completely inhibited growth of 133 isolates of C. gloeosporioides, with the exception of 7 isolates that were highly resistant to the fungicide, whereas all isolates of C. acutatum were only partially inhibited at 0.1 and 1.0 μg/ml. Analysis of variance indicated that the sensitivity of the isolates of C. acutatum was not affected by benomyl usage or grove of origin, and country of origin had only minor effects. No highly resistant or sensitive isolate of C. acutatum was recovered. Partial sequencing of the β-tubulin gene did not reveal nucleotide substitutions in codons 198 or 200 in C. acutatum that usually are associated with benomyl resistance in other fungi.

Evaluation of systems for timing of fungicide sprays for control of postbloom fruit drop of citrus in Brazil

Postbloom fruit drop (PFD) of citrus, caused by Colletotrichum acutatum, infects petals of citrus flowers and produces orange-brown lesions that induce the abscission of young fruitlets and the retention of calyces. Proper timing of fungicide applications is essential for good disease control. Different systems for timing of fungicide applications for control of PFD in a major citrus-growing region in southern São Paulo state in Brazil were evaluated from 1999 to 2002. The following programs were compared to an unsprayed control using counts of diseased flowers, persistent calyces, or fruit: (i) a phenology-based program currently recommended in Brazil with one application at early and another at peak bloom; (ii) the Florida PFD model; (iii) the postbloom fruit drop-fungicide application decision system (PFD-FAD), a new computer-assisted decision method; and (iv) grower's choice. In 1999, no disease developed, sprays applied with the phenology-based program had no effect, and the Florida PFD model saved two sprays compared with the phenology-based program. In 2000, PFD was moderate and the phenology-based and growers' choice treatments had a significantly lower number of persistent calyces and higher fruit numbers than the control, but no differences were found between those treatments and the PFD model. In 2001, PFD was severe with considerable yield loss. The PFD model, the phenology-based program, and the grower's choice reduced flower blight and the number of persistent calyces, and improved fruit yields with two to three applications, but the PFD-FAD achieved comparable yields with only one spray. In 2002, the disease was mild, with no yield loss, and the Florida PFD model and the PFD-FAD saved one spray compared with the other systems. The PFD model and the PFD-FAD were equally effective for timing fungicide applications to control PFD in Brazil. Scouting of trees is simpler with PFD-FAD; therefore, this system is recommended and should eliminate unnecessary sprays and reduce costs for growers.

Deposition and leaching of tebuthiuron on sugar cane straw applied with and without alkyl polyglycoside adjuvant

A laboratory experiment was carried out aiming to study the effects of an alkyl polyglycoside adjuvant (APG) on deposition and leaching of the herbicide tebuthiuron applied on sugar cane straw. Tebuthiuron, at concentration of 1200 mg L-1, was applied separately and in tank mix with the APG adjuvant, at concentrations of 0.07 and 0.09% (wt v-1), using a spraying volume of 204 L ha-1. A precipitation equivalent to 20 mm of rain was simulated, 24 h after the applications, to evaluate the herbicide leaching. The quantification of tebuthiuron was carried out by the high performance liquid chromatography (HPLC). It was observed that the addition of APG adjuvant at 0.07% (wt v-1) provided an increase of 11.5% in the deposition of tebuthiuron on straw, reduction of 50.4% in the drift of the herbicide and it did not affect significantly the leached amount (68.5%), when compared with the treatment where tebuthiuron was applied alone (70.8%). At the concentration of 0.09% (wt v-1), the APG adjuvant caused an increase of 22.7% in the deposition; it reduced the drift of the herbicide by 99.9% and reduced the leached amount by 7.6% thereby increasing the retention of the herbicide by straw.

Morphometry and histochemistry of the Rectus abdominis muscle fibers of tufted capuchin monkeys (Cebus apella Linnaeus, 1758)

The phylogenetic proximity of primates to humans, along with their behavioral, biochemical, and anatomical similarities, make such animals more interesting experimental models for biomedical researches, as compared to classical laboratory animals. Another aspect that has called the attention of researchers is the differentiated quadrupedalism present in some primates. The tufted capuchin monkey uses the ground and tree branches as its support for locomotion, showing various postures while performing this task. On the basis of this information, we have decided to study the rectus abdominis muscle of the tufted capuchin monkey, with the following goals: the frequency and area of fiber types; its possible compartmentalization; and identify if this muscle is better adapted to phasic or postural activities. To do this, samples were removed from 4 regions of the rectus abdominis muscle of 6 adult male tufted capuchin monkeys, and were submitted to reaction with m-ATPase, (with alkaline and acid pre-incubation), NADH, and H.E.. Results showed: a statistically significant difference (P<0.05) for both frequency and area, between fiber types FG and FOG and FG and SO, but did not show a statistically significant difference between fibers FOG and SO, in all studied regions; similarity in frequency and area of a same fiber type (FG, FOG, and SO) among the studied regions. Based on these data, it was concluded that: the rectus abdominis muscle of the tufted capuchin monkey does not show fiber compartmentalization, since the distribution and size patterns of the different fiber types are similar in the studied regions; there is a predominance of fast twitch fibers (FG + FOG) over slow twitch fibers (SO), for frequency and area, which characterizes the muscle as being more dedicated to phasic than to postural activities. © 2006 Sociedad Chilena de Anatom.

Multiresidue determination of herbicides in environmental waters from Primavera do Leste region (Middle West of Brazil) by SPE-GC-NPD

A study on the presence of herbicides, namely simazine, metribuzin, metolachlor, trifluralin, atrazine and two metabolites, deisopropylatrazine (DIA) and deethylatrazine (DEA), was performed in ground and surface waters from Primavera do Leste region, Mato Grosso state (Middle West of Brazil). The analytical procedure was based on solid-phase extraction (SPE) with Sep-Pak C18 disposable cartridges and ethyl acetate for elution solvent. Residue levels were determined by gas chromatography with nitrogen-phosphorus detection. For most of the pesticides average recoveries at different fortification levels were >with relative standard deviation < The recoveries of DIA and trifluralin in water were 25% and 56%, respectively, which were attributed to the incomplete retention of DIA and strong retention on the sorbing material and high volatility of trifluralin. Detection limits ranged from 0.023 to 0.088 μg L-1. This method was applied for the analysis of 5 superficial water samples and 28 groundwater samples, in places used for human consumption without previous treatment, collected in Primavera do Leste, Mato Grosso, Brazil. Results indicated that the highest level of contamination in a water sample was 1.732 μg L-1 for metolachlor, while metribuzin was the most frequently detected herbicide with maximum concentration of 0.351 μg L-1. ©2006 Sociedade Brasileira de Química.

Beta-carotene stability during drying and storage of cassava and sweet potato

The effect of blanching on the β-carotene stability during drying and storage of cassava and sweet potato was evaluated. The orange-fleshed sweet potato showed good retention of β-carotene during the blanching and drying (100% and 96%, respectively), but lower retention (84% and 91%) was observed in cassava. Cassava also showed lower β-carotene stability than sweet potato during the storage of unblanched dried samples. β-Carotene content of dried cassava was reduced from 8.6 μg/g to traces in 20 days of storage while the initial amount of dried sweet potato (463 μg/g) was reduced by about 45% (210 μg/g). Blanching did not affect the β-carotene retention during the drying, but enhanced the stability of this carotenoid during the storage of dried samples at room temperature, especially in cassava. The initial levels of blanched-dried cassava and sweet potato (7.8 and 513 μg/g, respectively) took 70 days to fall by around 50%.

Influência de diferentes sistemas adesivos na resistência de união de pinos de fibra à dentina intrarradicular

Objective: To evaluate the influence of three adhesive systems on the bond strength of fiber post luted to root dentine. The hypothesis was that the bond strength is influenced by the adhesive system. Method: The canals of thirty single-root bovine roots (16mm in length) were prepared using the preparation drill (FGM) until 12mm. 14 mm of each root was embedded with acrylic resin and the specimens were allocated into three groups (n=10), considering the factor adhesive (3 levels): Gr1- Scotchbond Multipurpose Plus (3M ESPE), Gr2- One Step (Bisco) and Gr3- Excite DSC (Ivoclar Vivadent). The adhesive systems were applied using a microbrush, according to the manufacture's recommendations. The fiber posts (White Post DC, FGM) were luted with dual resin cement (All-Cem,FGM). After, the cores with composite resin (Llis, FGM) were made and each set of root/post/core was submitted to the mechanical cycling (Erios, Brazil) (10 6 cycles, 84N, 4 Hz, inclination of 45 o, 37 oC, water). Each specimen was cut in 4 samples (1.8mm in thickness), which were submitted to the push-out test in a universal testing machine (ServoPulser - Shimadzu) (50Kgf, 1mm/min). The data (MPa) were analyzed using ANOVA (1-way) and Tukey test (5%). Results: The factor adhesive (P=0.00352) influenced the bond strength significantly (ANOVA). Gr1 (6.8±3.8 MPa) a presented higher bond strength values than Gr2 (3.1±1.5 MPa) b and similar to Gr3 (4.4±3.3) a,b. Moreover, Gr3 and Gr2 were similar between them (Tukey). The hypothesis was accepted. Conclusion: Based on the results it was concluded that chemical and dual polymerization adhesive system should be used for the adhesive luting fiber post procedures.

ANTIOXIDANT ACTIVITY OF ROSEMARY EXTRACT IN SOYBEAN OIL UNDER THERMOXIDATION

This study examined the antioxidant activity of lyophilized rosemary extract added to soybean oil, subjected to thermoxidation conditions and also its synergistic effect with the synthetic antioxidant tertiary butylhydroquinone (TBHQ). Soybean oil samples with no antioxidant added (SO), 3,000mg/kg rosemary extract (RE), 50mg/kg TBHQ (TBHQ), and a mixture of those two antioxidants (RE+TBHQ) were heated to 180C for 20h. After 0, 10 and 20h, the oxidative stability, total polar compounds, tocopherol content and fatty acid profile were determined. The addition of rosemary extract increased oxidative stability and resulted in a lower formation of total polar compounds and a higher retention of tocopherols. The RE treatment showed the highest amount of polyunsaturated fatty acids after 20h. There was not any synergy between TBHQ and rosemary extract in preventing oxidation of soybean oil. Rosemary extract showed a higher antioxidant potential when compared with TBHQ. PRACTICAL APPLICATIONS: Antioxidants are important ingredients in food processing because they have the capacity to protect foods, containing oils and fats, from damage caused by free radicals and reactive oxygen species. Synthetic antioxidants are widely used in the food industry; however, their utilization has been questioned because of toxicity. Therefore, there is a growing interest in the use of natural antioxidants to reduce or replace the synthetic antioxidants. Several species are used in cooking, medicine and by the pharmaceutical industry, standing out the rosemary. Being rich in compounds with high antioxidant activity, the rosemary extract can be used to replace synthetic antioxidants used in vegetable oils. © 2012 Wiley Periodicals, Inc.

Design of biogas pipeline - Energy and sanitation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação da resistência à fratura de raízes fragilizadas reabilitadas por diferentes técnicas de construção de núcleos intra-radiculares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência de soluções irrigadoras na resistência adesiva de pinos de fibra de vidro utilizando cimento resinoso: avaliação através do teste de push-out

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da qualidade de mourões de várias espécies de Eucalyptus spp. tratados pelo método de substituição de seiva

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Análise das influências do branqueamento na retenção de caulim e nas propriedades do papel

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise da interface adesiva entre cimentos resinosos e diferentes terços da dentina intrarradicular

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)