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991.
Gilberto Santos Andrade Dirceu Pratissoli Leandro Pin Dalvi Nicolas Desneux Hugo José Gonçalves dos Santos Junior 《Journal of pest science》2011,84(3):313-320
Trichogramma spp. are major parasitoids of lepidopteran pest eggs, but there is large variation in efficacy toward a given pest among
the numerous described Trichogramma species. It is important to select the Trichogramma species that most effectively parasitize and develop in target pest eggs for biological control. In this context, Trichogramma pretiosum, T. exiguum, T. atopovirilia and T. acacioi were studied in Heliothis virescens eggs under different thermal conditions. The parasitoids were reared at constant temperatures of 20, 25 and 30°C and tested
at these respective temperatures, while parasitoids reared at 25°C were also tested at 20 and 30°C, for a total of 20 species–temperature
combinations. About 30 H. virescens eggs were offered to the parasitoids for 24 h. Among the four species, parasitism rate by T. atopovirilia was highest at all temperature conditions, whereas T. acacioi had the lowest rates of parasitism at 25°C and 25/30°C. Parasitism ranged from 13.8 to 43.8% among all species–temperature
combinations. Viability (emerged parasitoids) ranged from 80.8 to 98.4%, and was deemed satisfactory. The emergence rates
of T. exiguum and T. acacioi were affected by temperature. Temperature also affected the sex ratio of T. exiguum at 25/30°C, whereas T. pretiosum and T. acacioi produced females predominantly independent of temperature. Overall, the parasitoid T. atopovirilia was the most efficient in parasitizing H. virescens eggs, though the levels of parasitism obtained might not ensure its successful use in biological control programs. The temperature-related
differences in biological traits observed in the four Trichogramma species tested hint at the importance of making careful choices regarding climatic conditions where the parasitoid is going
to be used when selecting a species for biological control programs. 相似文献
992.
Growth and ontogeny of digestive function were studied in pikeperch (Sander lucioperca) larvae weaned on artificial food at different ages. Three weaning treatments initiated respectively on day 9 (W9), day 15
(W15) or day 21 (W21) post-hatching (p.h.) were compared with a control group, fed Artemia nauplii from first feeding until the end of the rearing trial on day 36 p.h. The digestive enzyme activities and the ontogeny
of digestive structures were investigated using enzymatic assays and histological methods. Growth of pikeperch larvae was
significantly affected by precocious weaning. Pancreatic (trypsin and amylase) and intestinal (leucine-alanine peptidase,
leucine aminopeptidase N and alkaline phosphatase) enzyme activities were detected from hatching onwards, increased at the
moment of first feeding and then decreased. Pepsin secretion occurred at day 29 p. h. only, concurrently with the stomach
development and differentiation of gastric glands. In the early weaning group (W9) the maturation process of intestinal enterocytes
seems to be impaired and/or delayed and several signs of malnutrition were recorded. Except for alkaline phosphatase activity,
no differences in enzyme activities and development of digestive structures were observed among the control, W21, and W15
groups. Moreover, at the end of the experiment, no differences in proteolytic activities were observed among larvae from the
different treatments, indicating that, in surviving individuals, the digestive structures were properly developed and the
larvae had acquired an adult mode of digestion. Based on the artificial diet used, our results suggested that pikeperch larvae
can be weaned from day 15 p.h. without significant adverse effect on digestive capacities (except for alkaline phosphatase)
or development of digestive tract, while earlier weaning impaired the onset of the maturation processes of the digestive system,
both in terms of morphological structures and enzymatic activities. 相似文献
993.
Renata Pereira da Silva-Marques Joanis Tilemahos Zervoudakis Nelcino Francisco De Paula Luciana Keiko Hatamoto-Zervoudakis Pedro Ivo José Lopes da Rosa e Silva Núbia Bezerra do Nascimento Matos 《Tropical animal health and production》2018,50(3):495-501
Two experiments were conducted to evaluate reduced supplementation frequencies for grazing beef cattle in rainy season. In experiment 1, evaluating the nutritional parameters, four rumen-cannulated Nellore bulls (BW = 410 kg) were used. In experiment 2, evaluating animal performance, 48 Nellore bulls (BW = 358 kg) were used. The treatments were as follows: mineral supplement (MS) alone and MS plus protein-energy supplement provided 3×, 5× and 7×/week. Supplementation frequency did not affect (P > 0.05) intake and digestibility. Average daily gain was greater (P < 0.001) to supplementation compared with MS. The supplementation 5×/week resulted in greater weight gain per hectare (9.24) and higher economic returns during the study period (1.64%) compared to other supplementations. Supplementation 5×/week increased animal performance and positively influenced economic returns. 相似文献
994.
Hongbiao Cui Yuchao Fan Lei Xu Jing Zhou Dongmei Zhou Jingdong Mao Guodong Fang Long Cang Zhenqiu Zhu 《Journal of Soils and Sediments》2016,16(5):1498-1508
Purpose
In situ immobilization of heavy metal-contaminated soils with the repeated incorporation of amendments can effectively reduce the bioavailability of soil heavy metals. However, the long-term application of amendments would lead to the destruction of soil structure and accumulation of soil toxic elements, ultimately affecting food security and quality. Thus, the sustainability of the amendments in a heavy metal-contaminated soil was evaluated from 2010 to 2012.Materials and methods
Batch field experiments were conducted in the soils, which were amended with apatite (22.3 t ha?1), lime (4.45 t ha?1), and charcoal (66.8 t ha?1), respectively. The amendments were applied only one time in 2009, and ryegrass was sown each year. Ryegrass and setaria glauca (a kind of weed) were harvested each year. Concentrations of copper (Cu) and cadmium (Cd) were determined by batch experiments. Five fractions of Cu and Cd were evaluated by a sequential extraction procedure.Results and discussion
Ryegrass grew well in the amended soils in the first year, but it failed to grow in all the soils in the third year. However, setaria glauca could grow with higher biomass in all the amended soils. The treatment of apatite combined with plants was more effective than lime and charcoal treatments in removing Cu and Cd from the contaminated soils by taking biomass into account. Apatite had the best sustainable effect on alleviating soil acidification. The Cu and Cd concentrations of CaCl2-extractable and exchangeable fractions decreased with the application of amendments. Moreover, apatite and lime could effectively maintain the bioavailability of Cu and Cd low.Conclusions
Apatite had a better sustainable effect on the remediation of heavy metal-contaminated soils than lime and charcoal. Although all the amendment treated soils did not reduce soil total concentrations of Cu and Cd, they could effectively reduce the environmental risk of the contaminated soils. The findings could be effectively used for in situ remediation of heavy metal-contaminated soils.995.
This account showed that nanometer-active calcium carbonate (CaCO3) improved polyamide 1010/organic montmorillonite (OMMT) composites and OMMT boosted polyamide 1010/CaCO3. The mechanical performance suggested the composites to be reinforced through adsorption forces present between the nanofillers and the matrix. The synergistic effect of CaCO3 and OMMT increased the yields and shrunk cavities when observed by scanning electron microscopy. The obvious resulting synergism was verified by X-ray scattering techniques after the addition of OMMT. The concentration of CaCO3 did not change lamellar-size or influence the crystal growth. The effect of CaCO3 on melting behavior was found less significant than that exert on crystallization behavior. 相似文献
996.
997.
Biochar amendment can alter soil properties, for instance, the ability to adsorb and degrade different chemicals. However, ageing of the biochar, due to processes occurring in the soil over time, can influence such biochar-mediated effects. This study examined how biochar affected adsorption and degradation of two herbicides, glyphosate (N-(phosphonomethyl)-glycine) and diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) in soil and how these effects were modulated by ageing of the biochar. One sandy and one clayey soil that had been freshly amended with a wood-based biochar (0, 1, 10, 20 and 30% w/w) were studied. An ageing experiment, in which the soil-biochar mixtures were aged for 3.5 months in the laboratory, was also performed. Adsorption and degradation were studied in these soil and soil-biochar mixtures, and compared to results from a soil historically enriched with charcoal. Biochar amendment increased the pH in both soils and increased the water-holding capacity of the sandy soil. Adsorption of diuron was enhanced by biochar amendment in both soils, while glyphosate adsorption was decreased in the sandy soil. Ageing of soil-biochar mixtures decreased adsorption of both herbicides in comparison with freshly biochar-amended soil. Herbicide degradation rates were not consistently affected by biochar amendment or ageing in any of the soils. However, glyphosate half-lives correlated with the Freundlich Kf values in the clayey soil, indicating that degradation was limited by availability there. 相似文献
998.
Fernando Ibañez Tania Taurian Jorge Angelini Maria Laura Tonelli Adriana Fabra 《Soil biology & biochemistry》2008,40(2):537-539
Our previous studies of the native rhizobial population associated with peanut nodules in the Córdoba soils of Argentina revealed that this population is highly diverse and includes slow- and fast-growing isolates. The native fast-growing isolates NCHA22 and NET30 were selected on the basis of their plant growth promoting properties and their chromosomal genotypes were determined by 16S rDNA sequencing. NCHA22 and NET30 16S rDNA alleles were found to cluster with those of Rhizobium tropici group IIB and Rhizobium giardinii bv. giardinii strain H152, respectively. We have now characterized these isolates by analyzing the glnA and nifH genes to clarify their taxonomic position. These studies confirmed that fast-growing isolates belonging to species earlier described as bean symbionts were obtained from nodules of a leguminous plant that has been described as efficiently nodulated exclusively by slow-growing rhizobial strains. 相似文献
999.
Maria S. Serrano Pilar Fernández-Rebollo Paolo De Vita M. Esperanza Sánchez 《Agroforestry Systems》2013,87(1):173-179
Root rot caused by the soil-borne pathogen Phytophthora cinnamomi is leading to significant oak tree mortality in rangeland ecosystems in south western Spain. Susceptibility to P. cinnamomi infections of Q. ilex seedlings with a standard nutrition, deficient in K+, and deficient in Ca2+, was tested. Oaks deficient in K+ showed high values in Ca2+ content and were tolerant to the disease. Nutritional deficiency in Ca2+, however, did not lead to a higher K+ level in plants and induced poorer root development. In addition, K+ plant content does not appear to have any effect on pathogen tolerance. Based on these results, we conclude that satisfactory calcium nutrition may confer Holm oaks with a greater tolerance to root disease caused by P. cinnamomi. For this reason, limestone supplements are recommended as a measure against root rot caused by P. cinnamomi in rangelands in southern Spain, as a good option for control of oak root disease. 相似文献
1000.
Nimet Sema Gencer Nabi Alper Kumral H. Ozkan Sivritepe Melis Seidi Hilal Susurluk Bulent Senturk 《Phytoparasitica》2009,37(3):217-224
The spider mites Tetranychus urticae Koch and Panonychus ulmi (Koch) (Tetranychidae) cause severe economic losses to vegetable farms and deciduous fruit orchards in Turkey. One of their
predators, the ladybird beetle Stethorus gilvifrons (Muls.) (Col., Coccinellidae), aggregates on mite-infested patches of plants. The present study assessed whether there is
a role for herbivore-induced plant volatiles (HIPVs) and/or odors emitted directly from these two mite species in the aggregative
response of ladybird beetles. The olfactory responses of the predator females to volatiles from T. urticae- and/or P. ulmi-infested sweet pepper (four cultivars, viz. ‘Demre’, ‘Yalova Carliston’, ‘Kandil Dolma’ and ‘Yag Biberi’), kidney bean (cv.
‘Barbunya’) and apple (M9 rootstock) were investigated using a two-choice olfactometer. Our results showed that HIPVs emitted
from both T. urticae- and P. ulmi-infested plants significantly attracted S. gilvifrons adults for all plants except the sweet pepper cv. Yag Biberi. In addition, it was found that volatiles from apple plants
infested by T. urticae and, especially, P. ulmi are more attractive for S. gilvifrons females than those emitted by other infested plants. The results also suggest that the odors of T. urticae adults and their products might influence the attraction of S. gilvifrons females. 相似文献