Communications in agricultural and applied biological sciences最新文献

The single and simultaneous phytotoxic effect of copper sulphate and Pyrinex 48 EC insecticide were investigated on chicken embryos. The eggs were injected by 0.1 ml of copper sulphate solution (0.05%) and/or by 0.1 ml of Pyrinex 48 EC (chlorpyriphos, 480 g/l; 1%). The treatments were performed on day 0 of incubation, and the embryos were examined on day 3 and 19 of it. Germinal disc was prepared to study the early stage of development. Number of embryonic death, developmental abnormalities and body weight of embryos were recorded on day 19. Liver samples were taken for histology and the skeleton was stained by Dawson method. The embryo mortality was not influenced by single treatment of copper sulphate, however, Pyrinex 48 EC and the combination of the test items significantly increased it on day 3. Same tendency was observed in the case of developmental aberration. Single administration of both test items and their combination significantly increased the embryo mortality on day 19. Frequency of abnormalities was not influenced by copper sulphate but single and simultaneous application of insecticide increased it significantly. Pyrinex 48 EC alone and in combination with copper sulphate significantly reduced the body weight, however, the copper sulphate alone did not influence it. Developmental abnormalities were observed sporadically in all cases. There were no findings of drug-induced hepatopathy, however, the ratio of the mitotic cells were markedly reduced. Based on the results, addition and synergistic toxic interaction may be between the copper sulphate and Pyrinex 48 EC that can highly reduce the viability of the embryos.

Global increases in human population are creating an ever-greater need for food production. Poor soil management practices have degraded soil to such an extent that rapidly improved management practices is the only way to ensure future food demands. In South Africa, deciduous fruit producers are realising the need for soil health, and for an increased understanding of the benefits of soil ecology, to ensure sustainable fruit production. This depends heavily on improved orchard management. Conventional farming relies on the addition of artificial fertilizers, and the application of chemicals, to prevent or minimise, the effects of the soil stages of pest insects, and of plant-parasitic nematodes. Currently, there is resistance toward conventional farming practices, which, it is believed, diminishes biodiversity within the soil. The study aimed to establish the soil nematode community structure and function in organically, and conventionally, managed deciduous fruit orchards. This was done by determining the abundance, the diversity, and the functionality of the naturally occurring free-living, and plant-parasitic, nematodes in deciduous fruit orchards in the Western Cape province of South Africa. The objective of the study was to form the basis for the use of nematodes as future indicators of soil health in deciduous fruit orchards. Orchards from neighbouring organic, and conventional, apricot farms, and from an organic apple orchard, were studied. All the nematodes were quantified, and identified, to family level. The five nematode-classified trophic groups were found at each site, while 14 families were identified in each orchard, respectively. Herbivores were dominant in all the orchards surveyed. Organic apples had the fewest herbivores and fungivores, with the highest number of carnivores. When comparing organic with conventional apricot orchards, higher numbers of plant-parasitic nematodes were found in the organic apricot orchards. The Maturity Index (MI) indicated that all orchard soils had values below 1.5, indicating disturbed conditions. The conventionally managed apricot orchard had the highest MI value, of 1.48. The Plant Parasitic Index (PPI) value was highest in the organically managed apricot orchard. In order to determine the existing enrichment, structural, and basal conditions, the nematode faunal analysis was applied to each site. All the sites indicated enriched and structured conditions. Regarding the diversity, the richness, and the evenness of the distribution, soil from the conventional apricot orchard had the highest species richness, whereas the organic apple orchard soil had the most even distribution of families. Different management practices in fruit orchards did not show marked differences in terms of community composition and structure.

Neem plants (Rutales: Meliaceae) are well known for their multitude of human benefits in various fields. Specifically well investigated are the Indian neem tree Azadirachta indica A. Juss., the Thai neem A. siamensis Val., the originally Malaysian/Philippinean neem A. excelsa (Jack) and, as a close relative, the Persian lilac, Melia azedarach. The major and most active natural products are azadirachtin, salannin, nimbin and marrangin from Azadirachta species, and azadirachtin analogues like meliantriol from Melia species. Neem fruits, leaves, bark, and roots have specific virtues. They have been traditionally exploited for a considerable part of human history and are documented in Sanskrit texts. Due to human activity in trade and travel both at land and sea, the plant species has been distributed around the globe and is cultivated in many tropical, and subtropical regions. A multitude of natural products of neem have been isolated, chemically characterized or identified, and investigated for their properties in the management of insects, Acarina, Crustacea, nematodes, bacteria, fungi, viruses and soil fertility (for reviews see Kraus, 2002; Schmutterer, 2002A; Rembold, 2002; Koul, 2004; Schmutterer and Huber, 2005; Kleeberg and Strang, 2009; Hummel et al., 2008, 2011, 2012). Neem products are virtually nontoxic, compatible with beneficial insects, pollinators and bees. They are environmentally benign, sustainable, renewable, and of a price affordable for developed countries. In conclusion, neem is a prime example of a natural resource with many beneficial applications in agriculture, human and veterinary medicine. So far, its use is practically free of resistance problems which are frustratingly prevalent in many areas of synthetic insecticide and drug development. Investigating more neem applications will increase future human welfare and health while being of general ecological benefit to the planet.

The broad mite Polyphagotarsonemus latus (Banks) is considered a major pest in potted azalea, Flanders' flagship ornamental crop of Rhododendron simsii hybrids. In addition to severe economic damage, the broad mite is dreaded for its increasing resistance to acaricides. Due to restrictions in the use of broad spectrum acaricides, Belgian azalea growers are left with only three compounds, belonging to two mode of action groups and restricted in their number of applications, for broad mite control: abamectin, milbemectin and pyrethrin. Although P. latus can be controlled with predatory mites, the high cost of this system makes it (not yet) feasible for integration into standard azalea pest management systems. Hence, a maximum efficacy of treatments with available compounds is essential. Because abamectin, milbemectin and pyrethrin are contact acaricides with limited trans laminar flow, only broad mites located on shoot tips of azalea plants will be controlled after spraying. Consequently, the efficacy of chemical treatments is influenced by the location and spread of P. latus on the plant. Unfortunately, little is known on broad mites' within-plant spread or how it is affected by climatic conditions like temperature and relative humidity. Therefore, experiments were set up to verify whether climate conditions have an effect on the location and migration of broad mites on azalea. Broad mite infected azalea plants were placed in standard growth chambers under different temperature (T:2.5-25°C) and relative humidity (RH:55-80%) treatments. Within-plant spread was determined by counting mites on the shoot tips and inner leaves of azalea plants. Results indicate that temperature and relative humidity have no significant effect on the within-plant spread of P. latus. To formulate recommendations for optimal spray conditions to maximize the efficacy of broad mite control with acaricides, further experiments on the effect of light intensity and rain are scheduled.

The first series of field experiments with triticale F1 hybrids from 2009 confirmed usefulness of the rye 'Pampa' cytoplasmic system of mass crossing control in hexaploid (2n = 42 = AABBRR) winter triticale. The level of fertility restoration in 30 F1 hybrids varied within a range of 35.1% - 91.3%. However, the top F1 yield has not exceeded 92% of the check cultivar 'Moderato'. In the next series of field experiments with four winter F1 hybrids from 2012 the best yield reached 102% of the 'Moderato' standard and the fertility restoration index ranged between 16.7% and 100%. The top yielding F1 combination was produced using a male line derived from a cross with a restorer line from rye hybrid breeding. It supports the idea of using rye hybrid breeding as a source of variation in hybrid breeding of triticale. The advanced rye lines, representing well established complementary gene pools, show not only high potential for heterosis, but also high level of compensation for negative side effects of the 'Pampa' cytoplasm on plant vigor, which seems important in triticale. The gene flow from rye female and male gene pools to those of hexaploid triticale is facilitated with tetraploid triticale x diploid rye crosses. Numerous triploid F1 hybrids with relatively high fertility are produced, which are able to set seed after spontaneous pollination with hexaploid triticale.

During five subsequent growing seasons field experiments were carried out at the experimental farm of the University College Ghent (Belgium) to evaluate the selectivity and efficacy of herbicides for chemical weed control in triticale (x Triticosecale Wittmack). The experiments were set up on a sandy loam soil, according to a completely randomised block design with four replications. Several herbicides and combinations of herbicides were applied pre- and post-emergence, at different rates. The influence of the different treatments on weed diversity, weed density, growth inhibition and chlorosis of the crop and grain yield was studied. Results obtained from these field trials indicated differences between the different treatments.