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Bacterial wilt caused by Ralstonia solanacearum is a distributed and worldwide soilborne disease. The application of biocontrol microbes or agricultural chemicals has been widely used to manage tomato bacterial wilt. However, whether and how agricultural chemicals affect the antagonistic ability of biocontrol microbes is still unknown. Here, we combined potassium phosphite (K-Phite), an environmentally friendly agricultural chemical, and the biocontrol agent Bacillus amyloliquefaciens QPF8 (strain F8) to manage tomato bacterial wilt disease. First, K-Phite at a concentration of 0.05% (wt/vol) could significantly inhibit the growth of R. solanacearum. Second, 0.05% K-Phite enhanced the antagonistic capability of B. amyloliquefaciens F8. Third, the greenhouse soil experiments showed that the control efficiency for tomato bacterial wilt in the combined treatment was significantly higher than that of the application of B. amyloliquefaciens F8 or K-Phite alone. Overall, our results highlighted a novel strategy for the control of tomato bacterial wilt disease via application and revealed a new integrated pattern depending on the enhancement of the antagonistic capability of biocontrol microbes by K-Phite.

Traditional sprayers adopt large-area uniform pesticide application, resulting in a low effective utilisation of pesticide and a harmful effect to the natural environment. Variable-rate spray is the key point to precision chemical application. However, it is inevitable that the spray pressure sharply fluctuates during variable-rate spray, which will definitely influence the spray characteristics, such as spray droplet sizes, spray angles, spray droplet velocities, etc., and reduce the efficiency of pesticide applications. Therefore, the research on how to keep the spray pressure constant during the process of variable- rate spray has practical significance to precision pesticide applications. In order to achieve the stability of spray pressure for variable- rate spray, a sprayer with constant-pressure control was set up using a closed-loop proportion integration differentiation (PID) controller of constant-pressure water-supply, which employed the techniques of single-phase alternating current (AC) chopper variablevoltage control and PID feedback regulation. Using hollow-cone nozzles, the spray volume was changed by adjusting spray pressure, frequency, and duty cycle of electromagnetic valve switching. The spray features concerning the spray angle and the spray volume distribution were studied in laboratory. The conclusions are as follows: i) for a given input spray pressure, the closed-loop controller with AC chopper and PID feedback regulation can effectively control the pressure fluctuations during the variable-rate spray through varying the frequency and the duty cycle; ii) the spray angle was slightly affected by the flow-rate change through adjusting the frequency and the duty cycle of electromagnetic valves or changing the number of open nozzles. The spray angle changes were controlled within the range of the maximum deviation 0.87° from mean value and the minimum deviation 0.03° from mean value; iii) when the spray pressure was set as 0.3 Mpa, the peak radial position of the spray volume distribution basically unchanged and the spray volume and the peak values of the spray distribution gradually increased with the increasing duty cycle. When the setting pressure was increased, the spray volume increased and the peak radial position of the spray distribution gradually expanded toward outside, however the peak value of the spray distribution decreased a little.

Background : Daphnia magna is a useful aquatic organism for testing ecological toxicities of environmental pollutants. However, there were only a few studies on agricultural chemicals using these organisms. / Methods : We investigated acute and subchronic toxicities of 30 agricultural chemicals commonly used in Japan in D. magna. Acute toxicity of the agricultural chemicals was determined using the concentrations yielding 50% immobility of D. magna after 24 hr and 48 hr exposure as end points. D. magna was cultivated with the chemical and algae until the first brood production. Lethal toxicity and the number of survival broods were determined within 13 days....

The foregoing coverage treats the policy context for water-agriculture questions, provides a general characterization of the institutional setting, and explores some cases in more detail. the cases are chosen to highlight promising, successful, and/or innovative efforts. the preceding chapter provides implicit evidence regarding control capacity of the water supply sector in the US In the following pages, the focus on control capacity is made explicit.

The purpose of this study was to determine energy equivalents of inputs and output in maize production in Bursa province. The data in this study were collected from maize farms in Bursa province, Karacabey district. Questionnaires were administered through lace-to-face interview in 2011 Lily, 2011. The results of the study show that fertilizers have the highest rate of energy equivalency of all the inputs used in maize production at 51.47%. The energy equivalent rate of electricity is 20.30% and the energy equivalent rate of fuel is 23.29%. The energy equivalent rates for human power, machinery, chemicals and water for irrigation were determined to be low in maize production. According to the output/input ratio calculated, the energy ratio is 0.76 in maize production in the research area. This ratio implies that the inputs used in maize production have not been used effectively. Ineffective use of these resources also causes environmental problems.

Powdery mildew is one of the most devastating diseases in cucurbits. Crop yield can decline as the disease severity increases. In this study, we evaluated the effect of silver nanoparticles against powdery mildew under different cultivation conditions in vitro and in vivo . Silver nanoparticles (WA-CV-WA13B) at various concentrations were applied before and after disease outbreak in plants to determine antifungal activities. In the field tests, the application of 100 ppm silver nanoparticles showed the highest inhibition rate for both before and after the outbreak of disease on cucumbers and pumpkins. Also, the application of 100 ppm silver nanoparticles showed maximum inhibition for the growth of fungal hyphae and conidial germination in in vivo tests. Scanning electron microscope results indicated that the silver nanoparticles caused detrimental effects on both mycelial growth and conidial germination.

PHETCHABUN RAJABHAT JOURNAL, 12, 1, 117-129

This analysis addresses the case of the United States and the interaction of the water supply and agriculture sectors to encourage pollution prevention from agricultural chemicals of drinking water supplies. the term agricultural chemicals is employed here to refer to both fertilizers and also other chemicals - principally pesticides - used in agricultural production.

Pesticides on a nitrophenol basis and nitrophenols which may be formed by biotransformation from other plant-protecting agents may be extracted from aqueous samples with high recoveries by continuous liquid/liquid extraction using a rotary perforator and by solid phase extraction, respectively. Determination of these compounds in possible by high performance liquid chromatography with photodiode array detection where identification is based both on the retention time and the UV spectra. Alternatively, a gas chromatographic analysis after derivatization with heptafluorobutyric anhydride has been evaluated.

Chemicals/CAS: Pesticides

Chemicals/CAS: Pesticides

Niigata prefecture gives very high mortality rate for the bilialy tract cancer. Recent studies to explore this epidemiologic characteristics showed a significant correlation between the standerdized mortality ratio (SMR) for the biliary tract cancer and the amount of certain agricultural chemicals consumed. We detected agricultural chemicals in cholesterol gallstones of 99 patients, including 11 patients of gallbladder cancer, in order to clarify the possibility that these chemicals could be excreted into the bile and play a role in the etiology of the biliary tract cancer in this high risk area. DLD, pp'-DDT, β-BHC and PCB were detected in the gallstones, even though epidemiological study showed no positive correlation between them and the SMR for the biliary tract cancer. MCPA, MCPB, CNP, simetryn that showed significant correlation to the SMR were not detected. Further investigation on the biliary excretion of the metabolites of these chemicals is indicated.

A series of nitrogen- and phosphorus-containing pesticides (amines, anilides, carbamates, phosphonates, phenylureas, sulfonylureas, and triazines) was examined by thermospray (TSP) ionization. A method is described that employs off-line and on-line solid-phase extraction and TSP liquid chromatography—mass spectrometry (LC-MS) with time-scheduled selected ion monitoring (SIM) for environmental monitoring of these pesticides in aqueous samples. SIM detection limits for the pesticides analyzed in conjunction with reversed-phase high-performance liquid chromatography range from 40 to 600 pg. In addition, methods for inducing fragmentation in thermospray LC-MS are presented. The structural information gained therefrom can be used to confirm a tentative identification. Therefore, fragmentation pathways under certain experimental conditions were investigated. Atmospheric pressure chemical ionization, electrospray, fast-atom bombardment, 252Cf plasma desorption, and collision-activated dissociation spectra are presented for several pesticides to confirm the proposed pathways and to gain additional and complementary information. Further confirmation may be achieved by postcolumn addition of different alkylated amines to the carrier stream in TSP operation to induce postcolumn on-line derivatization (POD) reactions in the condensed phase of the vaporizer probe with selected pesticides. Additional clustering reactions in combination with solvent-mediated chemical ionization are observed by the POD technique. Both processes can be used to enhance the structural information from TSP spectra and thus the specificity of the method.