Monitoring of QoI fungicide resistance in Plasmopara viticola populations in Japan

BACKGROUND: The increasing occurrence of QoI fungicide resistance in Plasmopara viticola (Berk. & MA Curtis) Berl. & DeToni populations is becoming a serious problem in the control of grapevine downy mildew. In Japan, the existence of QoI‐fungicide‐resistant P. viticola was reported in 2009. RESULTS: The QoI fungicide resistance in P. viticola samples collected from vineyards in Japan in 2008 and 2009 was monitored. Resistant P. viticola were detected in the regions where QoI fungicides have been introduced in accordance with the pest management programme, whereas in Hokkaido vineyards, where QoI fungicides have not yet been introduced, QoI‐fungicide‐resistant P. viticola were not found. CONCLUSION: Japan comprises thousands of islands and is physically isolated from other countries by the sea. Monitoring the emergence, incidence and distribution of QoI fungicide resistance in P. viticola populations in Japan is necessary to improve pest management strategies for downy mildew disease in Japanese vineyards. Copyright © 2010 Society of Chemical Industry     

Nitrous oxide evolved from soil covered with plastic mulch film in horticultural field

Soil solarization practice, in which soil is covered with plastic mulch film and exposed to high temperature prior to crop cultivation, is expected to be an effective method for reducing weeds and pathogenic microorganisms without using agricultural chemicals. Although the production of nitrous oxide (N₂O), a major greenhouse gas, is enhanced in fertilized soil covered with plastic mulch films, its transport route to the atmosphere has not been sufficiently elucidated to date. In this study, we investigated the N₂O evolution from plastic-mulch-film-covered agricultural soil. In a horticultural field where ridge soil was covered with a plastic mulch film after fertilization, we observed significant N₂O flux from the soil surface of the unfertilized furrow between the ridges, indicating the horizontal diffusion of N₂O from the ridge soil covered with the mulch film to the adjacent furrow soil surface. On the other hand, the measurement of the permeance (permeation coefficient) of the plastic mulch film for gaseous N₂O by laboratory experiment revealed that N₂O gradually permeated the mulch film; the permeance increased exponentially with an increase in ambient temperature, indicating possible N₂O emission by permeation through the mulch film under field conditions. In winter, the amount of N₂O emission by permeation through the mulch film was estimated to be lower than that emitted from the furrow soil surface, and it was lower than that in summer. On the other hand, it was estimated to be much higher in summer owing to the higher permeance of the film at high temperatures.     

Palatability and physicochemical properties of sausages prepared via lactic acid fermentation and drying at low temperature

The present study aimed to assess the palatability of sausages undergoing low‐temperature fermentation and drying process. Lactobacillus sakei D‐1001 or Lactobacillus salivarius A001 were used as starter cultures for fermentation, and the following properties of the sausages were investigated: colony‐forming units of lactic acid bacteria; concentrations of lactic acid, protein, peptides, and free amino acids; distribution of protein; composition of free amino acids; and physical properties and taste. Alterations in the composition of proteins, peptides, and free amino acids as well as in various physical properties were caused by fermentation by lactic acid bacteria. A sensory test indicated that the palatability of the fermented sausages was greater than that of the non‐fermented sausages, particularly in terms of hardness and juiciness. This was considered to be due to protein degeneration and changes in the physical properties of the sausages as a result of fermentation by lactic acid bacteria. However, the taste of the fermented sausages was sourer than that of the non‐fermented sausages, and therefore, inferior. Our study revealed that the palatability of the sausages in terms of hardness and juiciness were increased by low‐temperature fermentation by lactic acid bacteria and the drying process.     

生物刺激素在春季花椰菜上的应用研究

为探究生物刺激素产品在春季花椰菜绿色防控生产中的应用效果,2019年在北京市大兴区开展4种生物刺激素对花椰菜生产的影响试验,比较植株长势、结球率、单球直径、单球质量、品质等指标,以筛选适合推广使用的生物刺激素。结果表明:苗期施用大丽轮枝孢激活蛋白(处理2)可以促进花椰菜苗期生长,推荐用量为苗期施用大丽轮枝孢激活蛋白5000倍液,定植后30 d施用12000倍液;定植后施用大丽轮枝孢激活蛋白(处理6)可以提高花椰菜的产量,推荐定植后7 d和结球前各施用1次大丽轮枝孢激活蛋白6000倍液;采用以上处理方法可以增加花椰菜的维生素C含量,提高品质和安全性。     

Phosphorus compounds and their solubility in swine manure compost

In the Japanese warm areas, as a result of intensive and repeated potato cropping, common scab, a soil-borne disease has become a serious problem. The soil moisture level has been shown to be an important factor affecting the incidence of common scab. That is, a high level of soil moisture reduces the severity of common scab. However, in this investigation, although during the spring cropping precipitation was abundant, a large number of tubers showing scab lesions were produced. The results indicate that the soil moisture level may not be an important factor affecting the incidence of potato scab in the humid region.

To identify other factors which may affect scab severity, the relation between sugar content in the peel of potato tuber and the incidence of common scab was investigated. Generally, the amount of reducing sugar in the tuber peel increased gradually with the growth of the tubers, then reached a maximum level two weeks after the start of tuber formation, and thereafter declined. The period corresponding to the highest sugar content in peels coincided with the most susceptible period for scab infection. The content of reducing sugar in the peel of susceptible cultivars was higher than that of the resistant cultivars, throughout the tuber growth, and the critical value of the content was 2.0 mg per 100 g fresh peel. These results suggest that the content of reducing sugar in tuber peel may be an important factor affecting the incidence of common scab.     

Hydrogen peroxide treatment on typical Hokkaido soils

G. W. ROBISON et al. (1) introduced a method of H²O² treatment for study of humification based on the fact that the humus substances in soils are perfectly destroyed under the treatment of H²O². W. O. ROBINSON (2) used 15% H²O² for the determination of total organic matters.     

Studies on the humus forms of forest soils

Samples described in the previous paper were analyzed for humus composition by the method of Kumada el al,, elementary composition of humic acids, nitrogen distribution among humic acid, fulvic acid, and humin, and organic matter composition by the modified Waksman method. The samples obtained by physical fractionation from each horizon of Higashiyama soil were as follows: f₁ and f₂ from the L layer, f₁, f₂ and f₃ from the F layer, f₁ f₂, sand, silt, and clay fractions from the H-A and A horizons.

With the progress of decomposition, the following tendencies were rather clearly observed.

The extraction ratio of soluble humus, amounts of humic acid and fulvic acid, and PQ, value tended to increase with some exceptions. The degree of humification of humic acid proceeded. Most humic acids belonged to the Rp type, but those of the clay fractions belonged to the B type.

As for the elementary composition of humic acid, transitional changes from the Lf₁ to the clay fraction of the A horizon were observed. But differences in elementary composition among humic acids were far less, compared with those among whole fractions.

Nitrogen contents in humic, fulvic, and humin fractions increased with the progress of decomposition and humiliation, and the largest relative increase was found in fulvic acid nitrogen.

According to the modified Waksman's method, the amounts of residues and protein increased, while the total amounts of each extract, except for the HCl extract, and the amounts of sugars and starch, phenolic substances, hemicelluloses and pectin, and cellulose decreased. Sugars and starch comprised only a small portion of the hot water extract, and polyphenols substances comparable to sugars and starch were also found in the extract. Hemicelluloses and pectin accounted for only about one-half of the HCl extract. Several characteristic differences in the elementary composition of extracts and residues were found.

Pheopigments existed in benzene-ethanol extracts and their amounts seemed to decrease from Lf₁ to Ff₂.     

Studies on the humus forms of forest soils

The results of elementary analysis of each fraction separated physically from each horizon of five forest soils were described.

The biggest fraction was Lf₂ (fresh litter) in L layers, Ff₂ (>2 mm) or Ff₂ (2-1 mm) is F layers and Hf₄ in H layers.

Of all the changes in various parameters which accompanied decomposition and humification, the change in C/N ratio was the most obvious; the C/N ratio for plant remains easily decreased to 25 or 30 during decomposition, but any further decrease in this value occurred with difficulty. It was specifically pointed out that Hf₇ and Hf₂ were fairly different materials from the other fractions.

As for A horizons, both carbon and nitrogen contents increased, and CIN ratios decreased in the order of sand, silt and clay fractions.     

Reactivity of green tea catechins with formaldehyde

In the reaction of green tea catechins with formaldehyde at room temperature (25°C), tea catechins were found to have reactivity. In particular, (-)-epicatechin gallate and (-)-epigallocatechin gallate, which have a galloyl moiety at the C-3 position, showed higher reactivity than (+)-catechin, (-)-epicatechin, or (-)-epigallocatechin. Reactivity of various kinds of simple phenolic compounds and flavonoids with formaldehyde was also examined. Among these compounds, only phloroglucinol showed reactivity to the same degree as that of nongalloylated catechins. These results suggest that factors for reactivity with formaldehyde at room temperature may be the presence of a phloroglucinolic A-ring structure and the absence of the electron-attractive group such as a carbonyl group in Cring. The comparison of the reactivity of 3-O-acylated catechins with that of 3-O-galloylated catechins indicated that only a galloyl group effectively enhanced reactivity with formaldehyde.     

Preparation of strongly acidic cation-exchange resins from gymnosperm acid hydrolysis lignin

The chemical preparation of strongly acidic cation-exchange resin from sulfuric acid lignin (Klason lignin) (SAL), a typical acid hydrolysis lignin, was investigated. Sulfonation of resinified SAL itself gave a resin with an ion-exchange capacity of 2.3 mEq/g. After resinification with formaldehyde, the phenolized SAL with a reactivep-hydroxyphenyl group yielded a resin with an ion-exchange capacity of 3.2 mEq/g. The latter capacity is superior to that of the corresponding commercial phenol-type resins (2–3 mEq/g), but did not reach the level of the corresponding commercial styrene-type resins (4-5 mEq/g).This paper was presented at the 43th Lignin Symposium, Fuchu, October 1998