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A total of 80 isolates of Phytophthora infestans were collected in Sichuan during 2010 to 2014 and analyzed against fluazinam. The results showed that there were no significant differences in sensitivity of isolates to fluazinam in different years, their sensitivities distributed as a unimodal curve, EC50 values ranged from 0. 1830 μg/mL to 0. 8767 μg/m L, the most insensitive was 4. 8 folds of the most sensitive,with a mean of (0. 4369 ± 0. 1426) μg/mL, which could be used as baseline-sensitivity of P. infestans to fluazinam in Sichuan. Meanwhile, resistant isolates were not detected in Sichuan province. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to optimize the medium composition and fermentation parameters of Trichoderma harzianum strain UN-2 producing β-glucanase, improve its β-glucanase production capacity, and study the antagonism of the crude enzyme solution of βglucanase on the pathogen of rice sheath blight and its field control effect, so as to clarify the application potential of T. harzianum strain UN2 in controlling rice sheath blight. [Method] In order to optimize the inducing conditions for the production of β-glucanase from T. harzianum strain UN-2, a single factor experiment was conducted to investigate the effects of carbon, nitrogen and metal ions on the production of β-glucanase from T. harzianum strain UN-2, and orthogonal experiments were used to determine the optimal temperature, pH, inoculation amount, bottled amount, shaking speed, and fermentation time for the production of glucanase from T. harzianum strain UN-2. The antifungal and preventive effects of crude β-glucanase solution on rice sheath blight were studied through in vitro antagonism and field experiments. [Result] The optimal carbon and nitrogen sources for the fermentation of β-glucanase from T. harzianum strain UN-2 were wheat bran and ammonium sulfate, respectively. Metal ions Ca2+ and Mg2+ had a significant promotional effect on the activity of β-glucanase induced from T. harzianum. The optimal culture medium for T. harzianum strain UN-2 to produce β-Glucanase were composed of 10.0 g/L wheat bran, 0.5 g/L β-glucan, 4.0 g/L ammonium sulfate, 1.5 mmol/L Ca2+,0.5 mmol/L Mg2+. And the optimal fermentation conditions for producing β-glucanase were as follows: 30 mL medium filled in 250 mL flask with 8 mL inoculum amount of the culture, initial pH 6.5, at 32 °C, with shaker speed 160 r/min, incubating for 64 hours. The crude β-glucanase solution induced from T. harzianum strain UN-2 had a significant inhibitory effect on the mycelial growth and sclerotia germination of Rhizoctonia solani and Rhizoctonia cerealis, and the field control effect on rice sheath blight caused by R. solani was 70.45%, which was equivalent to 5% Jinggangmycin treatment. The crude β-glucanase solution could improve rice seed setting rate and grain plumpness. [Conclusion】 Under the optimal fermentation conditions, the activity of β-glucanase induced from T. harzianum strain UN-2 is 97.68 U/mL, the crude β-glucanase solution has strong antifungal and preventive effects on rice sheath blight, and has a certain growth promotion effect on rice plants. [ABSTRACT FROM AUTHOR]

[Objective] The purpose of the study is to provide a scientific basis to control leaf spot disease on Salvia miltiorrhiza which happends in Zhongjiang county, Sichuan province, by identifying pathogenic fungus and screening of fungicides. [Method] The pathogen causing leaf spot disease on S. miltiorrhiza was isolated and purified by tissue separation and single spore culture, respectively. The pathogenicity of the isolate was determined according to Koch's rule and morphological characteristics were observed. The rDNA-ITS sequence primer ITSl/ ITS4, ACT (actin) and GDPH (glyceraldehyde-3-phosphate dehydrogenase) genes were used for molecule biology identification. Five fungicides were used to determine the inhibition effect on that pathogen, and the toxicity regression equation of them was also established. [Result] Combined with pathogenicity, colonymorphological characteristics and rDNA-ITS sequence analysis results, the pathogen was identified as Colletotrichum fructicola. The five fungicides including 80% Mancozeb WP, 80% Ethylicin EC, 250 g/L Azoxystrobin SC, 50% Kresoxim-methyl WG, and 500 g/L Fluazinam SC, had a certain inhibitory effect on mycelium growth, and the EC50 value of 80% Ethylicin EC was 19. 18 µg/mL, which showed a strong inhibitory effect. [Conclusion] The pathogen causing leaf spot disease on S. miltiorrhiza to happen in Zhongjiang county was C. fructicola. 80% Ethylicin EC had the strongest antibacterial activity and could be used for the prevention and control of the leaf spot disease. The study provides a theoretical basis for the treatment of leaf spot on S. miltiorrhiza. [ABSTRACT FROM AUTHOR]

206 strains of Thenatephorus cucumeris were isolated from samples of 12 cities in Sichuan province. Bioassays method was used to detect the resistance of T. cucumeris to Jinggangmysin. The results indicated that EC50 was positively correlated with the years. The trend of EC50 was rising up year by year. Besides, pathogens became resistant in the most tested parts of Sichuan. The frequencies of resistance were generally between 5 and 40 which represented low and middle level. According to the monitoring in those years, Chengdu, Meishan, Ziyang had a higher risk on the resistance of T. cucumeris to Jinggangmysin, considered to strengthen the monitoring of pesticides-resistance work. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to optimize pre-basic seed production and manipulate N nutrient management by aeroponics, effects of N levels on N, P and K uptake and distribution of potato during different growth stages were studied. [ Method] The experiment was laid out in a randomized block design of two factors with two potato cultivars of Chuanyul 17 and Mira by aeroponics. N levels were set at 5 levels of 120, 240, 360, 480 and 600 mg/L. In different growth stages, dry matter weight, nitrogen, phosphorus and potassium contents of different parts of plant were measured. Dry matter accumulation, nitrogen, phosphorus and potassium contents, uptake and distribution were analyzed. [Result] ( i) In the same N level, the dry matter accumulation of Mira was higher than that of Chuanyu 117 at the same grow period. The highest dry matter accumulations were achieved under the N level 240 mg/ L in the same growth stages with two cultivars. The dry matter accumulation of Chuanyu 117 and Mira was 2. 86 and 4. 23 g/plant in N Level 240 mg/L at 90 days after transplanting ( DAT) respectively. ( ii) The content of Nitrogen ( N), phosphorus ( P) and potassium ( K) in different organs increased as the nitrogen level increased at different growth stages with the two cultivars. The uptake and accumulation of N, P and K was higher under the N 240 mg/ L treatment than that of other N levels at 90 DAT, respectively, Chuanyul17 were 0. 306, 0. 070 and 0. 544 g!plant respectively; Mira were 0. 489, 0. 117 and 0. 899 g/plant. ( iii ) At the same growth periods, the distribution ratio of N, P and K in leave, stem and root under middle N levels was higher than that of low or high N levels, but the effect on tubers was contrary to the above. The distribution ratio of N, P and K in leave, stem and root was high at the early stage, and then N, P and K was transferred to tubers in the late growth stages. ( iv) The tuber number and weight per plant reached a maximum under the N level of 240 mg/ L with the two cultivars, respectively, was 24. 78 grain/plant, 53. 78 g/plant for Chuanyu 117, and 29. 31 grain/ plant, 82. 23 g/plant for Mira. [Conclusion ] Increasing nitrogen in an appropriate amount can promote the uptake and accumulation of nitrogen, phosphorus and potassium in plants, which is beneficial to the improvement of pre-basic seed production. Under the condition of low light intens ity ecology in Sichuan basin, we can obtain higher yield of potato pre-basic seeds under nitrogen level of 240 mg/L by aeroponics. [ABSTRACT FROM AUTHOR]

Hydroponics experiments by rhizosphere application with different concentrations of salicylic acid (SA) were conducted to investi­gate the effect of exogenous SA on carbohydrate metabolism in cucumber (Cucumis sativus L. ) seedlings leaves. The results showed that the appropriate concentration of SA treatment promote the growth of cucumber seedlings, and in 0. 1 mmol/L, for SA treatment, the effect was the best ; The soluble sugar, reducing sugar and total sugar content of the first true leaf were significantly higher than that of control when the leaf was treated, and the content reached the highest after 6 d; Raffinose and stachyose concentrations were lower than of control, and in 0. 5 mmol/L for SA treatment, the effect was the most obvious; Starch content had a sharp decline and fell to the lowest point after 6 days, about 10. 42 mg • g-1 with different concentrations of SA, and in 0. 5 mmol/L, for SA treatment, the effect was the best. AI and NI invertase activ­ity were lower than the control, synthase SS (cleavage direction) was slightly higher than the control activity in the early stage, late signifi­cantly lower than the control with different concentrations of SA, and in 0.5 mmol/L, for SA treatment, the effect was the best; SPS activity increased, the three concentrations reached a very significant difference in post-processing control with different concentrations of SA, and in 0. 5 mmol/L, for SA treatment, the effect was the best; SS and SPS activity changed with similar trend, in the overall look, SS activity was relatively lower than that of SPS activity; Amylase activity was higher thian control, the tendency for 0. 1 mmo/L, SA treatment effect was ob­vious with different concentrations of SA, which indicated that with exogenous SA the enzyme activity and size related to sucrose metabolism in leaves indirectly afected the accumulation of leaves of sugar. [ABSTRACT FROM AUTHOR]

Two pepper varieties ( ‘ eijintiao ' and ‘ chuanteng six ' )， which were used most in Sichuan province, were selected to intercrop with peanuts in this experiment. Disease incidences were investigated in different intercropping systems, planting distances between pepper and peanut and planting densities. The results showed that intercropping system reduced the incidence of pepper anthracnose and peanut leafspot diseases. Efficacy of different intercropping systems against pepper anthracnose reached 29. 71 % - 93. 75 % ， and the intercropping system of two rows of ‘ chuanteng six ' peppers and one row of peanuts achieved the highest efficacy ( 93. 75 % ) ； The disease index of planting distance between pepper and peanut at 10 cm was significantly ( 7 < 0. 05 ) lower than that of planting distance of 30 cm, which indicated that in a certain distance between pepper and peanut, the shorter both row distances were, the better the prevent diseases effects were. Efficacy of pepper and peanut intercropping against peanut leafspot got to 37. 68 % - 82. 80 %. Of which intercropping system of two rows chuanteng six peppers and one row peanuts was the best and reached 82. 80 % . Based on considering control efficacy of two kinds of disea ses, the intercrop planting ratio of two rows of peppers to one row of peanuts could reach the best control efficacy; The leafspot diseases index of peanut planting density at 30 cm was significantly ( 7 < 0. 05 ) lower than that at 10 cm, which indicated that the smaller the peanut density was, the lighter the peanut leafspot disease was. [ABSTRACT FROM AUTHOR]