Compounds from the subterranean part of Johnsongrass and their allelopathic potential

The allelopathic effects of the exotic invasive weed, Johnsongrass, on Lactuca sativa, a native plant in China, were evaluated and the phytotoxins were investigated under laboratory conditions. The crude extracts (chloroform and ethyl acetate fractions) that were obtained from the ethanol extract of the subterranean parts of Johnsongrass inhibited the germination speed and growth of the roots and shoots of the test plant. The four compounds, ethyl p‐hydroxybenzoate, diosmetin, apigenin, and luteolin, were isolated from the extract of the subterranean parts of Johnsongrass first, along with three other compounds (reported previously), p‐hydroxybenzaldehyde, p‐hydroxybenzoic acid, and dhurrin, and they all were evaluated on L. sativa. At the concentration of <0.5 mmol L^?1, ethyl p‐hydroxybenzoate, dhurrin, and the mixture of the compounds delayed the germination speed of the seeds of L. sativa at 24 h of incubation, while apigenin delayed the germination speed of the seeds of L. sativa at 72 h of incubation. Ethyl p‐hydroxybenzoate demonstrated the strongest delaying effect among the phenols and a similar effect was found with apigenin among the flavonoids, wheras ethyl p‐hydroxybenzoate induced a drastic inhibition of the germination at 2 mmol L^?1. In contrast, p‐hydroxybenzaldehyde and luteolin had no effect on the germination at any concentration at any stage. All the substances inhibited the shoot and root growth of L. sativa at 3 mmol L^?1. Increasing the concentration increased the inhibition of the growth of L. sativa. The inhibitory activity of ethyl p‐hydroxybenzoate and p‐hydroxybenzaldehyde was greater than that of the other compounds. This result suggested that the isolated phytotoxins might contribute to the successful invasion by Johnsongrass.     

Synthesis and herbicidal potential of substituted aurones

BACKGROUND: With the objective of exploring the herbicidal activity of substituted aurones, a series of 4,6‐disubstituted and 4,5,6‐trisubstituted aurones were synthesised, and their herbicidal activities against Brassica campestris L. and Echinochloa crusgalli (L.) Beauv. were evaluated in laboratory bioassays. Effects of some of the compounds were evaluated on seed germination. The most active compounds in the laboratory were evaluated in the greenhouse. RESULTS: The compounds were characterised by ¹H NMR, ¹³C NMR and HRMS; some of them were further identified by IR. A (Z)‐configuration was assigned to the aurones, based on spectroscopic and crystallographic data. Bioassay results of root growth showed that the aurones had a moderate herbicidal activity against the dicotyledonous plant Brassica campestris. (Z)‐2‐Phenylmethylene‐4,6‐dimethoxy‐3(2H)‐benzofuranone(6o) was the most active compound, with 81.3 and 88.5% inhibition at 10 and 100 µg ml^?1 respectively, equal to the activity of mesotrione. Some of the aurones possessed some inhibition of germination on several plant species. For glasshouse tests, the substituted aurones had lower herbicidal activity than metolachlor and mesotrione. CONCLUSION: It is possible that aurone derivatives, which possess structures different from those of the commercial herbicides, may become novel lead compounds for the development of herbicides against dicotyledonous weeds with further structure modification. Copyright © 2012 Society of Chemical Industry     

2-噻唑酰氨基环己烷基磺酰胺的合成与杀菌活性

为进一步研究环烷基磺酰胺类化合物的杀菌活性与构效关系,在前期工作基础上,合成了11个未见文献报道的2-噻唑酰氨基环己烷基磺酰胺类化合物 ( 7a ~ 7k ),其结构均经1H NMR、13C NMR、质谱和元素分析确证。分别采用菌丝生长速率法、黄瓜活体叶片法、孢子萌发法和番茄活体盆栽法对目标化合物进行了生物活性测定。结果表明:目标化合物对番茄灰霉病菌Botrytis cinerea表现出较好的抑制活性,其中化合物 7a 和 7c 在10 mg/L下对番茄灰霉病菌孢子萌发的抑制率分别为90%和67%;在200 mg/L 施药剂量下,对活体黄瓜叶片、番茄叶片和番茄花上灰霉病的防治效果,化合物 7a 分别为75%、78%和30%,化合物 7c 分别为78%、62%和44%,均优于对照药剂腐霉利,有进一步研究的价值。     

Allelopathy and the active metabolites of the endophytic fungus,Alternaria J46, from Platycladus orientalis

The endophytic fungus, Alternaria J46, was isolated from the stem of the medicinal plant, Platycladus orientalis. A suspension of Alternaria J46 mycelial segments and the culture filtrates of the fungi exhibited marked seed germination inhibition against the monocot wheat, large crabgrass, bromegrass, rice and barnyardgrass and weak inhibition against the dicot redroot pigweed and morning glory, but it was safe for use on soybean, rape, cucumber, tomato, lettuce and radish crops. It is possible to use J46 culture filtrates in order to prevent monocot weeds in dicot cropland. Three active metabolites were isolated from an extract of the fungus cultures and elucidated as 3‐acetyl‐5‐sec‐butyltetramic acid (1, tenuazonic acid), 3‐acetyl‐5‐iso‐butyltetramic acid (2, vivotoxin II) and cyclo‐(L‐leucyl‐L‐proline) (3). Among these three compounds, compounds 1 and 2 showed significant phytotoxic effects on the seed germination of large crabgrass, while compound 3 exhibited weak activity, and all were safe for lettuce at 100 μg mL^?1. Accordingly, compounds 1 and 2 were the main active metabolites that were responsible for endophytic fungus Alternaria J46's strong seed germination inhibition against monocotyledons.     

含哌啶噻唑结构的乙酰氨基衍生物的合成及杀菌活性

为了寻找高效的杀菌活性物质,以哌啶噻唑结构为母体,甘氨酸为连接基团,通过重氮化、氯化、成环和缩合等步骤合成了14个含哌啶噻唑结构的乙酰氨基衍生物,通过核磁共振氢谱 (1H NMR)、碳谱(13C NMR)及高分辨质谱 (HRMS)对化合物的结构进行确证。初步杀菌活性测定结果表明:甘氨酸作为连接基团对化合物杀菌活性的提高具有积极影响,其中,化合物 7a 、 7c 和 7g 在25 mg/L剂量下对黄瓜灰霉病菌的抑制率为68.7%、71.6%和67.2%,化合物 7a 、 7g 和 7i 对马铃薯晚疫病菌的抑制率分别为50.8%、61.9% 和55.8%。     

Synthesis of 2-amino-6-oxocyclohexenylsulfonamides and their activity against Botrytis cinerea

BACKGROUND: With the objective of exploring the fungicidal activity of 2‐oxocyclohexylsulfonamides (2), a series of novel 2‐amino‐6‐oxocyclohexenylsulfonamides (6 to 23) were synthesised, and their fungicidal activities against Botrytis cinerea Pers. were evaluated in vitro and in vivo. RESULTS: The compounds were characterised by IR, ¹H NMR and elemental analysis. Bioassay results of mycelial growth showed that compounds 6 to 23 had a moderate antifungal activity against B. cinerea. N‐(2‐methylphenyl)‐2‐(2‐methylphenylamino)‐4,4‐dimethyl‐6‐oxocyclohexenylsulfonamide (13) and N‐(2‐chlorophenyl)‐2‐(2‐chlorophenylamino)‐6‐oxocyclohexenylsulfonamide (21) showed best antifungal activities, with EC₅₀ values of 8.05 and 10.56 µg mL^?1 respectively. Commercial fungicide procymidone provided an EC₅₀ value of 0.63 µg mL^?1. The conidial germination assay showed that most of compounds 6 to 23 possessed excellent inhibition of spore germination and germ‐tube elongation of conidia of B. cinerea. For in vivo control of B. cinerea colonising cucumber leaves, the compound N‐cyclohexyl‐2‐(cyclohexylamino)‐4,4‐dimethyl‐6‐oxocyclohexenylsulfonamide (19) showed a better control effect than the commercial fungicide procymidone. CONCLUSION: The present work demonstrated that 2‐amino‐6‐oxocyclohexenylsulfonamides can be used as possible new lead compounds for further developing novel fungicides against B. cinerea. Copyright © 2011 Society of Chemical Industry     

Management of the invasive species Opuntia stricta in a Botanical Reserve in Portugal

Opuntia stricta is an invasive species in the Dom António Xavier Pereira Coutinho Nature Reserve (Portugal). Different chemical approaches were assessed to simultaneously manage it and preserve the natural flora of the Botanical Reserve. Glyphosate was applied at different concentrations (2.8–180 g a.e. L⁻¹) and times of application (April, July and October) by injection into cladophyll and direct application onto areas in which the cladophyll had been cut (90 and 180 g a.e. L⁻¹). The efficacy of the herbicide applied on the cut areas was good, but the pieces of the cladophyll that had been cut were difficult to remove and destroy. Herbicide injection of a 2 mL of solution containing 45 g a.e. L⁻¹ glyphosate in the summer proved to be the easiest and most effective way of controlling the weed. Germination studies were carried out in order to understand the importance of seeds in the dissemination of O. stricta. The optimum constant temperature for germination was generally 20–25°C, there was a tendency towards increased germination following leaching in water for 24 h (7% germination at 20°C 12-h light) and 60-min scarification in sulphuric acid (15% at 20°C 12-h light). Although germination rates may be considered low, they do indicate that the emergence of O. stricta seedlings is possible.     

N-(2-三氟甲基-4-氯苯基)-2-吡唑酰氨基环己烷基磺酰胺类化合物的合成与杀菌活性

吡唑酰胺类杀菌剂是近年新农药开发的热点。本研究采用EDCI/HOBt酰胺化法合成了14个结构新颖的N-(2-三氟甲基-4-氯苯基)-2-吡唑酰氨基环己烷基磺酰胺类化合物 ( 3a ~ 3n ),其结构均经1H NMR、13C NMR、质谱和元素分析确认,并用X-射线衍射法确定了化合物 3g 的单晶结构和立体构型。菌丝生长速率法试验结果表明,化合物 3a 、 3e 和 3j 对番茄灰霉病菌Botrytis cinerea KZ-9的EC₅₀值分别为4.28、10.08和11.31 mg/L,抑菌活性不及对照药剂啶酰菌胺和腐霉利;但在孢子萌发试验中,目标化合物表现出与对照药剂相近的抑菌活性,在10 mg/L下有7个化合物对灰霉病菌孢子萌发的抑制率超过了85%;在番茄活体盆栽试验中,化合物 3e 在200 mg/L下对番茄叶片及其花上灰霉病菌的防治效果分别为77.5%和65.2%,高于对照药剂啶酰菌胺 (防效分别为59.8%和30.3%),有进一步研究的价值。     

Germination response of Orobanche seeds subjected to conditioning temperature, water potential and growth regulator treatments

Broomrapes (Orobanche spp.) are parasitic weeds that cause significant losses of crop yield. Experiments were conducted to investigate the seed response to the artificial germination stimulant GR₂₄ in three species of Orobanche subjected to preconditioning under various temperatures, water potentials and with plant growth regulators. The highest germination percentages were observed in Orobanche ramosa, Orobanche aegyptiaca and Orobanche minor seeds conditioned at 18°C for 7 days followed by germination stimulation at 18°C. With the increase of the conditioning period (7, 14, 21 and 28 days), the germination percentage of O. ramosa and O. aegyptiaca progressively decreased. When conditioned at −2 MPa, the germination percentage was lower than at 0 and −1 MPa, especially at 13 and 28°C. Orobanche minor seeds could retain relatively high germination if conditioned at 18, 23 or 28°C, even after significantly extended conditioning periods (up to 84 days). GA₃ (30–100 mg L⁻¹), norflurazon and fluridone (10–100 mg L⁻¹), and brassinolide (0.5–1.0 mg L⁻¹) increased seed germination, while 0.01 mg L⁻¹ uniconazole significantly reduced germination rates of all three Orobanche spp. The promotional effects of GA₃ and norflurazon and the inhibitory effect of uniconazole were evident, even when they were treated for 3 days. Germination of Orobanche seeds was much lower when the unconditioned seeds were directly exposed to GR₂₄ at 10⁻⁶ m . This early GR₂₄-induced inhibition was however alleviated or even eliminated by the inclusion of GA₃ or norflurazon (10–50 mg L⁻¹) in the conditioning medium. On the contrary, the inclusion of uniconazole increased the inhibitory effect of GR₂₄, particularly in the case of O. ramosa.     

A pollen test to detect ACCase target‐site resistance within Alopecurus myosuroides populations

This study was conducted to determine a suitable medium for in vitro germination of Alopecurus myosuroides pollen and to develop a reliable test for the rapid screening of ACCase target site‐resistant plants within populations. The assay is based upon germination of pollen in a medium supplemented with ACCase inhibitors. A 0.25% agar medium, containing 200 mg L^–1 CaNO₃, 100 mg L^–1 H₃BO₃, 200 g L^–1 sucrose, was selected as a suitable medium for in vitro pollen germination. At 25 °C, this medium supported a mean germination rate of 85% within two hours. Plants highly resistant (Rh) to aryloxyphenoxypropionate (APP), owing to the expression of an insensitive ACCase, were found to express this resistance in their pollen. In contrast, plants moderately resistant (Rm) to APP herbicides, owing to an enhanced capacity to detoxify herbicides, did not exhibit this resistance in their pollen. Concentrations of 120 μM fenoxaprop and 1000 μM clodinafop were selected as the best for reliable discrimination of the target‐site‐resistant biotypes. At these concentrations there was more than 50% germination of the Rh pollen grains whereas less than 10% of the S and Rm pollen grains germinated. This test, using haploid material, may also permit distinction between homozygous‐ and heterozygous‐resistant individuals.     

Effect of hot water treatment on peach volatile emission and Monilinia fructicola development

The effect of hot water treatment (HWT) to control peach brown rot was investigated. Peaches were dipped in water at 60°C for 60 s and artificially inoculated with Monilinia fructicola conidia. HWT failed to control brown rot if applied before inoculation and microscopic observations revealed a stimulatory effect on germ tube elongation of M. fructicola conidia placed immediately after HWT on the fruit surface, compared to the control. The influence of fruit volatile emission due to HWT was performed on the pathogen conidia exposed to the headspace surrounding peaches. The results showed an increase of M. fructicola conidial germination ranging from 33 to 64% for cultivars Lucie Tardibelle and Red Haven heat‐treated peaches, respectively, compared to the control. The volatile blend emitted from heat‐treated fruit was analysed by solid‐phase microextraction/gas chromatography‐mass spectrometry (SPME/GC‐MS) and proton transfer reaction‐time of flight‐mass spectrometry (PTR‐ToF‐MS). Fifty compounds were detected by SPME/GC‐MS in volatile blends of cv. Lucie Tardibelle peaches and significant differences in volatile emission were observed among heated and control fruit. Using PTR‐ToF‐MS analysis, acetaldehyde and ethanol were detected at levels 15‐ and 28‐fold higher in heated fruit compared to unheated ones, respectively. In vitro assays confirmed the stimulatory effect (60 and 15%) of acetaldehyde (0·6 μL L^?1) and ethanol (0·2 μL L^?1) on M. fructicola conidial germination and mycelial growth, respectively. The results showed that volatile organic compounds (VOCs) emitted from heat‐treated peaches could stimulate M. fructicola conidial germination, increasing brown rot incidence in treated peaches when the inoculation occurs immediately after HWT.     

PEG 6000模拟干旱胁迫下甘蓝型油菜芽期及苗期抗旱指标筛选

采用聚乙二醇(PEG 6000)模拟干旱胁迫,分析干旱胁迫下8份甘蓝型油菜芽期和苗期抗旱相关指标,鉴定芽期和苗期抗旱性,筛选抗旱评价指标。结果表明,甘蓝型油菜种质芽期和苗期抗旱性强弱不同,芽期抗旱性鉴定的最适PEG 6000浓度为15%,成苗率可作为芽期抗旱性的鉴定指标。通过主成分分析、隶属函数等方法分析苗期相关指标的变化,利用抗旱性综合度量值D值评价甘蓝型油菜苗期抗旱性,结果表明叶片相对含水量(r=0.907~(**))、可溶性蛋白(r=0.921~(**))与抗旱度量值D值呈极显著正相关,丙二醛含量(r=-0.837~(**))与D值呈极显著负相关,这些指标可作为甘蓝型油菜苗期抗旱性的评价指标。     

Effect of fipronil seed treatments on the germination and early growth of rice

Fipronil seed treatments were evaluated to determine whether they directly influence germination and subsequent seedling growth in rice (Oryza sativa L). Continuous seed exposure to fipronil (four days) at 2 000 mg litre⁻¹ significantly impaired germination (P < 0.001). When exposure was restricted to a 1-h period 48 h after the initiation of germination, early post-germination growth was also impaired (assessment two days after exposure, P < 0.05). The proportion of seeds satisfying our criteria for normal germination fell by 2.3 and 2.6% respectively across 17 cultivars. Cultivar effects were highly significant (P < 0.001). When exposure to fipronil (2 000 mg litre⁻¹) was restricted to 2 h at initial seed wetting no significant growth impairment occurred. No significant differences (P > 0.05) were found between shoot lengths or root system dry weights of control plants and plants developing from seed exposed continuously (two days) to fipronil at rates of up to 2 000 mg litre⁻¹ during germination and harvested nine days after sowing. Treating germinated seed with fipronil for 1 h immediately prior to sowing at rates of up to 4 000 mg litre⁻¹ did not result in significant changes (P < 0.05) in plant growth parameters at either nine or 25 days after sowing. No evidence of fipronil having a direct phytostimulatory effect on rice was obtained. © 1999 Society of Chemical Industry     

Effect of the ecdysone agonists,RH-2485 and tebufenozide,on the southwestern corn borer,Diatraea grandiosella

The effect of the ecdysone agonists RH-2485 (proposed name methoxyfenozide) and tebufenozide (RH-5992), was examined on eggs and larvae of the southwestern corn borer, Diatraea grandiosella Dyar. Both compounds exhibited a concentration-dependent ovicidal activity. More than 95% of eggs died when egg masses were dipped in solutions of 100 or 200 mg liter^-1 of either compound in acetone+distilled water (1+1 by volume). Although some eggs treated with 1 or 10 mg liter^-1 of the compounds hatched, the survival rate was low. Newly hatched larvae were fed for seven days on an artificial diet containing RH-2485 or tebufenozide. The LC₅₀ values were 0·049 mg kg^-1 for RH-2485 and 0·185 mg kg^-1 for tebufenozide, showing that RH-2485 was about four times more active than was tebufenozide. Although increasing the time of exposure to either compound decreased the LC₅₀ value significantly, the relative potency of RH-2485 versus tebufenozide was not changed. Newly ecdysed 4th-instar larvae fed with diets containing 0·125, 0·25 or 0·5 mg kg^-1 RH-2485 or tebufenozide ceased feeding approximately 8 h after exposure, indicating that larvae had prematurely entered a molting cycle. Larvae treated with RH-2485 ecdysed earlier and died more quickly than those treated with tebufenozide. Ingestion of sublethal concentrations of RH-2485 (0·005 and 0·01 mg kg^-1) or tebufenozide (0·03 and 0·06 mg kg^-1) retarded larval growth, and decreased pupal weight and adult emergence. Increasing exposure time to tebufenozide tended to increase the larval mortality, significantly retarded larval growth, and decreased the mean weights of male and female pupae and adult emergence. RH-2485 (0·125 and 0·25 mg kg^-1) and tebufenozide (0·25 and 0·5 mg kg^-1) were lethal to newly hatched larvae, even after diets containing these compounds were held for 20 days at 30°C under long days (16 h light: 8 h dark). Our results suggest that field trials to assess the potential of RH-2485 and tebufenozide to control D. grandiosella are warranted. © 1998 SCI     

Plant growth inhibitors in turmeric (Curcuma longa) and their effects on Bidens pilosa

Turmeric (Curcuma spp.) has numerous biological activities, including anticancer, antibacterial, antifungal and insecticidal properties. Here, we evaluated the plant growth‐inhibitory activities of two cultivars of Curcuma longa (C. longa ; Ryudai gold and Okinawa ukon) against radish, cress, lettuce and Bidens pilosa (B. pilosa ). The methanol extracts of both turmeric varieties inhibited the seed germination and seedling growth of all the tested plants. Ryudai gold had a significantly higher inhibitory effect on the seed germination and root and shoot growth of the plants than Okinawa ukon. Therefore, Ryudai gold was chosen for the isolation of plant growth‐inhibitory compounds using a silica gel column and high‐performance liquid chromatography. The structural identification of the compounds was carried out using ¹H NMR, ¹³C NMR and liquid chromatography–tandem mass spectrometry. The growth inhibitors were identified as four curcuminoids; dihydrobisdemethoxycurcumin ( 1 ), bisdemethoxycurcumin ( 2 ), demethoxycurcumin ( 3 ) and curcumin ( 4 ). The IC₅₀ of the curcuminoids against the root and shoot growth of B. pilosa ranged from 8.7 ± 1.7 to 12.9 ± 1.8 and from 15.5 ± 1.8 to 38.9 ± 2.8 μmol L^?1, respectively. Compound 1 showed the lowest IC₅₀ against the root and shoot growth of B. pilosa . These results suggested that Ryudai gold has a potential growth‐inhibitory effect against B. pilosa .     

寡肽手性膦酸酯硫脲的合成及其抗烟草花叶病毒活性

为了寻找新型具有抗烟草花叶病毒 (TMV) 作用的化合物,在前期研究工作基础上,以取代苄胺、氨基酸及亚膦酸二烷基酯等为原料,按照由C端向N端依次接肽的合成策略,采用缩合剂O-苯并三氮唑-四甲基脲六氟膦酸酯 (HBTU) 合成酰胺的方法,获得了18个新型寡肽手性膦酸酯硫脲,其结构均经红外光谱、(1H、13C、31P、19F) NMR及元素分析确证和表征,并首次研究了该类化合物抗TMV活性。结果表明:部分目标物对TMV具有较高治疗作用,其中化合物 5i 、 5j 和 5p 在500 μg/mL时对TMV侵染的活体治疗作用效果分别为52.6%、55.7%和56.1%,接近对照药剂宁南霉素 (55.4%)。值得进一步结构改造和构型优化,并在此基础上进行作用机制研究。     

Synthesis and insecticidal/acaricidal activity of novel 3‐(2,4,6‐trisubstituted phenyl)uracil derivatives

A series of novel 3‐(2,4,6‐trisubstituted phenyl)uracil derivatives has been synthesised and assayed for insecticidal/acaricidal activity. The assay indicated certain requirements for optimal insecticidal activity, which can be summarised as follows: (a) the substituents on the phenyl ring should possess hydrophobicity and electron‐withdrawing properties, and the sum of their volumes determines the level of activity; (b) the substituent at the 6‐position on the uracil ring should also possess electron‐withdrawing properties and hydrophobicity, together with the correct volume; (c) the 1‐position on the uracil ring should be unsubstituted for activity against Nephotettix cincticeps and Epilachna vigintioctopunctata, but substituents with length C3 to C4 may be optimal for activity against Tetranychus urticae; (d) certain substituents at the 5‐position of the uracil ring give activity against E vigintioctopunctata and T urticae, but not against N cincticeps; (e) a thiocarbonyl group at the 2‐position of the uracil ring is less effective than a carbonyl group. Of the compounds assayed, 3‐(2,6‐dichloro‐4‐trifluoromethylphenyl)‐6‐trifluoromethyluracil showed high activity against all the species assayed. © 2000 Society of Chemical Industry     

Fenugreek root exudates show species-specific stimulation of Orobanche seed germination

Various Orobanche species are weedy and cause severe reduction in the yields of many important crops. The seeds of these parasitic weeds may remain dormant in the soil for many years until germination is stimulated by the release of a chemical signal from a host plant. In order to determine the effects of fenugreek root exudate on the induction of Orobanche crenata, Orobanche ramosa and Orobanche foetida seed germination, root exudate was collected from hydroponically grown fenugreek seedlings. Fractionation patterns obtained from column and thin layer chromatography of the fenugreek root exudate showed a set of metabolites differing in their polarity with stimulatory activity on Orobanche seed germination. The crude root exudate stimulated both O. ramosa and O. crenata seed germination to the same level caused by the synthetic germination stimulant GR24 at 10 mg L^?1. It also stimulated O. foetida seed germination which did not respond to GR24. Active fractions of root exudate stimulated the germination of Orobanche species differentially.     

含单氟甲氧基的双酰胺类化合物的合成及杀虫活性

以2,3-二氯吡啶为起始原料,经肼基化、环合、氧化、取代、水解、环合和胺解反应,合成了15个文献未见报道的新型含单氟甲氧基的吡唑邻甲酰氨基苯甲酰胺类化合物,其结构通过核磁共振氢谱和高分辨质谱确认。初步的杀虫活性测试结果显示,所有目标化合物在100 mg/L下对粘虫Oriental armyworm的致死率均为100%,当测试浓度降低至4 mg/L时,化合物 8a 、 8d 、 8g 、 8k 和 8n 的致死率仍为100%,值得进一步研究。     

Variations among field isolates of Botrytis cinerea in their sensitivity to antifungal compounds

Seventeen field isolates of Botrytis cinerea were compared by determining their radial growth on synthetic media containing various amounts of 21 antifungal compounds. Twelve of these compounds were fungicides that are recommended for the control of Botrytis infections. There were marked differences between the isolates in their sensitivity to the compounds. Individual isolates displayed high levels of resistance to some of the fungicides, including benomyl, carbendazim, iprodione, thiabendazole, thiophanate-methyl, vinclozolin and zineb. The most potent growth inhibitors were benomyl and carbendazim (ED₉₅ values for most isolates <0.1 μg fungicide ml^?1 media), dichlofluanid, iprodione, nystatin, thiabendazole, thiophanatemethyl and vinclozolin (ED₉₅ values for most isolates < 1.0 μg ml^?1), and captan, chlorothalonil, dicloran and thiram (ED₉₅ values for most isolates < 6.0 μg ml^?1). Zineb was much less potent than the other recommended anti-Botrytis fungicides; it was no more effective than carboxin, dinocap and mancozeb (ED₉₅ values for most isolates > 25 μg ml^?1).