The effect of benomyl and some related compounds on Lumbricus terrestris and other earthworms

Earthworm populations in apple orchard plots sprayed with benomyl and thiophanate-methyl were greatly reduced. Lumbricus terrestris, a surface-feeding species, was not found in the treated plots. Captive worms would not feed on leaf material with spray deposits of benomyl, MBC and thiophanate-methyl at 1.75 μg/cm², and feeding was significantly reduced when deposits were 0.87 μg/cm². There was 100 % kill of worms in pots of soil within 14 days following a benomyl drench at the rate of 7.75 kg/ha, and a 60 % kill following a drench at the rate of 1.55 kg/ha. Worms immersed for 1 min in benomyl suspensions of 0.05 or 0.5 % died within 27 and 13 days respectively; those immersed in lower concentrations would not feed for 2 weeks but eventually did so. It is suggested that the lethal effects of benomyl may be due to anti-cholinesterase activity of the carbamate moiety of the molecule.     

Uptake and translocation of fungicides in wheat after seed treatment,as measured by disease response to Fusarium culmorum

The toxicities of five systemic fungicides [benomyl, carbendazim, methyl 4-(2- aminophenyl)-3-thioallophanate (NF48), thiabendazole and thiophanate-methyl] and of two non-systemic fungicides (guazatine and phenylmercury acetate) against Fusarium culmorum were compared on agar plates; their performance as seed treatments was measured by inoculating the shoot bases of wheat seedlings with F. culmorum in pot experiments. The two most effective compounds, benomyl and thiabendazole, and the less effective thiophanate-methyl, were evaluated in further seed treatment experiments in which leaf sheaths and roots of slightly older plants were infected. The three fungicides protected the first leaf sheath for more than 5 weeks, but thiophanate-methyl was least effective. Against root disease, they were effective when infection was mild, but only thiabendazole significantly controlled severe infection. Bioautography confirmed that fungicide levels in shoots were greater after benomyl and thiabendazole, than after carbendazim and thiophanate-methyl treatments, and that concentrations of fungicide after benomyl, carbendazim and thiophanate-methyl treatments generally declined between 5-13 weeks after treatment. Thiabendazole produced a second fungitoxic component detectable in plants after 34 days.     

Evaluation of benomyl and thiophanate-methyl for the control of Verticillium wilt of strawberry in the Netherlands

In pot experiments the fungicides benomyl and thiophanate-methyl controlledVerticillium wilt of strawberry when applied as a soil drench after planting. Both compounds were ineffective as foliar sprays and as root dips prior to planting. Soil drenches applied to commercially grown runner plants in the waiting field (August) and to the same plants in the greenhouse (December or January) increased the yield. On infested ground, a soil drench with thiophanate-methyl promoted the occurrence of crown rot caused byPhytophthora cactorum.     

Systemic fungicides in strawberry: field control of fruit rot (Botrytis cinerea pers.) and residue study

In a detailed study of the effect of weekly sprays with benzimidazole-derivative fungicides on strawberry plants, cv. Tioga, higher yields were recorded, as well as reduced fruit rot caused by the fungusBotrytis cinerea Pers. The two fungicides tested, benomyl and flowable and soluble formulations of TBZ, gave similar control of fruit rot. The residue level found in leaves and fruits was about the same throughout the yielding season. Residue levels of 300-433 ppm TBZ (flowable form) and 94-110 ppm benomyl were detected in the leaves, whereas the levels in the fruit were 6.4-8.2 ppm and 1.5-3.8 ppm for the two compounds, respectively. Two weeks after the last spray application, the residue level of TBZ in teaves was reduced by 50%, and of benomyl by only 20%.     

隔沙层对盐碱地土壤水盐运动的影响

在80~100 cm范围土层设置沙层,对土壤电导率和含水量进行为期6个月的观察,分析隔沙层对土壤水盐运动的影响。结果表明:80~100 cm层沙层在大降雨量时能够提高土壤含水量;降雨量小,蒸发强烈的5~7月份,隔沙处理能够使土壤积盐程度较对照减少50%~70%;隔沙层延缓沙层以上土壤水分的下渗,从而提高降雨对土壤盐分的淋洗作用。当降雨量接近蒸发量的时候,隔沙处理土壤就能明显脱盐,而在此雨量下,对照只能保证土壤不发生积盐或少量积盐。雨季结束之后,隔沙处理土壤脱盐率较对照提高10%~35%,并能够使土壤脱盐过程持续到10月份,对植物生长十分有利。     

Systemic fungicide residues in oil from field-treated olive1

A survey was carried out in Sardegna (IT) on residues in olive oil from olive treated against Spilocaea oleugina with several systemic fungicides at normal and double dose rate: benomyl, thiophanate-methyl, bitertanol, penconazole and fenarimol, all currently not registered for this use in Italy. There was a rapid decrease in benomyl, thiophanate-methyl, and bitertanol in the samples of oil from treated olives collected 0, 10, and 20 days after last treatment, but the degradation of fenarimol appeared slower. In contrast, the concentration of penconazole increased with time. It is suggested that registration of the first four compounds for use on olive would be justified.     

Evaluation of systemic fungicides for use in the glasshouse industry

The primary evaluation of ten fungicides for the control of cucumber powdery mildew (Sphaerotheca fuliginea), tomato leaf mould (Cladosporium fulvum) and tomato grey mould (Botrytis cinerea) indicated that nine of them were systemically active against one or more of the pathogens when applied as soil drenches. Benomyl, thiophanate, thiophanate-methyl, thiabendazole and Cela W52A showed activity against all three diseases, but dimethirimol, triarimol and dodemorph were more specific and mainly active against cucumber powdery mildew. An in vitro bioassay generally indicated that fungitoxicity was not translocated from sprayed to unsprayed leaves, and though toxicity to B. cinerea, following soil drenches of benomyl, thiophanate and thiophanate-methyl, was detected by bioassay in leaf sap and calyces it was not detected in fruit. Furthermore, extended evaluation of benomyl for the control of grey mould on cropping tomotoes showed that in the presence of abundant B. cinerea inoculum, benomyl soil drench treatment effectively controlled flower and leaf infection but not fruit ghost-spotting.     

Field degradation of the herbicide metribuzin and its degradation products in a Manitoba sandy loam soil*

The degradation of the herbicide metribuzin (4-amino-6 r-butyl-3-(methylthio)-1, 2, 4-tnazin-5-(4H)one) applied at 1 and 2 kg/ha at times equivalent to pre-emergence (12 June), post-emergence (5 July), and pre-harvest (15 August), has been investigated in Almasippi very line sandy loam at Carman, Manitoba. Gas-liquid chromatographic analytical results showed that metribuzin degraded during the growing season, and that residue levels immediately prior to freeze-up (25 October) were in general less than 10% of applied metribuzin independent of application date, and were largely unchanged the following spring. The metabolites and photoproduct of metribuzin were present in maximum amounts near 13 July for the first two treatment dates, a time closely following maximum soil temperature readings, and these compounds in turn degraded almost completely by freeze-up. The following spring only very low levels were detected. Under the conditions described, metribuzin and its degradation products degraded to low levels and should not provide a carryover problem the next growing season.     

Characteristics of deep drainage and soil water in the mobile sandy lands of Inner Mongolia,northern China

 Quantification of deep drainage and the response of soil water content to rainfall patterns are critical for an effective management strategy of soil water conservation and groundwater utilization. However, information on how rainfall characteristics influence soil water dynamics and deep drainage in mobile sandy lands are lacking. We used an underground chamber to examine the response of deep drainage and soil water content in mobile sandy lands to rainfall characteristics during the growing season of 2010, 2011 and 2012. Results showed that rainfall in this area was dominated by small events (≤5 mm), which increased soil water content in the surface soil layers (0–40 cm), but did not increase soil water content at the deeper soil layers (greater than 40 cm). Soil water content at the 0–100 cm depth increased significantly when the total amount of rain was >20 mm. Rainfall amount, intensity and the duration of dry intervals were significantly related to the soil water content at different soil layers. Deep drainage was significantly correlated with rainfall amount and intensity, but not with the duration of the dry interval. The coefficients of deep drainage in mobile sandy lands ranged from 61.30% to 67.94% during the growing seasons. Our results suggested that rainfall infiltration in these widespread mobile sandy lands had considerable potential to increase soil water storage while recharging the groundwater in this region.     

A comparison of the in vitro antifungal spectra of thiophanates and benomyl

The antifungal spectra of thiophanate, thiophanate-methyl and its derivative 2-(3-methoxycarbonyl-2-thioureido) aniline (NF 48), were similar to that of benomyl. The order of effectivenessin vitro was: benomyl>NF 48> thiophanate-methyl > thiophanate, benomyl being by far the most and thiophanate by far the least active compound.The effect on mycelial growth of two fungi with an irregular inhibition pattern are presented in detail, viz. ofColletotrichum acutatum andGliocladium roseum. In the first case mycelial growth was inhibited to over 50% at low concentrations; the inhibition, however, was not further enhanced with increasing concentrations. Mycelial growth ofGliocladium roseum was maximally suppressed at low concentrations of the fungicides, whereas in this case an increase of the concentrations resulted in a decrease of inhibitory activity until a constant level had been reached. Conidiobolus eurymites, unlike the other Zygomycetes tested, proved to be sensitive to the four fungicides.Samenvatting Het fungitoxisch spectrum van de systemische fungiciden thiofanaat, thiofanaat-methyl en een derivaat hiervan, NF 48, bleek gelijk te zijn aan dat van benomyl.In vitro was de volgorde in remmende werking op de myceliumgroei: benomyl > NF 48> thiofanaat-methyl > thiofanaat. Van deze verbindingen was benomyl verreweg het meest en thiofanaat duidelijk het minst fungitoxisch. Thiofanaatmethyl en NF 48 gaven in dit opzicht slechts weinig verschil te zien.De invloed van de fungiciden op de myceliumgroei van twee schimmels met een onregelmatig remmingspatroon is weergegeven in de Fig. 1 en 2. Bij geringe concentraties van de fungiciden in het medium werd de myceliumgroei vanColletotrichum acutatum reeds tot ruim 50% geremd. Verdere toename van de fungiciden, zelfs tot zeer hoge concentraties (1000 M), had echter geen sterkere remming ten gevolge. BijGliocladium roseum bleek de myceliumgroei het sterkst geremd bij lage concentraties (bv. voor benomyl bij ca 4 M). Verhoging van de concentraties had een afname in remmende werking ten gevolge tot een niveau van 75% remming was bereikt.In tegenstelling tot de andere Zygomyceten, die tot nu toe op gevoeligheid ten aanzien van benomyl onderzocht werden, bleekConidiobolus eurymites, een saprofyt uit de bodem, gevoelig te zijn voor alle vier fungiciden.     

QuEChERS-超高效液相色谱-串联质谱法同时测定草莓中甲基硫菌灵、多菌灵和乙嘧酚残留

建立了QuEChERS-超高效液相色谱-串联质谱同时检测草莓中甲基硫菌灵、多菌灵和乙嘧酚残留的方法。样品经0.5%甲酸-乙腈提取,QuEChERS方法净化,以Agilent XDB-C18色谱柱(2.1 mm×150 mm,3.5 μm)进行UPLC分离,采用三重四极杆串联质谱以正离子多反应监测模式(MRM)进行测定。结果表明:在20~1 000 μg/L范围内,甲基硫菌灵、多菌灵及乙嘧酚的质量浓度与其相应的峰面积间呈现良好的线性关系,相关系数均大于0.997 8。在50~500 μg/kg添加水平下,草莓中甲基硫菌灵、多菌灵和乙嘧酚的平均回收率在86%~109%之间,相对标准偏差(RSD)在1.9%~13%(n=5)之间,检出限分别为2.5、0.50和1.0 μg/kg,定量限均为50 μg/kg。该方法样品前处理过程简单快速,分析时间短,灵敏度、准确度及精密度均符合农药残留检测要求,适用于草莓中甲基硫菌灵、多菌灵和乙嘧酚残留的检测。     

Characterization and PCR-based detection of benzimidazole-resistant isolates of Monilinia laxa in California

Monilinia laxa is a pathogen of brown rot of stone fruit and almond in California, causing blossom blights and fruit rots. In this study, low-level resistance to the benzimidazole fungicides benomyl and thiophanate-methyl was detected in field isolates of M laxa collected from stone fruits and almonds in California. Low-resistant (LR) isolates grew in potato dextrose agar (PDA) plates amended with benomyl and thiophanate-methyl at 1 and 5 microg ml(-1), respectively, but not in plates amended with benomyl at 5 microg ml(-1) or thiophanate-methyl at 50 microg ml(-1). The benzimidazole LR isolates were characterized by temperature sensitivity and the DNA sequence of the beta-tubulin gene. The LR isolates showed high-temperature sensitivity, being sensitive to 1 microg ml(-1) of benomyl at 28 degrees C but resistant at 8-24 degrees C. Analysis of the DNA sequence of the beta-tubulin gene showed that the LR isolates had a point mutation at the amino-acid position 240, causing substitution of leucine by phenylalanine. Based on the point mutation, a pair of allele-specific PCR primers was developed for rapid detection of LR isolates of M laxa. In addition, a pair of PCR primers specific to M laxa was developed on the basis of the differences in the DNA sequence of the intron 6 of beta-tubulin gene from M laxa, M fructicola and other fungal species. The primer pair amplified the expected 376-bp DNA fragment from all M laxa isolates tested, but not from 14 other fungal species isolated from stone fruit and almond crops. The restriction endonuclease BsmA I recognized the sequence GTCTCC in the PCR products from sensitive (S) isolates only, but not the GTTTCC sequence in the PCR products from LR isolates. The endonuclease digested the 376-bp PCR products from S isolates to produce two bands (111 and 265 bp) on agarose gels. Thus, both allele-specific PCR and the PCR-restriction fragment length polymorphism (PCR-RFLP) methods could be useful for rapidly detecting benzimidazole-resistant isolates of M laxa from stone fruit and almond crops in California.     

Resistance to benzimidazole fungicides in the gummy stem blight pathogen Didymelta bryoniae on cucurbits

Benzimidazoles were used successfully against gummy stem blight of cucurbits for only one growing season (1980). It was soon noticed in experiments in vivo that they were not effective against some isolates of the pathogen. In a survey during the 1981 crop season, 76 out of 102 isolates collected from 20 plastic greenhouses all over the main cucurbit-growing areas of Crete were resistant to benomyl. The average benomyl concentrations that reduced mycelial growth rates of seven resistant and seven sensitive isolates by 50% were 716 ± 49 and 1.2 ± 0.34μg/ml respectively. The average growth rate of resistant isolates was lower than that of sensitive isolates but there were no differences in spore production and spore germination. The pathogenicity of resistant isolates on young cucumber plants was lower than that of sensitive isolates. The application of benomyl, carbendazim, cypendazole and thiophanate methyl to young cucumber plants at the rate of 300μg a.i./ml 1 day before inoculation with 500 000 spores/ml of the resistant isolates did not affect the infection rate of the disease after 4 days. Sensitive isolates caused no onslight symptoms on similarly treated plants.     

Fungi in stored barley treated with systemic fungicides

Six fungicides (benomyl, carbendazim, fuberidazole, thiabendazole, thiophanate and thiophanate-methyl) were applied as dusts to barley in concentrations of 100, 1000 and 10 000 μg g^?1 and the barley then stored at 20°C and 90% relative humidity for 60, 105 and 150 days, respectively. Fungal development during storage was assessed by counting the visible patches of developing mould and by dilution plating. None of the fungicides completely prevented fungi developing but for the period up to 60 days, all provided a degree of control that was generally greatest for the highest concentration of fungicide. Benomyl was the most effective of the fungicides but no clear pattern was established for the others. Of the fungi that developed, species of Aspergillus and Penicillium accounted for 94% of the total count.     

Methyl benzimidazol-2-ylcarbamate,the fungitoxic principle of thiophanate-methyl

A correlation was found between the formation of benzimidazol-2-ylcarbamate esters from the thiophanate fungicides [thiophanate, thiophanate-methyl and 2-(3-methoxycarbonylthioureido)aniline] and the fungitoxie activity of these fungicides. Fungitoxic activity of the thiophanates is increased by ageing in aqueous media while fungitoxicity as well as conversion rate decrease at lower pH. It is concluded that it is not the thiophanates themselves but the corresponding benzimidazol-2-ylcarbamate esters that are responsible for the fungitoxic effect. Hence thiophanate-methyl, like benomyl, is a precursor of the fungitoxic agent methyl benzimidazol-2-ylcarbamate (MBC). Indications were obtained that fungal metabolic activity can increase the rate of conversion of thiophanate-methyl into MBC.     

梭梭固沙林水分平衡研究──Ⅰ．梭梭柴秋灌固沙林的水分状况

对梭梭秋灌人工林和荒漠林进行了林地土壤水分状况和林木生长状况的研究。结果表明，林地的土壤含水量和蒸散量与冬季降水量相关，林木生长状况与土壤水分状况相关。人工林的土壤水分状况和林木生长状况虽不如荒漠林，属生长一般类型，但水分供需平衡，在仅靠降水抚育的条件下，２．５×３ｍ株行距，１３３３株／ｈａ的密度不会因水分平衡问题出现人工林衰亡的恶果。     

Use of fungicides to control chocolate spot (Botrytis fabae) on winter field beans (Vicia faba)

Less chocolate spot (% leaf area affected) developed on winter–sown field beans sprayed with benomyl than on untreated beans or beans sprayed with iprodione, prochloraz or thiabendazole. A single benomyl spray during flowering reduced disease development and increased yield by 20% in 1982 when a severe chocolate spot epidemic developed in untreated plots during flowering. Benomyl sprays at flowering also increased yield in 1980 when there was less disease at flowering than in 1982, but did not increase yield in 1981 when there was little disease at flowering. In 1981 a severe chocolate spot epidemic developed early in the season and less chocolate spot developed on lower leaves of beans grown from seed treated with benomyl plus thiram than on beans grown from untreated seed. Treated plots yielded 70% more than untreated plots, although by early flowering there was no difference in chocolate spot between them. Seed treatment did not increase bean yields in 1982 and 1983, when chocolate spot did not develop early in the season. In the glasshouse, benomyl seed treatment prevented the development of aggressive lesions on lower leaves but thiram did not.     

Decay control and fungicide residues in citrus fruits seal-packed in a high-density polyethylene film

The effects of a new packaging method of sealing individual fruits in film of highdensity polyethylene (HDPE), on decay control and the residue levels of various fungicides applied to the fruit, were investigated with four different citrus cultivars. HDPE seal-packaging by itself reduced the decay of Marsh grapefruit but slightly enhanced the decay of Valencia orange fruit in comparison with conventionally handled fruit. Seal-packaging of individual fruit resulted in much less decay than sealing a whole carton of fruit together. The fungicides imazalil, sec-butylamine, 2-phenylphenol, benomyl and thiabendazole markedly reduced the decay of sealed fruit in all cultivars of citrus fruits tested. Residue levels in treated fruit were below the tolerances permitted. The new method of packaging had no effect on the residue levels of benomyl, 2-phenyl-phenol and thiabendazole in the fruit; neither did it affect the extent of absorption of these fungicides into the fruit. Only the volatile fungicide sec-butylamine was found at a higher level (73% higher in the packaged fruit compared with conventionally treated fruit).     

甲基硫菌灵及其代谢物多菌灵在猕猴桃上的残留及安全性评价

为了评估甲基硫菌灵在猕猴桃上使用的安全性,采用QuEChERS-超高效液相色谱-串联质谱分析方法,对甲基硫菌灵及其代谢物多菌灵在猕猴桃上的残留量进行了分析,明确了其消解规律及半衰期,通过进行膳食摄入风险评估,以推荐甲基硫菌灵在猕猴桃上的最大残留限量 (MRL),并对其代谢物多菌灵的残留量进行了安全性评价。结果表明:在0.01、0.1和1.0 mg/kg 3个添加水平下,甲基硫菌灵的回收率为85%~102%,相对标准偏差 (RSD) 为1.0%~7.1%;多菌灵的回收率为86%~101%,RSD为2.1%~5.2%;两者的定量限均为0.01 mg/kg。甲基硫菌灵在猕猴桃上的消解符合一级反应动力学方程,半衰期为10.1~10.5 d,属易消解农药。70%甲基硫菌灵可湿性粉剂在猕猴桃上按照推荐剂量及1.5倍推荐剂量 (875和1 166.7 mg/kg) 分别施药3次和4次,推荐采收间隔期为21 d,膳食风险商为78.7%,推荐MRL值为5 mg/kg,该结果通常不会对一般人群健康产生不可接受的风险。依据GB 2763多菌灵在猕猴桃上的MRL值0.5 mg/kg,代谢物多菌灵存在较大的超标风险。建议有关部门制定甲基硫菌灵在猕猴桃上的MRL值,并重新评估多菌灵在猕猴桃上的MRL值。     

Effect of sand-fixing vegetation on the hydrological regulation function of sand dunes and its practical significance

Soil water content is a key controlling factor for vegetation restoration in sand dunes. The deep seepage and lateral migration of water in dunes affect the recharge process of deep soil water and groundwater in sand dune ecosystems. To determine the influence of vegetation on the hydrological regulation function of sand dunes, we examined the deep seepage and lateral migration of dune water with different vegetation coverages during the growing season in the Horqin Sandy Land, China. The results showed that the deep seepage and lateral migration of water decreased with the increase in vegetation coverage on the dunes. The accumulated deep seepage water of mobile dunes (vegetation coverage<5%) and dunes with vegetation coverage of 18.03%, 27.12%, and 50.65% accounted for 56.53%, 51.82%, 18.98%, and 0.26%, respectively, of the rainfall in the same period. The accumulated lateral migration of water in these dunes accounted for 12.39%, 6.33%, 2.23%, and 7.61% of the rainfall in the same period. The direction and position of the dune slope affected the soil water deep seepage and lateral migration process. The amounts of deep seepage and lateral migration of water on the windward slope were lower than those on the leeward slope. The amounts of deep seepage and lateral migration of water showed a decreasing trend from the bottom to the middle and to the top of the dune slope. According to the above results, during the construction of sand-control projects in sandy regions, we suggest that a certain area of mobile dunes (>13.75%) should be retained as a water resource reservoir to maintain the water balance of artificial fixed dune ecosystems. These findings provide reliable evidence for the accurate assessment of water resources within the sand dune ecosystem and guide the construction of desertification control projects.