80%代森锰锌WP防治番茄早疫病试验

用80％代森锰锌WP防治番茄早疫病试验，3次药后200g／666．7m^2的防效达81％～86％，药效显著优于对照药剂50％代森锰锌WP，而且对番茄无不良影响，值得在生产上推广使用。     

抑制番茄早疫病菌活性化合物的 高通量筛选方法研究

以OD 630 值作为评价指标,在高通量筛选设备上建立了番茄早疫病菌Alternaria solania的高通量定量筛选方法,并对嘧菌酯、百菌清、 NFDA1 醚唑、霜脲氰、甲霜灵、代森锰锌、福美双和咪鲜胺8种常用杀菌剂对番茄早疫病菌孢子萌发和菌丝生长的抑制效果进行了评价,结果与孢子萌发法和目测筛选法所得结论基本一致。     

代森锰锌涂茎防治番茄早疫病效果好

番茄早疫病是我市番茄生产上的主要病害,随着保护地的发展,此病发生愈来愈早,愈来愈重。前几年用喷雾法防治效果较好,近年来用代森锰锌涂刷茎叶上病斑,经试验示范,现已大面积推广。方法是: 将50％代森锰锌加水稀释成100倍液,装入瓶内,用旧毛笔或用小细棍一端绑小棉团,发现病株时用刷头蘸取药液,在病部涂刷1次。 1990年5月作者在市郊朐山村调查,用     

番茄早疫病的化学防治

近年来,我县番茄早疫病的病情指数达71.6—94.0,一般减产20—30％,重者损失50％以上。1985年以来作者在化学防治试验的基础上于发病前7—10天,用70％代森锰锌于悬粉1750ppm、和58％扑海因可湿     

番茄早疫病和晚疫病的发生与防治

番茄栽培中常见的病害有早疫病和晚疫病,发生严重时,对番茄产量和品质影响很大。笔者现介绍这2种病害的发生和防治方法。1番茄早疫病1.1症状番茄早疫病又叫番茄轮纹病,各地普遍发生,也是保护     

番茄早疫病暴发成灾原因及防治对策

番茄旱疫病是塑料大棚、温室和露地栽培常见的重要病害 近年来受栽培制度、品种、气候条件、防治方法等多种因素影响，早疫病发生早，流行时间长，为害特别严重，对番茄产量及品质影响很大。     

68.75％噁酮·锰锌水分散粒剂防治番茄早疫病的药效试验

使用68.75％噁酮·锰锌WG75g/667m2药液能有效防治番茄早疫病.试验结果表明,在番茄早疫病发病初期,连续用药2～3次后,能有效控制番茄早疫病的蔓延,在多雨季节可作为防治该病的农药之一.     

番茄早疫病研究概述

番茄早疫病是番茄生产中最常见的1种病害.对番茄生产造成较大损失.综述了番茄早疫病病原菌生物学特性、病害发生流行规律和综合防治等方面的内容,为开展研究和生产应用提供参考.     

植物内生放线菌Fq24和Lj20对番茄早疫病菌的抑制作用

本文测定了2株植物内生放线菌在离体条件下对番茄早疫病菌的作用效果。结果表明,植物内生放线菌Fq24和Lj20的3种不同处理液对番茄早疫病痛原菌分生孢子萌发都有抑制作用,Lj20无菌发酵滤液的抑制效果最好;Lj20皿内和发酵液对番茄早疫病病原菌的抑制作用要好于Fq24;诱发接种后2株植物内生放线菌对采收后番茄果实上的番茄早疫病菌均有不同程度的控制作用,在30℃条件下的防治效果优于20℃的效果。     

枯草芽胞杆菌QM3防治番茄早疫病和促进幼苗生长的研究

［目的］ 枯草芽胞杆菌QM3是从青海牦牛粪中分离筛选的一株对番茄早疫病菌有显著抑菌效果的高效拮抗菌株,本文旨在进一步明确QM3对番茄早疫病的作用机制和在生物体内的防治效果。 ［方法］ 采用温室盆栽试验测定QM3发酵液对番茄早疫病的防治效果及对不同番茄品种的促生作用,并测定该菌株在番茄根际的定殖能力。［结果］ 不同处理的QM3发酵液均对番茄早疫病有明显的防治效果（p<0.05）,最高可达52.94%,且与化学农药联合使用防效更好,最高可达71.80%;经QM3发酵液处理后,番茄植株叶片数、株高及根部发育等指标有增加;此外,灌根接种QM3菌株后,根际总芽胞杆菌数量明显增加（p<0.01）。［结论］ QM3菌株是一株有益的促生根际细菌（PGPR）,具有应用于番茄早疫病生防的潜力。     

Effects of inoculum concentration, wetness duration and plant age on development of early blight (Alternaria solani) and on shedding of leaves in tomato plants

Effects of inoculum concentration, wetness duration and plant age on the development of tomato early blight were evaluated in relation to host susceptibility under controlled environmental conditions. The main effect of early blight was premature defoliation, which was linearly related to the percentage of leaf area showing symptoms. As ln(inoculum concentration, conidia mL⁻¹) increased from 6·2 to 11·5, the percentages of leaf area affected and of defoliation increased linearly. Four h of leaf wetness after inoculation were sufficient to initiate the disease on plants of hybrid Skala RZ but not on those of cv. Rio Rojo, for which at least 6 h leaf wetness were needed. As wetness duration increased up to 24 h, there was an increase in the percentage leaf area showing symptoms and in the percentage of defoliation, but thereafter there was no significant increase in either parameter. Tomato plants were susceptible to Alternaria solani at all growth stages, but susceptibility increased as plants matured. There were no significant differences in susceptibility between tomato cultivars and hybrids.     

Biochemical and molecular studies of early blight disease in tomato

Tomato early blight occurs worldwide and it is prevalent wherever tomatoes are grown. Alternaria solani Sorauer, the causal agent, has been recognized as a serious foliar pathogen of tomato and there are very few cultivars which possess resistance against early blight. Alternaric acid is the major toxin of A. solani. In this study, alternaric acid and fungal culture filtrate were used as an elicitor in NDT-96 (tolerant) and GP-5 (susceptible) tomato varieties in order to study and compare their abilities to induce defense-related enzymes, viz., catalase, peroxidase, β-1,3 glucanase, phenylalanine-ammonia-lyase (PAL), chitinase and polyphenol-oxidase (PPO) along with total phenols, and total soluble proteins. NDT-96 showed a rapid induction of all these pathogenesis-related enzymes except catalase along with total phenols as compared to GP-5 with both the treatments. Differential expression of total soluble proteins revealed higher protein content in NDT-96 as compared with GP-5. A 49.48 kDa protein was observed to be absent in GP-5. In addition, 25 microsatellite markers (SSR) were screened for polymorphisms among the above mentioned two tomato varieties. Of these, SSR 286 revealed a significant polymorphic band of 108 bp in NDT-96.     

Tomato late blight (Phytophthora infestans) in Uganda

A survey on the tomato late blight situation and current practices for disease management was carried out in Uganda using an informal structured questionnaire approach. Ten districts from different agroclimatic zones were selected for the survey. Phytophthora infestans isolates from tomatoes were obtained from the zones and only the A1 mating type was recovered. Tomato cultivation is practised year-round. The major commercial varieties grown, Moneymaker, Marglobe, Heinz and Roma, were susceptible to late blight. Late blight and bacterial wilt ( Pseudomonas solanacearum ) were the major diseases, with bollworm ( Helicoverpa armigera ) and thrips ( Thrips spp .) the major insect pests. Fungicides, mostly mancozeb, were the predominant control method used by farmers. Sanitation is practised by some farmers, but only in association with fungicides, to control late blight. Plant nutrition is not perceived as playing a major role in late blight management. Problems associated with pesticides and poor marketability were identified as major constraints to tomato production in Uganda.     

Phytophthora infestans Produces Oospores in Fruits and Seeds of Tomato

ABSTRACT Tomato fruits at the mature green stage coinoculated with A1 + A2 sporangia of Phytophthora infestans, the late blight causal fungus, showed abundant oospores in the vascular tissues, pericarp, columella, and placenta. Oospores were also formed on the surface of fruits kept in moisture-saturated atmosphere. Occasionally, oospores were enclosed between the epidermal hairs of the seed coat. In a few seeds, oospores were detected inside the embryo. The data suggest that blighted tomato fruits may carry a large number of oospores, thus making them a threatening source of blight inoculum. Such fruits may also release airborne oosporic inoculum that may introduce recombinant genotypes within a growing season. Although Phytophthora infestans is seedborne in tomato, to our knowledge, this is the first report on the occurrence of oospores in tomato seeds. Whether such tomato seeds produce blighted seedlings remains to be shown.     

微生物杀菌剂及其混配剂防治水稻纹枯病的田间药效试验

对微生物杀菌剂及其混配剂对水稻纹枯病进行田间防治试验,结果表明枯草芽孢杆菌10亿/g可湿性粉剂、井冈霉素·蜡质芽孢杆菌12.5%可湿性粉剂对水稻纹枯病有较好的防治效果。在发病初期施药,枯草芽孢杆菌10亿/g可湿性粉剂1500g/hm2防效为75.4%,产量增幅21.5%;井冈霉素·蜡质芽孢杆菌12.5%可湿性粉剂2880g/hm2防效为83.89%。可以作为井冈霉素的替代产品,进行推广应用。     

Tomato early blight (Alternaria solani): the pathogen, genetics, and breeding for resistance

Alternaria solani causes diseases on foliage (early blight), basal stems of seedlings (collar rot), stems of adult plants (stem lesions), and fruits (fruit rot) of tomato. Early blight is the most destructive of these diseases and hence receives considerable attention in breeding. For over 60 years, breeding for early blight resistance has been practiced, but the development of cultivars with high levels of resistance has been hampered by the lack of sources of strong resistance in the cultivated tomato and by the quantitative expression and polygenic inheritance of the resistance. In some accessions of wild species, high levels of early blight resistance have been found, but breeding lines still have unfavorable horticultural traits from the donor parent. Recently, the first linkage maps with loci controlling early blight resistance have been developed based on interspecific crosses. These maps may facilitate marker-assisted selection. This overview presents the current knowledge about the A. solani–tomato complex with respect to its biology, genetics, and breeding.     

A test of taxonomic predictivity: resistance to early blight in wild relatives of cultivated potato

Host plant resistance offers an attractive method of control for early blight (caused by the foliar fungus Alternaria solani), a widespread disease that appears annually in potato crops worldwide. We tested the assumed ability of taxonomy to predict the presence of early blight resistance genes in wild Solanum species for which resistance was observed in related species. We also tested associations to ploidy, crossing group, breeding system, and geography. As in a prior study of Sclerotinia sclerotiorum (white mold) resistance, tremendous variation for resistance to early blight was found to occur within and among species. There was no discernable relationship between the distribution of resistant phenotypes and taxonomic series (based on an intuitive interpretation of morphological data), clade (based on a cladistic analysis of plastid DNA data), ploidy, breeding system, geographic distance, or climate parameters. Species and individual accessions with high proportions of early blight resistant plants were identified, but high levels of inter- and intra-accession variability were observed. Consequently, the designation of species or accessions as resistant or susceptible must take this variation into account. This study calls into question the assumption that taxonomic or geographic data can be used to predict sources of early blight resistance in wild Solanum species.     

Resistance status of cultivated potatoes to early blight (Alternaria solani) in Denmark

Field experiments were conducted in 2015 and 2016 to classify the resistance level to early blight of the main potato cultivars in Denmark. A total of 38 cultivars were used. The experiment was designed as a randomized complete block design (RCBD) with four replicates. The potatoes were inoculated by spreading barley (Hordeum vulgare) kernels infested with Alternaria solani and A. alternata. Disease assessment was done at weekly intervals starting from the onset of the first symptoms. The disease progress curves (DPC) of early blight on the cultivars were compared to that of Bintje. A multivariate analysis was performed with the apparent infection rate, the relative area under the disease progress curve, the time to reach 50% severity, the daily defoliation, the disease severity in the middle of the epidemic and the duration of the epidemic to classify the resistance level of the cultivars. The analysis of the DPC of the cultivars showed that none of the cultivars was completely resistant to early blight. However, the epidemic development differed between the different cultivars. The resistance levels of the cultivars were thus classified into classes I, II, III and IV interpreted as ‘very susceptible’, ‘susceptible’, ‘moderately slow blighting’ and ‘slow blighting’, respectively. All the late maturity cultivars were classified as class IV, and the earlier maturing cultivars were either class I or class II.     

The effect of cropping systems and irrigation management on development of potato early blight

Crop and soil management may modify canopy and belowground microclimate, but their effects on potential development and control of early blight are not well documented. Several management systems (Status Quo, Soil Conserving, Soil Improving (SI), Disease Suppressive, and Continuous Potato) were evaluated for their effects on early blight potential under irrigated and rainfed conditions. In 2006 and 2007, microclimatic data at the canopy level were recorded with a data logger. Early blight incidence and severity was determined by visually assessing symptoms. Disease incidence and lesion numbers varied among cropping systems and between years. Disease incidence ranged from 31 to 64% (2006) and 12 to 43% (2007), and was significantly higher with the Continuous Potato system than with Disease Suppressive, Status Quo, Soil Conserving, and SI systems. The relationships of incidence and disease severity with microclimate varied and were mostly non-significant, suggesting that the chosen variables were not reflective of pathogen development. Incidence was significantly associated with cropping systems. Disease prediction based on the Tom-Cast model was not correlated with observed disease levels. This research demonstrated that early blight disease is enhanced through continuous potato production.     

Influence of canopy structure on sheath blight epidemics in rice

Sheath blight (caused by Rhizoctonia solani) is one of the most important constraints in achieving high grain yield in intensive rice production systems. Canopy structure can influence the development of sheath blight epidemics. The objective of this study was to determine the effect of canopy structure parameters such as shoot number, leaf area index, biomass production, contact frequency, light transmittance and plant height on the development of sheath blight epidemics in commercial fields. Field experiments were conducted in both early and late seasons of 2009 and 2010 in Wuxue, Hubei province, China. The effects of nitrogen (N) rate and hill density on structure and production parameters and sheath blight severity were investigated. Sheath blight severity was recorded as a sheath blight index or relative lesion height on inoculated and uninoculated plants in each crop. Lesion length was measured on inoculated plants in 2010. The results showed that the sheath blight index increased with an increase of N rate and hill density in uninoculated plots in each trial. Stepwise multiple regression analysis demonstrated that contact frequency was consistently related to sheath blight. Lesion length on inoculated plants was not correlated with canopy structure. These results indicate that canopy structure influences sheath blight epidemics. A ‘healthy’ canopy resulting from appropriate crop management practices can be used to suppress sheath blight epidemics in rice.