Diversity and population dynamics of Penicillium spp. on apples in pre- and postharvest environments: consequences for decay development

Isolates of Penicillium spp. were collected regularly from 2001 to 2003 from the surfaces of apple fruit pre- and postharvest, and from the atmosphere of orchards and storage rooms in France. Penicillium spp. were not detected from the atmosphere of conventional orchards, while their density did not exceed 50 spores m⁻³ in the atmosphere of organically managed orchards. Penicillium spp. were seldom detected on apple surfaces in the orchard. The density of Penicillium on apples increased from 10 to 50 spores cm⁻² after 1 month in storage to 300–400 spores cm⁻² after 6 months. The level of airborne Penicillium increased by up to 2 × 10⁴ and 2·5 × 10³ spores m⁻³ within nondisinfected and previously disinfected warehouses, respectively. Penicillium expansum (30–62%) and P. solitum (6–45%) were the most prevalent species on apple or in storage rooms. Other species of Penicillium isolated included P. commune, P. verrucosum, P. chrysogenum, P. rugulosum and P. digitatum. Apple fruit were also surveyed for wounds and the number of open lenticels using the sulphur dioxide test. The incidence of wounding at harvest varied from 12 to 36%, depending on cultivar and locality. When apples were inoculated at harvest by either aqueous or aerial inoculum of P. expansum, the decay incidence was constantly higher than the incidence of wounding. The number of open lenticels per cm² of apple surface varied from 0·5 on cv. Boskoop to 4·4 on cv. Golden Delicious. An average of 13 and 2·1% of lenticels, respectively, were infected when they were inoculated by P. expansum and P. verrucosum. Cultivars of apple fruit that showed a greater number of open lenticels, combined with a large diameter varying from 100 to 200 µm, were more susceptible to P. expansum.     

陕西苹果树腐烂病菌(Cytospora spp.)不同分离株的生物学特性与致病性研究

 本研究从陕西分离得到61株苹果树腐烂病菌(Cytospora spp.),选取在PDA培养基上菌落特征差异明显的7个分离株,对其生物学特性及致病性进行研究。结果表明:各分离株在PDA、PSA、PMA和PEMA培养基上菌落生长较好,但在PDA上的菌落颜色和产孢情况差异很大。各分离株均能在5~32℃生长,但对35℃以上高温的适应性差异较大;所有分离株均能在pH4~9的条件下生长,最适pH为5~6;光照对各分离株的菌落生长有明显的促进作用。各分离株均可在Cza-pek培养基及供试的其它碳、氮源培养基上生长,其中以葡萄糖、麦芽糖和酵母膏为最佳碳、氮源。采用烫伤接种的方法,分别以菌饼和分生孢子悬浮液接种苹果离体枝条,两者均可侵染发病,但各分离株致病力差异显著,其中菌落颜色为黄褐色的菌株致病性强。因此,根据菌落颜色、致病性和生物学特性可将这7个分离株划分为3个类群:Ⅰ型为黄褐色强致病类群,但各分离株的产孢量有差异;Ⅱ型为乳白色不产孢的弱致病类群;Ⅲ型为灰褐色易产孢弱致病类群。其余54株分离物均属于Ⅰ型,这些结果说明陕西省苹果树腐烂病菌具有多样性和致病性分化现象。     

Damping-off of soybean in southern Brazil can be associated with different species of Globisporangium spp. and Pythium spp.

Damping-off of soybean is a common problem in some fields in southern Brazil. Frequently, Phytophthora sojae has been pointed out as the main causal agent. However, questions were raised as to whether other oomycetes could also be present. Hence, the objectives of this study were to isolate, identify, and determine the pathogenicity and aggressiveness of oomycetes isolated from soybean seedlings. Thirty-three isolates were obtained from 13 fields. Isolates were identified based on morphology and molecular methods. Nine species were recovered: Pythium conidiophorum (n = 14, 42.4%), Globisporangium rostratifingens (n = 7, 21.2%), G. irregulare (n = 2, 6.1%), G. spinosum (n = 1, 3.0%), G. ultimum var. sporangiiferum (n = 2, 6.1%), Pythium acanthicum (n = 2, 6.1%), P. deliense (n = 1, 3.0%), P. inflatum (n = 1, 3.0%), and P. torulosum (n = 3, 9.1%). Pathogenicity and aggressiveness were determined with two soybean cultivars (DM57i52 and NEO530) in a seed rot assay and a root rot assay. All isolates were pathogenic to soybean with variable levels of aggressiveness in both assays. The range of seed disease severity index varied from 7.5 to 100 for DM57i52 and from 23.1 to 100 for NEO530. The mean root disease severity index of the soybean cultivars ranged from 29.4 to 92.8. This is the first official report of G. irregulare, G. rostratifingens, G. spinosum, G. ultimum var. sporangiiferum, P. acanthicum, P. conidiophorum, P. deliense, P. inflatum, and P. torulosum causing damping-off of soybean in the state of Rio Grande do Sul in southern Brazil.     

Identification of Neofabraea species causing bull's eye rot of apple in Poland and their direct detection in apple fruit using multiplex PCR

Based on partial sequence analysis of the β‐tubulin gene, 19 isolates of fungi causing bull's eye rot on apple in Poland were classified into species: Neofabraea alba, N. perennans and N. kienholzii. To the authors’ knowledge, the detection of N. kienholzii is the second in Europe and the first in Poland. Species affiliation of these fungi was confirmed by a new species‐specific multiplex PCR assay developed on the basis of previously published methods. The new protocol allowed for the specific identification of bull's eye rot‐causing species, both from pure cultures and directly from the skin of diseased or apparently healthy apples. In 550 samples of diseased fruits collected from nine cold storage rooms located in three regions of Poland, in 2011 and 2012, N. alba was detected as the predominant species causing bull's eye rot, occurring on average in 94% of the tested samples. Neofabraea perennans was found in a minority of apple samples, N. kienholzii was found only in two apple samples, while N. malicorticis was not detected in any sample tested. In tests on 120 apparently healthy fruits, only N. perennans was detected in a single sample. The results of genetic diversity analyses of bull's eye rot‐causing fungi based on the β‐tubulin gene sequence and an ISSR (inter‐simple sequence repeat) PCR assay with two primers were consistent, showing the expected segregation of tested isolates with respect to their species boundaries. However, the genetic distance between N. perennans and N. malicorticis was very low, as reported previously.     

Molecular phylogeny and morphological characterization of the aetiological agent of sour rot on fruits and vegetables in Brazil

In Brazil, sour rot is an important postharvest disease on fruits and vegetables. Geotrichum candidum (synonym Galactomyces candidus) has been reported as the main species causing this disease. However, the identity of the causal agent is still uncertain. This research aimed to determine the identity of 165 fungal isolates associated with sour rot obtained from fruits and vegetables in Brazil, and to evaluate the effect of different temperatures on the incidence of sour rot on artificially inoculated tomato fruits. Based on the phylogenetic analyses of DNA sequences from the D1/D2 domain of the large subunit (LSU) rRNA gene and morphological analyses, 129 samples belonged to Galactomyces candidus, 15 to G. candidum var. citri-aurantii, 6 to G. phurueaense, 2 to Gal. pseudocandidus, 1 to Hyphopichia burtonii, 1 to H. khmerensis, 3 to Saccharomycopsis crataegensis, 1 to S. vini, 1 to Magnusiomyces tetrasperma, 1 to Trichosporon coremiiforme, and 1 to Zygoascus meyerae. Two new species were found, namely, Geotrichum solani (on potato) and Geotrichum spondiadis (on red mombin). All isolates were pathogenic when inoculated on healthy tomato fruits, including the new species of Geotrichum, which were also inoculated into their respective hosts, that is, potatoes and red mombins. To the best of our knowledge, this study is the first to report the presence of five other genera besides Geotrichum associated with sour rot on fruits and vegetables in Brazil, which demonstrates the diversity of fungi and yeasts associated with this disease.     

Effects of fruit maturity and wetness on the infection of apple fruit by Neonectria galligena

Neonectria galligena can cause European canker of apple as well as fruit rot. Healthy unwounded fruits on potted trees of cvs Cox, Bramley and Gala were inoculated with conidia of N. galligena to investigate the effects of wetness duration and fruit maturity on rot development. Overall, the incidence of fruit rot was influenced more by fruit maturity at the time of inoculation than by duration of wetness (6–48 h). Young fruit were most susceptible to infection, with 50% of fruit infected when inoculated up to 4 weeks after full bloom. The susceptibility decreased initially until c. 2 months after full bloom and then increased gradually until harvest. Almost all preharvest symptoms (eye rot) developed only on the fruit inoculated up to 4 weeks after full bloom. All other rots were observed after six‐month postharvest storage under controlled atmospheric conditions. However, the relative proportion of preharvest eye rots and postharvest storage rots varied greatly among three years. The effect of wetness duration was only significant for fruit inoculated in their early stages of development but not for those inoculated near harvest. Regression models were developed to describe the observed effects of fruit maturity and wetness on the incidence of total nectria rots.     

灰霉菌(Botrytis cinerea)采后致病性研究

 灰霉菌(Botrytis cinerea)是引起葡萄采后病害的主要病原真菌之一。葡萄灰霉菌可在田间潜伏侵染,采后由健康果实携带进入销售市场,该菌的显著致病症状为果实软腐和脱落。灰霉菌与葡萄的其它采后致病菌,如链格孢菌(Alternaria alternata)、镰刀菌(Fusarium sp.)、芽枝霉(Cladosporium sp.)、青霉菌(Penicillium sp.)、黑曲霉(Aspergillus nigar)和粉红单端孢菌(Trichothecium roseum)相比,不仅表现出明显的潜伏侵染优势,而且具有较强的低温(4℃)条件下的致病优势。4℃低温下灰霉菌在寄主葡萄体外和体内分泌多聚半乳糖醛酸酶(PG)活力均显著高于以上各菌,而在25℃下无显著差异,这一结果与该2种温度下灰霉菌接种果实后的症状表现一致。     

戊唑·多菌灵·乙膦铝乳胶液对苹果枝干轮纹病的防治效果

近年,在矮砧密植苹果园发现苗木栽植后幼树主干上的枝干轮纹病发生严重,急需有效的防治方法。针对生产中的需求,本研究对幼树枝干轮纹病的防治方法进行了探索,结果显示:用乳胶液配制的戊唑·多菌灵·乙膦铝混合剂对枝干轮纹病防治效果显著高于同种药剂的水溶液,对剪锯口枝干轮纹病防治效果可达63.7%~100%,是药剂水溶液防效的2~3倍;生长季施用2次,对枝干轮纹病病斑的铲除率为45.2%,是药剂水溶液防效的9.6倍以上。结果表明,戊唑·多菌灵·乙膦铝乳胶液对枝干轮纹病防治效果显著,可以用于苗木剪锯口的防护,以及新建果园中幼树枝干轮纹病的治疗。研究结果为生产中幼树枝干轮纹病的防治提供了有效的方法。     

Dynamics of post‐harvest pathogens Neofabraea spp. and Cadophora spp. in plant residues in Dutch apple and pear orchards

Post‐harvest diseases of apple and pear cause significant losses. Neofabraea spp. and Cadophora spp. infect fruits during the growing season and remain quiescent until disease symptoms occur after several months in storage. Epidemiological knowledge of these diseases is limited. TaqMan PCR assays were developed for quantification of N. alba, N. perennans, C. malorum and C. luteo‐olivacea in environmental samples. Various host tissues, dead weeds and grasses, soil and applied composts were collected in 10 apple and 10 pear orchards in May 2012. Neofabraea alba was detected in 73% of samples from apple orchards and 48% from pear orchards. Neofabraea perennans was present in a few samples. Cadophora luteo‐olivacea was detected in 99% of samples from apple orchards and 93% from pear orchards, whilst C. malorum was not detected in any sample. In apple orchards, highest concentrations of N. alba were found in apple leaf litter, cankers and mummies, and of C. luteo‐olivacea in apple leaf litter, mummies and dead weeds. In pear orchards, N. alba and C. luteo‐olivacea were found in highest concentrations in pear leaf litter and in dead weeds. Substrate colonization varied considerably between orchards. The temporal dynamics of pathogens was followed in four apple orchards and four pear orchards. In apple orchards the colonization by pathogens decreased from April until August and increased from September until December. This pattern was less pronounced in pear. Knowledge on population dynamics is essential for the development of preventative measures to reduce risks of fruit infections during the growing season.     

河北省苹果果实黑点病的症状与病原研究初报

为明确河北省苹果果实黑点病的症状类型及其对应的病原菌,本研究对河北省6个市的果园进行了病害调查和样品采集,并对引起不同症状类型的病果进行了病原菌的分离和鉴定.结果表明,河北省的套袋苹果黑点病可以分为四大类型,分别是萼洼黑点型、果面黑点型、果面晕斑型和梗洼褐斑型.除了果面晕斑型为单一病原侵染之外,其他类型的病斑均分离获得...     

复合微生物菌肥对苹果再植病害调控及对根围土壤真菌群落结构的影响

 为研究复合微生物菌肥对再植苹果幼树的影响,从再植土壤酶活性、真菌群落结构和功能的方面分析,探究复合微生物菌肥的作用机理。本研究设置了KMM和对照CK两个处理,再植苹果树于春秋两次分别施用复合微生物菌肥(KMM)和有机肥(CK)。通过土壤常规农业化学分析法和Illumma MiSeq高通量测序技术,系统研究了两个处理再植苹果树的生长、根围土壤酶活性以及真菌群落结构和功能的变化。试验结果表明,施用复合微生物菌肥显著提高了再植苹果幼树株高、干径、叶绿素、分枝个数和分枝长度;提高再植土壤酶活性(中性磷酸酶、脲酶、蔗糖酶和过氧化氢酶);降低再植土壤真菌群落丰富度,改变真菌群落结构。相对丰度高于1%的优势真菌属中有21个菌属与再植果树的5项生长参数具有相关性,并且在不同分类水平上具有一定的差异,缝壳菌属(Lophiostoma)、织球壳菌属(Plectosphaerella)、赤壳菌属(Nectria)和维希尼克氏属(Vishniacozyma)显著增加,丝孢菌属(Anguillospora)和假丝酵母菌属(Pseudeurotium) 显著降低。通过对测序片段功能水平的分析,在二级功能水平上显著降低了真菌群落氨基酸、核苷和核苷酸的生物合成、电子转移、发酵、呼吸、CTP生物合成嘧啶脱氧核糖核酸功能序列的丰度值,共6种功能类群均与土壤酶活性呈负相关。施用复合微生物菌肥,改变了真菌群落结构,减弱真菌群落相关代谢的功能,提高土壤酶活性,促进再植苹果幼树的生长。     

Characterization of the host range and sensitivity to fungicides of Trichothecium spp. associated with fruit rot in the field and in storage

During 2017–2019, we observed Trichothecium spp. causing fruit rot in the field and in storage. This study was conducted to examine morphological differences of the species from different hosts, reveal the species’ potential host range, and evaluate the efficacy of five fungicides. Six strains of Trichothecium spp. isolated from nectarine, peach and walnut were selected. Although the colony morphology, mycelial growth rate and spore size differed among hosts, phylogenetic analysis based on the internal transcribed spacer and part of the 5ʹ end of the β-tubulin gene showed that all tested strains belonged to Trichothecium roseum. For its host range, 23 kinds of fruit were examined using T. roseum strain YT-1 as an inoculum; 10 kinds of fruit, including pear, apple, mango, Chinese chestnut, pepino melon, fig and durian, were susceptible to T. roseum, with minimum inoculation concentrations ranging from 10⁴ to 10⁵ spores/ml. The fungicides that most effectively inhibited the six isolates were fluazinam and fludioxonil, with EC₅₀ values of 0.07–0.1 and 0.01–0.04 μg/ml, respectively, followed by difenoconazole (0.81–2.96 μg/ml), boscalid (5.43–13.51 μg/ml) and azoxystrobin (9.18–27.25 μg/ml). Improvement of the shelf life of nectarines held in plastic trays was explored using allyl isothiocyanate (AITC) against T. roseum YT-1. The application of 10 μl/L AITC significantly suppressed disease symptoms. The findings provide useful information for future disease emergency management in the field and for food preservation.     

Effect of apple cultivar and of temperature on the biology and life table parameters of the twospotted spider mite<Emphasis Type="Italic">Tetranychus urticae</Emphasis>

Development duration and reproduction rate of the twospotted spider miteTetranychus urticae Koch (Acarina: Tetranychidae) were studied on five different apple cultivars (‘Amasya’ (local cultivar), ‘Golden Delicious’, ‘Granny Smith’, ‘Starking Delicious’ and ‘Starkrimson Delicious’) at 25°C, 65±10% r.h. and 16:8 L:D. In addition, the same parameters were determined on Golden Delicious leaves at three constant temperatures (20°, 30° and 35°C, 65±10% r.h. and 16:8 L:D) in the laboratory.T. urticae performed better on Granny Smith than on the other cultivars, due mainly to high daily egg production (4.6 eggs/♀/day) and the intrinsic rate of natural increase (r _m , which was 0.243 ♀/♀/day). The lowestr _m was observed on Amasya variety (0.231 ♀/♀/day). Development periods of immature stages ofT. urticae varied from 6.5 to 15.5 days at 35° and 20°C, respectively, for females, and from 5.9 to 14.5 days at 35° and 20°C, respectively, for males. The development thresholds of the eggs and pre-adult stages, respectively, were 10.78° and 8.43°C, and total effective temperatures were 57.80 and 172.41 degree-days. Mean generation time (T _o ) of the population ranged from 9.94 days at 35°C to 25.99 days at 20°C. The net reproduction rate increased from 66.99 ♀/♀ at 20°C to 92.19 ♀/♀ at 25°C, and decreased to 84.34 ♀/♀ at 30°C and to 12.04 ♀/♀ at 35°C. The highest r _m occurred at 30°C (0.302 ♀/♀/day) and the lowest at 20°C (0.161 ♀/♀/day). http://www.phytoparasitica.org posting Dec. 19, 2003.     

中国苹果病害发生与分布现状调查

本研究于2010-2012年在我国18个省(市、自治区)的1 100个苹果园采用隔行踏查法进行了实地调查。调查内容包括果园面积、品种名称、树龄结构以及各种病害发生情况。调查结果表明,3年间在我国苹果主产区共发现病害50种,其中包括新发现的2种病害:丝核菌叶枯病和炭疽菌叶枯病。通过分析确定了各种病害的严重度,明确了腐烂病、轮纹病、褐斑病和斑点落叶病4种主要病害及苹果锈病等8种中度发生病害的发生程度及区域分布,为各苹果主产省开展病害防控提供了理论依据。     

甘肃省苹果病虫害发生情况初探

采用抽样调查和定点调查相结合的方法,在2010-2011年对甘肃省苹果病虫害种类、分布范围和危害程度进行了系统调查。结果表明:甘肃省危害苹果的病害共22种,虫害40种,主要病虫害有苹果树腐烂病、斑点落叶病、褐斑病、锈病、山楂叶螨、金纹细蛾、绣线菊蚜、康氏粉蚧、桃小食心虫等;其中苹果树腐烂病在全省各市(州)均有发生,天水、平凉、庆阳、陇南为中度偏重发生,平均发病率达30%,斑点落叶病和褐斑病在兰州、白银、天水、平凉、庆阳、陇南、定西普遍发生,庆阳、平凉中度发生,山楂叶螨在天水、平凉、武威、庆阳中度发生,苹果绵蚜在平凉、定西轻度发生,庆阳中度偏重发生,检疫性害虫苹果蠹蛾在酒泉、嘉峪关、张掖轻度发生。     

近50年陕西省无霜期的变化及果区霜冻风险分布

利用陕西省96个气象台站1961～2010年的日最低气温资料,计算了陕西各站历年霜冻的初日、终日及无霜期,并对其分布特征及年际变化进行分析。结果显示,陕西省初霜日、终霜日、无霜期等值线在陕北大致呈经向分布,在关中和陕南大致呈纬向分布;50年间,全省96站初霜日最早和最晚平均值相差44天,终霜日最早和最晚平均值相差49天,无霜期最长和最短天数平均值相差68天;全省平均初霜日呈推迟趋势,推迟幅度约为1.4天/10年;平均终霜日呈提前趋势,提前幅度约为1.7天/10年;平均无霜期呈加长趋势,加长幅度约为3.1天/10年。最后依据风险分析理论对陕西多个苹果基地县进行了花期霜冻风险分析,得出其风险的空间分布特点,结论对精确指导和开展防灾减灾工作有参考作用。     

玉米种质对玉米粗缩病的抗性研究初报

采用罩笼法对6个主栽玉米品种进行粗缩病抗性鉴定,结果表明,登海3622、金海5号、农大108对粗缩病具有抗性,其中农大108的抗性还表现在灰飞虱对它的趋向性较弱上。结合不同品种的种质分析,发现不同血缘种群间存在一定的差异,以Reid种质血缘为主的品种抗性较差,含有PB种质血缘的品种则表现出抗性。     

黑龙江省马铃薯干腐病菌种类鉴定及致病性

本研究将采自黑龙江省不同地区的马铃薯干腐病病样进行分离和病原菌纯化,得到27个镰刀菌菌株,通过致病性鉴定,其中的18个菌株具有致病性。运用培养性状和形态特征综合分析的方法,对上述18个菌株进行鉴定,结果显示为6种镰刀菌,分别为拟枝孢镰孢(Fusarium sporotrioides)、茄镰孢(F.solani)、接骨木镰孢(F.sam-bucinum)、拟丝孢镰孢(F.trichothecioides)、燕麦镰孢(F.avenaceum)和茄病镰孢蓝色变种(F.solanivar.coerule-um)。同时对上述6种镰刀菌进行致病性测定,结果表明不同种类镰刀菌致病性不同,以接骨木镰孢、燕麦镰孢和拟丝孢镰孢致病力最强,拟枝孢镰孢致病力最弱。     

陇东旱塬地表覆盖方式对苹果生育后期叶片质量及根际土壤微环境的影响

为探明陇东旱塬区不同覆盖方式对苹果生育后期叶片质量、根际生态环境的影响,以16 a生,连续6 a覆盖的盛果期“长富2号”苹果树为试材,设清耕（CK)、覆膜、麦草覆盖、覆黑膜+麦草（膜+草）等4个处理,调查叶片养分、活性氧代谢功能,测定0～100 cm内不同深度土层土壤水分、容重、有机质等,对根际土壤微生物数量及土壤酶活性进行分析。结果表明：麦草覆盖处理可有效提高苹果叶片叶绿素与淀粉含量,增幅分别为CK的2.79%、29.09%;根系集中分布层（20～40 cm）土壤水分、有机质含量增高,分别为CK的102.93%,135.96%;土壤容重仅为CK的96.32%,并有效提高各土层土壤酶活性,特别提高土壤表层（0～20 cm）酶活性,脲酶、碱性磷酸酶、过氧化氢酶、蔗糖酶活性为CK的157.14%、218.5%、118.02%、193.21%,可有效提高土壤中微生物总量,为CK的134.19%,其中细菌与真菌的数量增高,放线菌的数量降低;根系活力与土壤水分、孔隙度、微生物含量及脲酶、蔗糖酶等呈极显著正相关,与土壤容重、过氧化氢酶呈极显著负相关。覆膜与膜+草处理对叶片及土壤环境改善效果较差。综合分析根际土壤理化性状及土壤酶、微生物空间分布特征等,认为麦草覆盖处理是陇东旱塬区苹果园适宜的地表覆盖方式。     

中国苹果树腐烂病发生和防治情况调查

2008年4～5月,通过国家苹果产业技术体系网络系统,对我国10个苹果主产省市的147个果园进行了苹果树腐烂病发生和防治情况调查。结果显示,在所调查苹果树中,总体发病率达52.7%。随着树龄的增大,腐烂病发病株率提高,4～10年生果树株发病率为26.8%,11～17年树龄的果树株发病率为54.0%,18～24年树龄的树株发病率为59.3%。不同省份之间以及不同品种之间,腐烂病在发生程度上存在一些差异,但不很明显。在腐烂病的化学防治中,石硫合剂是使用最多的药剂。在刮治病斑中,使用最多的是福美胂,其他还包括松焦油、腐殖酸、腐殖酸铜、过氧乙酸等。调查中发现防治腐烂病的用药比较混乱,由于福美胂毒性高,在无公害果园生产中已被禁用,因此研究替代福美胂的药剂成为当务之急。