Reduced volume application of fungicides for the control of onion rots

A survey was conducted to define the fungi population contaminating onion bulbs in Israel during three growing seasons. Significant rots were found to be caused byBotrytis allii, B. cinerea andAspergillus niger. All the onion stocks tested showed infections, but the severity and identity of the pathogens varied between seasons.B. cinerea andB. allii were the most prevalent fungi in winter-harvested onions. Species ofAspergillus, Penicillium, Fusarium, Rhizopus andTrichoderma were also isolated. The first two were the only species found on summer onions. High fungal contamination had been the main factor affecting an attempt to improve the storage quality and shelf life of the harvested bulbs. Chemical disinfection using a reduced-volume application (RVA) technique was efficient in controlling the major storage rots (caused byA. niger andB. cinerea) of the bulbs, without the major disadvantages of the dipping method. The rate of control was directly correlated with the cover density of the deposited fungicide, but not with the amount deposited. The RVA technique should enable prolongation of postharvest shelf life and storability of onion bulbs.     

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%.     

进境水果重要真菌病害——星裂壳孢梨果腐病和苹果果腐病

星裂壳孢梨果腐病和苹果果腐病分别由Phacidiopycnis(缩写:Ph.)pyri和Ph.washingtonensis侵染所致,这两种真菌性病害在我国尚未有发生为害的报道,前者在欧洲和北美梨和苹果产区为害严重,而目前后者则仅在美国报道.本文介绍了以上两种病害的发生分布、寄主范围、病原菌及其形态特征、侵染特点及为害症状、病原菌培养性状、生物学特性、分离和鉴定方法、致病性测定及简要的防治方法;初步分析了病害的传播途径.自2008年4月起首次并连续3次从佛山澜石口岸截获的美国进境苹果中截获星裂壳孢苹果果腐病(Ph.washingtonensis),根据此疫情本文阐述了梨果腐病和苹果果腐病在我国口岸检疫的重要性.     

Biological approaches for control of root pathogens of strawberry

ABSTRACT Soil fumigation with methyl bromide plus chloropicrin is used as a preplant treatment to control a broad range of pathogens in high-value annual crop production systems. In California, fumigation is used on approximately 10,125 ha of strawberry production to control pathogens ranging from Verticillium dahliae to root pruning pathogens such as Pythium, Rhizoctonia, or Cylindrocarpon spp. In addition to pathogen control, fumigation also causes an enhanced growth response of the plant and reduces weed pressure. The development of successful, long-term cost effective biocontrol strategies most likely will require the development of an integrated systems approach that incorporates diverse aspects of the crop production system. Although application of single microbial inoculants may provide some level of control for specific production problems, it will be a challenge to provide the broad spectrum of activity needed in production fields.     

Development and validation of a set of standard area diagrams to assess severity of gray mold in strawberry fruit

European Journal of Plant Pathology - Gray mold (Botrytis cinerea) is one of the main diseases that affect strawberries. Severity assessments of the disease in fruits have been mainly performed...     

湖北省草莓病害发生特点及防治技术

草莓是一种营养丰富的保健水果 ,随着农村产业结构的调整 ,由于它栽培容易 ,当年结果 ,产量较高 ,经济效益好等优点 ,在我地发展较快 ,栽培面积不断扩大。但草莓病害时有发生 ,若防治不及时 ,严重影响草莓的产量和质量。笔者根据近年来对我地草莓病害的调查研究及防治实践 ,总结出了草莓主要病害的发生特点及防治技术 ,现将结果报告如下 :1　草莓的主要病害草莓主要病害有草莓灰霉病、白粉病、叶斑病、病毒病、芽枯病、草莓果畸形等病害 ,这些病的大量发生和流行 ,严重为害草莓的茎、叶、果 ,影响草莓的产量和质量 ,造成很大的经济损失。1 .…     

Physiological and physical measures to control postharvest diseases of fruit

Preharvest and postharvest decay of persimmon fruits caused byAltemaria alternata can be effectively alleviated by a growth hormone effect on the physiology of the fruit An orchard application of gibberellin (GA₃), prior to harvest, maintains the calyx in an upright, erect position, thus preventing the formation of a microclimate beneath the calyx, which is conducive to decay development in this region. The additional effect of delaying fruit maturation, leads to an increased resistance of the fruit to postharvest decay development on the entire fruit surface during storage. Other measures, of a physical nature, which can be employed to control postharvest disease, include a change in environment, such as achieved by controlled atmosphere storage or modified atmosphere packaging. The dominant control factors appear to be the naturally produced CO₂ and possibly acetaldehyde.     

Glasshouse trials of Coniothyrium minitans and Trichoderma species for the biological control of Sclerotinia sclerotiorum in celery and lettuce

Coniothyrium minitans, Trichoderma harzianum (HH3) and Trichoderma sp. (B1) were tested for ability to control disease caused by Sclerotinia sclerotiorum in a sequence of a celery crop and two lettuce crops in the glasshouse. In control plots, over 80% of celery and 90 and 60% of lettuce in first and second crops, respectively, were infected at harvest. Only the C. minitaris treatment in the first lettuce crop decreased disease and increased marketable yield. Nevertheless, C. minitans reduced the number of sclerotia recovered at harvest in the celery and first lettuce crops and decreased sclerotial survival over the autumn fallow periods following the celery and second lettuce crop. C. minitans survived in soil for over 1 year and spread to infect sclerotia in virtually all other plots. C. minitans infected sclerotia at all times of the year but sclerotia still failed to degrade during the summer months when the soil was dry. The Trichoderma species tested had no effect on disease and almost no effect on the survival of the sclerotia. even though they could be recovered from soil for the duration of the experiments.     

Control of postharvest Botrytis fruit rot of strawberry by volatile organic compounds of Candida intermedia

A study was conducted to identify volatile organic compounds or volatiles produced by Candida intermedia strain C410 using gas chromatography-mass spectrometry, and to determine efficacy of the volatiles of C. intermedia in suppression of conidial germination and mycelial growth of Botrytis cinerea and control of Botrytis fruit rot of strawberry. Results showed that, among 49 volatiles (esters, alcohols, alkenes, alkanes, alkynes, organic acids, ketones, and aldehydes) identified from C. intermedia cultures on yeast extract peptone dextrose agar, two compounds, 1,3,5,7-cyclooctatetraene and 3-methyl-1-butanol, were the most abundant. Synthetic chemicals of 1,3,5,7-cyclooctatetraene; 3-methyl-1-butanol; 2-nonanone; pentanoic acid, 4-methyl-, ethyl ester; 3-methyl-1-butanol, acetate; acetic acid, pentyl ester; and hexanoic acid, ethyl ester were highly inhibitory to conidial germination and mycelial growth of B. cinerea. Inhibition of conidial germination and mycelial growth of B. cinerea by volatiles of C. intermedia was also observed. Meanwhile, results showed that incidence and severity of Botrytis fruit rot of strawberry was significantly (P < 0.01) reduced by exposure of the strawberry fruit to the volatiles from C. intermedia cultures or C. intermedia-infested strawberry fruit. These results suggest that the volatiles of C. intermedia C410 are promising biofumigants for control of Botrytis fruit rot of strawberry.     

Trichoderma species associated with green mould disease of Pleurotus ostreatus and their sensitivity to prochloraz

Green mould disease causes serious economic losses in Pleurotus ostreatus crops worldwide, including in Italy, where prochloraz is the only chemical fungicide allowed to control the disease. The effectiveness of the doses 0.01, 0.05, 0.25 and 1.25 μL L⁻¹ (field dose) of prochloraz (Sponix Flow, 450 g L⁻¹), against colony growth rate and spore germination of Trichoderma pleuroti, T. pleuroticola and T. guizhouense strains on wheat straw extract agar plates were evaluated. Complete inhibition of Trichoderma pleuroti and T. pleuroticola growth was shown by the field dose of prochloraz, and also by the 0.25 μL L⁻¹ dose for T. pleuroti. Complete inhibition of spore germination occurred for all Trichoderma strains at field dose, and at 0.25 μL L⁻¹ for T. pleuroti strains. In in vivo assays, the effect of prochloraz doses 0.05, 0.25 and 1.25 μL L⁻¹ on colonization of straw substrate by T. pleuroti, T. pleuroticola and T. guizhouense inoculated at two spore densities (10² and 10⁵ spores mL⁻¹) immediately after P. ostreatus spawn was studied. Trichoderma pleuroti and T. pleuroticola were both responsible for green mould disease, whereas T. guizhouense was not pathogenic. Trichoderma pleuroti was more aggressive than T. pleuroticola. Prochloraz was effective against T. pleuroti at the field dose, and against T. pleuroticola at 0.25 and 1.25 μL L⁻¹. The study on Trichoderma × Pleurotus interaction type showed that Trichoderma species were active against the mycelial growth of P. ostreatus by competition for space and nutrients, and neither hyphal interaction nor effect by volatile or nonvolatile metabolites occurred.     

2%武夷菌素水剂对草莓白粉病的毒力测定及田间防效

武夷菌素是一种农用抗生素类生物杀菌剂,温室及田间试验表明它对粮食、蔬菜、果树上的多种真菌病害有很好的防治效果,并且已经应用于农业生产中.为了考查其对草莓白粉病的防治效果,进行了室内孢子萌发抑制试验,结果表明武夷菌素能够抑制草莓白粉病菌孢子的萌发,其EC50为9.550 6μg/mL.同时田间药效试验结果表明,2％武夷菌素水剂对草莓白粉病具有良好的防治效果,其300倍液防治草莓白粉病的效果和化学农药10％苯醚甲环唑水分散粒剂相当,武夷菌素200倍液的防效显著高于化学农药,同时对草莓自身的生长发育没有影响.试验表明武夷菌素对草莓白粉病有很好的防治作用,可为生产上防治草莓白粉病和科学用药提供依据.     

An adapted selective medium for the quantitative isolation of Trichoderma species

Further modifications were made to a previously amended Trichoderma -selective medium (TSM), by replacing fenaminosulf with propamocarb or metalaxyl. Both were effective in suppressing Oomycetes but propamocarb was superior. Quantitative isolation of Trichoderma species from soil was possible.     

The potential of fludioxonil for anthracnose control on China chili fruit

Anthracnose, caused by Colletotrichum scovillei, is one of the most destructive disease which causes massive yield losses in chili. Our preliminary study has demonstrated that fludioxonil had high activity against mycelial growth and spore germination of C. scovillei but it has not been labeled on chili. The aim of this study was to investigate the impact of fludioxonil on C. scovillei infection. In greenhouse and field trials, fludioxonil was applied to chili plants to determine the duration of protection of fruit provided by this compound against chili anthracnose. Fludioxonil may have impact on the early stage of chili anthracnose infection by inhibiting the germ tube elongation and appressorium formation. Moreover, it inhibited the secondary infection of C. scovillei by inhibiting the sporulation, germination of spores and formation of appressoria. Fludioxonil provided high level of protective activity for up to 96 h, as well as excellent curative activity of within 24 h in vivo tests. In field trials, fludioxonil can reduce the incidence and severity of chili anthracnose while giving a higher chili yield. These results suggest that fludioxonil could be a promising fungicide for anthracnose control in chili production.     

山东临朐不同品种樱桃上果蝇发生种类及种群动态调查

为了解不同品种樱桃果蝇的发生情况,于2019年在山东临朐应用糖醋液诱捕器监测果蝇成虫发生动态,并调查了不同品种樱桃受果蝇为害情况及相关品质指标.结果表明,不同樱桃品种间果蝇成虫发生量及发生高峰期不同,以黄蜜和美早上果蝇的发生数量最多,监测成虫发生高峰期较先锋、红灯、拉宾斯晚.樱桃果实成熟期,美早和黄蜜上果蝇幼虫数量和蛀...     

Genetic diversity and pathogenic variability among isolates of colletotrichum species from strawberry

ABSTRACT Ninety-five isolates of Colletotrichum including 81 isolates of C. acutatum (62 from strawberry) and 14 isolates of C. gloeosporioides (13 from strawberry) were characterized by various molecular methods and pathogenicity tests. Results based on random amplified polymorphic DNA (RAPD) polymorphism and internal transcribed spacer (ITS) 2 sequence data provided clear genetic evidence of two subgroups in C. acutatum. The first subgroup, characterized as CA-clonal, included only isolates from strawberry and exhibited identical RAPD patterns and nearly identical ITS2 sequence analysis. A larger genetic group, CA-variable, included isolates from various hosts and exhibited variable RAPD patterns and divergent ITS2 sequence analysis. Within the C. acutatum population isolated from strawberry, the CA-clonal group is prevalent in Europe (54 isolates of 62). A subset of European C. acutatum isolates isolated from strawberry and representing the CA-clonal and CA-variable groups was assigned to two pathogenicity groups. No correlation could be drawn between genetic and pathogenicity groups. On the basis of molecular data, it is proposed that the CA-clonal subgroup contains closely related, highly virulent C. acutatum isolates that may have developed host specialization to strawberry. C. gloeosporioides isolates from Europe, which were rarely observed were either slightly or nonpathogenic on strawberry. The absence of correlation between genetic polymorphism and geographical origin in Colletotrichum spp. suggests a worldwide dissemination of isolates, probably through international plant exchanges.     

Biological control of postharvest diseases of fruit

Postharvest decay in harvested fruit causes considerable economical losses. Fungicides are the primary means to control these losses. Public concern in food safety and environmental issues and the increase of pathogen resistant populations have enhanced the interest in developing alternative methods to fungicides to control postharvest fruit decay. During the last two decades a huge information and advances concerning the selection of antagonists, mode of action, different approaches to enhance biocontrol activity, formulation and production have been achieved, and some biofungicides are already in the market. It is likely that several more products will enter the market in the near future, as the result of the biological control research programs worldwide. Nonetheless, it is necessary to continue finding new potential microorganisms, better understanding the mode of action, and pathogen, antagonist and host interactions, to increase the potential of biocontrol helping to become a real alternative to synthetic postharvest fungicides. This article presents an overview of postharvest biological control approaches and explores new research possibilities to improve biocontrol activity.