Infected Plant Debris Research Articles

Pest categorisation of Coniella castaneicola.

The European Commission requested the EFSA Panel on Plant Health to conduct a pest categorisation of Coniella castaneicola (Ellis & Everh) Sutton, following commodity risk assessments of Acer campestre, A. palmatum, A. platanoides, A. pseudoplatanus, Quercus petraea and Q. robur plants from the UK, in which C. castaneicola was identified as a pest of possible concern to the EU. When first described, Coniella castaneicola was a clearly defined fungus of the family Schizoparmaceae, but due to lack of a curated type-derived DNA sequence, current identification based only on DNA sequence is uncertain and taxa previously reported to be this fungus based on molecular identification must be confirmed. The uncertainty on the reported identification of this species translates into uncertainty on all the sections of this categorisation. The fungus has been reported on several plant species associated with leaf spots, leaf blights and fruit rots, and as an endophyte in asymptomatic plants. The species is reported from North and South America, Africa, Asia, non-EU Europe and Oceania. Coniella castaneicola is not known to occur in the EU. However, there is a key uncertainty on its presence and geographical distribution worldwide and in the EU due to its endophytic nature, the lack of systematic surveys and possible misidentifications. Coniella castaneicola is not included in Commission Implementing Regulation (EU) 2019/2072 and there are no interceptions in the EU. Plants for planting, fresh fruits and soil and other growing media associated with infected plant debris are the main pathways for its entry into the EU. Host availability and climate suitability in parts of the EU are favourable for the establishment and spread of the fungus. Based on the scarce information available, the introduction and spread of C. castaneicola in the EU is not expected to cause substantial impacts, with a key uncertainty. Phytosanitary measures are available to prevent its introduction and spread in the EU. Because of lack of documented impacts, Coniella castaneicola does not satisfy all the criteria that are within the remit of EFSA to assess for this species to be regarded as potential Union quarantine pest.

EFFICACY OF BIO-CONTROL AGENTS AGAINST SCLEROTIUM ROLFSII CAUSING COLLAR ROT DISEASE OF CHICKPEA, UNDER IN VITRO CONDITIONS

Chickpea is the most important pulse crop widely grown in India, accounts for nearly 75 per cent of the total pulse production in the world. Chickpea crop is prone to many diseases. Among these, collar rot caused by Sclerotium rolfsii is one of the destructive soil-borne diseases of fungal origin and which is gaining importance elsewhere has been recently observed in and around different parts of country is a serious hazard. S. rolfsii survives in mycelium in the infected tissues and plant debris and as sclerotial structures in the soil or associated with plant debris and usually attacks the collar region of plants. Biological control of the disease through antagonists is an eco-friendly approach apart from superior alternative to the use of chemicals. In the present study, the four antagonistic micro-organisms were evaluated by dual culture and paper disc technique for their antagonistic effect against S. rolfsii under in-vitro conditions. Maximum inhibition of mycelial growth (78.61%) was noticed in T. viride which was followed by T. harzianum (75.28%). Least inhibition was observed in P. fluorescence (68.89%).

Inoculum Level and Inoculation Method Influences on the Pathogenic Activities of Meloidogyne incognita in Studied Model Plant Okra (Abelmoschus esculentus L. Moench)

Agricultural activities such as watering crops with nematode-infested water from wells and boreholes, and using infected plant debris as manure or mulch increase root-knot nematode infection. So, this study aims at assessing the influence of the inoculation method and inoculum level of Meloidogyne incognita on the development of root galls on okra plants. Two M. incognita inoculation methods (suspension of individuals and galled root explants) and six inoculum levels (0, 10, 100, 500, 1000 and 2000 second-stage larvae/plant) were studied. The gall index, total numbers and reproductive factor of M. incognita were used to assess the effect of treatments on root gall development. Unlike the reproductive factor, gall index and the total numbers of M. incognita increased with their inoculum level. The pathogenic activities of M. incognita were most significant when crop soils were infested with galled root explants. However, an inverse relationship was found between the inoculum levels of M. incognita and the okra plant’s development. It is reflected by negative correlation coefficients ranging from -0.90 to -0.62. It is therefore important to burn roots infected with root-knot nematodes left in fields so that they do not act as an inoculum for crops.

Low-Cost Spore Traps: An Efficient Tool to Manage Fusarium Head Blight through Improved Cropping Systems

Fusarium head blight (FHB) is a devastating disease of wheat. Worldwide, Fusarium graminearum is the most dominant FHB-causing species. Its most common toxin, deoxynivalenol (DON), impairs food and feed safety and has an enormous economic impact. Agronomic factors such as crop rotation, soil management and host genotype strongly influence the occurrence of F. graminearum. Infected plant debris from previous crops, on which perithecia and ascospores develop, represent the main source for FHB, and hence, improved cropping systems aim to reduce this inoculum to decrease the infection risk. The best measure to evaluate the disease pressure is spore traps that detect deposited airborne ascospores. Commercial spore traps are expensive and require power sources, thus, they are not suitable for investigations in field experiments with different treatments. In consequence, we developed spore traps containing a Petri dish with Fusarium-selective agar, protected by aluminum dishes and attached on a wooden board. We compared the data of our low-cost trap with those of a commercial high-throughput jet sampler and obtained equivalent results. In field experiments to compare cropping systems, we observed a high correlation between the DON content in wheat grains and the number of colonies from deposited spores. Our spore trap proved to be a highly valuable tool to not only study FHB epidemiology but also to identify innovative cropping systems with a lower risk for FHB and DON contamination.

Detection and chemical control of Cercospora sojina infecting soybean seed in Argentina

Frogeye leaf spot (FLS) of soybean caused by Cercospora sojina Hara is an important disease in the Argentine Pampas region. The primary inoculum sources of the disease are infected seeds and plant debris. Thus, use of pathogen-free or fungicide-treated seeds is crucial to prevent the introduction and further spread of the disease. The aims of this research were i) to quantify C. sojina incidence in harvested soybean seeds, ii) to compare media-based incubation methods for detection of the pathogen in seeds, and iii) to evaluate the effect of fungicide seed treatments in reducing FLS incidence. Among eight different detection methods evaluated, no difference in pathogen incidence was found, but the water restriction blotter method should be recommended as it is more time and cost-effective. Out of 13 different fungicide seed treatment combinations in three independent experiments, benzimidazole seed treatments resulted in zero FLS incidence. Any other of the tested fungicidal active ingredients either did not control the disease or did so poorly only when initial infection levels were low. Treating seeds with benzimidazole fungicides may help to reduce FLS incidence during initial soybean field stands when using infected seed lots.

Genetic structure of Cercospora beticola populations on Beta vulgaris in New York and Hawaii

Cercospora leaf spot (CLS), caused by Cercospora beticola, is a major disease of Beta vulgaris worldwide. No sexual stage is known for C. beticola but in its asexual form it overwinters on infected plant debris as pseudostromata, and travels short distances by rain splash-dispersed conidiospores. Cercospora beticola infects a broad range of host species and may be seedborne. The relative contribution of these inoculum sources to CLS epidemics on table beet is not well understood. Pathogen isolates collected from table beet, Swiss chard and common lambsquarters in mixed-cropping farms and monoculture fields in New York and Hawaii, USA, were genotyped (n = 600) using 12 microsatellite markers. All isolates from CLS symptoms on lambsquarters were identified as C. chenopodii. Sympatric populations of C. beticola derived from Swiss chard and table beet were not genetically differentiated. Results suggested that local (within field) inoculum sources may be responsible for the initiation of CLS epidemics in mixed-cropping farms, whereas external sources of inoculum may be contributing to CLS epidemics in the monoculture fields in New York. New multiplex PCR assays were developed for mating-type determination for C. beticola. Implications of these findings for disease management are discussed.

دراسة مرجعية لمرض لفحة الأسكوكيتا على الحمص = A Review of Ascochyta Blight of Chickpea

This article aimed to present detailed literature review on chickpea Ascochyta blight disease. Ascochyta blight caused by Ascochyta rabiei is one of the most biotic stresses reducing chickpea yield. The fungus now exists in the most chickpea growing areas in the world. The most damaging symptoms are stem breakage and pod infection. The life cycle of the fungus consists of a single sexual generation (Didymella rabiei) per season which develops on infected plant debris during winter followed by several asexual generations during the growing season of the crop. The use of resistant cultivars is the most effective, economical and environmentally safe means to manage the disease. Other cultural practices, such as the use of disease free seeds or treated seeds, crop rotation for at least 4 years and deep ploughing of previous infested crop debris accompanied with spraying suitable fungicides in the correct times will minimize the disease severity.

Genetic groups of Clavibacter michiganensis subsp. michiganensis identified by DNA fingerprinting and the effects of inoculation methods on disease development

Clavibacter michiganensis subsp. michiganensis (CMM) strains collected in nine different prefectures in Japan were fingerprinted by inter-simple sequence repeats–polymerase chain reaction (PCR) and repetitive sequence–based PCR. Forty-three CMM strains corresponded to 22 DNA fingerprinting patterns, indicating that the CMM population in Japan has high genetic diversity. Tomato plants were inoculated with CMM by two different methods: defoliation using infected scissors and planting in soil containing infected plant debris. Defoliation resulted in a larger number of diseased plants, disease developed earlier, and plants survived for significantly fewer days. Upon planting in the infected soil, 33.3 % of plants were infected and 6.7 % were diseased, i.e., 20.1 % of infected plants developed disease symptoms. These results indicate that some plants are infected with CMM through plant debris in the soil as the primary inoculum and most infected plants maintain latent infection. Thus, growers may unwittingly carry out disbudding and defoliation of latently infected plants, resulting in secondary inoculum.

Evaluation of some Iranian wheat elite lines’ reaction to Septoria tritici leaf blotch

Septoria tritici blotch is an important wheat disease in many areas of the world including Iran’s warm, humid regions. In this study, reaction of 79 lines from elite regional wheat yield trials of the Cereal Research Department from four climate zones was evaluated to S. tritici leaf blotch in adult plant stage under an artificial field inoculation in Khuzestan province in the south of Iran for two years (2008–2009 and 2009–2010). Nurseries were artificially inoculated by spreading infected plant debris (from last growing season). Taking notes was performed with a modified Saari and Prescott method in 00–99 double-digit scale. Wheat lines were classified in groups of immune (00), highly resistant (11–14), resistant (15–34), moderately resistant (35–44), moderately susceptible (45–64), susceptible (65–84) and highly susceptible (85–99). Result showed that from 79 lines, 37 lines had susceptible reaction; 2 lines had moderately susceptible; and 40 lines showed immune.

Factors affecting incidence and severity of leaf spot disease on lettuce caused by Septoriabirgitae

AbstractIn the 1990s during wet seasons a new disease causing brown leaf spots on lettuce (Lactuca sativa) was found for the first time in many lettuce‐growing areas of Austria and Germany. The causal agent, a new pathogenic species called Septoria birgitae, may be responsible for total crop loss. To study how temperature, inoculum density and leaf wetness period influence disease incidence and severity of leaf spot on lettuce caused by S. birgitae, we carried out in vivo experiments in growth chambers and in the field. Additionally, we evaluated the relevance of infected plant debris acting as a primary inoculum source in soil for subsequent crops. S. birgitae produces spores over a wide temperature range between 5°C and 30°C, and can infect plants at temperatures between 10°C and 30°C, with an optimum between 20°C and 30°C. Spores of S. birgitae at a density of at least 103 conidia mL–1 are essential for disease outbreak on lettuce. Because leaf wetness is crucial for releasing conidia from pycnidia, we studied the impact of leaf wetness duration on disease development under various temperature conditions. For relevant leaf spot disease development on lettuce in vivo, a leaf wetness duration of at least 24 h and temperatures higher than 10°C were necessary. Leaf spot disease development in the field required several leaf wetness periods longer than 20 h at approximately 15°C at the beginning of crop cultivation. Incorporating S. birgitae infected plant debris in soil as a primary inoculum was not relevant for leaf spot disease outbreak in the next year. However, in cases of continuous cropping of lettuce on the same field and in the same season, Septoria‐infected lettuce debris may become more relevant.

Black rot-A devastating disease of crucifers: A review

Crucifers are popular temperate vegetables and occupy important place among vegetables in India as well as in the world. India is the second largest producer of crucifers in the world. These crops are affected by many diseases during the growing period which reduce the yield as well as the quality of the produce. Amongst all the diseases, black rot caused by Xanthomonas campestris pv. campestris (Pam.) Dowson is the most destructive one causing heavy losses. The disease affects primarily above ground parts of the plant at any stage of growth and causes high losses, in yield and quality especially in tropical and subtropical regions during the rainy season. All vegetables in the cruciferous family, including broccoli, brussels sprouts, cabbage, cauliflower, chinese cabbage, kale, mustard, radish, rutabaga, and turnip are susceptible to black rot. Many cruciferous weeds such as Shepherd's Purse, wild mustard, and yellow rocket are also known to be hosts of this pathogen. The pathogen is seed borne and also survives in the infected plant debris as well as cruciferous weed hosts. The disease can be managed through cultural practices, resistant hosts, seed treatment with hot water and antibiotics, fungicides, biological control as well as chemical control methods.

Survival of <i>Xanthomonas campestris</i> pv. <i>Vignicola</i> in infested soil, cowpea seed and cowpea debris

Field and laboratory experiments were conducted in the Sudan savanna site of IITA's experimental Station, Minjibir, Kano State, to study the survival of Xanthomonas campestris pv. vignicola in infested soil, cowpea seed, and debris. The experiment was conducted in a randomised complete block design with five cowpea varieties over three cropping seasons (from 1996 to 1998). The results showed that the bacterium survived in infected plant debris, seed, and soil but after 8 months off-cropping season, the bacterium was not recovered from the soil. This implies that seeds and plant debris are the major means by which X. campestris pv. vignicola survives through seasons. Key words : Bacterial blight; Vigna unguiculata; Cowpea; Xanthomonas campestris pv. Vignicola DOI: 10.4038/tare.v11i0.1787 Tropical Agricultural Research and Extension Vol.11 2008 pp.45-48

Plasmopara halstedii

<i>Plasmopara halstedii</i>

A novel postharvest rot of okra pods caused by Rhizoctonia solani in Brazil

Okra pods with unusual brown lesions and rot were collected in a local supermarket in Brasília DF. The objective of this paper was to characterize the causal agent, to fulfill Koch's postulates and to determine some conditions conducive to disease. The pathogen was identified as Rhizoctonia solani based on morphological characteristics which fitted the fungus description, such as pale to brown hyphae, with nearly right-angled side branches constricted at the base, hyphal cells 6-10 µm wide with a septum near the base. Five isolates were obtained from infected pods and identified as AG 1-IB anastomosis group. Wounded or unwounded okra pods cv. Santa Cruz 47 were inoculated with mycelium disks of R. solani and kept in humid chambers at 12 ºC or 25 ºC. After seven days at 25 ºC, both wounded and unwounded pods were completely rotted and brown, while those kept at 12 ºC showed small lesions ranging from 0.6 to 1.0 mm only in wounded pods. The pathogen was able to grow in different materials used for assembling crates and packs of horticultural products, such as pinewood, corrugated carton, plastic, Styrofoam and newspaper sheets when kept in humid chambers (24 ºC, 96 % RH). The disease occurrence can be related to careless handling practices and to the transmission of R. solani propagules by infected plant debris or soil particles. This is the first report of Rhizoctonia solani causing postharvest rot in okra pods in Brazil.

시설 및 노지재배 고추의 바이러스병 발생과 분포

2002년 노지 및 시설재배 고추를 대상으로 전국적인 규모의 바이러스병 발생실태를 조사하였다. 시설(155시료) 및 노지포장(227시료)에서 바이러스 감염주를 채집하여 전자현미경과 RT-PCR로 분석하였다. 시설 및 노지재배 고추에서 수집한 시료에서 TMV, RMV, PVY, AMV, TSWV에 감염된 것은 없었다. 그러나 CMV, BBWV, PepMoV, PMMoV, ToMV, TMGMV는 RT-PCR에 의해 검출되었다. 시설 및 노지재배 포장에서 바이러스 발병율은 상당히 다르게 나타났다. 시설재배에서는 10%의 발병율을 보였으나, 노지재배에서는 약 30%의 발병율을 나타냈다. 복합감염율은 시설 및 노지재배에서 각각 16%와 61%로 나타났다. 시설재배에서는 PMMoV가 우점하는 것으로 보아, 바이러스에 오염된 종자와 재배지에서의 바이러스 감염잔재물이 중요한 전염원이 된 것으로 보인다. 반대로 노지재배에서는 CMV와 BBWV가 우점하였다. 이것으로 보아 바이러스를 보독한 매개충의 이동이 가장 중요한 전염원으로 나타났다. 또한 이 연구에서 BBWV2는 우리나라에서 방제해야 할 새로운 바이러스로 대두되었다. 노지 및 시설재배에서 바이러스병의 발병율과 분포의 차이로 볼 때 연작에 따른 전염원의 축적 및 분포상과 재배지로의 바이러스 보독매개충의 이동이 바이러스 발생을 결정하는 중요한 요소로 보인다. 그러므로 식물병 역학과 고추의 새로운 육종 프로그램에 대한 진전된 연구가 바이러스 병을 줄이는데 필수적일 것이다. In the year of 2002 annual nationwide survey of virus diseases occurring in the pepper fields and greenhouses in Korea, the distribution and the incidence of viral diseases was investigated. The pepper samples from both greenhouses (155 samples) and open fields (227 samples) were collected and further analyzed to detect eleven different viruses by RT-PCR. The results indicate that no sample collected from both greenhouse and open field seems to be infected by TMV, RMV, PVY, AMV, and TSWV. On the other hand, CMV, BBWV2, PepMoV, PMMoV, TMGMV and ToMV are readily identified from greenhouse and open field samples by RT-PCR. The infection rates of the collected samples between greenhouse and open field are largely different. Comparing with 10% of virus-infected pepper samples grown in greenhouse, approximately one third of pepper samples collected from open field are infected. The mixed-infection rates in the virus-infected greenhouse and open field samples are 16% and 61%, respectively. The dominant virus occuring in greenhouse is PMMoV, indicating that virus-infected seed stocks and infected plant debris in the growing area may be important sources of inocula. On the other hand, both CMV and BBWV2 are dominant viruses in open field. This may indicate that the migration of viruliferous insect vectors into pepper fields may be the most important source of inoculum. Also, the survey shows that BBWV2 is newly immerging virus to be controlled in Korea. The discrepancies on the distribution and the occurrence of viral diseases between field and greenhouse may provide a fact that the accumulation and distribution of inoculum by successive cultivation and the migration of viruliferous vectors into growing areas are likely to be important factors to determine the incidence of viral diseases. Therefore, the further studies on epidemiology and the consideration of new breeding program of pepper are essential to minimize virus diseases.

Septoria cirsii . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Septoria cirsii . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leaf spot, leaf blight (VURRO et al. , 1993), drying of leaves, perforation of leaf tissues, sometimes causing defoliation. HOSTS: Cirsium altissimum, C. appendiculatum, C. arvense, C. discolor, C. erisithales, C. heterophyllum, C. hillii, C. incanum, C. iowense, C. lanceolatum, C. laniflorum, C. leo, C. oleraceum, C. rivulare, C. segetum , C. setosum , C. vulgare , Saussurea sp., Serratula coronata, S. quinquefolia, S. radiata ( Asteraceae ). GEOGRAPHICAL DISTRIBUTION: NORTH AMERICA: Canada, USA. ASIA: Armenia, Azerbaijan, China, Republic of Georgia [ www.cybertruffle.org.uk/gruzmaps/index.htm ], Iran, Kazakhstan, Kirgizstan, Russia (West Siberia, Far East), Turkmenistan, Uzbekistan. EUROPE: Austria, Bulgaria, Czech Republic, Denmark, Estonia, France, Germany, Hungary, Italy, Latvia, Lithuania, Netherlands, Poland, Romania, Russia, Ukraine [ www. cybertruffle. org. uk/ukramaps/index. htm ]. TRANSMISSION: By airborne or splash-dispersed conidia from infected plant debris. Spores in droplets in suspension have been used in inoculation experiments.

Septoria pistaciae . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Septoria pistaciae . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leaf spot. May cause leaf mortality and defoliation (TETEREVNIKOVA-BABAYAN, 1962). Septoria fruit spot (MICHAILIDES, 1997). HOSTS: Pistacia exotica, P. integerrima, P. lentiscus, P. vera ( Anacardiaceae ). GEOGRAPHICAL DISTRIBUTION: NORTH AMERICA: USA (California). ASIA: Armenia, Republic of Georgia, India, Israel, Kazakhstan, Kirgizstan, Syria, Tadjikistan, Turkey, Turkmenistan, Uzbekistan. EUROPE: Albania, France, Greece, Italy, Portugal, Ukraine. TRANSMISSION: The fungus is transferred from infected plant debris by airborne or splash-dispersed conidia. Conidia of S. pistaciae overwinter on fallen leaves and in cracks of bark (TETEREVNIKOVA-BABAYAN, 1962).

Septoria cornicola . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Septoria cornicola . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leaf spot. Development of the disease leads to severe blight with infected leaves drying. Causing defoliation of some dogwoods (NEELY &amp; NOLTE, 1989). HOSTS: Cornus alba, C. alba var. siberica, C. alternifolia , C. amomum, C. asperifolia, C. baileyi , C. californica, C. canadensis, C. candidissima, C. florida, C. mas, C. nuttallii, C. occidentalis, C. paniculata, C. pubescens, C. racemosa, C . ( Thelycrania ) sanguinea, C. sericea, C. sibirica, C. stolonifera, C. stolonifera var. aurea , C. stolonifera var. flaviramea , C. stolonifera var. lutea , Swida australis ( C. sanguinea subsp. australis ) ( Cornaceae ). GEOGRAPHICAL DISTRIBUTION: NORTH AMERICA: Canada, USA. ASIA: Armenia, China, Republic of Georgia [ www.cybertruffle.org.uk/gruzmaps/index.htm ], Iran, Russia (West Siberia, Far East), Turkey. EUROPE: Albania, Austria, Belarus, Belgium, Bulgaria, Czech Republic, Estonia, France, Germany, Great Britain, Greece, Hungary, Italy, Latvia, Lithuania, Moldova, Netherlands, Norway, Portugal, Romania, Russia, Spain, Sweden, Switzerland, Ukraine [ www.cybertruffle.org.uk/ukramaps/index.htm ], former Yugoslavia. TRANSMISSION: By airborne or splash-dispersed conidia from infected plant debris. For infection, leaves must be wet, but moisture is required for a few hours only (NEELY &amp; NOLTE, 1989).

Septoria antirrhini . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Septoria antirrhini . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leaf spot, leaf drying, defoliation. HOSTS: Antirrhinum antirrhiniflorum , A. majus, A. siculum ( Scrophulariaceae ). GEOGRAPHICAL DISTRIBUTION: AFRICA: South Africa. NORTH AMERICA: Canada, USA. SOUTH AMERICA: Chile, Colombia. ASIA: Armenia, Azerbaijan, China, Iran, Israel. AUSTRALASIA: Australia, New Zealand. EUROPE: Bulgaria, Czech Republic, Estonia, France, Germany, Great Britain, Hungary, Ireland, Italy, Netherlands, Portugal, Romania, Ukraine, former Yugoslavia. TRANSMISSION: Not reported, but almost certainly by airborne, splash-dispersed conidia from infected plant debris and seed stocks. The disease is significantly more severe under wet weather conditions (SINADSKIY et al. , 1985).

Septoria urticae . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Septoria urticae . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leaf spot, severe foliar necrosis, defoliation. Sometimes spots eventually fall out and leave a round shot-hole (GROVE, 1935). In inoculation experiments the fungus has caused complete wilting of the leaves followed by the intense defoliation. The disease can affect plant growth and can considerably reduce numbers of seeds produced (DAL-BELLO et al. , 1993). HOSTS: Laportea canadensis, Parietaria officinalis, Urtica angustifolia, U. cannabina, U. chamaedryoidis, U. dioica, U. gracilenta, U. gracilis, U. lyallii, U. pilulifera, U. urens ( Urticaceae ). GEOGRAPHICAL DISTRIBUTION: NORTH AMERICA: Canada, USA. SOUTH AMERICA: Argentina. ASIA: Azerbaijan, Republic of Georgia [ www.cybertruffle.org.uk/gruzmaps/index.htm ], India, Iran, Israel, Kazakhstan. AUSTRALASIA: Australia. EUROPE: Austria, Belgium, Bulgaria, Czech Republic, Denmark, Estonia, France, Germany, Great Britain, Greece, Hungary, Italy, Latvia, Lithuania, Moldova, Netherlands, Norway, Poland, Romania, Spain, Sweden, Ukraine [ www.cybertruffle.org.uk/ukramaps/index.htm ], former Yugoslavia. TRANSMISSION: Not reported, but almost certainly by airborne or splash-dispersed conidia, also from infected plant debris. Successful application of spore suspensions in water and humid chambers in inoculation experiments with S. urticae confirms the role of moisture in infection transmission.