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Comparative studies of different isolates of Neonectria ditissima obtained from canker lesions and rotten fruit showed that both five-septate macroconidia and aseptate microconidia were capable of germination by germ-tube formation, but that growth commenced earlier and proceeded faster from the former than the latter type of spore. Further, following wound inoculation of apple fruit with different numbers of conidia (50, 500 or 5000 per wound) the resulting rot lesions were always significantly larger with macroconidia than microconidia, and in both conidial types lesion size increased with higher inoculum loads. These data confirm that microconidia are capable of causing infections, but indicate that their contribution to the success of the pathogen in the field is probably negligible.

In Northern Germany, a major share of postharvest losses of apple fruit is due to preharvest infections by pathogenic fungi. Little is known about their infection biology. Inoculation experiments were conducted with the most important storage-rot pathogen Neofabraea perennans, as well as with the recently discovered minor rot Phacidiopycnis washingtonensis, by spraying developing fruit on apple trees with conidial suspensions to drip wetness between June and harvest time (September / October). All inoculation events in three trial seasons were chosen to coincide with natural rainfall. Phenological stages and meteorological parameters of each infection event were used for correlation analyses. Both pathogens produced increasing fruit rot levels with inoculation dates closer to harvest. In addition, for N. perennans seven environmental factors were positively correlated with disease incidence, the most significant ones being the duration of post-infection leaf wetness and the scab infection quotient incorporating wetness and temperature. With P. washingtonensis, in addition to fruit maturity three environmental factors were identified. In a second step, multifactorial models for both pathogens were created using the phenological and meteorological factors. For N. perennans, scab infection quotient until first drying-off, dry hours within the leaf wetness period and post-inoculation precipitation levels were identified as important factors, whereas for P. washingtonensis only the average temperature during the leaf wetness period had a significant influence on the rot incidence. Either model was extended by the viability of conidia used for inoculation. Possibilities to deploy these models for a more accurate a priori prediction of the likely severity of storage rot and a more targeted use of pre- and postharvest fungicides and physical postharvest treatments are discussed.

Neonectria ditissima is a major cause of blossom-end rot (eye rot, calyx-end rot) as a pre-harvest fruit rot of apple in Northwestern Europe. Artificial inoculation of trees was undertaken at close intervals under natural conditions during flowering in order to obtain a higher-resolution definition of the most susceptible phenological stage of apple for blossom-end rot infections by N. ditissima. Similar trials were conducted for another blossom-end rot fungus, Botrytis pseudocinerea. Results for N. ditissima showed full bloom to be the most susceptible stage for infection in cultivar ‘Pinova’, whereas with cultivar ‘Nicoter’ the highest infection rates were obtained at full bloom to petal fall, reflecting temporal differences in flower development between one-year-old and older wood. Few infections were observed by inoculation at the beginning of flowering or about one week after petal fall when no petals were left on the flowers, and the fruit knots were enlarging. This finding shortens the time-span for infections as compared to previous knowledge. Floral inoculations with conidia of B. pseudocinerea were unsuccessful. Options to control blossom-end rot in integrated pest management include a timing of scab or powdery mildew fungicide sprays to full bloom, and canker pruning just ahead of flowering in orchards strongly affected by N. ditissima.

Second only to brown rot caused by Monilinia spp., grey mould caused by Botrytis spp. is one of the most important pre- and post-harvest diseases of stone fruit in northern Germany. Among 484 Botrytis isolates from sweet cherries produced under integrated pest management (IPM), 60.3% showed resistance to QoI fungicides and 54.6% to boscalid, reflecting the heavy use of these compounds in regional production. More modest resistance frequencies were recorded for fenhexamid (20.7%), fluopyram (8.3%), fludioxonil (9.1%) and cyprodinil (21.9%). A 7.6% share of isolates possessed multiple resistance to at least five of these fungicides. Resistance was also detected for two fungicides no longer registered in cherries, viz. thiophanate-methyl (15.7%) and iprodione (20.9%). Similar results were obtained for 141 Botrytis isolates from IPM plum orchards. In contrast, in organically produced cherries (88 Botrytis isolates) resistance frequencies were < 20% for all fungicides. The dominant species on cherries and plums was B. cinerea. The share of B. pseudocinerea, which is not known to have developed resistance to commercial fungicides, was 18.0% in cherries and 9.9% in plums from IPM, but 50.0% in organically produced cherries. A 10-year annual survey of a sweet cherry orchard under IPM showed the immigration of multi-resistant B. cinerea strains in 2011, followed by their increase and decline in subsequent years. An understanding of the effects of fungicide spray regimes on Botrytis population dynamics in stone fruit has implications for resistance management. In practice, a limitation of the number of pre-harvest sprays to a maximum of two will give a satisfactory control of brown rot in most situations, while a higher number will promote multi-resistant B. cinerea strains.

In den Jahren 2010–2019 wurden insgesamt 2824 Botrytis-Isolate aus 203 norddeutschen Erdbeerfeldern auf Resistenzbildung gegen die zugelassenen Wirkstoffe Fenhexamid, Trifloxystrobin, Boscalid, Fluopyram, Fludioxonil und Cyprodinil sowie die seit 2009 bzw. ca. 1975 nicht mehr verwendeten Wirkstoffe Iprodion bzw. Thiophanate-methyl untersucht. In allen Jahren waren die Resistenzanteile sehr hoch (>65 %) gegen Trifloxystrobin, hoch (>30 %) gegen Iprodion, Fenhexamid, Fludioxonil und Cyprodinil, sowie masig (10–35 %) gegen Thiophanate-methyl. Ein Anstieg der Resistenzbildung gegen Boscalid auf hohem Niveau (von 20 % auf >50 %) und gegen Fluopyram auf geringem Niveau (von 1–5 % auf 10 %) wurde im Analysezeitraum beobachtet. Der Anteil von Stammen mit Resistenzen gegen funf oder alle sechs der zugelassenen getesteten Fungizide stieg von 2 % im Jahr 2010 auf 20 % im Jahr 2013 an und verharrte danach auf diesem erhohten Niveau. Diese multipel resistenten B. cinerea-Stamme besasen haufig bzw. fast immer auch Resistenzen gegen Thiophanate-methyl bzw. Iprodion, wahrend Stamme ohne Resistenz gegen die zugelassenen Fungizide auch gegen die beiden Altwirkstoffe sensitiv waren. Zu diesen sensitiven Stammen zahlte auch die Art B. pseudocinerea, welche in jahrlich variablen Anteilen von 3–16 % der Gesamtpopulation vorkam.

Background European canker, caused by Neonectria ditissima, is a disease of worldwide importance in apple production, yet knowledge about it is limited, highly regional and sometimes contradictory. This is an obstacle to successful disease management. Key aspects for Northern Europe are reviewed, based on research results from Northern Germany and Norway and on international literature data. Main topics Trunk cankers developing on young trees within the first 1–3 seasons of explanting can often be traced back to latent infections initiated in the nurseries. The most important nursery infection is a lateral canker on the main trunk of ‘knip’ trees, which are the standard tree type in Northern Europe. In strongly affected batches, up to 25% of trees have to be uprooted after the first growing season due to such trunk cankers. The establishment and maintenance of healthy orchards requires clean nursery material, especially in the case of susceptible cultivars. In Northern Germany, infections within commercial orchards most often proceed through wounds caused by fruit picking or leaf fall in autumn, as shown by the appearance of cankers in the following spring and by the high efficacy of fungicide treatments at leaf fall. Ascospores, commonly thought to be relevant for long-distance spread of infections, are not released until the end of leaf fall even in wet autumn seasons in Northern Germany. Therefore, their role in the disease remains unclear. Strong nitrogen-induced vegetative growth favours apple canker. In field trials conducted under conditions of current commercial practices, autumnal sprays with copper hydroxide or copper oxide were consistently more efficacious than copper oxychloride or captan in preventing new infections. Conclusions Restricted fertilisation and other measures to curb excessive vegetative growth during the first few years of an orchard, repeated canker pruning and well-timed treatments with effective fungicides in autumn are essential for IPM of apple canker. Nonetheless, canker remains capable of severely impairing the commercial success of susceptible cultivars in regions with wet climates even if all available measures are taken. This opens up long-term perspectives for the breeding of more resistant cultivars.

In a four-year survey of strawberry nursery plants, 340 Botrytis isolates were collected and examined for fungicide resistance. High percentages of isolates with resistance to members of all fungicide classes registered on strawberries in Germany were found, i.e. trifloxystrobin (90.3%), boscalid (53.8%), cyprodinil (41.5%), fludioxonil (28.2%) and fenhexamid (15.6%). Of these isolates, 10.3% possessed multiple resistance to all compounds. At 5.0%, resistance to the recently registered fungicide fluopyram was low. Dutch nursery material harboured significantly higher proportions of isolates with resistance to any or all fungicides than plants produced in Germany. These data point to nursery plants as a possible route of introducing fungicide-resistant Botrytis strains into commercial strawberry fields.

Sooty blotch and flyspeck (SBFS) fungi colonize the surface wax layer of the fruit of apple, pear, persimmon, banana, orange, papaya, and several other cultivated tree and vine crops. In addition to colonizing cultivated fruit crops, SBFS fungi also grow on the surfaces of stems, twigs, leaves, and fruit of a wide range of wild plants. The disease occurs worldwide in regions with moist growing seasons. SBFS is regarded as a serious disease by fruit growers and plant pathologists because it can cause substantial economic damage. The smudges and stipples of SBFS often result in downgrading of fruit from premium fresh-market grade to processing use. This review describes the major shifts that have occurred during the past decade in understanding the genetic diversity of the SBFS complex, clarifying its biogeography and environmental biology, and developing improved management strategies.

Grey mould, the most important disease of strawberry worldwide, is caused by Botrytis cinerea and a few additional Botrytis spp. Fungicide resistance is a growing problem and has become a limiting factor in strawberry production. In northern Germany, an annual survey of Botrytis isolates from commercial strawberry fields in 2010 to 2017 has revealed high (> 20%) frequencies of resistance to quinone-outside inhibitors, fenhexamid, boscalid, fludioxonil and cyprodinil, as well as lower (

'Long-canes' which produce the first fruit crop within three months of being planted in spring are becoming the preferred raspberry nursery material in north-western Europe. However, infections of these canes by grey mould fungi (Botrytis spp.) are common. In a survey of Botrytis infections in 22 batches of long-cane plants from six different nurseries, high proportions of strains with resistance to fenhexamid (45.5 %), trifloxystrobin (87.3 %), boscalid (75.9 %), fludioxonil (35.0 %) and cyprodinil (46.4 %) were found. Further, 29.4 % of all strains harboured multiple resistance to all five of these fungicides. Fungicide-resistant strains increased in frequency during the first cropping season and were shown in one case to spread to an adjacent raspberry field within one season. Contaminated planting material may therefore compromise the long-term productivity of raspberry plantations.

Sooty blotch and flyspeck (SBFS) fungi colonise the surface of a range of fruits, especially apple, without penetrating the cuticle. Economic damage results from the exclusion of severely affected fruit batches from being marketed as table apples. A study of SBFS was conducted in 2007–2012 in the two largest German apple production areas, i.e. the Lake Constance and Lower Elbe regions. The absence of this disease complex from orchards under integrated pest management in both regions in all years was explained by the collateral effects of scab and storage-rot sprays with captan and quinone-outside inhibitors (QoI) such as trifloxystrobin. However, SBFS was economically relevant in organically managed orchards, being generally more severe in Southern Germany than in the North. In both regions, Peltaster cerophilus was the most frequently isolated SBFS fungus and was chiefly responsible for crop losses. Cyphellophora sessilis, Microcyclosporella mali and Schizothyrium pomi also contributed to SBFS in some organic orchards, whereas a diversity of additional species was confined to untreated orchards. Evidence was obtained that P. cerophilus overwinters within orchards, fruit mummies being one of presumably several colonised plant organs. Infections of young apple fruits were initiated at any time following the end of flowering, and P. cerophilus was capable of causing several infection cycles per season by means of conidial inoculum. The colonisation of sheets of waxed paper by P. cerophilus indicated that this species does not require fruit leachates for growth. No further expansion of colonies was observed during cold storage; instead, P. cerophilus was gradually displaced by other fungi. Differences in the susceptibility of apple varieties to P. cerophilus were due to fruit ripening, late-maturing cultivars being most heavily colonised, and to surface properties, varieties with a waxy bloom being conspicuously less strongly colonised than others. This fungus was unable to colonise russeted fruit areas. Repeated spray treatments with lime-sulphur and potassium bicarbonate throughout the season were effective and necessary to control SBFS in organic production. This strategy threatens the fungicide-saving potential offered by scab-resistant apple varieties. Cultural measures against SBFS include summer pruning as well as the manual removal of fruit mummies in winter.

In a long-term survey of black root rot of strawberries and raspberries in Northern Germany in 2007–2014, fungi with and without Cylindrocarpon-like anamorphs were isolated as potential pathogens. Dactylonectria torresensis was the most common species, being isolated from 18% of strawberry roots obtained from nursery plants and 37% of roots from production fields, as well as 21% and 29% (respectively) of raspberry roots. Less frequently isolated fungi with Cylindrocarpon-like anamorphs included Ilyonectria crassa, Ilyonectria sp. 2, I. pseudodestructans, I. robusta, C. obtusisporium and Ilyonectria sp. 1. Severe disease symptoms were reproduced by artificial inoculation of strawberries with D. torresensis, I. crassa and Ilyonectria sp. 2, milder symptoms with C. obtusisporium. A wide range of other root-pathogenic fungi such as Fusarium oxysporum, Verticillium dahliae, Ceratobasidium fragariae, Gnomoniopsis fructicola, Hainesia lythri, and species of Cadophora, Leptodontidium, Pythium, Phytophthora, Plectosporella, Pestalotiopsis and Truncatella were either isolated only sporadically or were not associated with black root rot symptoms, suggesting that they did not play any major role in this disease in Northern Germany. Visible disease symptoms and high frequencies of D. torresensis isolations in many batches of nursery plants indicated that these may comprise a major source of contamination of production fields. The previously unrecognised prominence of D. torresensis resolves a long-standing puzzle concerning the cause of the ongoing black root rot epidemic in Northern German strawberry and raspberry production.

Botrytis cinerea causes pre- and postharvest decay of many fruit and vegetable crops. A survey of German strawberry fields revealed Botrytis strains that differed from B. cinerea in diagnostic PCR markers and growth appearance. Phylogenetic analyses showed that these strains belong to an undescribed species in Botrytis clade 2, named Botrytis fragariae sp. nov. Isolates of B . fragariae were detected in strawberry fields throughout Germany, sometimes at frequencies similar to those of B. cinerea , and in the southeastern United States. B . fragariae was isolated from overwintering strawberry tissue but not from freshly infected fruit. B . fragariae invaded strawberry tissues with an efficiency similar to or lower than that of B. cinerea but showed poor colonization of inoculated nonhost plant tissues. These data and the exclusive occurrence of this fungus on strawberry plants indicate that B . fragariae is host specific and has a tissue preference different from that of B. cinerea . Various fungicide resistance patterns were observed in B . fragariae populations. Many B . fragariae strains showed resistance to one or several chemical classes of fungicides and an efflux-based multidrug resistance (MDR1) phenotype previously described in B. cinerea . Resistance-related mutations in B . fragariae were identical or similar to those of B. cinerea for carbendazim (E198A mutation in tubA ), azoxystrobin (G143A in cytB ), iprodione (G367A+V368F in bos1 ), and MDR1 (gain-of-function mutations in the transcription factor mrr1 gene and overexpression of the drug efflux transporter gene atrB ). The widespread occurrence of B . fragariae indicates that this species is adapted to fungicide-treated strawberry fields and may be of local importance as a gray mold pathogen alongside B. cinerea . IMPORTANCE Gray mold is the most important fruit rot on strawberries worldwide and requires fungicide treatments for control. For a long time, it was believed to be caused only by Botrytis cinerea , a ubiquitous pathogen with a broad host range that quickly develops fungicide resistance. We report the discovery and description of a new species, named Botrytis fragariae , that is widely distributed in commercial strawberry fields in Germany and the southeastern United States. It was observed on overwintering tissue but not on freshly infected fruit and seems host specific on the basis of its occurrence and artificial infection tests. B . fragariae has also developed resistance to several fungicides that is caused by mutations similar to those known in B. cinerea , including an efflux-based multidrug resistance. Our data indicate that B . fragariae could be of practical importance as a strawberry pathogen in some regions where its abundance is similar to that of B. cinerea .

Botrytis cinerea is a major plant pathogen, causing gray mold rot in a variety of cultures. Repeated fungicide applications are common but have resulted in the development of fungal populations with resistance to one or more fungicides. In this study, we have monitored fungicide resistance frequencies and the occurrence of multiple resistance in Botrytis isolates from raspberries, strawberries, grapes, stone fruits and ornamental flowers in Germany in 2010 to 2015. High frequencies of resistance to all classes of botryticides was common in all cultures, and isolates with multiple fungicide resistance represented a major part of the populations. A monitoring in a raspberry field over six seasons revealed a continuous increase in resistance frequencies and the emergence of multiresistant Botrytis strains. In a cherry orchard and a vineyard, evidence for immigration of multiresistant strains from neighboring fields was obtained. Inoculation experiments with fungicide-treated leaves in the laboratory and with strawberry plants cultivated in the greenhouse or outdoors revealed a nearly complete loss of fungicide efficacy caused by multiple resistance. B. cinerea field strains carrying multiple resistance mutations against all classes of site-specific fungicides were found to show similar fitness as sensitive field strains under laboratory conditions, based on their vegetative growth, reproduction, stress resistance, virulence and competitiveness in mixed infection experiments. Our data confirm an alarming increase in the occurrence of multiresistance in gray mold populations from different cultures, which presents a major threat to the chemical control of gray mold.

In the Lower Elbe region of Northern Germany and in other Northern European fruit production areas, about 80 % of all storage rots of apples are caused by Neofabraea alba and N. perennans. Other pathogens include Colletotrichum acutatum, Monilinia fructigena, Phaci­diopycnis washingtonensis, Neonectria galligena, Botrytis cinerea, Penicillium expansum and Fusarium avenaceum. Hot-water treatments of freshly harvested fruits for 3 min at 50–52 °C gave high efficacies against most of these storage rots except F. avenaceum. Substantial evidence supported a heat shock-induced antimicrobial response rather than a direct killing of fungal inoculum as the principal mode of action of hot-water treatments in apples. Shorter exposures for < 30 s at 55–60 °C also provided good control of fungal storage rots and thereby offer new possibilities for this technology in Northern European fruit production. These possibilities include the integration of a hot-water unit into existing grading lines and the option to treat fruits at different time points, e.g. at harvest, after short-term storage and/or after long-term storage.

In 2010–2012, a to talof 309 isolates of Botrytis cinerea from 23 lettuce fields in Northern Germany was examined for sensitivity to seven fungicides with specific modes of action. Resistance against the frequently used compounds boscalid (45.0% of all isolates), iprodione (37.2%) and quinone-out-side inhibitors (strobilurins, 56.3%) was the most common. Isolates combining resistance to two or all three of these fungicides were more frequent than those showing resistance against only one. Strains with cyprodinil (31.4%) or thiophanate-methyl (11.6%) resistance were also observed in the majority of fields. In contrast, resistance against fludioxonil (1 isolate) and fenhexamid (3 isolates) was rare. The abundance of B. cinerea strains with multiple resistance to several currently used fungicides has implications for future lettuce crop management which are discussed.

Im Sommer 2010 wurde im sudlichen Niedersachsen an Heidelbeeren (Vaccinium corymbosum) insbesondere in jungeren Anlagen der Sorte ‘Duke’ ein Triebsterben beobachtet, welches auch in den beiden Folgejahren auftrat. Die plotzlich einsetzende Chlorose und Nekrose einzelner Zweige war mit einer Zerstorung des Kambiums sowie mit langsstreifigen Verbraunungen im Holzgewebe des Vorjahres assoziiert. Es fand jedoch ein Neuaustrieb aus dem intakten Wurzelwerk und aus bodennahen Regionen alterer Aste statt. Die potentiellen Schadpilze Godronia cassandrae, Phomopsis spp., Diplodia seriata, Pestalotiopsis sp., Paraconiothyrium sporulosum, Colletotrichum acutatum, Fusarium avenaceum und F. lateritium waren an abgestorbenen Trieben sporadisch und auf jeweils hochstens 6 der insgesamt 12 untersuchten Flachen nachweisbar. Als Hauptursache des Schadbildes wurde winterlicher Holzfrost ermittelt, der durch einen verspateten Triebabschluss mit fehlender Winterharte zum Zeitpunkt der ersten strengen Froste gefordert wurde.

In zwei stark durch Triebsterben geschadigten Heidelbeer-Junganlagen der Sorte ‘Duke’ wurden Wirkungsversuche mit den Fungiziden Cuprozin WP (aktiver Wirkstoff Kupferhydroxid), Malvin WG (Captan), Switch (Cyprodinil und Fludioxonil) und Signum (Pyraclostrobin und Boscalid) durchgefuhrt. Behandlungen wurden zweimalig wahrend des Blattfalls im Herbst 2011 oder einmalig zum Austrieb im Fruhjahr 2012 ausgebracht. Keine Behandlung zeigte eine Wirkung gegen die Symptome des Triebsterbens. Diese Ergebnisse bestatigen Hinweise auf winterliche Holzfrostschaden als primare Ursache des Schadbildes in Norddeutschland. Der beobachtete Befall toter Zweige durch Godronia cassandrae war somit wahrscheinlich eine Folge, nicht Ursache, dieses Schadens.

Botrytis cinerea is a major plant pathogen, causing gray mold rot in a variety of cultures. Repeated fungicide applications are common but have resulted in the development of fungal populations with resistance to one or more fungicides. In this study, we have monitored fungicide resistance frequencies and the occurrence of multiple resistance in Botrytis isolates from raspberries, strawberries, grapes, stone fruits and ornamental flowers in Germany in 2010 to 2015. High frequencies of resistance to all classes of botryticides was common in all cultures, and isolates with multiple fungicide resistance represented a major part of the populations. A monitoring in a raspberry field over six seasons revealed a continuous increase in resistance frequencies and the emergence of multiresistant Botrytis strains. In a cherry orchard and a vineyard, evidence of the immigration of multiresistant strains from the outside was obtained. Inoculation experiments with fungicide-treated leaves in the laboratory and with strawberry plants cultivated in the greenhouse or outdoors revealed a nearly complete loss of fungicide efficacy against multiresistant strains. B. cinerea field strains carrying multiple resistance mutations against all classes of site-specific fungicides were found to show similar fitness as sensitive field strains under laboratory conditions, based on their vegetative growth, reproduction, stress resistance, virulence and competitiveness in mixed infection experiments. Our data indicate an alarming increase in the occurrence of multiresistance in B. cinerea populations from different cultures, which presents a major threat to the chemical control of gray mold.

Sooty blotch and flyspeck (SBFS) is a complex of more than 80 fungal species in 24 genera, mostly belonging to the order Capnodiales within the Dothideomycetes. Colonies of these epiphytes become visible on the surface of apples in mid- to late summer. Several species of SBFS fungi have been previously identified from apples in Germany, but little is known about species diversity, prevalence patterns, or relationship to orchard management practices. To address these questions, apple orchards were surveyed during the 2008 to 2011 seasons in the two largest German apple-growing regions along the Lower Elbe river (northern Germany) and Lake Constance (southern Germany). Using a combination of approaches based on morphology and ITS sequence data, 19 known or putative SBFS species were found, of which 10 belonged to Capnodiales. Abandoned orchards harboured a higher species diversity than organically managed orchards, and no SBFS disease was seen in orchards under integrated pest management. Peltaster cerophilus was the most common SBFS fungus, being associated with 96 and 84 % of SBFS-affected apples sampled from northern and southern German organic orchards, respectively. Microcyclosporella mali and Cyphellophora sessilis were the next most commonly found SBFS species in northern and southern Germany, respectively. Schizothyrium pomi was the only cause of the flyspeck mycelial type of SBFS disease in Germany.

Unterentwickelte abgestorbene Fruchte (Fruchtmumien) konnen an bestimmten Sorten von Tafelapfeln wie ‘Elstar’ oder Zierapfeln wie ‘Golden Hornet’ uber 12 Monate lang am Baum verbleiben und werden dadurch zum geeigneten Substrat fur Pilze. Eine Methode zum Nachweis der Besiedlung solcher Fruchtmumien durch wichtige pilzliche Erreger von Fruchtfaulen wurde entwickelt. Innerhalb einer 30-minutigen Inkubation getrockneter Fruchtmumien in Wasser wurden Sporen von Diplodiaseriata, Phacidiopycnis washingtonensis, Neofabraea alba, N. perennans, Neonectria galligena und Colletotrichum acutatum in ausreichenden Konzentrationen fur den sicheren mikroskopischen Nachweis freigesetzt. Wahrend P. washingtonensis fast ausschlieslich an ‘Golden Hornet’-Mumien vorkam, wurden die anderen Schadpilze vornehmlich an ‘Elstar’ gefunden. Die Vorteile dieser Methode liegen in der Moglichkeit des ganzjahrigen und quantitativen Nachweises von Erregern sowie im einfachen Versand und in der mehrjahrigen Aufbewahrung von Proben als Herbarmaterial vor oder nach der Untersuchung.

During the vegetation period 2010, 353 isolates of Botrytis cinerea from 23 Northern German strawberry, raspberry, highbush blueberry, and redcurrant fields were examined for sensitivity to the benzimidazole derivative thiophanate-methyl and the dicarboximide iprodione, as well as five fungicides currently used against gray mold in Germany. Of all isolates, 40.5% were highly resistant to thiophanate-methyl, 64.0% to iprodione, 45.0% to fenhexamid, 76.8% to trifloxystrobin, 21.5% to boscalid, and 14.7% to cyprodinil. No high resistance to fludioxonil was observed but medium resistance was recorded to fludioxonil as well as cyprodinil (41.1 and 27.2% of all isolates, respectively). In all, 63 isolates were sensitive to all five of the currently registered botryticides whereas 43, 81, 94, 49, and 23 isolates were medium or highly resistant to one, two, three, four, and five fungicides, respectively. Isolates resistant to five fungicides in vitro were capable of causing fruit rot on wounded apple pretreated with any one of the three commercially available products containing fenhexamid, pyraclostrobin plus boscalid, or cyprodinil plus fludioxonil. These results question the sustainability of the current gray mold control strategy relying exclusively on fungicides with specific, single-site modes of action.

Phacidiopycnis washingtonensis was identified by morphology and ITS sequence analysis as the cause of rubbery rot, a new storage disease of apples in northern Germany. Infected fruits had an unusually firm texture and pale appearance after storage in ultra-low oxygen conditions, but turned dark brown to black in ambient atmosphere. Ultimately, the surface of rotted fruits became covered by black pycnidia producing cream-coloured conidial exudates. Rubbery rot affected several apple varieties, including the commercially important ‘Jonagold’ and ‘Elstar’. Losses during storage were commonly below 1% but reached 5–10% in a few cases. Fruits of ‘Golden Hornet’ crab apple trees planted as pollinators in commercial orchards became heavily infected by P. washingtonensis in October. Conidia were released throughout the following season from infected fruit mummies, which remained attached to the crab apple tree.

A simple test based on the germination of conidia of Botrytis on agar media augmented with various fungicides has been developed. Average concentrations causing a 50% reduction of germ-tube growth (EC50) of highly sensitive isolates were determined on 1% malt extract agar (thiophanate-methyl 0.090 ppm; iprodione 0.566 ppm; fludioxonil 0.026 ppm; fenhexamid 0.144 ppm), 1% malt extract agar with 100 ppm salicyl hydroxamic acid (QoI fungicides, viz. trifloxystrobin 0.009 ppm; pyraclostrobin 0.013 ppm; azoxystrobin 0.087 ppm), 0.5% yeast extract agar (boscalid 0.069 ppm) and 0.5% sucrose agar (cyprodinil 0.053 ppm). In order to detect different levels of resistance against these various fungicides, two discriminatory concentrations were identified for each compound. A routine assay method was developed in which drops of a conidial suspension harvested directly from diseased plant material or sporulating cultures were incubated on each of 20 different agar media. Because of a very short time-span of 24–48 h between sample collection and evaluation of results, field-specific information on the occurrence, frequency and types of resistance of Botrytis against common botryticides in soft-fruit production may be generated prior to the main fungicide spray season at blossom time.

Isolate von Botrytis cinerea aus norddeutscher Erdbeer- und Himbeerproduktion liesen sich bezuglich ihrer Resistenz gegen den fungiziden Wirkstoff Fenhexamid in drei Gruppen einteilen. Baseline-Stamme zeigten ED50-Werte von 0,06–0,10 ppm (Elongation des Konidienkeimschlauches) bzw. 0,07–0,16 ppm (Mycelwachstum). Die ED50-Werte fur partiell resistente Isolate waren ahnlich im Keimschlauchwachstum, aber deutlich hoher (> 0,39 ppm) im Mycelwachstum. Komplett resistente Isolate zeigten in beiden Tests uber 50 % Wachstum selbst bei 200 ppm Fenhexamid, der hochsten untersuchten Konzentration. Diese Isolate erfullten die Kriterien der Resistenzgruppe Hyd R3. Ein einfacher Keimungstest, bestehend aus der direkten Entnahme von Konidien aus sporulierendem infiziertem Pflanzenmaterial und der Beobachtung des Keimschlauchwachstums, konnte die Hyd R3-Resistenz innerhalb von 24 h nach Probenahme identifizieren. Wird dieser Test mit uberwintertem Material vor der Blute durchgefuhrt, kann dem Obsterzeuger noch in der laufenden Vegetationsperiode eine flachenspezifische Entscheidungshilfe zum Einsatz von Fenhexamid gegeben werden.

Stamme von Neofabraea perennans liesen sich bezuglich ihres Resistenzverhaltens gegen Thiophanate-methyl in drei Kategorien einteilen. Fur sensitive Stamme (Baseline) wurden ED50-Werte von 0,067 ± 0,003 ppm (Mycelwachstum) bzw. 0,202 ± 0,028 ppm (Konidienkeimung) ermittelt, fur partiell resistente Stamme 1,35 ± 0,30 ppm bzw. 9,75 ± 3,18 ppm. Hochresistente Stamme zeigten in beiden Testmethoden selbst bei 400 ppm Thiophanate-methyl keine Hemmung. Der Mycelwachstumstest war somit deutlich sensitiver als die Konidienkeimung und wird aufgrund seiner einfachen und reproduzierbaren Auswertung fur weiterfuhrende Untersuchungen zur Benzimidazol-Resistenz bei Bitterfaule-Erregern empfohlen. Eine Anleitung fur diesen Test wird gegeben.

Wahrend der Temperaturanstieg der vergangenen 30–40 Jahre bereits klare Auswirkungen auf die Phanologie von Obstbaumen und Schadinsekten gezeigt hat, fehlen solche Korrelationen fur Schadpilze im Obstbau. Am Beispiel von Fruchtfauleerregern wird deutlich, dass Schadpilze aufgrund ihrer komplexen Infektionsbiologie differenziert auf den Klimawandel reagieren. Das Auftreten des Erregers der Schwarzen Sommerfaule (Diplodia seriata) in Nordwesteuropa lasst sich durch steigende Temperaturen wahrend der Vegetationsperiode erklaren. Ein Anstieg der Krebsfruchtfaule (Nectria galligena) wird erwartet, wenn die prognostizierte milde und feuchte Winterwitterung zu verstarktem Krebsbefall an Asten und Zweigen der Baume fuhrt und dadurch das Inokulum fur Fruchtinfektionen steigt. Der aktuell in Norddeutschland beobachtete Anstieg von Neofabraea alba und Glomerella cingulata bzw. G. acutata als Lagerfaulen an Apfeln kann nicht mit Sicherheit in einen Zusammenhang mit dem Klimawandel gestellt werden. Am OVB Jork wird die pilzliche Diagnose ausgebaut, um auf das Auftreten neuer Schadpilze schneller reagieren und ihre Infektionsbiologie untersuchen zu konnen.

Zu den pilzlichen Erregern der Himbeerrutenkrankheit in Norddeutschland gehorten in den Jahren 2006–2008 Fusarium avenaceum, Leptosphaeria coniothyrium, Colletotrichum gloeosporioides und Botrytis cinerea (in absteigender Bedeutung). Diese Erreger und ihre Symptome werden kurz beschrieben. Fusarium avenaceum ist hauptverantwortlich fur die schweren rezenten Ausbruche der Rutenkrankheit in Norddeutschland, wo diese Art auf kultivierten und wilden Himbeeren weit verbreitet ist. Im Jahr 2007 fanden Infektionen bereits Mitte Mai wahrend einer Nasseperiode statt und korrelierten mit der naturlichen Bildung von epidermalen Rissen bei einsetzendem Dickenwachstum der Jungruten, nicht aber mit den erst ab 6. Juni stattfindenden Einbohrungen der Himbeerrutengallmucke (Resseliella theobaldi). Im Jahre 2008 verzogerten sich aufgrund einer langen Trockenheitsphase im Mai und Juni die F. avenaceum-Infektionen bis Mitte Juli. Zu diesem Zeitpunkt hatte R. theobaldi die Jungruten bereits besiedelt. Abgestorbene oberirdische Stumpfe und Rutenfragmente stellten neben bereits kolonisierten Jungruten das wichtigste Uberwinterungsquartier fur F. avenaceum dar. Mogliche Anwendungen von Hygienemasnahmen zur Eindammung von F. avenaceum werden kurz besprochen.

Botrytis cinerea is one of the most important pathogens worldwide, causing gray mold on a large variety of crops. Botrytis pseudocinerea has been found previously to occur together with B. cinerea in low abundance in vineyards and strawberry fields. Here, we report B. pseudocinerea to be common and sometimes dominant over B. cinerea on several fruit and vegetable crops in Germany. On apples with calyx end rot and on oilseed rape, it was the major gray mold species. Abundance of B. pseudocinerea was often negatively correlated with fungicide treatments. On cultivated strawberries, it was frequently found in spring but was largely displaced by B. cinerea following fungicide applications. Whereas B. cinerea strains with multiple-fungicide resistance were common in these fields, B. pseudocinerea almost never developed resistance to any fungicide even though resistance mutations occurred at similar frequencies in both species under laboratory conditions. The absence of resistance to quinone outside inhibitors in B. pseudocinerea was correlated with an intron in cytB preventing the major G143A resistance mutation. Our work indicates that B. pseudocinerea has a wide host range similar to that of B. cinerea and that it can become an important gray mold pathogen on cultivated plants.

In a survey of Botrytis populations in Northern Germany in 2012-2014, an average of 67.7% and 73.8% of isolates from strawberry and raspberry fields (respectively) were resistant to QoI fungicides whilst 40.2% and 64.9% (respectively) were resistant to the SDHI boscalid. There was a sporadic occurrence (2.8% and 3.3%, respectively) of strains resistant to the new SDHI fungicide fluopyram, due to be used in German soft fruits from 2015 onwards. Both moderate (EC50 = 0.5–5.0 mg 1−1) and high (EC50 > 10mg 1−1) levels of resistance to fluopyram were observed in a spore germination assay in which the baseline sensitivity was 0.02–0.2 mg 1−1. Among several amino acid substitutions in the SDHI target site found in Botrytis isolates from fields of strawberries, raspberries and other horticultural crops, P225F and N230I, based on mutations in the sdhB gene, as well as a type of resistance of unknown basis, caused positive cross-resistance to boscalid and fluopyram. Further, N230I and the unknown type of resistance were detected in strains with multiple resistance to all other currently used fungicides, i.e. fenhexamid, cyprodinil, fludioxonil and QoIs. For resistance management purposes, it is suggested that the number of fluopyram applications should be limited to one per season.

Phacidiopycnis washingtonensis, cause of rubbery rot of apples during long-term storage, was first observed in Denmark in April 2010 on fruits of the 2009 harvest. Hot-water treatments were examined as a possible way to control P. washingtonensis. The effective temperature causing a 50% mortality of infectious spores (conidia) after a 3-min submersion in water was 40.2°C. A significant reduction of rubbery rot was achieved by dipping artificially infected fruit in a water bath at 47–52°C for 3 min. Using naturally infected apples, P. washingtonensis as well as the widespread storage-rot pathogen Neofabraea perennans were effectively controlled by a post-harvest dip at 50°C for 3 min or by a rinse at 55°C for 20 s, followed by cold storage in controlled-atmosphere conditions. In contrast, a treatment of freshly harvested fruits with 1-methylcyclopropene (1-MCP) instead of hot water failed to control P. w a s h i n g t o -nensis.

Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:29:41Z No. of bitstreams: 0Bitstream added on 2014-05-27T14:43:14Z : No. of bitstreams: 1 2-s2.0-84878810585.pdf: 810889 bytes, checksum: fedf0dbbc2200bb5de245a25d4c6083d (MD5) Made available in DSpace on 2014-05-27T11:29:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-14 Background It is generally accepted that material collected by leaf-cutting ants of the genus Acromyrmex consists solely of plant matter, which is used in the nest as substrate for a symbiotic fungus providing nutrition to the ants. There is only one previous report of any leaf-cutting ant foraging directly on fungal basidiocarps. Findings Basidiocarps of Psilocybe coprophila growing on cow dung were actively collected by workers of Acromyrmex lobicornis in Santa Fé province, Argentina. During this behaviour the ants displayed typical signals of recognition and continuously recruited other foragers to the task. Basidiocarps of different stages of maturity were being transported into the nest by particular groups of workers, while other workers collected plant material. Conclusions The collection of mature basidiocarps with viable spores by leaf-cutting ants in nature adds substance to theories relating to the origin of fungiculture in these highly specialized social insects. © 2013 Masiulionis et al. Instituto de Biociências UNESP -Univ Estadual Paulista Campus de Rio Claro, SP. Centro de Estudos de Insetos Sociais, Rio Claro, SP 13506-900 Esteburg-Obstbauzentrum Jork, Moorende 53, Jork 21635 Instituto de Biociências UNESP -Univ Estadual Paulista Campus de Rio Claro, SP. Centro de Estudos de Insetos Sociais, Rio Claro, SP 13506-900

The gray mold fungus Botrytis cinerea is a major threat to fruit and vegetable production. Strawberry fields usually receive several fungicide treatments against Botrytis per season. Gray mold isolates from several German strawberry-growing regions were analyzed to determine their sensitivity against botryticides. Fungicide resistance was commonly observed, with many isolates possessing resistance to multiple (up to six) fungicides. A stronger variant of the previously described multidrug resistance (MDR) phenotype MDR1, called MDR1h, was found to be widely distributed, conferring increased partial resistance to two important botryticides, cyprodinil and fludioxonil. A 3-bp deletion mutation in a transcription factor-encoding gene, mrr1 , was found to be correlated with MDR1h. All MDR1h isolates and the majority of isolates with resistance to multiple fungicides were found to be genetically distinct. Multiple-gene sequencing confirmed that they belong to a novel clade, called Botrytis group S, which is closely related to B. cinerea and the host-specific species B. fabae . Isolates of Botrytis group S genotypes were found to be widespread in all German strawberry-growing regions but almost absent from vineyards. Our data indicate a clear subdivision of gray mold populations, which are differentially distributed according to their host preference and adaptation to chemical treatments.

Hot-water rinsing (3 or 4 min) and dipping (15, 20 or 25 s) at a range of incubation temperatures was applied to apples (cv. ‘Ingrid Marie’ and ‘Pinova’) naturally infected with a range of North West European storage-rot fungi. Significant reductions in the incidence of fruit rot were achieved by incubation periods of 3 min at 50–54 °C (dipping) and 20 or 25 s at 55 °C (rinsing), followed by up to 100 d cold-storage at 2 °C and 14 d at 18 °C. Pathogens controlled in this way were Neofabraea alba, N. perennans, Monilinia fructigena, Colletotrichum acutatum, Phacidiopycnis washingtonensis and Cladosporium spp. Neonectria galligena was reliably controlled by dipping but not rinsing. No effects of either heat treatment on Gibberella avenacea and Botrytis cinerea were apparent. Following rinsing at 65 °C for 20 s, the incidence of P. washingtonensis, Penicillium expansum, Mucor spp. and Phoma exigua was higher than in untreated control fruit or in apples rinsed at lower temperatures, and was associated with heat damage. The relative contributions of heat effects on inoculum viability and activation of defence responses of apple fruit are discussed. Hot-water rinsing has several advantages over hot-water dipping related to the efficient processing of fruit either directly after harvest or after long-term storage.

In the mild and humid climate of northwestern Europe, fungal pre-harvest rots are a major factor limiting the production of soft-fruits such as strawberries and raspberries. By far the most important fungal disease is grey mould caused by Botrytis cinerea Pers.:Fr., now known to be an aggregate of at least two distinct species (Fournier et al., 2005; Giraud et al., 1999). Primary infections are initiated at flowering, resulting in a quiescent colonisation of floral organs (Bristow et al., 1986; Puhl & Treutter, 2008). Upon ripening of the infected fruit, a brown rot becomes apparent (Fig. 1A) which rapidly engulfs the entire fruit, culminating in the production of conidiophores (Fig. 1B). If mild and humid conditions prevail at harvest time, conidia released from fruits with primary infections may infect healthy fruits, causing a catastrophic grey mould epidemic (Fig. 1C). Repeated fungicide applications during flowering are therefore essential to control B. cinerea in soft-fruit production.

A strain harbouring an insertion within the promoter of the CON7 gene of Magnaporthe grisea was isolated. This gene was previously shown to be essential for appressorium formation and growth in planta and is predicted to encode a transcription factor. Microarray-based gene expression analysis was used to identify several genes whose transcription during germination depends on Con7p. These include the pathogenicity factor-encoding gene PTH11 and several other genes which like PTH11 are predicted to encode G protein-coupled receptors. Microarray analysis also revealed several Con7p-dependent genes which may encode factors determining cell wall structure or function, either through the synthesis/degradation of cell wall components or by association with the cell exterior. One Con7p-dependent gene predicted to encode a class VII chitin synthase was deleted, leading to dramatic consequences on the pathogenic development of the resultant strain. Within the con7(-) mutant, a 29% reduction in chitin content of germinated spores was found and the mutant was hypersensitive to the chitin synthase inhibitor nikkomycin Z. A green fluorescent protein-tagged Con7p was found to have nuclear localization within spores. Taken together, these observations suggest that Con7p encodes a transcription factor required for the transcription of several genes which participate in disease-related morphogenesis in M. grisea.

Antiamoebins I, III and XVI as well as several others in minor amounts were produced by four strains of the coprophilous fungus Stilbella erythrocephala (syn. S. fimetaria) in its natural substrate and in liquid culture. The total antiamoebin concentration in dung was 126-624 microg g(-1) fresh weight, with minimum inhibitory concentrations against most other coprophilous fungi being at or below 100 microg mL(-1). Myrocin B, not previously described from S. erythrocephala, was also produced, but only at low, nonfungicidal levels (5.3 microg g(-1)). No other antifungal substances were detected. It is concluded that antiamoebins are responsible for antibiosis in dung colonized by S. erythrocephala.

Severe rust infections on wild and cultivated daisies (Bellis perennis L.) were found in April and May 2000 in an isolated coastal location of Croatia between Lovran and Opatija. The pathogen was identified as Puccinia distincta McAlpine which has been spreading rapidly across Europe for the past four years and may be of Australian origin. In the current paper, we describe the diagnostic features of P. distincta using Croatian material, and suggest spraying with myclobutanil-containing fungicides to protect ornamental daisies in flowerbeds. Without such treatments, it may no longer be possible to grow daisies in areas affected by P. distincta., Teška infekcija hrđe na divljim i uzgajanim tratinčicama (Bellis perennis L.) otkrivena je u travnju i svibnju 2000. na izoliranom priobalnom području izme|u Lovrana i Opatije. Patogena gljiva bila je determinirana kao Puccinia distincta McAlpine, koja se protekle četiri godine brzo širi po Europi, a možda dolazi iz Australije. U ovom prikazu opisujemo dijagnostičke značajke gljive P. distincta primjenjujući materijal iz Hrvatske i predlažemo prskanje fungicidima na osnovi miklobutanila kako bismo zaštitili dekorativne tratinčice u cvjetnim nasadima. Bez takvih tretmana postoji mogućnost da na područjima zaraženim s P. distincta više neće biti moguć njihov uzgoj.