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V poletnih mesecih leta 2019 smo preiskušali delovanje osmih vodnih izvlečkov invazivnih tujerodnih rastlinskih vrst na pojav bolezni ter na rast in razvoj mehkolistne solate sorte 'Marina'. Poskus smo zasnovali na Laboratorijskem polju Biotehniške fakultete v Ljubljani. Pridelovalno zemljišče smo razdelili v tri bloke, znotraj katerih smo naključno razporedili 10 obravnavanj (po 18 sadik v vsakem obravnavanju/parcelici), in sicer: 1 – vodni izvleček listov orjaške zlate rozge (Solidago gigantea), 2 – vodni izvleček listov kanadske zlate rozge (Solidago canadensis), 3 – vodni izvleček listov japonskega dresnika (Fallopia japonica), 4 – vodni izvleček listov češkega dresnika (Fallopia bohemica), 5 – vodni izvleček velikega pajesena (Ailanthus altissima), 6 – vodni izvleček listov octovca (Rhus typhina), 7 – vodni izvleček listov navadne amorfe (Amorpha fructicosa), 8 – vodni izvleček listov smrdljive ditrihovke (Dittrichia graveolens), 9 – pozitivna kontrola (uporaba fungicidov in insekticidov), ter negativna kontrola (neškropljeno). Vse vodne izvlečke smo uporabili v 25 % koncentraciji. Sredstva smo nanašali na rastline med rastno dobo, škropljenje smo opravili trikrat. Z rezultati smo dokazali razlike v delovanju različnih invazivnih tujerodnih rastlinskih vrst na povzročitelja črne listne pegavosti (Alternaria cichorii) na solati in pridelek solate. Pri preučevanju učinkovitosti zatiranja črne listne pegavosti smo pri nekaterih izvlečkih invazivnih tujerodnih rastlinskih vrst dobili zadovoljive rezultate. Največjo povprečno maso nadzemnega dela solate smo ugotovili v pozitivni in negativni kontroli, med izvlečki invazivnih tujerodnih rastlinskih vrst pa se je kot najboljši biostimulant izkazal vodni izvleček kanadske zlate rozge. In the summer of 2019, we tested the effects of eight water extracts of invasive alien plant species on the occurrence of diseases, and on the growth and development of the butterhead lettuce, the variety 'Marina'. The experiment was carried out at the Laboratory Field of the Biotechnical Faculty in Ljubljana. We divided the cultivated land into three blocks, inside this blocks we distributed 10 treatments (18 seedlings in each treatment/plot) at random: 1 – water extract of giant knotweed leaves (Solidago gigantea), 2 – water extract of Canadian knotweed leaves (Solidago canadensis), 3 – water extract of Japanese knotweed leaves (Fallopia japonica), 4 – water extract of Bohemian knotweed leaves (Fallopia bohemica), 5 – water extract of three of heaven (Ailanthus altissima), 6 – water extract of staghorn sumac leaves (Rhus typhina), 7 – water extract of false indigo leaves (Amorpha fructicosa), 8 – water extract of stinkwort leaves (Dittrichia graveolens), 9 – positive control (use of fungicides and insecticides), and negative control (unsprayed). All aqueous extracts were used in 25 % concentration. We applied the extracts on the plants during the growing season we sprayed the luttuce three times. We found differences in the activity of differrent invasive alien plant species on the causer of the Alternaria leaf spot and lettuce production. Good results have been obtained in suppressing Alternaria leaf spot with water extracts of some invasive alien plant species. In the positive and negative control we established the highest average mass of the above-ground part of the lettuce, while among extracts of invasive alien plant species, the extract of the Canadian knotweed proved to be the best biostimulant.

During 2004 and 2005 the activity of sulphur, soya lecithin, and salicylic acid on endive and on the fungus Alternaria cichorii were investigated in a field block experiment. In both years, the plants sprayed five times with soya lecithin or three times with sulphur yearly, were significantly less infected than untreated plants. In 2005, the effect of salicylic acid (five sprays) was also shown to be satisfactory. Compared to the untreated plants, the plants treated with natural substances exhibited higher total mass as well as higher net mass. In both years a significant positive correlation was established between the total mass of the plants and yield loss (r2 = 0.66 in the 2004 soya lecithin treatment, and r2 = 0.62 in the 2005 salicylic acid treatment). In 2005, when the fungus occurred to a higher extent, a lower correlation (r2 = 0.30) was confirmed between yield loss and the extent of infection on the exterior leaves. The variety Eros was the most heavily infected with the fungus in both years, while the varieties Escariol gruner, Pancalieri, Avance, and Palmira showed greater resistance to infection with A. cichorii. The varieties Perfect, Pancalieri, and Avance had the highest net mass, while only the first of them showed the highest total mass.

Sementes de feijão podem transportar grande número de patógenos que têm a capacidade de afetar sua qualidade fisiológica ou causar doenças em diferentes estádios da cultura, afetando seu rendimento. O agente causal da mancha de Alternária do feijoeiro é um desses patógenos, porém não existem muitos estudos avaliando a transmissão de diferentes espécies de Alternaria associadas a essa doença e seu efeito sobre a qualidade fisiológica. Sendo assim, desenvolveu-se este trabalho com o objetivo de verificar a transmissão de espécies de Alternaria através das sementes de feijão e seu efeito sobre a germinação das mesmas e sobre a emergência de plântulas em casa de vegetação. Isolados de Alternaria alternata, A. carthami e A. cichorii foram inoculados em sementes de feijão e estas foram submetidas aos testes de sanidade, germinação e emergência de plântulas em casa de vegetação. A inoculação com os isolados de A. alternata proporcionou sementes com quase 100% de incidência; os resultados obtidos com os demais isolados variaram de zero, para os isolados 3 (A. cichorii) e 8 e 9 (A. carthami), até 75% para o isolado 7 (A. carthami). A maioria dos isolados foi transmitida para as plântulas, sendo os isolados 1 (Alternaria cichorii) e 4, 5, 8, 9 e 11 (A. carthami) transmitidos em maior porcentagem. Não se constatou efeito dos isolados sobre a emergência das plântulas e não houve correlação positiva entre a porcentagem de incidência do fungo e a porcentagem de plântulas infectadas. Alguns isolados de A. carthami causaram queda na germinação das sementes. A great number of pathogens can be transported by seeds; they had capacity to affect physiological quality or to cause diseases in many stages of the culture, reducing yield. One of these pathogens is the causal agent of Alternaria leaf spot. There aren't many researches about seed transmission of distinct Alternaria species and its effects on common bean physiological quality. The present study was carried out with the aim to verify Alternaria species transmission by common bean seeds and the effects on germination and plant emergence in the greenhouse. About 100% of inoculated common bean seeds became infected with isolates of A. alternata. Other isolates of Alternaria from distinct species promoted seed infection varying from zero (3 - A. cichorii) to 75% (7 - A. carthami). The majority of these isolates was transmitted to seedlings; isolates 1 (Alternaria cichorii) and 4, 5, 8, 9 and 11 (A. carthami) were transmitted in greater percentage. There was no effect on the plant emergence caused by these isolates, and no positive correlation between incidence and infected seedlings was observed. Some isolates of A. carthami reduced seed germination.

A description is provided for Alternaria cichorii . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Cichorium endivia L. (Endive); Cichorium intybus L. (Cichory) and Lactuca sativa L. (Lettuce), all members of the tribe Lactuceae (Cichorieae), Asteraceae . It has recently been reported (69, 1978) as occurring on Acroptilion repens , a member of the Cynareae , growing as a weed in western Canada. DISEASE: Leaf spot of Endive and Cichory. GEOGRAPHICAL DISTRIBUTION: Africa: Egypt. North America: Canada, USA (Florida). South America: Argentina (52, 544). Asia: India, New Guinea, Pakistan. Europe: Austria, Cyprus, Denmark, Greece, Italy, Slovenia. TRANSMISSION: By wind dispersal of airborne conidia.

Conidiation of Alternaria cichorii was inhibited by blue-light (360–530 nm) radiation; a small dose of blue-light energy (6 × 10 −1 μE m 2 s −1 ) was enough to suppress conidiation. Blue light was most effective in inhibiting conidiation when the fungus was exposed to it between 4 and 6 h after the termination of a period of inductive radiation. Near ultraviolet (uv) radiation (0.54 μE m −2 s −1 for 30 min), following blue light, reversed the inhibition.

The vegetative reversion of Alternaria cichorii conidiophores was affected by relative humidity in a temperature-dependent response. The higher the relative humidity and temperature the greater the extent and length of vegetative reversion of conidiophores.

Coniditation the fungus, Alternaria cichorii Nattras (IMI 225641), was repeatedly induced and inhibited by alternating doses of near ultraviolet and blue radiation. The final response largely depended on the last kind of radiation administered. When the final radiation was near ultraviolet, conidiophore formation was induced, and conidia were then produced in the subsequent dark period; when it was blue, the induction of conidiation was suppressed. The inductive effect of near ultraviolet was promoted by anaerobiosis, but the reversing effect by blue radiation was not influenced by molecular oxygen. Thus, the “mycochrome” system apprears to control induction of conidiation in Alternaria cichorii, and oxidation-reduction processes may be involved in its function.

Sporulation in Alternaria cichorii had two distinct phases: an ‘inductive phase’ leading to formation of conidiophores and a ‘terminal phase’ leading to formation of conidia. The ‘inductive phase’ was induced by nuv irradiation below 340 nm and proceeded most efficiently at high temperatures, while the ‘terminal phase’ was inhibited by exposure to blb irradiation (Black Light Blue, 310–420 nm) and blue light (360–530 nm) and was operative at lower temperatures. Inhibition of conidiation by blb was caused by the blue wavelengths and it increased with increase in temperature. The inhibition was temporary under continuous blb irradiation but permanent under continuous blue light alone. Extended exposure (≥ 3 days) to blb promoted sporulation in a temperature-dependent response.

Summary: An action spectrum for photoinduced conidiophore formation in the fungus Alternaia cichorii was determined by exposing colonies to monochromatic radiation obtained from a diffraction grating monochromator. The action spectrum showed a peak near 290 nm with a noticeable shoulder between 310 and 330 nm and another one between 260 and 265 nm. This action spectrum has many common characters with those for photoinduced conidiophore formation of Helminthosporium oryzae and Alternaria tomato, where the induction of conidiophore formation is controlled by a blue-light-inducible, near-UV-reversible, photoreaction.

The development of the conidiophores of the fungus Alternaria cichorii Nattrass was induced by near ultraviolet irradiation (

Light intensity affected conidial morphology in Alternaria cichorii only at low temperatures (15 °C). At higher light intensities ( ca 1240 lx) beak length, body length and width of conidia were increased. Temperature changes affected conidial size at all light intensities tested. Large conidia with short beaks were produced at low temperatures (15°), but small ones with long beaks at high temperatures (33°).

Sporulation in Alternaria cichorii Nattrass was induced by near ultraviolet irradiation (

Prolonged exposure to blue light was necessary for almost complete inhibition of sporulation in Alternaria cichorii Nattrass. When a 24-h blue light exposure was followed by darkness, the inhibition of sporulation decreased gradually.