Apple production suffers significant economic losses and fruit quality reduction due to fungal pathogens, particularly ones that cause postharvest fruit rot, such as Botryosphaeriaceae fungi. Isolates used in this study were obtained from symptomatic apples and, based on morphological characteristics and sequence analysis of two genes (EF 1-? and ?-tubulin), they were identified as Diplodia seriata and Botryosphaeria dothidea. Pathogenicity tests on healthy apple fruits revealed that D. seriata was more aggressive than B. dothidea, with significantly higher average values of lesion diameter and depth. Fungicide sensitivity tests showed that D. seriata was more sensitive to the combination fluopyram + tebuconazole (EC50=0.00023 ?g a.i. ml-1), while B. dothidea exhibited higher sensitivity to pyraclostrobin (EC50=0.025 ?g a.i. ml-1). With 98.44% and 97.56% percent growth inhibition (PGI) rate of D. seriata and B. dothidea (respectively) at 10 ?g a.i. ml-1, the tested combination of fungicides surpassed pyraclostrobin in inhibition potential. Four essential oils (thyme, rosemary, lavender and lemongrass) were also tested for antifungal activity using the fumigant macrodilution method. Thyme oil demonstrated the highest antifungal potential, completely inhibiting the mycelial growth of both species at 0.05 ?l ml-1 of air. Strong inhibition potential was also shown by lemongrass oil with 100% inhibition of D. seriata and B. dothidea mycelial growth at 0.07 and 0.09 ?l ml-1 of air, respectively. Rosemary oil showed a moderate inhibition potential, while lavender oil was the least effective. These findings highlight the inhibiting potential of fungicides against D. seriata and B. dothidea, but they also indicate that thyme and lemongrass essential oils could be used as viable alternatives. Further research is needed to determine their effectiveness in in vivo assays and potential impact on fruit quality and the environment.

In Europe, two fastidious phloem-limited pathogens, 'Candidatus Phytoplasma solani' (16SrXII-A) and 'Candidatus Arsenophonus phytopathogenicus', are associated with rubbery taproot disease (RTD) and syndrome basses richesses (SBR) of sugar beet, respectively. Both diseases can significantly reduce yield, especially when accompanied by root rot fungi. This study investigates the presence, geographic distribution and genetic traits of fastidious pathogens and the accompanying fungus, Macrophomina phaseolina, found on sugar beet across four geographically separated plains spanning seven countries in Central Europe. The survey revealed variable incidences of symptoms linked to these fastidious pathogens in the Pannonian and Wallachian Plains, sporadic occurrence in the North European Plain, and no symptomatic sugar beet in the Bohemian Plain. Molecular analyses unveiled the occurrence of both 'Ca. P. solani' and 'Ca. A. phytopathogenicus' throughout Central Europe, with a predominance of the phytoplasma. These fastidious pathogens were detected in all six countries surveyed within the Pannonian and Wallachian Plains, with only a limited presence of various phytoplasmas was found in the North European Plain, while no fastidious pathogens were detected in Bohemia, aligning with observed symptoms. While 16S rDNA sequences of 'Ca. P. solani' remained highly conserved, multi-locus characterization of two more variable loci (tuf and stamp) unveiled distinct variability patterns across the plains. Notably, the surprising lack of variability of tuf and stamp loci within Central Europe, particularly the Pannonian Plain, contrasted their high variability in Eastern and Western Europe, corresponding to epidemic and sporadic occurrence, respectively. The current study provides valuable insights into the genetic dynamics of 'Ca. P. solani' in Central Europe, and novel findings of the presence of 'Ca. A. phytopathogenicus' in five countries (Slovakia, Czech Republic, Austria, Serbia, and Romania) and M. phaseolina in sugar beet in Slovakia. These findings emphasize the need for further investigation of vector-pathogen(s)-plant host interactions and ecological drivers of disease outbreaks.

The result of this study was accepted technical solution of disease/pest control of cultivated mushroom (Agaricus bisporus L.) based on biological pesticides (Biogenesis d.o.o., Serbia): microbial biofungicide Bacillus subtilis Ch-13 (Ekstrasol 1×108 CFU/cm3) and botanical bioinsecticide azadirachtin (Ozoneem trishul 1 %). Effectiveness of bio/pesticides in disease/pest control and impact on mushroom yield were evaluated in large and small-scale experiments. Efficacy of biofungicide in control of Trichoderma aggressivum Samuels and W. Gams (green mould disease) was evaluated in comparison with chemical fungicide prochloraz (2×1.5 mL). Biofungicide was applied in different procedures, in two (2×30 mL/m2), three (30 + 2×15 mL/m2), or six split doses (6×10 ml/m2). The highest statistically significant effectiveness in pathogen control was shown in three (53.57-58.43%) and six doses (63.05%), that could be recommended. Biofungicide significantly improved yield in all different procedures, compared with untreated control in small-scale experiements 6.11-12.12% and in large-scale 5.07-8.41%. The impact of the bioinsecticide azadirachtin (4 × 0.5 ml/m2) on the density of the mushroom fly Lycoriella ingenua (Dufour) (Sciaridae: Diptera) was compared to the effects of the chemical insecticide malathion (2×0.3 ml/m2). The average number of the mushroom fly adults on yellow sticky traps per each mushroom row was significantly lower in the test chamber in comparison with two controled chambers. The results of our study suggest that biofungicide Bacillus subtilis Ch-13 and bioinsectide azadirachtin may provide a good alternative to conventional chemicals. The study was funded by grant 451-03-47/2023-1/200214 of the Ministry of Science, Technological Development and Innovation, Republic of Serbia.

The study was focused on improvement of the integrated management strategy against green mould disease agent Trichoderma aggressivum Samuels & Gams and mushroom fly Lycoriella ingenua (Dufour) as pests of the white button mushroom Agaricus bisporus (Lange) Imbach. The impact of neem cake amendment in casing soil on regulation of the abundance of mushroom sciarid fly adults, efficacy in controlling the green mould disease agent, and mushroom yield was evaluated. Casing soil was supplemented with different concentrations of neem cake: 1, 2.5, 5, 10 and 15%. Neem cake added as a supplement to casing soil at a rate of 2.5% reduced the number of mushroom fly adults by 83.93% and green mould disease incidence by 59.6% in comparison to the control. No adverse effect on mushroom formation, yield and quality of fruiting bodies was observed at that concentration. Amendment of 2.5% neem cake in the casing soil could be recommended for application in mushroom production to control L. ingenua and symptoms of green mould disease without negative impact on mushroom yield.

A previous study had confirmed good selective features of a biofungicide based on Bacillus subtilis Ch-13 regarding green mould disease control and increase in white button mushroom (Agaricus bisporus) production. The recommended application rate of the biofungicide in three split doses (30 + 15 + 15 ml m-2) enhanced mushroom yield by 8.41% and control of green mould disease (Trichoderma aggressivum) by 53.57%. A different application procedure of the biofungicide B. subtilis Ch-13 was then further investigated, involving six split doses (6 ? 10 ml m-2) of the same total dose of 60 ml which was previously tested in three split doses. The impact of the biofungicide on fruiting body yield and its effectiveness in disease control were evaluated on white button mushroom artificially infected with Trichoderma aggressivum f. europaeum in the experimental mushroom growing room (in vivo). No statistically significant differences in disease control efficacy were found between the fungicide prochloraz (71.08%) and the biofungicide applied either in six split doses (63.05%) or three (58.43%). As for the fungicide/biofungicide positive impact on mushroom production, no statistically significant differences were detected among treatments. The B. subtilis Ch-13-based biofungicide may be applied in three split doses, as well as in six split applications, depending on the watering or picking schedule during mushroom cultivation, as both schemes showed satisfactory efficacy in disease control and positive effects on mushroom yield.

Croatian isolates of Monilinia fructicola, M. laxa and M. fructigena have been collected from peach, nectarine, sweet cherry, plum and apricot fruits and assessed for their sensitivity to thiophanate-methyl. Out of 66 isolates collected, 34 were identified as M. fructicola (52%), 22 as M. fructigena (33%) and 10 as M. laxa (15%). Mycelial radial growth on water agar amended with thiophanate-methyl was measured to determine half maximal effective concentration values (EC50). All isolates of M. laxa and M. fructigena showed as sensitive, with EC50 values lower than 1 µg ml− 1 in 31 from 32 isolates. In M. fructicola, 19 isolates (56%) were sensitive, nine (26%) were resistant (EC50 2–30 µg ml− 1), and six (18%) were highly resistant (EC50 > 30 µg ml− 1). Positive allele-specific PCR with primer pair HRR/HRF, detecting resistant point mutations in β-tubulin gene, was recorded in 15 out of 16 highly resistant, resistant and less sensitive M. fructicola isolates. Among all species, PCR assay coincided with agar assay in 95% of cases. Highly resistant M. fructicola isolates AL 24/19 and VR 8/18 caused typical brown rot on nectarine fruits inoculated with conidia suspended in 5 or 10 µg ml− 1 of thiophanate-methyl. Four sensitive isolates of all three species did not develop on inoculated fruits. Besides implications for brown rot management, the finding of M. fructicola strains resistant to thiophanate-methyl may indicate that this species could be adapting to fungicides more rapidly than M. laxa or M. fructigena. As resistant M. fructicola isolates were also found in orchards where benzimidazoles have never been used, there is a possibility they originate from already benzimidazole-resistant strains which entered and established in Croatia.

The efficacy of a formulated product of tea tree oil (TTO) and a standard copper based bactericide in combinations with acibenzolar-S-methyl (ASM) for control of bacterial spot of pepper and bacterial speck of tomato was evaluated under controlled conditions. Treatments with copper hydroxide+ASM at both application rates and TTO+ASM showed the best efficacy in control of bacterial spot disease in pepper plants (with respective efficacy values 83.5%, 83.7 % and 86.9%). Similar efficacy was achieved by treatment with copper hydroxide alone (82.2%). On the other hand, the efficacy of TTO, applied alone, was significantly lower at both rates (63.8% and 71.5%) in bacterial spot control in pepper. The same treatments (copper hydroxide +ASM at both application rates and TTO+ASM) were most efficient in suppressing the causal agent of bacterial speck disease in tomato (87%, 82.3% and 81.6%). The efficacy of treatment with the standard bactericide copper hydroxide, applied alone, was significantly lower compared to its combination with ASM (79.1%). Similarly to the bacterial spot experiment, TTO treatments alone showed lower, although satisfactory efficacy at both application rates (66.1% and 68.9%). The results of this study showed that combination of the bioactive compound - ASM with either the standard copper hydroxide bactericide or TTO significantly improved their efficacy in both bacterial spot and speck disease control, and thus implied that combining different biorational compounds, such as essential oils and bioactive products, with standard copper treatments and their inclusion into integrated management programs are of essential importance for the control of bacterial diseases of pepper and tomato.

The impact of a bioinsecticide based on azadirachtin (Ozoneem trishul 1 %) on the abudance of mushroom flies (Sciaridae: Diptera) was compared to the effect of a commercial formulation of the malathion-based chemical insecticide Etiol tecni. Experiments were conducted in three growing chambers (B6, B7 and B8) of a commercial mushrom farm ?Delta Danube? d.o.o., Kovin. Casing treatments were performed in eight replications in a random block design. The azadirachtin-based bioinsecticide was applied in chamber B8 four times (0.5 ml/m2): during casing and later at seven-day intervals. The standard chemical insecticide based on malathion was applied in chambers B6 and B7 twice (2 x 0.3 ml/m2), on the third and sixth day after casing. In all three chambers, the abudance of mushroom flies was monitored by using yellow sticky traps, which were collected weekly and replaced with new ones four times at seven days intervals. The yellow sticky traps were examined in the laboratory under a binocular microscope to determine the presence and density of mushroom flies. Only one species of mushroom fly, Lycoriella ingenua (Dufour), was found on the yellow sticky traps throughout the experimental period. The average number of sciarid flies per mushroom block 15 and 22 days after treatment (DAT) was significantly lower in the test chamber B8 than in chambers B7 and B6, while there was no significant difference 30 and 36 DAT, compared to the control chamber B6. The average number of sciarid flies per mushroom row throughout the experiment was significantly lower in the test chamber B8 than in chambers B6 and B7. The results of our study suggest that the azadirachtin-based bioinsecticide can suppress populations of the mushroom fly L. ingenua and may provide a good alternative to conventional chemical insecticide.

HomePlant DiseaseVol. 102, No. 5First Report of ‘Candidatus Phytoplasma solani’ Infecting Parsnip in Serbia PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of ‘Candidatus Phytoplasma solani’ Infecting Parsnip in SerbiaS. Medić Pap, J. Gvozdanović Varga, J. Červenski, J. Stepanović, E. Rekanović, M. Stepanović, and B. DudukS. Medić Pap†Corresponding author: S. Medić Pap; E-mail: E-mail Address: sladjana.medicpap@ifvcns.ns.ac.rsSearch for more papers by this author, J. Gvozdanović VargaSearch for more papers by this author, J. ČervenskiSearch for more papers by this author, J. StepanovićSearch for more papers by this author, E. RekanovićSearch for more papers by this author, M. StepanovićSearch for more papers by this author, and B. DudukSearch for more papers by this authorAffiliationsAuthors and Affiliations S. Medić Pap † J. Gvozdanović Varga J. Červenski , Institute of Field and Vegetable Crops, Novi Sad, Serbia J. Stepanović E. Rekanović M. Stepanović B. Duduk , Institute of Pesticides and Environmental Protection, Belgrade, Serbia. Published Online:28 Feb 2018https://doi.org/10.1094/PDIS-02-17-0197-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat The parsnip (Pastinaca sativa L.) is a biennial plant native to Eurasia. During August and September 2016, typical phytoplasma yellows symptoms were observed on parsnip plants grown in a 105-m2 experimental field in South Bačka, Vojvodina, Serbia. A phytoplasma-like disease, expressed as leaf and petiole redness and chlorosis, was observed on approximately 5% of plants. Some plants had signs of complete foliage necrosis and at the harvest time in October were not suitable for human consumption. Total nucleic acid was extracted from leaf midveins collected from eight symptomatic and four asymptomatic plants. Phytoplasma infection was detected using nested polymerase chain reaction (PCR) assays with specific primer pair P1/P7 followed by R16F2n/R2 for the amplification of phytoplasma 16S rRNA gene. Phytoplasmas were detected in all eight extracts from symptomatic plants as well as in two of four asymptomatic ones. Fragments amplified with R16F2n/R2 primers were analyzed by restriction fragment length polymorphism with TruI restriction enzyme. The phytoplasmas produced identical restriction profiles to those of ‘Candidatus Phytoplasma solani.’ One amplicon obtained with P1/P7 primers (16S-23S rDNA) was subjected to direct sequencing yielding a 1,640-bp nucleotide sequence. The obtained sequence has been deposited in NCBI GenBank under accession no. KY579338 and shared sequence identity with 11 ‘Ca. P. solani’ strains and >99.7% sequence similarity with the ‘Ca. P. solani’ reference strain (AF248959). Parsnip infected by ‘Ca. P. solani’ has been reported in Spain (Alfaro-Fernández et al. 2011). In Serbia, ‘Ca. P. solani’ has been detected in the family Appiacae on carrot and celery while ‘Ca. P. asteris’ has also been detected on carrot (Duduk et al. 2008; Ivanović et al. 2011). To our knowledge, this is the first report of phytoplasma infecting parsnip in Serbia. The presence of Stolbur on parsnip in Serbia as another natural host can be of importance for the management of the disease in other crops in Eastern Europe.References:Alfaro-Fernández, A., et al. 2011. Bull. Insectology 64:S63. ISI, Google ScholarDuduk, B., et al. 2008. Bull. Insectology 61:327. ISI, Google ScholarIvanović, Ž., et al. 2011. Bull. Insectology 64:S239. ISI, Google ScholarDetailsFiguresLiterature CitedRelated Vol. 102, No. 5 May 2018SubscribeISSN:0191-2917e-ISSN:1943-7692 Metrics Article History Issue Date: 20 Apr 2018Published: 28 Feb 2018First Look: 27 Nov 2017Accepted: 20 Nov 2017 Pages: 1026-1026 Information© 2018 The American Phytopathological SocietyCited byCandidatus Phytoplasma solani (Stolbur phytoplasma)CABI Compendium, Vol. CABI CompendiumRubbery Taproot Disease of Sugar Beet in Serbia Associated with ‘Candidatus Phytoplasma solani’Živko Ćurčić, Jelena Stepanović, Christina Zübert, Ksenija Taški-Ajduković, Andrea Kosovac, Emil Rekanović, Michael Kube, and Bojan Duduk6 January 2021 | Plant Disease, Vol. 105, No. 2Oxidative Stress and Antioxidative Activity in Leaves and Roots of Carrot Plants Induced by Candidatus Phytoplasma Solani10 February 2021 | Plants, Vol. 10, No. 2

Antifungal activity of two essential oils, cinnamon (Cinnamomum verum J. Presl) and clove (Syzygium aromaticum (L.) Merrill & Perry), was evaluated against Cladobotryum dendroides (Bull.) W. Gams & Hooz, and Lecanicillium fungicola var. fungicola (Preuss) Hasebrauk, the causal agents of cobweb and dry bubble disease of cultivated mushroom. Inhibitory and fungicidal activity of the selected essential oils was assayed using three methods: microdilution, macrodilution fumigant and macrodilution contact method. Comparing all three methods, clove essential oil showed stronger activity than cinnamon against both fungi, having minimum inhibitory concentration (MIC) at the lowest concentrations tested (1.56, 0.02 and 0.1 ?l ml-1, respectively). However, cinnamon oil was more toxic to L. fungicola var. fungicola then to C. dendroides in all three methods. Both oils exhibited stronger antifungal effects when used in the macrodilution fumigant than in contact method. The results showed that both cinnamon and clove essential oils have the potential for further in vivo experiments against L. fungicola var. fungicola and C. dendroides and indicated a possible use of these oils in integrated disease management in mushrooms.

Fifty bacterial isolates obtained from compost were tested in vitro against the causal agents of green mould in Agaricus bisporus. Isolate B-38 which induced 48.08% in vitro growth inhibition of T. harzianum T54 and 52.25% of T. aggressivum f. europaeum T77 was identified as Bacillus subtilis, based on 16S rDNA sequence and used in mushroom growing room experiments. B. subtilis B-38 did not decrease mycelial growth rate of Agaricus bisporus A15 in mushroom compost in glass tubes. After applying prochloraz-manganese, B. subtilis B-38 and B. subtilis QST 713, no significant differences in BE values among treatments were found concerning both total yield and the weight of healthy mushrooms. Statistical analyses showed that only inoculation significantly influenced the healthy mushroom yield. In plots inoculated with T. harzianum T54 disease incidence was significantly lower after treatments with prochloraz-manganese (11.81%), B. subtilis QST 713 (12.26%) and B. subtilis B-38 (14.19%) compared to the control (28.16%), as well as in plots inoculated with T. aggressivum f. europaeum T77 11.88%, 12.2% and 15.03%, respectively, in comparison with the control (23.47%). Statistically significant differences were not found among the efficacy values of tested bio-fungicides based on B. subtilis and the commercial fungicide prochloraz-manganese suggesting the use of B. subtilis B-38 and B. subtilis QST 713 as good alternatives to chemical fungicides.

Monitoring of button mushroom bacterial diseases was conducted to estimate the presence and identity of mycopathogenic bacteria and to determine the predominant bacterial pathogen in Serbia. Samples were collected from mushroom farms during 2006- 2010 and also from fresh markets during 2014-2015. The collected samples showed either symptoms of brown blotch or different degrees of brown discoloration on caps and stalks of Agaricus bisporus resembling bacterial infection. The presence of bacterial droplets on gills was not recorded. The isolated bacteria were Gram-negative and fluorescent on King?s medium B. In pathogenicity tests, most bacterial isolates induced superficial or sunken brown lesions with differences in the level of discoloration on A. bisporus tissue blocks after artificial inoculation. Based on LOPAT characteristics, the isolates were divided into two groups, showing characteristics of either the LOPAT group Va or group III. Based on these features and other differential biochemical characteristics, the presumptive Pseudomonas tolaasii isolates were confirmed by specific PCR. The other group of isolates was subjected to sequencing of the 16S rDNA. Based on these sequences most isolates were identified as Pseudomonas agarici, while two strains belonged to Pseudomonas fluorescens. The survey resulted in detection and identification of P. tolaasii in 11 locations and P. agarici in 7 locations in Serbian mushroom farms. Most samples from fresh markets were infected with P. tolaasii, suggesting that this pathogen has been the predominant cause of bacterial diseases in Serbian mushroom-growing facilities over the past 10 years.

Seven fungicide mixtures (epoxiconazol + metconazole, boscalid + epoxiconazole, pyraclostrobin + epoxiconazole, prothioconazole + tebuconazole, picoxistrobin + cyproconazole, azoxystrobin + cyproconazole and spiroxamine + tebuconazole + triadimenol) were evaluated for control of net blotch of barley caused by Drechslera teres, as well as yield losses, over the 2010 and 2011 growing seasons. Two applications of the fungicide combination pyraclostrobin + epoxiconazole at the rate of 1.0 l ha-1 were the most effective treatment in controlling the disease and improving yield in both experimental years. Treatments with the fungicide mixtures epoxiconazol + metconazole and spiroxamine + tebuconazole + triadimenol showed the least effectiveness in disease control, as well as yield increase.

Disease control with few or no chemicals is a major challenge for mushroom growers in the 21st century. An alarming incidence of resistance to antibiotics in bacteria, and to fungicides among mycopathogenic fungi requires effective alternatives. Previous studies have indicated that various plant oils and their components demonstrate strong antimicrobial effects against pathogens on cultivated mushrooms. The strongest and broadest activity to pathogens obtained from mushroom facilities in Serbia was shown by the oils of oregano, thyme and basil. Five oils inhibited the growth of pathogenic bacteria Pseudomonas tolaasii: wintergreen, oregano, lemongrass, rosemary and eucalyptus. The essential oils of oregano, geranium and thyme were considerably toxic to the pathogenic fungi Mycogone perniciosa, Lecanicillium fungicola and Cladobotryum spp. The strongest activity against Trichoderma aggressivum f. europaeum was shown by the oils of basil and mint. Oils of juniper and pine showed neither inhibitory nor lethal effects on mushroom pathogens. Although the fungitoxic activity of oils is not strong, they could be used as a supplement to commercial productus for disease control, which will minimize the quantity of fungicides used.

The isolation of bacteria was carried out from samples of straw and chicken manure, compost at various stages of the composting process and casing soil used for growing button mushrooms. A preliminary screening of 108 bacterial isolates for antagonistic activity against Trichoderma aggressivum f. europaeum showed that 23 tested isolates inhibited mycelial growth of the pathogenic fungus. Further screening with four indicator isolates of fungi revealed that all 23 bacterial isolates inhibited the growth of T. aggressivum f. europaeum, T. harzianum and T. koningii, while only 13 isolates inhibited the growth of T. atroviride. T. aggressivum f. europaeum proved to be the most sensitive, with many bacterial isolates generating a high percentage of growth inhibition. Only two bacterial isolates (B-129 and B-268) were successful in inhibiting the growth of all 4 tested pathogens. All 23 bacterial isolates were characterized as Gram-positive and catalase-positive and were subjected to molecular identification based on the partial sequence, the hypervariant region of the 16S rDNA. It was shown that the obtained bacterial strains belong to Bacillus subtilis, B. amyloliquefaciens, B. licheniformis and B. pumilus species.

ASBTRACTToxicity of twenty-two essential oils to three bacterial pathogens in different horticultural systems: Xanthomonas campestris pv. phaseoli (causing blight of bean), Clavibacter michiganensis subsp. michiganensis (bacterial wilt and canker of tomato), and Pseudomonas tolaasii (causal agent of bacterial brown blotch on cultivated mushrooms) was tested. Control of bacterial diseases is very difficult due to antibiotic resistance and ineffectiveness of chemical products, to that essential oils offer a promising alternative. Minimal inhibitory and bactericidal concentrations are determined by applying a single drop of oil onto the inner side of each plate cover in macrodilution assays. Among all tested substances, the strongest and broadest activity was shown by the oils of wintergreen (Gaultheria procumbens), oregano (Origanum vulgare), and lemongrass (Cymbopogon flexuosus. Carvacrol (64.0–75.8%) was the dominant component of oregano oils, while geranial (40.7%) and neral (26.7%) were the major constituents of lemongrass oil. Xanthomonas campestris pv. phaseoli was the most sensitive to plant essential oils, being susceptible to 19 oils, while 11 oils were bactericidal to the pathogen. Sixteen oils inhibited the growth of Clavibacter michiganensis subsp. michiganensis and seven oils showed bactericidal effects to the pathogen. The least sensitive species was Pseudomonas tolaasii as five oils inhibited bacterial growth and two oils were bactericidal. Wintergreen, oregano, and lemongrass oils should be formulated as potential biochemical bactericides against different horticultural pathogens.

A study of in vitro sensitivity of five Alternaria solani isolates to cooper-oxychloride, chlorothalonil, difenoconazole, pyraclostrobin and a biofungicide based on tea tree essential oil was carried out. The isolates were obtained from infected tomato leaves collected from five different locations in Serbia. The tested isolates showed the highest sensitivity to pyraclostrobin with EC50 values ranging from 0.0014 to 0.0041 ?g ml-1. The EC50 values of difenoconazole were 0.018-0.037 ?g ml-1, chlorothalonil 2.99-4.54 ?g ml-1, and cooper-oxychloride 13.27-15.63 ?g ml-1. All tested A. solani isolates were the least sensitive to tea tree oil (1323.97-3307.08 ?g l-1).

The most commonly cultivated basidiomycetes worldwide and in Serbia are button mushroom (Agaricus bisporus), oyster mushroom (Pleurotus sp.) and shiitake (Lentinus edodes). Production of their fruiting bodies is severely afflicted by fungal, bacterial, and viral pathogens that are able to cause diseases which affect yield and quality. Major A. bisporus fungal pathogens include Mycogone perniciosa, Lecanicillium fungicola, and Cladobotryum spp., the causal agents of dry bubble, wet bubble, and cobweb disease, respectively. Various Trichoderma species, the causal agents of green mould, also affect all three kinds of edible mushrooms. Over the past two decades, green mould caused by T. aggressivum has been the most serious disease of button mushroom. Oyster mushroom is susceptible to T. pleurotum and shiitake to T. harzianum. The bacterial brawn blotch disease, caused by Pseudomonas tolaasii, is distributed globally. Disease control on mushroom farms worldwide is commonly based on the use of fungicides. However, evolution of pathogen resistance to fungicides after frequent application, and host sensitivity to fungicides are serious problems. Only a few fungicides are officially recommended in mushroom production: chlorothalonil and thiabendazol in North America and prochloraz in the EU and some other countries. Even though decreased sensitivity levels of L. fungicola and Cladobotryum mycophilum to prochloraz have been detected, disease control is still mainly provided by that chemical fungicide. Considering such resistance evolution, harmful impact to the environment and human health, special attention should be focused on biofungicides, both microbiological products based on Bacillus species and various natural substances of biological origin, together with good programs of hygiene. Introduction of biofungicides has created new possibilities for crop protection with reduced application of chemicals.

Potato is one of the most important processed vegetable crops in Serbia. Diseases affecting the crop both in the field and during storage can be limiting factors in sustainable and profitable potato production. Full potential of the crop can be realized only if these diseases are kept under control. Many diseases caused by fungi and pseudofungi are important and require a variety of management practices to reduce them to tolerable economic levels. Such diseases are early blight (Alternaria solani), dry rot (Fusarium sambucinum and Fusarium solani), fusarium wilt (Fusarium sp.), verticillium wilt (Verticillium dahliae and Verticillium albo-atrum), sclerotinia stalk rot (white mold) (Sclerotinia sclerotiorum), black scurf (Rhizoctonia solani), pythium leak (Pythium spp.), powdery scab (Spongospora subterranea f. sp. subterranea), common scab (Streptomyces scabies), and silver scurf (Helminthosporium solani). Different control measures such as cultural practices, planting of tolerant/resistant cultivars, clean seed, crop rotation, and fungicides application are necessary for disease control. This paper highlights the basics of each pathogen and, based on disease epidemiology, the strategies used for control.

Trichoderma species, the causal agents of green mould disease, induce great losses in Agaricus bisporus farms. Fungicides are widely used to control mushroom diseases although green mould control is encumbered with difficulties. The aims of this study were, therefore, to research in vitro toxicity of several commercial fungicides to Trichoderma isolates originating from Serbian and Bosnia-Herzegovina farms, and to evaluate the effects of pH and light on their growth. The majority of isolates demonstrated optimal growth at pH 5.0, and the rest at pH 6.0. A few isolates also grew well at pH 7. The weakest mycelial growth was noted at pH 8.0-9.0. Generally, light had an inhibitory effect on the growth of tested isolates. The isolates showed the highest susceptibility to chlorothalonil and carbendazim (ED50 less than 1mg L-1), and were less sensitive to iprodione (ED50 ranged 0.84-6.72mg L-1), weakly resistant to thiophanate-methyl (ED50 = 3.75-24.13mg L-1), and resistant to trifloxystrobin (ED50 = 10.25-178.23mg L-1). Considering the toxicity of fungicides to A. bisporus, carbendazim showed the best selective toxicity (0.02), iprodione and chlorothalonil moderate (0.16), and thiophanate-methyl the lowest (1.24), while trifloxystrobin toxicity to A. bisporus was not tested because of its inefficiency against Trichoderma isolates.