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1.
Preharvest treatments with low-risk plant protection products can help apple growers fulfill the demands of supermarket chains regarding pesticide residues and marketing apples under 0-residue brands
Andrej Paušič, Mihaela Roškarič, Mario Lešnik, 2023, izvirni znanstveni članek

Opis: As a result of worried consumer pressure, European supermarket chains (ESC) have developed very strict rules about the number and concentration of pesticide active substance residues (AS) accepted in fruits. So-called fruit quality toxicological burden indicators were developed. If fruit suppliers do not comply with ESC requirements, their fruit is often rejected. It is becoming increasingly difficult for apple producers to meet all the requirements of the ESC, so they need new residue reduction tools. One of the options to lower the concentrations of residue on apples is a preharvest application of low-risk preparations (LRP) based on potassium bicarbonate (KHCO3) = PBC, coconut di-ethanol amide ((CH3(CH2)nC(=O)N(CH2CH2OH)2) = DEA, hydrogen peroxide (H2O2) = HP, and a mixture of microbes (EM) that have the ability to dissolve or disintegrate the AS residue. Trials were carried out to test the concept mentioned above. The application of LRP during the last four weeks of preharvest significantly reduced the residue concentration of pesticide AS in apples. Reduction rates among 25 active substances ranged from 0 to 100%, depending on the combination of LRP and AS. HP had the highest capacity to accelerate AS degradation, PB was the second most efficient, and DEA and EM displayed a low residue disintegration ability. The application of the tested LRP can enable apple growers to produce fruits with significantly lower residue concentrations and allows them to comply more successfully with strict ESC rules based on the calculations of toxicological burden indicators.
Ključne besede: hydrogen peroxide, potassium bicarbonate, effective microbes, detergent, pesticide residues, fruit marketing rules
Objavljeno v DKUM: 19.04.2024; Ogledov: 167; Prenosov: 2
.pdf Celotno besedilo (330,68 KB)
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2.
The role of ascorbate–glutathione system and volatiles emitted by insect-damaged lettuce roots as navigation signals for insect and slug parasitic nematodes
Žiga Laznik, Mitja Križman, Jure Zekič, Mihaela Roškarič, Stanislav Trdan, Andreja Urbanek Krajnc, 2023, izvirni znanstveni članek

Opis: The effect of wireworm-damaged lettuce roots on the antioxidative defense system (ascorbate–glutathione cycle, photosynthetic pigments) and movement of insect/slug parasitic nematodes towards determined root exudates was studied in a glasshouse experiment. Lettuce seedlings were grown in a substrate soil in the absence/presence of wireworms (Elateridae). The ascorbate– glutathione system and photosynthetic pigments were analyzed by HPLC, while volatile organic compounds (VOC) emitted by lettuce roots were investigated by GC-MS. Herbivore-induced root compounds, namely 2,4-nonadienal, glutathione, and ascorbic acid, were selected for a chemotaxis assay with nematodes Steinernema feltiae, S. carpocapsae, Heterorhabditis bacteriophora, Phasmarhabditis papillosa, and Oscheius myriophilus. Root pests had a negative effect on the content of photosynthetic pigments in the leaves of infested plants, indicating that they reacted to the presence of reactive oxygen species (ROS). Using lettuce as a model plant, we recognized the ascorbate–glutathione system as a redox hub in defense response against wireworms and analyzed its role in root-exudate-mediated chemotaxis of nematodes. Infected plants also demonstrated increased levels of volatile 2,4-nonadienal. Entomopathogenic nematodes (EPNs, S. feltiae, S. carpocapsae, and H. bacteriophora) proved to be more mobile than parasitic nematodes O. myriophilus and P. papillosa towards chemotaxis compounds. Among them, 2,4-nonadienal repelled all tested nematodes. Most exudates that are involved in belowground tritrophic interactions remain unknown, but an increasing effort is being made in this field of research. Understanding more of these complex interactions would not only allow a better understanding of the rhizosphere but could also offer ecologically sound alternatives in the pest management of agricultural systems.
Ključne besede: lettuce, wireworms, ascorbate–glutathione system, root volatile organic compounds, entomopathogenic nematodes, slug parasitic nematodes
Objavljeno v DKUM: 15.02.2024; Ogledov: 302; Prenosov: 9
.pdf Celotno besedilo (3,96 MB)
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3.
Development of a “0-Pesticide Residue” grape and wine production system for standard disease-susceptible varieties
Mihaela Roškarič, Andrej Paušič, Janez Valdhuber, Mario Lešnik, Borut Pulko, 2023, izvirni znanstveni članek

Opis: In order to realize the goals of the EU Farm to Fork strategy, grape growers are introducing new grape-growing technologies. Among the new trends, "0-pesticide residue" protection is quite a promising one. Field trials were carried out in vineyards located in the Mediterranean part of Slovenia in 2021 and 2022 to test the "0-pesticide residue" (ZPR) grape protection system with the goal of producing wine without pesticide residues above the limit of 0.001 mg kg(-1). The standard integrated grape protection program (IP) was compared to the ZPR program. The level of infection of leaves and grapes by fungal pathogens did not significantly increase due to the implementation of the ZPR spray program. The amount of yield and quality of yield were not decreased significantly, but a small financial loss of EUR 70-400 ha(-1) appeared at ZPR grape production when compared to the IP production system. The ZPR system enabled a significant decrease in pesticide residue concentration in wine at a rate of 27 applied pesticide active substances in a rage from 20% to 99%. The goal of producing wine without pesticide residues above the limit concentration of 0.001 mg kg(-1) was not completely achieved in these experiments, but we came very close to it with the tested spraying programs. Further finetuning of pesticide positioning and alternative plant protection products in 0-pesticide residue systems is needed.
Ključne besede: grape, wine, pesticide, reduction, economics, IPM, alternative plant protection products
Objavljeno v DKUM: 09.02.2024; Ogledov: 301; Prenosov: 12
.pdf Celotno besedilo (1,04 MB)
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4.
Testiranje 0.0-residue pridelave jabolk za zmanjšanje vsebnosti ostankov fitofarmacevtskih sredstev v plodovih : magistrsko delo
Mihaela Roškarič, 2021, magistrsko delo

Opis: Jabolka spadajo s stališča obremenjenosti z ostanki fitofarmacevtskih sredstev (FFS) med najbolj obremenjene kmetijske pridelke. Zato smo v letu 2020 na različnih lokacijah v Sloveniji in na različnih sortah izvedli poskus z vpeljavo 0.0-residue sistema varstva jablan (v nadaljevanju 0.0R). 0.0R lahko ob pravilnem izvajanju občutno zmanjša tako število kot tudi količino ostankov aktivnih snovi FFS v pridelkih. V poskusu smo primerjali rezultate integrirane pridelave (IP) in 0.0R glede pojava škodljivih organizmov (ŠO), višine pridelka, ostankov aktivnih snovi in izgub pridelka zaradi glivičnih okužb v času skladiščenja. Glede pojava ŠO in višine pridelka med testiranima škropilnima programoma v večini ni bilo statistično značilnih razlik, kar pomeni, da je tudi 0.0R lahko zelo uspešen pri varstvu pred ŠO. Glede na ostanke aktivnih snovi so bile razlike med škropilnima programoma večje. Pri sorti 'Jonagold' je bila opazna redukcija ostankov aktivnih snovi pri 0.0R, prav tako pa je le-ta zmanjšal kumulativne vrednosti parametrov MRL (največja dovoljena količina ostankov) in ARfD (akutni referenčni odmerek). Pri sorti 'Zlati delišes' smo kumulativne vrednosti MRL in ARfD zmanjšali za približno 50 % (0.0R), pri sorti 'Fuji' pa je bilo opazno 50 % znižanje števila najdenih aktivnih snovi. Kumulativni MRL in ARfD sta se pri sorti 'Fuji' zmanjšala za približno 30 % (0.0R). Pri sorti 'Evelina' je bila vidna največja razlika glede kumulativnih vrednosti MRL in ARfD, v številu najdenih aktivnih snovi pa ni bilo razlik. Tudi s stališča izgub v skladišču med škropilnima programoma v večini primerov ni bilo statističnih razlik. Glede na rezultate poskusa smo ugotovili, da je 0.0R lahko konkurenčen IP programu varstva jablan.
Ključne besede: 0.0-residue pridelava, jabolka, ostanki fitofarmacevtskih sredstev, integrirana pridelava
Objavljeno v DKUM: 19.11.2021; Ogledov: 1031; Prenosov: 170
.pdf Celotno besedilo (1,96 MB)

5.
Vpliv biostimulatorjev na zatiranje bolezni vinske trte
Mihaela Roškarič, 2019, diplomsko delo

Opis: V letih 2017 in 2018 smo na raziskovalni postaji Meranovo (Prinčev vrh) FKBV UM na vinski trti sorte 'Sivi pinot' izvajali poskuse z biostimulatorji Epin extra®, Cirkon® in Siliplant® ter preverjali njihov vpliv na glive povzročiteljice peronospore vinske trte (Plasmopara viticolaBerl., & de Toni), pepelovke vinske trte (Uncinula necator Burr.) in sive grozdne plesni (Botryotinia fuckeliana Fuck.). Preizkušali smo njihovo samostojno učinkovitost ter učinkovitost v kombinaciji s stoodstotnim odmerkom fitofarmacevtskih sredstev (FFS) ali sedemdesetodstotnim odmerkom FFS. Stopnjo okužbe smo ocenjevali po standardni vizualni metodi z opazovanjem napadene površine listja in grozdja. Učinkovitost škropilnih programov smo računali po standardni Abbotovi formuli, ki upošteva razmerje med stopnjo napada pri škropljenih in neškropljenih variantah. Rezultati kažejo, da dodajanje testiranih biostimulatorjev fitofarmacevtskim sredstvom lahko poveča učinkovitost le teh pri zatiranju preučevanih bolezni. Testirani biostimulatorji pa samostojno niso primerni za zatiranje, saj je njihova učinkovitost v primeru močnega napada bolezni premajhna. Njihov učinek je viden tudi na količini pridelka, le-ta se je povečala pri varianti, kjer smo jih dodali stoodstotnemu odmerku FFS.
Ključne besede: vinska trta, bolezni, biostimulatorji, pridelek
Objavljeno v DKUM: 12.09.2019; Ogledov: 1578; Prenosov: 0

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