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Biological control of fungal diseases of edible mushrooms
No full textThe production of button mushroom (Agaricus bisporus) is severely afflicted by fungal pathogens able to cause diseases that affect yield and quality. Major A. bisporus fungal pathogens are Mycogone perniciosa, Lecanicillium fungicola, Cladobotryum spp. and various Trichoderma species. The usual method of disease control on mushroom farms worldwide is based on the use of fungicides. However, development of pathogen resistance to fungicides after frequent application, and host sensitivity to fungicides are serious problems. Disease control with few or no chemicals is a major challenge for mushroom growers in the 21st century. Only a few fungicides are officially recommended in mushroom production: chlorothalonil, thiabendazol and tiophanate-methyl in North America and prochloraz and metrafenone in European Union and many other countries. Considering such resistance development, harmful impact to the environment and human health, special attention have been focused on biofungicides, together with good programs of hygiene. Previous studies have indicated that various biological agents seem to be suitable eco-friendly alternative as demonstrated strong antifungal effects against pathogenic fungi on cultivated mushrooms. Two groups of biofungicides are mainly used, microbiological products based on antagonistic microorganisms (Streptomyces spp., Bacillus spp., etc.) and various biochemicals, substances of biological origin (plant extracts, essential oils, etc.). The introduction of biofungicides has created new possibilities for crop protection with reduced application of chemicals
Acceptability of wheat baits pre-treated with high temperature and humidity to commensal rodent species
No full textExtreme environmental conditions, i.e. high humidity and temperature,
rapidly degrade baits, which results in failed eradication programmes. The
present study aimed to determine the time period over which grain maintains
freshness after exposure to detrimental environmental conditions, and
acceptability of such baits to house mice and brown rats.
Ten wild-born house mice (Mus musculus) and eight wild-born brown rats
(Rattus norvegicus) were used in a choice-test. Placebo and challenge baits
were offered daily. Broken wheat was used in placebo bait, while challenge
bait had the same component but was pre-exposed to 32º C temperature and
80–95% humidity. Challenge bait pre-treated for 24 h with high temperature and humidity was offered on the first day, while pre-treatment of baits laid on each consecutive day was successively 24 h older. The average acceptability of baits offered to house mice and rats in the first four days ranged from 23.69% to 72.23 %, and from 75.94% to 82%, respectively. Acceptability by mice was merely 4.66% on the fifth day, and decreased further to 0.44% on the following day, while the consumption was terminated on the seventh day. Acceptability by rats on the fifth day was 12.38% and consumption of the bait ceased on the sixth day.
Additives suppressing mold and decay will significantly improve effectiveness of baits used in control programs, but the issue requires further research
Prevazilaženje rezistentnosti na antikoagulantne rodenticide u populacijama komensalnih vrsta glodara
No full textUpotreba rodenticida predstavlja najviše primenjivan način suzbijanja štetnih glodara. Pojava
rezistentnosti u populacijama glodara je najčešći uzrok smanjene efikasnosti suzbijanja. Antikoagulanti,
na koje je razvijena rezistentnost, deluju selektivno prouzrokujući uginuće osetljivih jedinki pri
čemu utiču na širenje rezistentnih alela u populacijama glodara.
Isključivanje antikoagulanata iz primene, na koje je rezistentnost već razvijena, ima veliki značaj
za gubitak rezistentnih alela u populaciji. Međutim, potpuno isključivanje antikoagulanata na
duži vremenski period uglavnom nije ekonomski prihvatljivo s obzirom na nedovoljnu efikasnost
samostalno primenjenih nehemijskih metoda suzbijanja i ekonomske gubitke koje u tom slučaju
mogu naneti komensalne vrste glodara kao što su domaći miš (Mus musculus) i sivi pacov (Rattus
norvegicus) usled oštećenja i zagađenja uskladištenih proizvoda kao i negativnog uticaja na zdravlje
ljudi i domaćih životinja.
Do gubitka rezistentnih alela u populacijama glodara može doći ukoliko se u primenu uvedu
druge efikasnije metode, uključujući i primenu rodenticida na koje nije razvijena rezistentnost. Stalnim
monitoringom kao i kombinovanjem hemijskih i nehemijskih metoda suzbijanja značajno će se
doprineti smanjenju širenja rezistentnih alela unutar populacije što predstavlja značajan doprinos
u suzbijanju rezistentnih jedinki na lokalitetima gde to primenom određenih rodenticida više nije
moguće
Effects of bifenthrin formulation with natural zeolite on Sitophilus oryzae (L.), Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst) in wheat grain
No full textEffects of the insecticide bifenthrin (BIF) formulated with natural zeolite (NZ)
were examined in the laboratory (T=25+1°C and 60+5% r.h) to find out potential improvements
of ће existing management programmes for 5. oryzae, R. dominica and T. castaneum.
Adults of each insect species separately were released into wheat grain (12.5% m.c.) treated
with bifenthrin (0.3 %) and two fractions of natural zeolite (particle sized 20 џт апа 100-
300 шт) at the doses of 0.075, 0.15 and 0.3 g/kg. Their combined effects were determined
after 7 and 14 days of exposure, as well as impact on F1 progeny production/reduction percentage
(%). The results showed that the mortality of adults of all insect species increased
with exposure duration, especially of T. castaneum. After both exposure periods, mortality
of S. oryzae and R. dominica adults was high, 87-100%, while it was 63 and 79 % at the lowest
application rate of bifenthrin (0.075 g/kg), and 66 and 100 % when the NZ particle size was
100-300 шт. Also, а high progeny reduction of 98-100% was found in both species, except
1 5. oryzae when the lowest BIF application rate ап the larger NZ particle size were used,
when it reached 81%. Тће mortality ог T. castaneum adults after 7 days of exposure was low,
merely 0-50%, while it reached 100 % after 14 days, but only at the application rate of 0.3
g/kg NZ with BIF in wheat grain. Also, a full progeny reduction of 100 % was found in all
variants о ће experiment with T. castaneum adults
Sensitivity of the mycelia of plant pathogenic fungi to low temperature
No full textOver the last decade Serbia is among top world producers and exporters of raspberry. According to the FAOSTAT
official data, an average production in the period 2004/2014 was 77,988 tons on the area of about 15,000 ha.
'!be whole production is realized on properties of individual farmers, while a negligible amount is produced
by small or medium companies. Plant disease causal agents severely affect raspberry production in all growing
regions. Gray mold, caused by a phytopathogenic fungus Botrytis cinerea, is the major fruit disease, whereas spur
blight, caused by Dydimella applanata, is by far the most important cane disease. Both species overwinter on
diseased plant debris in the soil or in infected plant parts in the form of overwintering structures or mycelium.
However, it is very difficult to claim that mycelium of the phitopathogenic fungi is the one that survives low
winter temperatures. Instead, survival in plant material could be an outcome of the presence of hlamidospores,
microsclerotia or some other overwintering structures. The fact that fungal pathogens survive short-term freezing
in plant material is successfully used for the detection oflatent infections in fruits and seeds. On the other hand,
how long a young mycelium can survive exposure to freezing temperature is still unknown. Therefore, the aim of
this study was to determine minimum freezing duration that had lethal effect to the mycelium of B. cinerea and D.
applanata. Mycelium of B. cinerea and D. applanata, isolates, grown on· PDA for three or seven days respectively,
was inoculated on PDA plates and exposed to the temperature of -20 •c for 1-50 days. Afterwards, survival
of the mycelium was assessed by additional 7-day incubation at 20°C and regrowth observation. The results
showed that all tested isolates could not survive the temperature of -20 •c longer than 44 days. The differences
between species, as well as among isolates of the same species will be discussed. The article is the result of activities
within the project III46008 funded by the Ministry of Education, Science, and Technological Development of the
Republic of Serbia
Effects of antagonistic bacteria and their mixtures on Monilinia fructicola
No full textPostharvest losses, caused by fungal diseases, are the major factor limiting the
storage period and market life of stone and pome fruits. Currently, the control of postharvest
decay is mainly based on the use of synthetic fungicides during growing season. In recent
years, the use of microbial biofungicides has increased continuously due to public concerns
regarding the risk of pesticide residues in food and their negative impact on the environment.
One of the main practical constrains in the use of microbial biopesticides is their
variable efficacy, mainly because of unfavorable environmental effects on their activity and
survival. To practically solve this problem, a combination of two or more microorganisms
has been proposed. The aim of this study was to test a hypothesis that a mixture of two microorganisms
with profound antimicrobial properties could improve their effectiveness under
different environmental conditions. In vitro antagonistic activity assays were performed
at three different temperatures, 12°C, 24°C and 30°C, using wells technique. As a model
organism Monilinia fructicola was used. Based on antagonistic effect, seven of 108 strains
were chosen for further studies and identified to the species level. The results showed that
the temperature significantly affects antimicrobial activity of the strains, and that the effectiveness
of the studied strains in vitro was not improved by their combined use regardless
the temperature
Essential oils as an alternative bactericides against soft-rot bacteria, Pectobacterium carotovorum subsp. carotovorum
No full textBacterial soft-rot disease caused by Pectobacterium carotovorum subsp. carotovorum is a
very destructive disease with a diverse host range in agricultural crops, during the plant growth in
the field and in storage. Control, usually based on the use of chemical products, is not satisfactory
because of their harmful effect on human health and environment, as well as the possibility for
pathogen resistance development. Therefore, developing of new natural products (such as
essential oils-EOs, plant extracts etc.) with a sufficient efficacy in control of the disease was
imposed. The current study included in vitro testing of bactericidal activity of 51 different oils
against P. c. subsp. carotovorum, using an agar-diffusion assay. Bacterial suspension was mixed
in Nutrient Agar to final concentration of 107-108 cells/mL and poured in sterilized Petri plates (ø
90 mm). After media solidified, sterile filter paper discs (ø 5 mm) were placed on the surface of
the Petri plates and supplemented with 20 μL of each tested oils. The experiment was performed
in a completely randomized design. The results were expressed as a width of inhibition zone
(mm) and analyzed by one-factor analysis of variance by using the software package Statistica
7.0 (StatSoft, Inc.). Results showed that the 7 most efficient EOs against P. c. subsp.
carotovorum (Thymus vulgaris, Cinnamomum cassia, Cassia angustifolia, Origanum vulgare,
Boswellia serrata, Eucalyptus globulus, Satureja montana, respectively) achieved inhibition zone
greater than 20 mm. Inhibition zones in the range of 15-20 mm were achieved by 8, 10-15 mm by
9, and less than 10 mm by 6 EOs. The rest of 21 Eos did not show any bactericidal effect
Field dodder life cycle and interaction with host plants
No full textVilina kosica je parazitska cvetnica koja se vezuje za stablo i lišće biljaka domaćina i parazitira značajan broj ekonomski značajnih vrsta, korove i ukrasno bilje. Postoje različite mere koje se mogu preduzeti za suzbijanje viline kosice, počev od preventivnih (čist semenski materijal, otporne sorte), preko mehaničkog uklanjanja (košenje, ručno uklanjanje) do korišćenja herbicida, ali je veoma teško postići efektivnu kontrolu ove parazitne cvetnice, zbog prirode vezivanja sa biljkom domaćinom. Za pravljenje dobre strategije u suzbijanju viline kosice pored integrisanja gore pomenutih mera, neophodno je i poznavanje njenog razvoja i životnog ciklusa.Field dodder is a parasitic plant that attaches to stems and leaves of broadleaf plants, including weeds, field crops, vegetables and ornamentals, across most agricultural regions of the world. Effective field dodder control is extremely difficult to achieve due to the nature of attachment and close association between the host and the parasite, which require a highly effective and selective herbicide to destroy the parasite without damaging its host. To establish a strategy for controlling parasite growth and restricting the spread of field dodder in crop fields, it is important to learn more about this weed, its life cycle and development
Toxicity of clomazone and its formulations to zebrafish embryos (Danio rerio)
No full textHerbicides are the most widely used group of pesticides but after reaching water bodies they are able to cause adverse effects on non-target organisms. Different formulations using the same active ingredient are frequently available, which raises the issue of potential influence of different formulation types on herbicide toxicity. The present study evaluated the toxicity and teratogenic effects of the active ingredient clomazone and its two formulations (Rampe (R) EC and GAT Cenit 36 CS, both containing 360 g a.i./l of clomazone) on zebrafish embryos. The crucial difference between the two formulation types is the way of active substance release. This investigation is the first report on zebrafish embryotoxicity of both clomazone and its formulations. The technical active ingredient and formulations caused mortality and diverse teratogenic effects, showing different levels of toxicity. The LC50 values for the technical ingredient, Rampa (R) EC and GAT Cenit 36 CS were 61.4, 9.6 and 92.5 mg a.i./l, respectively. Spontaneous movements in 22 hpf embryos decreased under exposure to both the technical ingredient and formulations. A significant number of underdeveloped embryos was detected after exposure to clomazone and Rampe EC, while no underdevelopment was noted in embryos exposed to GAT Cenit 36 CS. Exposure to the technical ingredient and formulations led also to a series of morphological changes and interfered with the growth of zebrafish embryos. The EC50 based on detection of edemas, spine and tail tip deformations and gas bladder absence (120 hpf) was 12.1, 10.1 and 24.1 mg/l for technical clomazone, Rampe EC and GAT Cenit 36 CS, while teratogenicity index (TI) based on LC50/EC50 ratio was 5.1, 1 and 3.8, respectively. The data in this study showed that the emulsifiable concentrate formulation (Rampa. EC) caused statistically significantly higher toxicity, and the aqueous capsule suspension (GAT Cenit 36 CS) lower toxicity than technical clomazone. It indicates that different formulations with the same active ingredient may have different environmental impacts, which is why risk assessment based only on active ingredient toxicity might not be sufficient in terms of preventing formulation effects on the environment.Published version: [https://ripest.pesting.org.rs/handle/123456789/406]This is the peer-reviewed version of the article: Stevanović, M., Gašić, S., Pipal, M., Blahova, L., Brkić, D., Nešković, N., & Hilscherova, K. (2017). Toxicity of clomazone and its formulations to zebrafish embryos (Danio rerio). Aquatic Toxicology, 188, 54–63.[ https://doi.org/10.1016/j.aquatox.2017.04.007
Acaricidal and sublethal effects of biopesticides on Tetranychus urticae Koch (Acari: Tetranychidae)
No full textAkaricidni i subletalni efekti komercijalnih preparata biopesticida na bazi oksimatrina, azadirahtina, spinosada i entomopatogene gljive Beauveria bassiana na običnu grinju-paučinara Tetranychus urticae Koch (Acari: Tetranychidae) ispitivani su u laboratorijskim biotestovima, u cilju kompletiranja profila njihove biološke aktivnosti kao osnove za definisanje održive strategije primene. Biotestovi su izvedeni na temperaturi 27±2°C i relativnoj vlažnosti 50-70% uz fotoperiod svetlo/tama 16h/8h. Biopesticidi su aplicirani prskanjem lisnih isečaka (prečnika 30 mm) ili celih primarnih listova pasulja, postavljenih adaksijalno u Petri sudove, pomoću aparata Potter Tower (2 ml tečnosti, pritisak 100 kPa, vodeni depozit 2,7 mg/cm2). Toksičnost biopesticida za životne stadijume T. urticae ocenjena je izvođenjem biotestova u kojima su jaja, juvenilni stadijumi (larve, protonimfe, ženke deutonimfe) ili odrasle preovipozicione ženke tretirane serijom simetrično raspoređenih koncentracija, a dobijeni podaci obrađeni postupkom probit-analize. Nijedan od ispitivanih biopesticida nije uzrokovao značajnu ovicidnost, već je akaricidni efekat nastao usled rezidualnog delovanja biopesticida na larve ispiljene iz tretiranih jaja. U svim biotestovima direktno tretirane larve bile su najosetljiviji životni stadijum. Direktno tretiranje preovipozicionih ženki preparatima na bazi azadirahtina i B. bassiana uzrokovaloje RO-efekat („run-off“-efekat: napuštanje tretirane površine) kao dominantan u odnosu na smrtnost. Vrednosti LC90 za preparat na bazi oksimatrina bile su znatno niže od koncentracije preporučene za primenu (2 ml/l), dok su kod spinosada bile više od preporučenih koncentracija (60-300 mg/l). Vrednosti LC90 za azadirahtin bile su niže a vrednosti EC90 za RO-efekat ovog biopesticida viša od preporučene koncentracije (50 mg/l a.m.). U biotestovima sa preparatom na bazi B. bassiana sve LC/EC90 vrednosti (osim za LC90 za larve) bile su više od preporučene koncentracije (3 ml/l). Repelentnost i ovipoziciona deterentnost biopesticida ocenjena je izvođenjem biotesta sa mogućnošću izbora u kojem su preovipozicione ženke postavljane na centralni nerv lista čija je samo jedna polovina tretirana; broj ženki i broj položenih jaja utvrđivani su posebno na tretiranoj i netretiranoj polovini lista posle 24, 48 i 72 h. Značajne repelentne i deterentne efekte (posle 24 h i kumulativno za ceo period) uzrokovale su serije koncentracija preparata na bazi oksimatrina (0,5-2 ml/l), azadirahtina (1,56-50 mg/l a.m.) i B. bassiana (0,82-7 ml/l). Efekti biopesticida na životne parametre i populacioni rast T. urticae ocenjeni su izvođenjem dve varijante biotesta u kojima su ženke koje su preživele tretiranje u stadijumu jajeta starosti do 24 h i izloženost reziduama tokom juvenilnog razvića (prva varijanta) ili preovipozicionom periodu (druga varijanta) prebačene na netretiranu površinu na kojoj su tokom perioda od sedam dana dnevno utvrđivani broj položenih jaja i broj živih ženki.Preparat na bazi oksimatrina (0,025-0,1ml/l) značajno je redukovao fekunditet, dužinu života ženki i trenutnu stopu rasta (ri), posebno u drugoj varijanti gde je zabeležena negativna rivrednost. Značajna redukcija ovih parametara zabeležena je i u biotestovima sa preparatima azadirahtina (prva varijanta: 3,75-15 mg/l a.m; druga varijanta: 17,5-70 mg/l a.m.), spinosada (60-240 mg/l a.m.) i B. bassiana (1,5-6 ml/l). Efekti biopesticida na prirodnu stopu rasta (rm) i druge demografske parametre T. urticae ocenjeni su formiranjem tabela života sa podacima o uzrasno-specifičnim stopama preživljavanja i fertiliteta (produkciji ženkog potomstva) ženki preživelih tretiranje u stadijumu jajeta starosti do 24 h (prva varijanta) ili preovipozicionom periodu (druga varijanta). Demografski biotestovi sa preparatima oksimatrina (0,05 ml/l), azadirahtina (prva varijanta: 7,5 mg/l a.m; druga varijanta: 35 mg/l a.m.) pokazali su da ovi biopesticidi redukuju populacioni rast redukujući fertilitet i stope preživljavanja, ali i usporavajući juvenilno razviće jedinki ispiljenih iz tretiranih jaja. Značajna redukcija demografskih parametara zabeležena je i u obe varijante biotesta sa preparatom na bazi B. bassiana (3 ml/l). Preparat spinosada (120 mg/l a.m.) takođe je značajno redukovao demografske parametre nakon tretiranja u preovipozicionom periodu, dok je tretiranje u stadijumu jajeta povećalo rm vrednost preživelih jedinki, zahvaljujući većem fertilitetu na početku perioda reprodukcije tretiranih ženki. Dobijeni rezultati razmatrani su u kontekstu populacione strukture i dinamike T. urticae kao kolonizirajuće vrste i heterogene distribucije aktivne materije u uslovima praktične primene.Acaricide and sublethal effects of several commercial biopesticide products based on oxymatrine, azadirachtin, spinosad and the entomopathogenic fungus Beauveria bassiana on the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) were examined in laboratory bioassays in order to round off a profile of their biological activity as a basis for defining a sustainable application strategy. Bioassays were performed at 27±2°C temperature, 50-70% relative humidity and 16h/8h light/dark photoperiod. The biopesticides were sprayed on bean leaf discs (30 mm in diameter) or intact leaves positioned adaxially in Petri dishes using a Potter Tower device (2 ml liquid, 100 kPa pressure, 2.7 mg/cm2 water deposit). Toxicity of the biopesticides to different stages of T. urticae mites was assessed in bioassays in which eggs, juvenile stages (larvae, protonymphs, female deutonymphs) or adult preovipositing females were treated with a series of symmetrical concentrations, and the data were processed by probit analysis. None of the investigated biopesticides caused a significant ovicide effect, while acaricide effects resulted from their residual effects on larvae hatched from the treated eggs. In all bioassays, directly treated larvae were found the most sensitive life stage. Direct treatment of preovipositing females with azadirachtin and B. bassiana products caused a run-off effect which was dominant compared to mortality. The LC90 values of the oxymatrine product were significantly lower than its recommended concentration (2 ml/l), while those of spinosad were higher than the recommended concentration (60-300 mg/l). Azadirachtin LC90 values were lower and those of its RO-effect higher than the recommended concentration (50 mg/l a.i.). In B. bassiana bioassays, all LC/EC90 values (except LC90 for larvae) were higher than the recommended concentration (3 ml/l). Repellence and ovipositional deterrence of the biopesticides were assessed in bioassays in which preovipositing females were offered a choice by releasing them onto the central nerve dividing each leaf into a treated and untreated half; and the number of females and eggs were counted on each half after 24, 48 and 72 h. Significant repellent and deterrent effects (after 24 h and cumulative over the entire period) were caused by oxymatrine (0.5-2 ml/l), azadirachtin (1.56-50 mg/l a.i.) and B. bassiana (0.82-7 ml/l) concentration series. Biopesticide effects on the life-table parameters and population growth of T. urticae were evaluated by conducting two variants of bioassay in which females that survived treatment at the 24h-old egg stage and were exposed to residues over their entire juvenile development (first variant) or during preovipositing period (second variant) were transferred to untreated surface on which the number of eggs they laid and live females were counted daily for seven days. The oxymatrine product (0.025-0.1ml/l) significantly reduced fecundity, life span and instantaneous rate of increase (ri), particularly in the second variant, in which a negative ri was found. Significant reduction in these parameters was also detected in bioassays testing azadirachtin (first variant: 3.75-15 mg/l a.i; second variant: 17.5-70 mg/l a.i.), spinosad (60-240 mg/l a.i.) and B. bassiana (1.5-6 ml/l). The effects of the biopesticides on intrinsic rate of increase (rm) and other demographic parameters of T. urticae were assessed by constructing life-tables that included age-specific survival and fertility rates (female offspring production) of females that survived treatment at the egg stage of up to 24 h (first variant) or during preoviposition (second variant). Demographic bioassays with oxymatrine (0.05 ml/l) and azadirachtin (first variant: 7.5 mg/l a.i; second variant: 35 mg/l a.i.) showed that these two biopesticides reduced population growth by suppressing fertility and survival rates, but also by slowing down the juvenile development of mites hatched from treated eggs. Both bioassay variants testing B. bassiana (3 ml/l) also showed significant reductions in demographic parameters. Spinosad (120 mg/l a.i.) also significantly reduced those parameters after treatment at the preovipositing period, while treatment at the egg stage increased the rm values of the surviving mites, owing to the higher fertility of treated females at the beginning of reproduction. The results were discussed in terms of population structure and dynamic of T. urticae as a colonizing species and the heterogenous distribution of active ingredients under practical conditions