EMU DSpace
Digitaalarhiiv EMU DSpace kogub, säilitab ja loob ligipääsu Eesti Maaülikooli liikmeskonna poolt loodud või Eesti Maaülikooli vastutusvaldkondadega seotud teadustöödele toetamaks maaülikooli konkurentsivõimet ja teadmistepõhist ühiskonna arengut. Digitaalarhiivi haldab Eesti Maaülikooli raamatukogu.
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Hiljutised sisestused
Kartuli-lehemädaniku tekitaja virulentsus ja patotüüpide koosseis Eesti kartulipõldudel
(Eesti Maaülikool; Maaelu Teadmuskeskus, 2026) Runno-Paurson, Eve; Agho, Collins A.; Niinemets, Ülo; Eesti Maaülikool. Põllumajandus- ja keskkonnainstituut. Taimebioloogia ja maaviljeluse õppetool
Over the past seven growing seasons (2018–2024), weather conditions in Estonia have
been unfavourable for the development and spread of potato late blight pathogen Phytophthora
infestans. This may have created a misleading perception of the potential impact
of this destructive disease. However, as late blight remains a major threat to potato
production and pathogen populations are continuously evolving, ongoing monitoring of
pathogen distribution and population variability is necessary.
The aim of this study was to monitor the frequency of virulence factors (R1−R11) and
race composition and possible temporal changes in P. infestans populations across three
different production systems (breeding/screening, conventional and organic fields)
based on isolates collected from Estonian potato fields over a period a five-year period.
All 11 virulence factors were detected among the collected isolates. The majority of isolates
were virulent against genotypes R1, R3, R4, R7, R10, and R11. Virulence frequency
was low against differential factors R9 (9%) and R5 (15%) and relatively low against
R8 (26%) and R6 (32%). Significant variation in the occurrence of virulence factors was
observed for R5, R6, and R8, however, a clear temporal increase was observed only for
R2, whose frequency increased significantly from 35% in 2010 to 77% in 2014. In the
comparison among production systems, the greatest difference was observed for virulence
factors R2 and R6; with higher occurrence in breeding/screening fields (R2 86%
and R6 49%) than in conventional and organic production fields. The five most common
pathotypes were 1.2.3.4.7.10.11, 1.3.4.7.10.11, 1.2.3.4.6.7.10.11, 1.2.3.4.5.6.7.8.10.11,
and 1.2.3.4.7.8.10.11, accounting for 42% of all isolates. The occurrence of moderately
complex (5–7 virulence factors) and highly complex (8 or more virulence factors) races
varied between years, but remained constantly high throughout the study period. The
proportion of complete pathotype was also high in all production systems, while isolates
with 8 or more virulence factors were most prevalent in breeding/screening fields
(54%). The abundance of unique pathogen types was high (66%), varying between
61–80% across years and 63–70% across production systems, with the highest abundance
in isolated from organic fields.
The presence of highly virulent races in Estonian population indicates a regional threat
and suggests a critical need to adjust disease management approaches, emphasising the
development of novel approaches to sustainable late blight control in Estonian potato
production.
Eesti Vabariik 108
(Eesti Maaülikooli raamatukogu, 2026) Naruskov, Karin
Eesti Vabariigi 108. aastapäeva piduliku sündmuse esitlus.
Kuivlaiksuse esinemine õlikanepil erinevate väetustasemete juures
(Eesti Maaülikool; Maaelu Teadmuskeskus, 2026) Mäeorg, Erkki; Lääniste, Peeter; Nassar, Helina; Kännaste, Astrid; Tedersoo, Leho; Niinemets, Ülo; Runno-Paurson, Eve; Eesti Maaülikool. Põllumajandus- ja keskkonnainstituut. Taimebioloogia ja maaviljeluse õppetool
Oilseed hemp (Cannabis sativa L.) has been considered relatively pest-free so far. Alternaria-
like symptoms were observed on the experimental field of oilseed hemp (cv
‘Finola’) in 2018. The aim of this research was to evaluate the resistance of hemp to
Alternaria leaf spot, and to assess the effects of nitrogen application rate (0–150 kg/ha),
fertilization method (at sowing vs. top dressing), fertilizer type (complex fertilizer vs.
ammonium nitrate) and sowing rate (20–40 kg/ha) on the variation of disease progression.
Within this study Alternaria leaf spot reduced leaf area, plant biomass and seed yield of
oilseed hemp. In addition, strong negative relationship (p<0.001) was found between
disease severity and nitrogen application rate. Although hemp biomass and seed yield
were significantly higher under top-dress fertilization, no clear relationship was observed
between fertilizer type, application timing and disease severity. Furthermore,
sowing rate had a statistically significant effect on the AUDPC value (p<0.001) in each
of the three experimental years. However, it was not a straight-forward trend, indicating
the existence of covariates such as annual weather conditions, plant biomass and related
field microclimate. Although warmer and drier seasons might suppress Alternaria
occurrence, the pathogen is progressively dispersing in the Northern climates. Under
changing climate conditions, continued research on oilseed hemp diseases in essential
to avoid the increased reliance on pesticides in the future. The role of endophytic microorganisms
within hemp microbiome should be considered, when explaining the effects
or developing management strategies.
Rootsi kärbse (Oscinella frit L.) esinemine talinisu ja taliodra põldudel
(Eesti Maaülikool; Maaelu Teadmuskeskus, 2026) Jõgar, Katrin; Annuk, Tiiu; Tennokese, Hanna-Maria; Ploomi, Angela; Eesti Maaülikool. Põllumajandus- ja keskkonnainstituut. Taimetervise õppetool
In Estonia frit fly (Oscinella frit L.) is a common pest of cereals and grasses. The greatest
damage is caused by larvae feeding at the plant growth point, while control options
against them are limited. Although contact insecticides can be used against ovipositing
adults, their effective use requires reliable monitoring methods, which are currently
lacking in Estonia. The results of this experiment showed that throughout the study
period, the highest number of frit fly larvae occurred in fields where winter wheat was
grown as the test crop. Larval abundance of frit fly in winter wheat was nearly twice as
high as in winter barley. This suggests that, among the crops studied, winter wheat provided
the most favourable conditions for frit fly development. Although winter barley
is attractive for oviposition and shoot damage was considerable, larval development in
winter barley may be significantly slower, which likely reduces their survival rates. As
this was a pilot study, no definitive conclusions can be drawn from the present results.
Future studies should also investigate the occurrence and abundance of frit flies in other
winter cereals, such as rye and winter triticale, as well as in grass species.
Mendeli- ja CRE1-tüüpi rapsisortide resistentsus ristõieliste nuutri vastu Eesti põldudel
(Eesti Maaülikool; Maaelu Teadmuskeskus, 2026) Annuk, Tiiu; Loit, Kaire; Eesti Maaülikool. Põllumajandus- ja keskkonnainstituut
Clubroot pressure caused by Plasmodiophora brassicae is high across Estonian oilseed
rape fields, as confirmed by greenhouse biotests using 31 plant- and soil-derived field
populations. The susceptible control cultivar ‘Picard’ was heavily infected in nearly all
samples, indicating a high inoculum potential. Classical Mendel-type resistance (‘Cromat’)
was effective in only 26% of all cases and showed particularly poor performance
against plant-derived isolates (18%), demonstrating that this resistance type is largely
eroded under Estonian conditions.
Extended CRE1-type resistance (‘Credo’) provided a clear but incomplete advantage,
with resistant reactions in 48% of all samples. Its effectiveness was strongly influenced
by disease pressure: resistance was maintained in 71% of soil-derived populations but
dropped to 30% in plant-derived isolates, which were consistently more virulent. Compared
with German monitoring data, Estonian P. brassicae populations appear more
aggressive, suggesting either higher inoculum loads or a higher frequency of resistance-
breaking pathotypes.
For practical farming, these results underline that clubroot management in Estonia cannot
rely on cultivar resistance alone. On infested or high-risk fields, CRE1-type resistant
cultivars should be preferred, but only as part of an integrated management strategy
including extended crop rotation (≥4–5 years without brassicas), soil pH management
above 7.0, effective drainage, and strict machinery hygiene. Under high inoculum pressure,
even extended resistance may fail, making field history and preventive measures
decisive for sustainable oilseed rape production.