Preharvest application with calcium and maturity at harvest affects postharvest fungal fruit decay of European plum

The combination of preharvest treatments with calcium chloride and fungicides, and storage of maturity graded fruit were assessed in five European plum cultivars. At harvest, samples of fruit within a commercially suitable range in ripening were divided into two categories: less-ripe (tree ripe-) and more-ripe (tree ripe+). The fruit were stored for 10–14 days at 4 °C followed by 2–3 days at 20 °C before the assessment of fungal decay. If calcium chloride was applied six times each season, postharvest fruit decay was significantly reduced in four of nine experiments, with a total mean reduction of around 50%. Two calcium applications in combination with a fungicide treatment reduced decay by approx. 60% compared to the untreated in one experiment. In six of seven experiments there was no effect of preharvest fungicide applications. In six of 10 experiments, fruit of the category tree ripe- had fewer fruit with fungal decay after storage than the tree ripe+fruit. The higher incidence in the category tree ripe+fruit was primarily due to brown rot, Mucor rot, and blue mould. For the category tree ripe+, there was two to ten times more decay than on tree ripe- fruit after a simulated shelf-life period. To ensure low incidence of fungal decay, fruit of commercial harvest maturity may thus be separated in two ripening categories, one for rapid distribution to the market (tree ripe+) and another for extended distribution time (tree ripe-).publishedVersio

Strawberry black spot

Jordbærsvartflekk er en farlig sykdom på jordbær. Den er forårsaket av soppen Colletotrichum acutatum. Angrep av sykdommen viser seg ved først brune, senere mere svarte, noe nedsenkede runde flekker på bærene. Etter hvert som flekkene vokser i størrelse kan de omfatte det meste av bæret, som til slutt kan råtne fullstendig. I råteflekkene på bærene dannes det en karakteristisk oransje væske med sporer. Soppen danner mørke, nedsunkne flekker på blad, bladstilker, blomsterstilker og utløpere. Skaden kan forveksles med angrep av gråskimmel. Det kan også dannes en rødbrun, fast råte i rotsokken. Som regel begynner råten på en side nær basis av en bladstilk og brer seg ut i V-form. Hele planta kan visne. Mulighet for å redusere kostnadene ved fornying av enga.JordbærsvartflekkStrawberry black spotpublishedVersio

Sclerophoma sp.

I 2003 vart det funne store mengder sporehus og sporar av soppen Schlerophoma på visnande årsskot av vanleg gran i Vestfold og Rogaland. I 2004 vart det stadfesta Schlerophoma-angrep på nordmannsedelgran i Rogaland.Sclerophoma sp.publishedVersio

Ascospore release by Venturia inaequalis during periods of extended daylight and low temperature at Nordic latitudes

Darkness suppresses ascospore release in Venturia inaequalis, but the impact of light levels during the extended twilight and dusk that typify Nordic spring conditions is poorly understood. Volumetric spore traps were operated at two different locations in Norway over several years. During the season of asocspore release (approximately 1 April to 30 June), on 25 occasions when rain started during night (after 23:00h and before 04:00h) and leaves remained wet until at least midnight the following day, the cumulative percentage of spores trapped at sunrise did not exceed 1%, irrespective of temperature. Three hours after sunrise, cumulative ascospore release reached 0.8%, 3.0%, and 8.1% at temperatures of 0 to 5°C, 5 to 10°C, and >10°C, respectively, and 50% release occurred at 11, 9, and 8h after sunrise. Additional field and laboratory studies indicated that the protracted dawn and dusk of Nordic latitudes, either alone or in combination with low temperatures, does not substantially alter previously reported patterns of ascospore releas

Kabatina spp.

Soppar innan slekta Kabatina har i mange år ført til daude nåler og skot på tuja, einer og sypress i Noreg. I 2002 vart denne soppen også registrert på skadde nåler av nobeledelgran.Kabatina spp.publishedVersio

Phytophthora spp.

Algesoppartar innan slekta Phytophthora gjer stor skade i norske planteskular, klyppegrøntfelt, parkar, anlegg og privathagar. Lawsonsypress er spesielt utsett for denne skadegjeraren.Phytophthora spp.publishedVersio

Pestalotiopsis spp.

Soppen Pestalotiopsis spp. er svært vanleg her i landet, spesielt på ulike bartre. Denne soppen vert ofte omtala som ein sekundær skadegjerar, men spesielt på ulike sypressartar, tyder mykje på at Pestalotiopsis er ein primær skadegjerar

Cytospora sp.

Cytospora sp. er ein svak parasitt, men dersom til dømes frost eller insektangrep har såra plantevevet, kan denne soppen føra til daude nåler og kreftsår på ulike edelgranartar.Cytospora sp.publishedVersio

Fusarium spp.

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Genome analysis of Phytophthora cactorum strains associated with crown- and leather-rot in strawberry

Phytophthora cactorum has two distinct pathotypes that cause crown rot and leather rot in strawberry (Fragaria × ananassa). Strains of the crown rot pathotype can infect both the rhizome (crown) and fruit tissues, while strains of the leather rot pathotype can only infect the fruits of strawberry. The genome of a highly virulent crown rot strain, a low virulent crown rot strain, and three leather rot strains were sequenced using PacBio high fidelity (HiFi) long read sequencing. The reads were de novo assembled to 66.4–67.6 megabases genomes in 178–204 contigs, with N50 values ranging from 892 to 1,036 kilobases. The total number of predicted complete genes in the five P. cactorum genomes ranged from 17,286 to 17,398. Orthology analysis identified a core secretome of 8,238 genes. Comparative genomic analysis revealed differences in the composition of potential virulence effectors, such as putative RxLR and Crinklers, between the crown rot and the leather rot pathotypes. Insertions, deletions, and amino acid substitutions were detected in genes encoding putative elicitors such as beta elicitin and cellulose-binding domain proteins from the leather rot strains compared to the highly virulent crown rot strain, suggesting a potential mechanism for the crown rot strain to escape host recognition during compatible interaction with strawberry. The results presented here highlight several effectors that may facilitate the tissue-specific colonization of P. cactorum in strawberry.publishedVersio