MAT-SLF-Matprogr.:Prosj.fullfin.av SLF

Smarter raspberry production - how to succeed with biennial cropping in Norway This project aims at reducing the risk in raspberry production through increased knowledge among the growers and the agricultural advisory service (NLR) on three topics: -Optimal cane density -Pros and cons of biennial cropping (i.e., growing primocanes and floricanes in separate rows) -Rubus stunt phytoplasma (a plant disease giving substantial losses for some growers in recent years) In traditional raspberry production, primocanes (one year old canes, not bearing fruits) and floricanes (two year old canes, bearing fruits) are grown in the same row. In biennial cropping, only canes of the same age are kept in the row, and after harvest, every second year, all above ground plant material is removed. This allows more efficient picking and floricane removal, as well as more targeted plant protection measures and less opportunity for pests and diseases to spread from old to new shoots. In both growing techniques it is important to know the optimal cane density. A too low density does not fully exploit the yield potential, whilst a too high density promotes cane diseases that lead to higher winter mortality. Rubus stunt phytoplasma leads to many small and thin shoots with less yield, and can spread with plants or with insect vectors. This disease has increased in importance lately. Norwegian raspberry production is characterized by a combination of cold climate, Glen Ample as the dominating cultivar, and high labour costs. This calls for a national investigation of the three topics mentioned above to supplement results known from other countries. Eight growers, as well as NIBIO Apelsvoll, have conducted test plots with biennial cropping (three cane densities), and five also with traditional cropping (three densities). The test plots are in high polytunnels or open field, and are situated in South-Eastern, Western and Northern Norway. Two more growers participate due to their problems with Rubus stunt phytoplasma. All test plots (in experimental tunnel at NIBIO Apelsvoll, and in the six growers fields) were recorded over a period of four seasons, with two cropping years. Yield, phenology, plant architecture, and occurrence of cane diseases and spider mites were recorded. In the field of one of the growers practicing biennial cropping only, time spent on picking and post-harvest removal of floricanes was measured.In both cropping years, berry yields per unit area were about 20% higher in the biennial cropping system, whereas yields per shoot were not different in the two systems. In both cropping systems, yields per shoot strongly declined with increasing shoot density, while yields per metre row increased slightly. Regardless of cropping system, yields per metre row did not increase with increasing shoot density beyond eight shoots per metre. The concentrations of dry matter, soluble solids, titratable acidity and ascorbic acid as well as the intensity of juice colour all declined with increasing shoot density. We conclude that under controlled shoot density conditions, there is little scope for biennial yield increases that fully compensates for the lost crops every second year. However, the system greatly facilitates berry harvest and eases plant disease pressure. In 2017, resistance in grey mould against fungicides used against this disease was investigated by sampling from test fields with biennial growing. Our hypothesis is that less resistance will be found in these fields than in traditional ones, as a reduced spraying programme is conducted in biennial growing. In 2015, NIBIO started a cage-experiment to verify that the leafhopper Macropsis fuscula, the reported vector of Rubus stunt phytoplasma in other European countries, can transmit the disease in Norway as well. We collected specimens in a raspberry crop totally infected with phytoplasma and introduced them to healthy young primocanes of two cultivars, from Sagaplant. No phytoplasma was detected in the year following the inoculation. The experiment was repeated in 2016 and 2017, including a couple of other leafhopper species. NLR has also revisited some of the growers visited earlier in the project, to map the development in number of affected plants. The biennial growing technique was presented in the grower journal «Norsk Frukt og Bær» in October 2017 and in March 2018. Results were presented at the annual Norwegian berry seminar in March 2018, as well as in a final seminar for project participants in October 2018.

Bringebærdyrking er kostnads- og arbeidskrevende.Næringens hovedmål er å kunne utøve en dyrkingspraksis som gir stabil avling, og som er høy nok til å gi dyrkerne en stabil god inntekt og avkastning på investert kapital. Prosjektet Smartere bringebærdyrki ng er et viktig bidrag for å nå et slikt mål. Bringebær er en toårig plante. I tradisjonell bringebærproduksjon har hver planterad (hekk) både nye og bærende skudd samtidig. Ved for lav skuddtetthet utnyttes ikke potensialet i plantene, mens for høy skudd tetthet fører til dårligere kvalitet på avlingen og økt risiko for skuddsjukdommer. Skuddsjukdommer øker blant annet vinterdødeligheten. Ved såkalt annethvertårs-bæring er alle skuddene i hekken jevnaldrende, og etter høsting hvert annet år kan hekken kli ppes helt ned. Hvis gjort riktig, kan annethvertårs-bæring gi mer stabil avling og mer rasjonelt plantestell gjennom sesongen. Behovet for plantevernmidler er mindre, fordi sprøytingen kan målrettes for én type skudd, og fordi skadegjørerne får lengre smi ttevei fra gamle til nye skudd. Forskningsutfordringen er å finne hvordan potensialet til begge dyrkingsformene kan realiseres best mulig under norske klima- og dyrkingsforhold. Trolig vil annethvertårs-bæring som dyrkingsmetode være godt tilpasset økolog isk produksjon på grunn av et lavere smittepress av viktige skadegjørere. 11 bringebærdyrkere vil være med i prosjektet. Dvergsjuke i bringebær har vært beskrevet som forekommende i flere europeiske land, også i Norge, men har i liten grad fått oppmerkso mhet. De to siste årene har vi imidlertid sett flere utbrudd på Østlandet. I første omgang må forskningen finne ut hvilke smitteveier og fytoplasma-arter som finnes i norske bringebær. Er det vanlig med fytoplasma i villbringebær, hvilke mulige insektvekt orer finnes i norske felt, og er hovedsorten Glen Ample spesielt utsatt for sjukdommen? Tiltrekkes mulige vektorer av mer vegetativ vekst utover høsten, slik det vil være i skuddoppalet i annethvertårs-bæring?