The withdrawal of soil fumigants like methyl bromide is forcing strawberry growers to consider supplementary and alternative ways of producing crops. In addition to controlling soil-borne pests, soil fumigation causes an increased growth response in strawberry roots, and the use of biostimulants may offer an alternative to replace this response. We tested the hypothesis that treatment with a commercial extract (Seasol®) from the seaweeds Duvillaea potatorum and Ascophyllum nodosum can increase root growth, and transplant (runner) and fruit yields of strawberry. From 2014 to 2016, we conducted three field trials on strawberry farms in the nursery sector at Toolangi and in the fruiting sector at Coldstream in Victoria, Australia. We applied the seaweed extract as a monthly drench (10 L ha−1) to two cultivars of strawberry (‘Albion’ and ‘Fortuna’), compared with an untreated control. In the nursery sector, use of the extract significantly increased the density of secondary roots (feeder roots) on harvested runners by up to 22%. Treatment with the extract also significantly increased yields of marketable runners by 8–19%. In the fruit sector, use of the extract significantly increased the root length density (root length per volume of soil) of strawberry plants by 38% and marketable fruit yields by 8%. Root length density at final harvest and marketable fruit yield of strawberry were highly correlated (r = 0.94). This relationship provides an insight into the mode of action of seaweed extracts and is discussed. Overall, the results show the potential benefits of the integrated use of seaweed extracts in strawberry production across the nursery and fruit sectors, and their promise for supplementing or replacing the increased growth response provided by soil fumigants.

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At the micropropagation laboratory of the Potato Research Centre in Gucha, the following five virus-free in vitro potato cultivars are produced: 'Desiree', 'Kennebec', 'Agria', 'Cleopatra' and 'Sinora'. Acclimatized and rooted plants were transplanted and grown in the three production systems: 1) the aeroponic system, 2) the substrate system, and 3) a combination of the substrate and aeroponic systems. The results obtained indicate that the cultivation system exerts a significant effect on the number and the total yield of potato mini-tubers. In the aeroponic production system, 4.08 times as many mini-tubers were produced compared to the number of mini-tubers produced in the substrate system, whereas 1.29 times as many mini-tubers were produced compared to the number of mini-tubers produced in the combined production system (substrate + aeroponics). The aeroponic mini-tuber production system offers an opportunity to improve the production of seed potatoes in Serbia..