Stimulation of wild strawberry (Fragaria vesca) arbuscular mycorrhizas by addition of shellfish waste to the growth substrate: interaction between mycorrhization, substrate amendment and susceptibility to red core (Phytophthora fragariae)

Wild strawberry (Fragaria vesca) microplants were inoculated at establishment in the glasshouse with the commercial inoculants Endorize IV, Vaminoc and Glomus mosseae. After 2 weeks, plants were transferred to control peat-based growth substrate and Suppressor®, a commercial peat substrate amended with chitin-containing shellfish waste. Percentage root length colonisation (%RLC) by Vaminoc and G. mosseae, but not Endorize IV, was stimulated significantly after 4 weeks growth in the amended substrate but there were no significant differences for any of the inoculants at 8 weeks. Runner production in Vaminoc-inoculated plants was unaffected by either growth substrate. Runner production was significantly reduced in Endorize IV and G. mosseae treatments in the control growth substrate, other growth parameters were not significantly affected. Disease resistance to red core was increased by growth of the Vaminoc-inoculated plants for 4 weeks in Suppressor® before challenge in control compost. Neither Vaminoc inoculation nor growth in Suppressor® resulted in increased disease resistance. © 2000 Elsevier Science B.V. All rights reserved.