Cultural practices and microbial inoculants have variable impact on a bedding plant (Lantana camara L.) performance in the landscape

Abstract

Microbial inoculants are commercially-available products which have been promoted as biofertilizers, biopesticides, and phyto-stimulators. Research efforts have primarily focused on microbial inoculant performance on food crops and there has been limited information regarding their effectiveness on ornamental and bedding plants. We assessed the impact of two microbial inoculants: Companion® Biological Fungicide and Effective Microorganisms-1® on the growth of an annual bedding plant, Lantana camara L. under varying irrigation and fertilizer regimes and with or without presence of organic soil amendment. Both microbial inoculants appeared to positively boost growth index when compared to untreated plants in 2016. However, in 2017, both of these growth parameters were higher in untreated plants and in those treated with Companion® Biological Fungicide. We found that under low supplemental irrigation (2.54 cm water/per week) and low nutrition (1 lb 10N-10P2O5-10K2O per 9.29 m3 applied at transplant) and in a growing season with normal rainfall (approximately 30 cm), microbial inoculants could offer slightly improved growth and number of inflorescences in lantana. However, in the second year of the study, when there was above normal rainfall (over 60 cm June-October), plants receiving no microbial inoculant exhibited highest growth index and number of inflorescences. Our findings suggest that the use of microbial inoculants in a regular maintenance program should be evaluated after determining product and application costs as well as landscape environmental and cultural conditions.