Harnessing Nature’s Arsenal to Combat Invasive Gutenbergia cordifolia

A new study by Sarah Mero and her team, published in Acta Oecologica, has uncovered innovative ways to control the invasive Gutenbergia cordifolia plant. By using natural extracts from the Artemisia annua plant, controlling fire regimes, and manipulating shade conditions, researchers have identified potential environmentally-friendly methods to suppress this invasive species, which could help preserve native plants and animals.

Gutenbergia cordifolia is a problematic invasive plant in Tanzania, where it is rapidly replacing plants that local herbivores eat. Until now, little was known about its preferred environmental conditions and non-chemical control methods. Mero’s team investigated the effects of Artemisia annua crude extract concentrations, synthetic herbicides, fire regimes, and shade on Gutenbergia cordifolia’s growth.

The results showed that high concentrations (75%) of Artemisia annua crude extracts significantly reduced the germination of Gutenbergia cordifolia by 25%. The extracts also suppressed the plant’s shoot and root dry biomass, seedling height, and leaf chlorophyll. These findings suggest that Artemisia annua could be a potential bio-herbicide for controlling Gutenbergia cordifolia.

The study also revealed that medium temperature (60°C) and long exposure time (5 minutes) significantly increased Gutenbergia cordifolia germination. This is not good, but only brief exposure to extreme temperatures (≥150°C) was needed to suppress its germination completely. This suggests that controlling fire regimes might be another viable method to control the invasive plant.

Moreover, high shade conditions also had a significant impact on Gutenbergia cordifolia. Under high shade, germination percentage was reduced to one-third, mean germination took twice as long, and shoot fresh biomass was reduced by half. Shoot and root dry biomass were decreased by more than a third, while seedling height was halved. However, leaf chlorophyll content remained unaffected.

Mero and her team recommend using Artemisia annua as a potential bio-herbicide and considering fire and shade as suppressor tools to control Gutenbergia cordifolia. They also emphasize the importance of conducting in-situ trials to assess the impacts of these methods on native plants and animals before implementing them on a larger scale. In locations where the ecosystem is already in need of protection. Mero and colleagues’ methods of the potential of providing a herbicide that’s eco-friendly, except for the part of the ecosystem you want to remove.

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Mero, S.A., Ngondya, I.B. and Treydte, A.C. (2023) “Environmental factors and non-chemical methods to suppress growth of the invasive plant Gutenbergia cordifolia,” Acta Oecologica, 119(103913), p. 103913. Available at: https://doi.org/10.1016/j.actao.2023.103913.