Efficacy of invasive alien plants in controlling Arionidae slugs

Aim of study: To develop an alternative slug control method, we explored the use of plant material from seven invasive plant species against Arion slugs.Area of study: The experiments were performed at the University of Ljubljana (Slovenia).Material and methods: In laboratory (exp. A-C) and semi-field studies (exp. D), we investigated the contact and barrier efficacy of plant material (powder or liquid formulation) of seven invasive plant species (Japanese knotweed, bohemian knotweed, Canadian goldenrod, giant goldenrod, staghorn sumac, tree of heaven, and false indigo) against Arion slugs. In order to test a contact efficacy of the substance (exp. A), slugs were rolled in a plant material powder. In exp. B, powder made from a plant material was used as a barrier for slugs. Antifeedant effect of the slugs was tested in exp. C, where lettuce leaves were treated with a liquid formulation of a plant material. In exp. D, all above mentioned techniques were used in a semi-field trial.Main results: The results of our studies showed that the plant material of staghorn sumac, giant goldenrod, and Japanese knotweed showed the strongest anti-feedant and barrier effects against the slugs. In the semi-field trial, only 7% of the plants treated with giant goldenrod plant material were attacked by slugs.Research highlights: A contact efficacy of plant powders against Arion slugs was not confirmed in our investigation. Furthermore, several plant powders (goldenrods, staghorn sumac) showed good barrier efficacy. A semi-field trial showed that plant material (giant goldenrod) could represent an alternative solution in slug control.

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Invasive-Plant-Removal Frequency—Its Impact on Species Spread and Implications for Further Integration of Forest-Management Practices

Forests ◽

10.3390/f9080502 ◽

2018 ◽

Vol 9 (8) ◽

pp. 502

Author(s):

Bernabas Wolde ◽

Pankaj Lal

Keyword(s):

Forest Management ◽

Plant Species ◽

Management Practices ◽

Invasive Plant ◽

Control Method ◽

Trend Test ◽

Invasive Plant Species ◽

Management Plans ◽

Plant Removal ◽

Armitage Trend Test

For a given invasive plant species and control method, effective invasive plant eradication requires regular monitoring and management. While most previous studies characterize invasive plant species, develop appropriate control methods, or prioritize species for management using aggressiveness and other considerations, few study why some forestland owners are less likely than others to regularly remove invasive plant species. Such information is useful in prioritizing and targeting forestland owners who are at greater risk for invasion, with the stands threatening adjacent forestlands. Towards this end, we surveyed 1800 forestland owners in Virginia and Texas. We use data on forestland owners’ socioeconomics and forestland features—such as acreage, forestland ownership objectives, and forest management activities—to determine how these factors affect the regularity of invasive-plant removal. For these purposes, we used the Cochran–Armitage trend test, the Cochran–Mantel–Haenszal regression, odds ratio estimates, and partition-analysis techniques. Our results suggest that female forestland owners, owners with smaller forestlands, and forestland owners without written forest-management plans are less likely than others to regularly remove invasive plant species. Forest-management activities, such as building/maintaining roads in the forestland, partially harvesting stands, and wildlife- and fisheries-improvement projects, also significantly predict a more regular invasive-plant-removal tendency. However, since these activities are potential pathways for the spread of invasive plant species, we controlled for the other significant covariates and measured the relationship between frequent practice of the given forest-management activities and having a tendency to regularly remove invasive plant species. The results suggest that forestland owners that regularly practiced the said forest-management activities have higher odds for tending to remove invasive plant species regularly, suggesting that, despite their demonstrated effort at removing invasive plant species from their forest, their management activities may be inadvertently contributing to the spread of invasive plant species. These results highlight the importance of integrating invasive-plant-removal plans with forest-management plans as well as forestland owners’ educational and outreach needs.

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