Biological Control of Weeds: Is it Safe?

Invasive plants are non-native plant species that cause harm in their introduced range. Classical biological control of invasive plants is the use of natural enemies, imported insects and mites or pathogens, to control the target plants. This publication explains the strategies and rules in place to ensure that organisms released for the biological control of weeds are safe and effective.

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Biological and Host Range Characteristics of Lysathia flavipes (Coleoptera: Chrysomelidae), a Candidate Biological Control Agent of Invasive Ludwigia spp. (Onagraceae) in the USA

Insects ◽

10.3390/insects12050471 ◽

2021 ◽

Vol 12 (5) ◽

pp. 471

Author(s):

Angelica M. Reddy ◽

Paul D. Pratt ◽

Brenda J. Grewell ◽

Nathan E. Harms ◽

Ximena Cibils-Stewart ◽

...

Keyword(s):

Biological Control ◽

Host Range ◽

Plant Species ◽

Biocontrol Agent ◽

Biological Control Agent ◽

Control Agent ◽

Native Plant ◽

Native Plant Species ◽

The Usa ◽

Physical And Chemical

Exotic water primroses (Ludwigia spp.) are aggressive invaders in aquatic ecosystems worldwide. To date, management of exotic Ludwigia spp. has been limited to physical and chemical control methods. Biological control provides an alternative approach for the management of invasive Ludwigia spp. but little is known regarding the natural enemies of these exotic plants. Herein the biology and host range of Lysathia flavipes (Boheman), a herbivorous beetle associated with Ludwigia spp. in Argentina and Uruguay, was studied to determine its suitability as a biocontrol agent for multiple closely related target weeds in the USA. The beetle matures from egg to adult in 19.9 ± 1.4 days at 25 °C; females lived 86.3 ± 35.6 days and laid 1510.6 ± 543.4 eggs over their lifespans. No-choice development and oviposition tests were conducted using four Ludwigia species and seven native plant species. Lysathia flavipes showed little discrimination between plant species: larvae aggressively fed and completed development, and the resulting females (F1 generation) oviposited viable eggs on most plant species regardless of origin. These results indicate that L. flavipes is not sufficiently host-specific for further consideration as a biocontrol agent of exotic Ludwigia spp. in the USA and further testing is not warranted.

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Postrelease Evaluation of Mecinus janthinus Host Specificity, a Biological Control Agent for Invasive Toadflax (Linaria spp.)

Weed Science ◽

10.1614/ws-06-093.1 ◽

2007 ◽

Vol 55 (2) ◽

pp. 164-168 ◽

Cited By ~ 10

Author(s):

Nehalem C. Breiter ◽

Timothy R. Seastedt

Keyword(s):

Biological Control ◽

Host Specificity ◽

Plant Species ◽

Field Experiments ◽

Biological Control Agent ◽

Control Agent ◽

Native Plant ◽

Weed Biological Control ◽

Native Plant Species ◽

Mecinus Janthinus

Toadflax invasion into natural areas has prompted interest in weed management via biological control. The most promising biological control agent currently available for the control of Dalmatian toadflax is Mecinus janthinus, a stem-boring weevil that has been shown to significantly reduce toadflax populations. Some land managers, however, are reluctant to release approved weed biological control agents based on concerns about possible nontarget impacts. Few postrelease examinations of biocontrol impact and host specificity have been performed, despite the call for such information. This study examined the host specificity of Mecinus janthinus, postrelease, in relation to Colorado sites to provide information to managers about its relative safety as a weed biological control agent. This study employed three components: (1) greenhouse choice and no-choice experiments; (2) no-choice caged field experiments; and (3) release-site evaluation of nontarget use of native plant species where this weevil has been released and has established. Both greenhouse and field experiments failed to demonstrate nontarget use of native plant species by M. janthinus in the region where it was studied, even in no-choice starvation tests. We found no evidence of nontarget herbivory on native plants growing at toadflax sites where M. janthinus was well established. These results support the continued use of M. janthinus as a low-risk biological control agent for the management of toadflax in the Rocky Mountain Front Range.

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Evolutionary responses of native plant species to invasive plants: a review

New Phytologist ◽

10.1111/nph.12429 ◽

2013 ◽

Vol 200 (4) ◽

pp. 986-992 ◽

Cited By ~ 36

Author(s):

Ayub M. O. Oduor

Keyword(s):

Plant Species ◽

Invasive Plants ◽

Native Plant ◽

Native Plant Species

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Increase in nutrient availability promotes success of invasive plants through increasing growth and decreasing anti-herbivory defenses

10.1101/2021.10.18.464765 ◽

2021 ◽

Author(s):

Liping Shan ◽

Ayub M.O. Oduor ◽

Wei Huang ◽

Yanjie Liu

Keyword(s):

Invasive Species ◽

Plant Species ◽

Invasive Plants ◽

Nutrient Availability ◽

Nutrient Enrichment ◽

Native Species ◽

Native Plants ◽

Native Plant ◽

Simulated Herbivory ◽

Native Plant Species

Invasive plant species often exhibit greater growth and lower anti-herbivory defense than native plant species. However, it remains unclear how nutrient enrichment of invaded habitats may interact with competition from resident native plants to affect growth and defense of invasive plants. In a greenhouse experiment, we grew five congeneric pairs of invasive and native plant species under two levels of nutrient availability (low vs. high) that were fully crossed with simulated herbivory (clipping vs. no-clipping) and competition (alone vs. competition). Invasive plants produced more gibberellic acid, and grew larger than native species. Nutrient enrichment caused a greater increase in total biomass of invasive plants than of native plants, especially in the absence of competition or without simulated herbivory treatment. Nutrient enrichment decreased leaf flavonoid contents of invasive plants under both simulated herbivory conditions, but increased flavonoid of native plants under simulated herbivory condition. Nutrient enrichment only decreased tannins production of invasive species under competition. For native species, it enhanced their tannins production under competition, but decreased the chemicals when growing alone. The results indicate that the higher biomass production and lower flavonoids production in response to nutrient addition may lead to competitive advantage of invasive species than native species.

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Non-native plants add to the British flora without negative consequences for native diversity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1423995112 ◽

2015 ◽

Vol 112 (14) ◽

pp. 4387-4392 ◽

Cited By ~ 58

Author(s):

Chris D. Thomas ◽

G. Palmer

Keyword(s):

Invasive Species ◽

Plant Species ◽

Invasive Plants ◽

Native Species ◽

Vegetation Change ◽

Plant Invasions ◽

Native Plant ◽

Negative Consequences ◽

Native Plant Species ◽

Total Cover

Plants are commonly listed as invasive species, presuming that they cause harm at both global and regional scales. Approximately 40% of all species listed as invasive within Britain are plants. However, invasive plants are rarely linked to the national or global extinction of native plant species. The possible explanation is that competitive exclusion takes place slowly and that invasive plants will eventually eliminate native species (the “time-to-exclusion hypothesis”). Using the extensive British Countryside Survey Data, we find that changes to plant occurrence and cover between 1990 and 2007 at 479 British sites do not differ between native and non-native plant species. More than 80% of the plant species that are widespread enough to be sampled are native species; hence, total cover changes have been dominated by native species (total cover increases by native species are more than nine times greater than those by non-native species). This implies that factors other than plant “invasions” are the key drivers of vegetation change. We also find that the diversity of native species is increasing in locations where the diversity of non-native species is increasing, suggesting that high diversities of native and non-native plant species are compatible with one another. We reject the time-to-exclusion hypothesis as the reason why extinctions have not been observed and suggest that non-native plant species are not a threat to floral diversity in Britain. Further research is needed in island-like environments, but we question whether it is appropriate that more than three-quarters of taxa listed globally as invasive species are plants.

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A Trait-Based Protocol for the Biological Control of Invasive Exotic Plant Species

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.586948 ◽

2021 ◽

Vol 9 ◽

Author(s):

Hui Zhang ◽

Kai Jiang ◽

Yang Zhao ◽

Yuting Xing ◽

Haijie Ge ◽

...

Keyword(s):

Biological Control ◽

Plant Species ◽

Native Species ◽

Invasive Plant ◽

Exotic Plant ◽

Native Plant ◽

Exotic Plant Species ◽

Native Plant Species ◽

Software Program ◽

Invasive Exotic

Selecting appropriate native species for the biological control of invasive exotic plants is a recurring challenge for conservationists, ecologists, and land managers. Recently developed trait-based approaches may be an effective means of overcoming this challenge. However, we lack a protocol and software platform that can be used to quickly and effectively select potential native plant species for performing biological control of the invasive exotic plant species. Here, our study introduces a protocol and a software program that can be used for trait-based selection of appropriate native plant species for performing biocontrol of invasive exotic plant species. In particular, we illustrate the effectiveness of this software program and protocol by identifying native species that can be used for the biological control of Leucaena leucocephala (Lam.) de Wit, a highly invasive plant species found in many parts of the world. Bougainvillea spectabilis was the only native species selected by our software program as a potential biocontrol agent for L. leucocephala. When separately planting 4 seedlings of B. spectabilis and two unselected species (Bombax ceiba, and Ficus microcarpa) as neighbors of each individual of L. leucocephala for 3 years, we found that B. spectabilis, which was functionally similar to the invasive L. leucocephala, significantly limited the invasion of the latter, while the unselected native plant species could not. That was because all the seedling of B. spectabilis survived, while half seedlings of unselected species (B. ceiba and F. microcarpa) died, during the experimental period when planted with L. leucocephala seedlings. Moreover, the growth of L. leucocephala was restricted when planted with B. spectabilis, in contrast B. ceiba and F. microcarpa did not influence the growth of L. leucocephala. Overall, our software program and protocol can quickly and efficiently select native plant species for use in the biological control of invasive exotic plant species. We expect that this work will provide a general protocol to perform biological control of many different types of invasive exotic plant species.

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Yellow Brazilian Pepper-tree Leaf Galler (suggested common name) Calophya latiforceps Burckhardt (Insecta: Hemiptera: Calophyidae: Calophyinae)

EDIS ◽

10.32473/edis-in1186-2017 ◽

2017 ◽

Vol 2017 (6) ◽

Author(s):

James P. Cuda ◽

Patricia Prade ◽

Carey R. Minteer-Killian

Keyword(s):

Biological Control ◽

North America ◽

Natural Enemies ◽

Host Plants ◽

Classical Biological Control ◽

Biological Control Agents ◽

Pepper Tree ◽

Brazilian Pepper ◽

Close Relatives ◽

Tree Leaf

In the late 1970s, Brazilian peppertree, Schinus terebinthifolia Raddi (Sapindales: Anacardiaceae), was targeted for classical biological control in Florida because its invasive properties (see Host Plants) are consistent with escape from natural enemies (Williams 1954), and there are no native Schinus spp. in North America. The lack of native close relatives should minimize the risk of damage to non-target plants from introduced biological control agents (Pemberton 2000). [...]

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