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The most commonly used method to control insect pests, such as leaf-cutting ants (LCA) in forest plantations, is the application of chemical insecticides, but their use was forbidden in plantations certified by the Forest Stewardship Council because of their negative effect on the environment. 2 A 5-year derogation of their prohibition was obtained in 2016 in Argentina, on the condition that forestry companies reduce pesticide doses by 5% per year and inform the Economic Injury Level (EIL). 3 The EIL and the Economic Threshold (ET) were estimated for the first time for the Acromyrmex genus in a Salicaceae forestation. As a model, we used the damage caused by the most detrimental LCA species of Argentina (Acromyrmex lundii) in the first, most critical year of a willow plantation (Salix nigra) in the lower basin of the Paraná River. 4 The EIL (8-15 nest/ha) was useful to demonstrate the real magnitude of the damage caused by A. lundii, which justified the need for its control. The ET for profitable production (∼3 nests/ha) would not be operatively applicable in a long-term management program in our study site. This methodology could be extrapolated to other Neotropical forest plantations attacked by Acromyrmex species.

Environmental education seeks to foster an appreciation for nature and the impact of humans on it while introducing citizens to scientific thinking. Biological invasions affect different aspects of life on earth and mandate urgent management actions. Education and public awareness are strongly recommended for successful prevention and management of invasive alien species (IAS). This work presents a study on knowledge and perception of the educational community of Argentina about native species and IAS. We designed an on-line semi-structured questionnaire to examine perception of the environment, recognition of native species and IAS and awareness about biological invasions. Educators recognised an important number of biotic components, mostly represented by trees, birds and mammals. Recognition of native species and IAS, and awareness of biological invasions were different between NST (Natural Science Teachers) and non-NST. Respondents had different performances when they were exposed to recognising native species though written names or photographs. Out of 532 respondents, 56% knew what biological invasions are, 21% answered “Maybe” and 23% had never heard about them. We need to foster capacity-building and encourage a two-way communication between educators and scientists, formally and informally, to engage the participation of the whole society in recognition, prevention and management of IAS.

The objective of this study was to estimate and compare some important reproductive parameters of Myocastor coypus over time (June 2006-May 2008, in wetlands of the Middle Delta of the Paraná River (MD) Entre Ríos province, R. Argentina. Within the original coypu distribution range, the MD is among the areas of highest habitat suitability for the species. Coypus were captured and the following reproductive parameters were estimated on a monthly, seasonal and annual basis: pregnancy rate (PR), litter size (LS), gross productivity (GP) and annual production (AP). Statistical non-parametric tests were used for comparisons. Additionally, the expected birth date of each embryo and fetus was estimated by assigning it to a developmental stage category and considering the gestation period of the species. All the parameters showed high values and PR and LS differed significantly between the dry (2006) and humid years (2007). Two peaks of birth were detected, one in spring and another one in mid-autumn. The implications of these results for ensuring the sustainable management of this rodent are discussed.Keywords: Myocastor coypus, Paraná River, peaks of birth, reproductive parameters, wetlands. Ecología reproductiva do coipo (Myocastor coypus) no Delta Meio do RíoParaná (Entre Ríos. Argentina) ResumoO objetivo deste trabalho é a descripção e comparação ao longo do tempo (junho 2006 -maio 2008), de diversos parámetros da ecologia reprodutiva de Myocastor coypus nas terras úmidas do Delta Meio do Río Paraná (DM), una das zonas de maior aptidão de hábitat para a espécie dentro da sua área de distribuição original. Com base em capturas de exemplares estimaram-se en forma mensal, sazonal y anual, a taxa de prenhez (TP); o tamanho da camada (TC), a produtividade bruta (PB) e a produção anual (PA) e foram realizadas as comparações correspondentes mediante provas estatísticas não paramétricas. Alem disso, com base no estádio de desenvolvimento dos fetos y embriões observados, levando em consideração a duração do período de gestação, estimou-se quais teriam sido as datas de nascimento mais prováveis. Observaram-se valores relativamente altos para todos os parámetros e diferenças significativas entre as TP y os TC de anos secos (2006) e anos úmidos (2007). Também foram detectados dois picos de parição, um em plena primavera e o outro a meados do outono. Discutem-se as implicâncias destes resultados para assegurar o manejo sustentável do coipo, o principal recurso de fauna silvestre argentina.Palavras-chave: Myocastor coypus, Río Paraná, picos de parição, parámetros reprodutivos, terras úmidas.

Leaf‐cutting ants are major pests of Neotropics forest plantations. The lower delta of the Paraná River contains the main Argentine Salicaceae production, strongly attacked by Acromyrmex lundii and Acromyrmex ambiguus. Nevertheless, there is no damage quantification in willow plantations attributed to leaf‐cutting ant species. In an area without leaf‐cutting ant control, we installed 15 blocks with eight willow stakes each: four clones × two treatments; with and without leaf‐cutting ant exclusion. We used two traditional (Americano, Nigra 4) and two new (Géminis, Yaguareté) commercial clones. During 2014–2018, we measured the damaged foliage, height and diameter of each tree. Foliage was damaged intensely during the first 2 years. After 1537 days, the loss in height and diameter was greater in Americano (70%), followed by Géminis (50%–60%), Yaguareté (40%–50%) and Nigra 4 (45%–40%). Stake survival with exclusion was greater (>80%) than stakes without exclusion (<50%). Total loss of wood volume was 93% for Americano, followed by Géminis (77%), Yaguareté (66%) and Nigra 4 (51%). Although the new clones were heavily attacked, they produced two to three times more wood volume than Americano; replacing Americano with the new clones would help to reduce leaf‐cutting ants impact on plantations and pesticides released into the environment.

Several components of classical biological control (CBC) programmes are necessary to assess the success of the management strategy (e.g., post‐release monitoring) and also help prevent reintroductions or resurgences of invasive species (e.g., public awareness). Water hyacinth, Pontederia (= Eichhornia) crassipes (Mart.) Solms (Pontederiaceae) is an aquatic plant naturally distributed in the north‐eastern region of the Del Plata basin in Argentina. In the 1960s it was introduced into the Dique Los Sauces reservoir located outside of its native range in La Rioja Province, in western Argentina, where it became invasive. The natural enemy, Neochetina bruchi Hustache (Coleoptera: Curculionidae), was intentionally introduced in 1974 to control the weed. To assess the success of this CBC programme, a long‐term post‐release study was conducted. Between 1965 and 2023, we monitored plant coverage, estimated N. bruchi densities, and quantified the associated damage by reanalysing previously published data and incorporating new sampling. We also conducted an online survey to analyse public knowledge and perception about this programme. Water hyacinth coverage fluctuated from its first record in 1965 (maximum coverage 90%) until the control of germinated plants (coverage 0%) in 2018. The plant decline was accompanied by an increase in the weevil population. In our survey, out of 325 respondents only a small group of mostly middle‐aged and elderly people knew that the restoration had been achieved through a management strategy and even fewer were aware of the biocontrol approach taken. Respondents who had a positive approach to biological control were more aware of the management plan than respondents who had neutral or negative opinions. Neochetina bruchi has played a key factor in the control of P. crassipes. The intrinsic dynamics of these populations, the dormant seed bank, and the lack of public awareness support the need for long post‐release evaluations including outreach campaigns to make a sustainable successful management programme.

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