Simposio: Invertebrados vectores de enfermedades de importancia agropecuaria

SIMPOSIO

Invertebrados vectores de enfermedades de importancia agropecuaria

COORDINA: Christina B. McCARTHY

Soluciones innovadoras para el control de vectores agrícolas: Un camino hacia adelante

Los vectores invertebrados desempeñan un papel crucial en la transmisión de una amplia variedad de patógenos que afectan tanto a plantas como a animales, lo que conlleva importantes pérdidas económicas en la agricultura a nivel mundial.
Este simposio incluye varios vectores invertebrados clave que revisten especial importancia para nuestra región latinoamericana: chicharritas (Cicadellidae), psílidos (Psylloidea), Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) y Varroa destructor (Parasitiformes: Varroidae).
Las chicharritas y los psílidos son conocidos por transmitir patógenos vegetales devastadores, incluidos fitoplasmas, espiroplasmas y virus, que provocan enfermedades como el espiroplasma del achaparramiento del maíz y el huanglongbing (HLB) o «greening» de los cítricos, además de causar daños directos por alimentación.
Bemisia tabaci, una mosca blanca altamente polífaga, es un vector reconocido a nivel mundial por transmitir numerosos begomovirus y otros virus vegetales, contribuyendo a reducciones significativas en los rendimientos de cultivos hortícolas y de campo.
A diferencia de los patógenos vegetales directos, Varroa destructor es un ácaro ectoparásito de las abejas melíferas (Apis mellifera) que se encuentra ampliamente distribuido en la región. La alimentación parasitaria de V. destructor no solo debilita las colonias de abejas mediante inmunosupresión, sino que también favorece la replicación y transmisión de diversos virus de ARN, como el Virus de las Alas Deformadas (DWV), que en conjunto provocan el debilitamiento y colapso de las colonias.
Comprender las complejas interacciones entre estos vectores, los patógenos asociados y sus respectivos hospedadores es fundamental para desarrollar estrategias de manejo integrado de plagas. Este simposio destaca la necesidad urgente de continuar con la investigación en biología de vectores, epidemiología de patógenos y nuevas medidas de control, con el fin de mitigar los graves impactos agrícolas y apícolas que representan estos vectores invertebrados de enfermedades.

Palabras claves: chicharritas, psílidos, Bemisia tabaci, Varroa destructor, manejo de vectores.

New vectors, new challenges: an integrated approach to emerging agricultural diseases

BONGIORNO, Vanina A. ^1,2,3

¹ Instituto de Patología Vegetal. Centro de Investigaciones Agropecuarias. Instituto Nacional de Tecnología Agropecuaria (IPAVE-CIAP-INTA), Córdoba, Argentina.
² Consejo Nacional de Investigaciones Científicas (CONICET), Córdoba, Argentina.
³ Facultad de Ciencias Agropecuarias. Universidad Nacional de Córdoba (FCA – UNC), Córdoba, Argentina.
E-mail address: bongiorno.vanina@inta.gob.ar

Vector-borne plant diseases represent a persistent challenge for crop production and plant health, particularly those involving systemic pathogens such as phytoplasmas, cell wall-less bacteria transmitted by phloem-feeding hemipteran insects. The epidemiological complexity of these pathosystems highlights the necessity of integrated approaches that encompass vector identification, biological characterization, and disease management. In this context, the present study is used as a case model to demonstrate how entomological and molecular tools contributed to the identification of Paratanus exitiosus (Beamer) as the vector of Yellow Wilt Disease (YWD) in fodder beet (Beta vulgaris subsp. vulgaris) in Argentina, marking the first confirmed report for this vector–pathogen association in the country. The study combined field surveys of the hemipteran community, molecular detection of phytoplasmas, experimental transmission trials, and evaluations of vector abundance, host preferences, and life cycle traits. The findings obtained not only support the development of more effective and environmentally sustainable management strategies, but also advance the understanding of the interactions between the vector, host plants, and pathogens. This integrated knowledge is essential for addressing complex epidemiological scenarios, particularly in the context of climate change, where shifts in the distribution and population dynamics of insects may favor the emergence or intensification of crop diseases.

Keywords: Hemiptera, Phytoplasma, Disease transmission.

Dalbulus maidis: A challenging target for entomopathogenic fungi

TOLEDO, Andrea V.

Centro de Investigaciones de Fitopatología (CIDEFI), Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata. La Plata, Buenos Aires, Argentina.
E-mail: avtoledo1975@gmail.com

The corn leafhopper Dalbulus maidis is considered the most important maize pest from an epidemiological standpoint, due to its wide geographic distribution (from the southern United States to central Argentina), its high population density compared to other species, and its high efficiency in pathogen transmission. It is capable of persistently, circulatively, and propagatively transmitting two viruses and two mollicutes, which, in single or mixed infections, cause Corn Stunt Disease (CS). In tropical and subtropical regions, this disease can result in crop losses of up to 100%. Currently, the only viable strategy for managing CS is prevention, mainly aimed at avoiding vector population growth. Control of the vector relies primarily on the use of synthetic chemical insecticides, with seed treatments being more effective than foliar applications. However, the emergence of resistance in D. maidis populations and the increasingly stringent regulations on maximum residue limits in fresh food products at both regional and global levels underscore the urgent need to explore alternative tools for vector control. Among the biological alternatives available for pest management, entomopathogenic fungi stand out, with Beauveria bassiana being one of the most widely used for the development of commercial biopesticides. Traditionally, fungal insecticides are applied via foliar spraying in a manner similar to chemical insecticides, aiming to suppress pests through contact. However, this inoculation method can limit the efficacy of entomopathogenic fungi due to the susceptibility of conidia to ultraviolet radiation and their requirement for high humidity levels to germinate. In the case of D. maidis, fungal efficacy is further reduced by antagonistic interactions with the insect’s cuticular microbiota, grooming behavior, and the presence of brochosomes secreted and distributed across the insect’s body. During grooming, the insect rubs its entire body with its spiny legs, removing a significant portion of the inoculated product. This repeated behavior reduces the number of conidia adhering to the host cuticle, thereby lowering infection probabilities and/or extending the disease development period. Similarly, brochosomes act as an anti-adhesive coating, causing conidial suspension droplets to slide off the insect’s body, further reducing the chances of infection. These biological barriers highlight the need and the challenge of developing alternative and effective strategies for controlling D. maidis populations using entomopathogenic fungi, while overcoming the physical and chemical defenses intrinsic to the vector’s biology. A promising alternative is the asymptomatic internal colonization of plant tissues by these entomopathogens, given that endophytic fungi not only act as plant growth promoters, but also produce metabolites that induce plant defenses and may exert negative effects on insects, such as antibiosis or antixenosis.

Keywords: Biological control, Corn leafhopper, Corn stunt disease.

Olfactory Orientation for Vector Control in Agricultural Disease Management

COLL ARAOZ, Maria Victoria

SEMION, Argentina
Facultad de Ciencias Naturales e IML, UNT, Tucuman, Argentina
E-mail address: victoria@semionbio.com

Olfactory orientation is an increasingly relevant approach for the sustainable control of insect vectors in agriculture, particularly within integrated pest management (IPM) strategies. Insect pests such as the psyllid Diaphorina citri, the primary vector of Candidatus Liberibacter asiaticus, causal agent of citrus Huanglongbing (HLB), depend heavily on olfaction to locate host plants, mates, and oviposition sites. Understanding and manipulating these olfactory-mediated behaviors presents a promising tool for reducing disease spread. Pheromone-based methods are widely applied in pest management, however their utility is limited when the target insects either do not respond to pheromones or require complex blends to elicit a reliable behavioral response. In the case of D. citri, responses to pheromones have been inconsistent, prompting the exploration of alternative semiochemical cues such as plant volatiles. Volatile organic compounds (VOCs) released by citrus flush are highly attractive to D. citri and essential for its feeding and reproductive behavior. Key volatiles like methyl salicylate and limonene derivatives have been identified as potent attractants, leading to the development of lure-based traps for monitoring and potentially mass capture. However, the use of plant volatiles presents challenges, particularly those that are also associated with flowers or fruits. Many beneficial insects, including pollinators and predators, also respond to these cues, increasing the risk of non-target captures in traps. To address this, new strategies are focusing on modifying or interfering with host-location mechanisms rather than attracting the insects. This includes using masking odors or altering the olfactory landscape of the crop, thereby reducing the psyllid’s ability to identify suitable hosts. Intercropping with non-host plants or deploying visual and olfactory camouflage have shown potential in disrupting host recognition. In Brazil, for example, push-pull systems using trap crops like Murraya koenigii, which are highly attractive to D. citri, are combined with repellent volatiles or masking stimuli applied to citrus crops. Other approaches being developed by our company involve altering the volatile blends targeting those volatiles that trigger insect behavior. These methods reduce psyllid colonization pressure while helping to preserve the main crop. One of the key advantages of olfactory-based interventions is their high specificity. Unlike chemical insecticides, which often have broad-spectrum activity and ecological side effects, semiochemical approaches can be finely tuned to affect only the target species. This specificity supports beneficial insect conservation, enhancing the overall effectiveness and sustainability of IPM programs. Future research should continue to refine these tools, explore synergistic effects with visual and behavioral cues, and ensure adaptability across diverse agroecological regions.

Keywords: Huanglongbing (HLB), Semiochemicals, Behavioral manipulation.

Dynamics of Bemisia tabaci in Brazil and interaction with viruses

Krause-Sakate, Renate.¹; Nogueira-Portilho, Angelica M.¹; Oliveira, Cintia S.¹; Silveira, Barbara.R.R.¹; Barreto da Silva, Felipe.¹; Bello, Vinicius H.¹; Marubayashi, Julio M. ¹; Martines, Caroline C.¹; Favara, Gabriel M.²

¹ Faculdade de Ciências Agronômicas, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil.
² Faculdade de Engenharia, Universidade Estadual Paulista (UNESP), Ilha Solteira, São Paulo, Brazil.
E-mail address: renate.krause@unesp.br

Bemisia tabaci is recognized as one of the most significant pests and virus vectors. Brazil has a long-standing history with whiteflies, first recorded in Bahia in 1928. Native whitefly species (biotype A, B. tabaci New World group) were not considered major virus vectors, with only sporadic virus-related issues in beans during the 1970s.
The population dynamics of this insect changed dramatically following the introduction of the Middle East-Asia Minor 1 (MEAM1)—formerly known as the “B biotype” and B. argentifolii Bellows & Perring—and the Mediterranean (MED) biotype, previously referred to as “Q biotype”, considered B. tabaci sensu stricto. MEAM1 and MED are the most invasive members of this complex and have spread globally. Both are highly efficient vectors of plant viruses, contributing to the emergence, establishment, and epidemics of several destructive viral diseases.
B. tabaci MEAM1, a highly polyphagous insect, was responsible for the begomovirus outbreak in tomato crops in Brazil. MED was first reported in 2014 in Rio Grande do Sul associated to pepper and sweet potato plants and 2015 in São Paulo State, associated with ornamental plants. Two years later, frequent outbreaks of MED whiteflies were observed in pepper greenhouses in São Paulo, causing substantial damage to this crop. In 2021, MED was reported in open-field soybean cultivation.
Since then, we have conducted transmission studies involving four MED populations and one MEAM1 population. Tomato plants infected with the brazilian native begomoviruses: tomato severe rugose virus (ToSRV) and tomato rugose mosaic virus (ToRMV), and the crinivirus tomato chlorosis virus (ToCV), as well as bean plants infected with cowpea mild mottle virus (CPMMV) and bean golden mosaic virus (BGMV), were used as inoculum sources. Our findings indicate that MED is a poor vector of the begomoviruses tested but an efficient vector of ToCV and CPMMV. Meanwhile, MEAM1 is an excelent vector of ToSRV, ToRMV and BGMV. These results underscore the importance of understanding virus transmission differences among whitefly species and suggest that the increasing prevalence of B. tabaci MED may significantly influence the epidemiological landscape of viral diseases across various crops.

Keywords: Whitefly, begomovirus, crinivirus and carlavirus.

Varroa destructor in Latin America: Past, Present, and Future Challenges

MAGGI, Matías D.¹

¹Centro de Investigaciones en Abejas Sociales, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata Mar del Plata, Buenos Aires, Argentina.
²Instituto de Investigaciones en Producción Sanidad y Ambiente (IIPROSAM CONICET-UNMdP); Facultad de Ciencias Exactas y Naturales – UNMdP; Centro Científico Tecnológico Mar del Plata – CONICET. Mar del Plata, Buenos Aires, Argentina.
E-mail address: mmaggibio@gmail.com

The global spread of Varroa destructor, the main ectoparasite of honey bees (Apis mellifera), has had profound consequences for beekeeping in Latin America. This presentation offers a comprehensive analysis of the challenges this mite has historically posed, as well as those that persist or are emerging, with a special focus on its role as a virus vector, its health and productivity impacts on colonies, and the increasing resistance to conventional acaricide treatments. We will discuss the mechanisms underlying its efficiency as a parasite and viral vector, the sublethal effects on bees, and the progression of acaricide resistance across different regions of the continent. In light of this scenario, we emphasize the need to improve resistance monitoring, diversify available control tools, and promote integrated strategies tailored to the productive and ecological realities of Latin America

Keywords: varroa mites, honey bees, Latin-American.

Créditos de las imágenes utilizadas en esta página web
Diaphorina citri, imagen por USGS Bee Inventory and Monitoring Lab, CC-BY 2.0, Wikimedia Commons (https://commons.wikimedia.org/wiki/File:Citrus_psyllid,hand_sanitizer,_adult,_ft_detrick_2014-05-01-09.43.40_ZS_PMax(15234786967).jpg) | Las imágenes de las personas miembro de los distintos comités de LA SOVE RELCOV 2025 así como las imágenes de los/as oradores/as fueron provistas por las mismas personas para uso exclusivo en esta página web. Los/as autores/as de estas imágenes se reservan el derecho de uso y reproducción de las mismas.

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