Idoneidad de Ephestia kuehniella (Lepidoptera: Pyralidae) y Aleurodicus cocois (Hemiptera: Aleyrodidae) como fuentes de alimento para Ceraeochrysa cornuta (Neuroptera: Chrysopidae)

This study aimed to compare the suitability of Ephestia kuehniella (Zeller, 1879) and Aleurodicus cocois (Curtis, 1846) as food sources for Ceraeochrysa cornuta (Navás, 1925) based on the assessment of the development and reproductive parameters of this predator. For this, E. kuehniella eggs or all developmental stages of A. cocois were used as prey and the effects were evaluated on developmental time, survival, viability, longevity, and fecundity of C. cornuta. Ceraeochrysa cornuta completed its development cycle from larvae to adult in 22 d or in 27 d when it preyed on E. kuehniella or on A. cocois, respectively. This could be explained by longer larval instars for C. cornuta feeding on A. cocois. The larval survival was higher when C. cornuta larvae fed on E. kuehniella than when it fed on A. cocois, increasing progressively from 79.82 % in the first to 97.56 % in the third instar. Although the diets did not influence female longevity, oviposition period and egg viability, the total number of eggs laid per female of C. cornuta was higher when their larvae fed on A. cocois. The results indicate that both E. kuehniella eggs and A. cocois developmental stages are suitable prey for rearing C. cornuta. In addition, this predator showed an outstanding potential for controlling A. cocois.Este estudio tuvo como objetivo comparar la idoneidad de Ephestia kuehniella (Zeller, 1879) y Aleurodicus cocois (Curtis, 1846) como fuentes de alimento para Ceraeochrysa cornuta (Navás, 1925), sobre la base de la evaluación de sus parámetros reproductivos y de desarrollo. Para esto, se utilizaron como presa huevos de E. kuehniella o todas las etapas de desarrollo de A. cocois y se evaluaron sus efectos sobre el tiempo de desarrollo, sobrevivencia, viabilidad, longevidad y fecundidad de este depredador. C. cornuta completó su ciclo de desarrollo de larva a adulto en 22 días y en 27 días cuando se alimenta de E. kuehniella y A. cocois, respectivamente. La supervivencia del período larvario fue mayor cuando las larvas de C. cornuta se alimentaron de E. kuehniella en comparación con A. cocois como fuente de alimento, que aumentó progresivamente del 79,82 % en el primero al 97,56 % en el tercer estadio. Aunque las dietas no influyeron en la longevidad de las hembras de esta especie, el periodo de oviposición y la viabilidad de los huevos, así como el número total de huevos puestos por hembra fueron mayores cuando sus larvas se alimentaron de A. cocois. Los resultados indican que tanto los huevos de E. kuehniella como los estados inmaduros de A. cocois son presas adecuadas para la cría de C. cornuta. Adicionalmente, este depredador podría considerarse como un agente de control biológico promisorio para el manejo de A. cocois

Entomopathogenic fungi biomass production and extracellular biosynthesis of silver nanoparticles for bioinsecticide action

Entomopathogenic fungi are microbial agents of insect control in nature. They have been used as biologic strategies to manage insect invasion; however, the challenge is to maintain their shelf life and viability when exposed to high temperatures, ultraviolet radiation, and humidity. Synthesized silver nanoparticles (AgNPs) from fungal extracellular enzymes are an alternative using these microorganisms to obtain nanoparticles with insecticidal action. The present study evaluates the biomass production and the potential to synthesize silver nanoparticles using entomopathogenic fungi isolates. Sixteen isolates of entomopathogenic fungi were used in this study. The fungi pathogenicity and virulence were evaluated using the insect model Tenebrio molitor, at a concentration of 5 × 106 conidia/mL. The fungal biomass was produced in a liquid medium, dried, and weighed. The synthesis of silver nanoparticles was performed with aqueous extracts of the entomopathogenic fungi and silver nitrate solution (1 mM), following characterization by a UV/vis spectrophotometer, mean size, and polydispersity index. The results showed a significant variation in pathogenicity, virulence, and biomass production among the evaluated fungi isolates; however, only one of the isolates did not have the potential to synthesize silver nanoparticles. Pearsons correlation showed significant correlation values only between virulence × biosynthesis potential and biomass production × biosynthesis potential, both with negative values, indicating an inverse correlation. Thus, AgNPs with entomopathogenic fungus extract can produce an innovative bioinsecticide product using a green production process.This work was supported by the Fundação de Amparo à Pesquisa do Estado de Sergipe (FAPITEC), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, #443238/2014-6, #470388/2014-5) and Banco do Nordeste (FUNDECI/2017.0014), the Portuguese Science and Technology Foundation (FCT/MCT), and from European Funds (PRODER/COMPETE) for the project UIDB/04469/2020 (strategic fund), co-financed by FEDER, under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio

Spittlebug Cephisus siccifolius damaging eucalypt plants in the State of Bahia, Brazil

Os insetos-praga mais comuns em plantios de eucalipto no Brasil são formigas cortadeiras e lagartas desfolhadoras. Eventualmente, outros insetos como percevejos e cigarrinhas podem danificar essas plantas. O objetivo deste trabalho foi identificar e descrever os sintomas de ataque, em um plantio de eucalipto de 25,77 hectares, no Estado da Bahia, onde 99,3% das árvores tinham sido atacadas pela cigarrinha-de-espuma Cephisus siccifolius (Walker 1851) (Hemiptera: Aphrophoridae). Os danos foram maiores em galhos e folhas. A mortalidade de árvores foi baixa, apesar de se observar 4,7 colônias de cigarrinhas por árvore, com 21,9 ninfas por colônia. O corte das árvores infestadas foi recomendado como controle.Most common pests of eucalyptus plants in Brazil are leaf cutting ants and defoliating caterpillars. Other groups, eventually, feeding on eucalyptus include Heteroptera and cicadas. The objectives of this work were to identify and to describe attack symptoms of Cephisus siccifolius (Walker 1851) (Hemiptera: Aphrophoridae) on eucalyptus trees in a stand of 25.77 hectares in the State of Bahia, Brazil, where 99.3% of them were attacked by this spittlebug. Damage was more severe on branches and leaves. Tree death was, relatively, low while those cut showed 4.7 colonies of this spittlebug with 21.9 nymphs per colony. Cultural control with the removal of trees attacked was recommended

Biosynthesis of silver nanoparticles mediated by entomopathogenic fungi: antimicrobial resistance, nanopesticides, and toxicity

Silver nanoparticles are widely used in the biomedical and agri-food fields due to their versatility. The use of biological methods for the synthesis of silver nanoparticles has increased considerably due to their feasibility and high biocompatibility. In general, microorganisms have been widely explored for the production of silver nanoparticles for several applications. The objective of this work was to evaluate the use of entomopathogenic fungi for the biological synthesis of silver nanoparticles, in comparison to the use of other filamentous fungi, and the possibility of using these nanoparticles as antimicrobial agents and for the control of insect pests. In addition, the in vitro methods commonly used to assess the toxicity of these materials are discussed. Several species of filamentous fungi are known to have the ability to form silver nanoparticles, but few studies have been conducted on the potential of entomopathogenic fungi to produce these materials. The investigation of the toxicity of silver nanoparticles is usually carried out in vitro through cytotoxicity/genotoxicity analyses, using well-established methodologies, such as MTT and comet assays, respectively. The use of silver nanoparticles obtained through entomopathogenic fungi against insects is mainly focused on mosquitoes that transmit diseases to humans, with satisfactory results regarding mortality estimates. Entomopathogenic fungi can be employed in the synthesis of silver nanoparticles for potential use in insect control, but there is a need to expand studies on toxicity so to enable their use also in insect control in agriculture.The work was funded by the Coordination for the Improvement of Higher Education Personnel (Capes); Sergipe Agricultural Development Company (Emdagro), the Industrial Biotechnology Program, University Tiradentes, Sergipe Technological Park (SergipeTec), and the Banco do Nordeste.info:eu-repo/semantics/publishedVersio