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Cattle production is one of the main economic activities in the state of Roraima, and insect pest attacks in pastures have a negative effect on this sector in the region. Little is known about the species that cause damage to forage fields in the state. This study presents the first report of the occurrence of the chinch bug Blissus pulchellus Montandon (Hemiptera: Blissidae) in Roraima, Brazil and a description of the population dynamics of this pest in pasture areas in this state. Pasture areas were sampled in nine municipalities of Roraima to detect the insect. The population dynamics study was conducted for two years in Alto Alegre municipality, two of which have Brachiaria brizantha cv. Marandu and one of Megathrysus maximus cv. Mombaça (Poaceae) crops. Blissus pulchellus was found in all sampled areas, except in Rorainópolis and São João da Baliza. High densities of this bug were found in in Alto Alegre. This is the first report of B. pulchellus in Brazil. The factors that affect the population dynamics and the damage caused by this insect pest to pastures as well as the risk of dispersal of this pest in Brazil are discussed. Made available in DSpace on 2021-08-04T18:00:22Z (GMT). No. of bitstreams: 1 Elisangela-first-occurrence.pdf: 3635711 bytes, checksum: f3f21f629cd0afcb5a6f2f26e5845a10 (MD5) Previous issue date: 2021

Encyrtids (Hymenoptera: Encyrtidae) are the most important and diverse group of natural enemies of mealybugs (Hemiptera: Pseudococcidae). Blepyrus clavicornis (Compere) is the most common parasitoid associated with Pseudococcus viburni (Signoret) in the Serra Gaúcha region, Brazil. We conducted laboratory studies to assess the development time, sex ratio, adult longevity, host stage selection for parasitism, and effect of food on the longevity of adult females of B. clavicornis. The experiments were conducted in a climate chamber at 25 ± 1 °C, 70 ± 10% RH and 12:12 L:D photoperiod. The solitary parasitoid B. clavicornis parasitized third-instar and adult female stages of P. viburni. The development time was more than 30 days (31.75 ± 0.38 for females and 30.02 ± 0.34 for males) when B. clavicornis laid eggs in adult mealybug females, and 35 days (36.50 ± 0.50 for females and 34.24 ± 0.43 for males) on third-instar mealybug nymphs. The wasps did not survive longer than four days when they were fed only water, while females survived for about 30 days when fed with honey. The lifespan of females is about 20 days longer than the lifespan of males. Although B. clavicornis can provide significant natural control, reducing the number of individuals in the next generation by parasitizing advanced mealybug instars, we consider it unpromising for use in applied biological-control programs. Furthermore, the predominance of males in the progeny observed here suggests that P. viburni may not be the most suitable or preferred host for B. clavicornis. Keywords: Biological control, Chalcidoidea, Obscure mealybug, Parasitism

The main objective of this study was to characterize the toxicity and genetic divergence of 18 Bacillus thuringiensis strains in the biological control of Spodoptera eridania . Bacterial suspensions were added to the S. eridania diet. Half of the selected B. thuringiensis strains caused high mortality seven days after infection. The genetic divergence of B. thuringiensis strains was assessed based on Enterobacterial Repetitive Intergenic Consensus (ERIC) and Repetitive Extragenic Palindromic (REP) sequences, and five phylogenetic groups were formed. Despite their genetic diversity B. thuringiensis strains did not show any correlation between the collection sites and toxicity to larvae. Some B. thuringiensis strains are highly toxic to S. eridania, thus highlighting the potential of their endotoxins as biopesticides. Made available in DSpace on 2020-01-24T18:15:54Z (GMT). No. of bitstreams: 1 Molecularcharacterization.pdf: 1710147 bytes, checksum: 97496a069d958bd447d0de28d1e7209b (MD5) Previous issue date: 2020

Species of thrips (Insecta, Thysanoptera) in two strawberry production systems in Rio Grande do Sul, Brazil. Thrips are tiny insects responsible for the reduction of strawberry fruit quality. The work aimed to record and quantify the thysanopterofauna present in two strawberry production systems, low tunnel and semi-hydroponic. Leaves, flowers and fruits were collected weekly, from July 2005 to December 2006 in Caxias do Sul and Bom Princípio municipalities, RS. A total of 664 individuals were collected, representing two families, four genus and 10 species: Frankliniella occidentalis (Pergande, 1895), F. schultzei (Trybom, 1910), F. rodeos Moulton, 1933, F. simplex (Priesner, 1924), F. williamsi (Hood, 1915), F. gemina (Bagnall, 1919), Frankliniella sp., Thrips tabaci (Lindeman, 1888), Thrips tabaci (Lindeman, 1888), Caliothrips fasciatus (Pergande 1895) from Thripidae and Heterothrips sp. from Heterothripidae. Frankliniella occidentalis represented 89.7% of the samples with 95.8% of the species collected in flowers, 3.9% in fruits and 0.8% in leaves. The results show that flowers are the most important food resource for these insects on strawberry plants. Frankliniella rodeos, F. simplex, F. williamsi, C. fasciatus, and Heterothrips sp. are new records on strawberry for Brazil.Espécies de tripes (Insecta, Thysanoptera) associadas à cultura do morangueiro em dois sistemas de produção no Rio Grande do Sul, Brasil. Tripes são insetos diminutos responsáveis pela redução da qualidade dos frutos do morangueiro. O trabalho objetivou registrar e quantificar a tisanopterofauna presente em dois sistemas de produção de morangueiro, túnel baixo e semihidropônico. Folhas, flores e frutos foram coletados semanalmente, de julho de 2005 a dezembro de 2006 em Caxias do Sul e Bom Princípio, RS. Foram coletados 664 indivíduos pertencentes a duas famílias, quatro gêneros e 10 espécies: Frankliniella occidentalis (Pergande, 1895), F. schultzei (Trybom, 1910), F. rodeos (Moulton, 1933), F. simplex (Priesner, 1924), F. williamsi (Hood, 1915), F. gemina (Bagnall, 1919), Frankliniella sp., Thrips tabaci (Lindeman, 1888) e Caliothrips fasciatus (Pergande, 1895) pertencentes a Thripidae, e Heterothrips sp. pertencente a Heterothripidae. Com 593 ocorrências, F. occidentalis representou 89,3% dos insetos coletados, com 87,9% dos indivíduos nas flores, 8,4% nas folhas e 3,7% nos frutos. Os resultados sugerem que as flores do morangueiro representam o recurso preferido pelos tripes. Frankliniella rodeos, F. simplex, F. williamsi, C. fasciatus e Heterothrips sp. são novos registros na cultura para o Brasil.

A agressividade da presa altera o comportamento de ataque do predador Supputius cincticeps (Stål) (Hemiptera, Pentatomidae)? O percevejo Supputius cincticeps (Stål) (Hemiptera, Pentatomidae) é um predador encontrado em várias regiões brasileiras, que possui atributos desejáveis como agente de controle natural ou em programas de controle biológico. O objetivo deste trabalho foi testar se diferentes espécies de presa podem afetar o comportamento de ataque e o sucesso de predação de S. cincticeps. Larvas de Tenebrio molitor (L.) (Coleoptera, Tenebrionidae), Spodoptera frugiperda (J. E. Smith) (Lepidoptera, Noctuidae) e Thyrinteina arnobia (Stoll) (Lepidoptera, Geometridae) foram oferecidas a S. cincticeps, em bioensaios de laboratório, onde o comportamento de ataque do predador e o comportamento de defesa das presas foram observados por período de duas horas. O comportamento de ataque de S. cincticeps às presas apresentou variações nas frequências dos atos predatórios. O sucesso da inserção dos estiletes na presa depende da parte do corpo que é atacada (anterior, mediana ou posterior), apresentando maior sucesso quando o ataque ocorre na região anterior. As larvas de T. arnobia e S. frugiperda apresentaram maior frequência de movimentos bruscos quando atacadas por S. cincticeps, enquanto as de T. molitor não exibiram tais reações. Consequentemente, o sucesso da predação de S. cincticeps foi maior sobre T. molitor e S. frugiperda e consideravelmente menor em T. arnobia. Essas informações sobre as diferenças no comportamento de ataque de S. cincticeps a diferentes presas são úteis para os programas de controle biológico envolvendo hemípteros predadores. Does the aggressiveness of the prey modify the attack behavior of the predator Supputius cincticeps (Stål) (Hemiptera, Pentatomidae)? The stink bug Supputius cincticeps (Stål) (Hemiptera, Pentatomidae) is a predator found in several Brazilian regions, which possesses desirable attributes as a natural control agent and in biological control programs. The aim of this study was to test if the attack behavior and predation success of S. cincticeps were affected by prey species. Larvae of Tenebrio molitor (L.) (Coleoptera, Tenebrionidae), Spodoptera frugiperda (J. E. Smith) (Lepidoptera, Noctuidae), and Thyrinteina arnobia (Stoll) (Lepidoptera, Geometridae) were offered to S. cincticeps in laboratory bioassays where predatory attack and prey defensive behaviors were observed for 2-hour periods. The attack behavior of S. cincticeps changed with the prey species offered. More than 25% of T. molitor and S. frugiperda larvae were immediately attacked, but T. arnobia was not immediately attacked by S. cincticeps. Successful attack (i.e., successful insertion of the predator stylets into the prey) depends on the region of the body attacked, with a greater proportion of successful attacks in the anterior than in the median or posterior regions. Larvae of T. arnobia and S. frugiperda displayed a sequence of abrupt head and body movements in response to S. cincticeps attack. Attempts of predation were more successful on T. molitor and S. frugiperda than on T. arnobia. Information about the differential attack behavior of S. cincticeps on different prey species is important for designing successful biological control programs using this hemipteran predator.

Survey of ear flies (Diptera, Ulidiidae) in maize (Zea mays L.) and a new record of Euxesta mazorca Steyskal in Brazil. Species of Euxesta (Diptera, Ulidiidae), known as silk flies or ear flies, are becoming increasingly important as maize insect pests in South America, although very little is known about them in Brazil. The larvae of some species of this genus initially damage female reproductive tissues, and then the developing kernels on the ear. As a result of feeding, fermentation and associated odors cause complete loss of the grain because it is no longer fit for human or livestock consumption. The main objective of th is work was to evaluate the incidence of Euxesta spp. in Brazilian maize fields and to determine the most prevalent species using two different hydrolyzed protein foods attractants, BioAnastrepha® (hydrolyzed maize protein) and Torula, placed inside McPhail traps. The two species identified were E. eluta Loew and E. mazorca Steyskal, the latter being a new record from Brazil. Between the two species, E. eluta was the more abundant in maize fields. Both attractants were efficient in capturing the two species. However, BioAnastrepha® captured significantly more insects than Torula. Levantamento de mosca-da-espiga (Diptera: Ulidiidae) em milho (Zea mays L.) e primeiro relato de ocorrência de Euxesta mazorca Steyskal no Brasil. Espécies de Euxesta (Diptera, Ulidiidae), conhecidas como moscas do cabelo ou moscas da espiga estão aumentando em importância nas culturas de milho em diferentes países, embora muito pouco se conheça sobre elas no Brasil. As larvas das espécies representativas de Ulidiidae inicialmente danificam a parte reprodutiva feminina da planta e depois os grãos em desenvolvimento. Como resultado da alimentação das larvas ocorre fermentação e odor forte tornando a espiga inapropriada para o consumo humano ou animal. O principal objetivo deste trabalho foi avaliar a incidência de espécies de Euxesta em áreas de produção de milho e identificar as espécies predominantes usando dois atraentes alimentares diferentes à base de proteínas hidrolisáveis, BioAnastrepha® (proteína hidrolisável de milho) e Torula, colocados no interior de armadilha McPhail. As duas espécies identificadas foram E. eluta Loew and E. mazorca Steyskal, registrada pela primeira vez no Brasil. Entre as espécies, E. eluta foi predominante no milho. Ambos os atraentes foram eficientes na captura das duas espécies. No entanto, as armadilhas com BioAnastrepha® capturaram significativamente mais insetos do que aquelas com Torula.