Diones Krinski

Insecticidal potential of the Annonaceae family plants

A utilizacao de plantas para o controle de insetos tem aumentado em todo o mundo. Isto ocorre porque os inseticidas vegetais apresentam moleculas biodegradaveis, sao menos toxicos a mamiferos e potencialmente adequados para utilizacao no controle de pragas. As plantas da familia Annonaceae estao ganhando destaque como biopesticidas por serem naturalmente bioativas, apresentando atividade citotoxica, antitumoral, vermicida, antimicrobiana, imunossupressora, antiemetica, inibidora do apetite e crescimento, antimalarica e tambem inseticida. A atividade inseticida das anonaceas deve-se a presenca de acetogeninas, substâncias que atuam nas mitocondrias, inibindo a NADH - ubiquinona oxidorredutase, causando a morte dos insetos. Nesta revisao, relatamos a utilizacao de anonaceas no controle de insetos, mostrando que ate o momento, apenas 42 especies de anonaceas possuem informacoes de atividade inseticida contra pouco mais de 60 especies de insetos-praga. Estas informacoes mostram que muita pesquisa ainda e necessaria, principalmente para conhecer a atividade inseticida de outras especies de anonaceas, alem de seus efeitos sobre insetos-praga ainda nao estudados. Assim, teremos como alternativa para o desenvolvimento sustentavel, a utilizacao de novos inseticidas vegetais, como os obtidos das diferentes especies de anonaceas, os quais podem atuar como mais uma ferramenta para equilibrar os exageros da agricultura quimica ou convencional.

Nymphicidal effect of vegetal extracts of Annona mucosa and Anonna crassiflora (Magnoliales, Annonaceae) against rice stalk stink bug, Tibraca limbativentris (Hemiptera, Pentatomidae)

This study aimed to verify the chloroform-methanol nymphicidal action of extracts of Annona mucosa leaves and seeds and of A. crassiflora seeds on second instar nymphs of rice stalk stink bug, Tibraca limbativentris. For each extract the concentrations of 0.5%, 1.0%, 2.0%, 4.0%, 8.0%, and two control treatments (water and Tween80®) were used. The results show that the seed extracts of A. mucosa and A. crassiflora have insecticidal activity against the T. limbativentris nymphs with statistical significance for all concentrations when compared with controls. The seed extract of A. mucosa showed the higher toxicity with greater than 75% mortality at a concentration of 1.0% in the first 24 h after application. The leaf extract of A. mucosa presented the lowest toxicity with no more than 40% mortality. The seed extract of A. crassiflora showed intermediate toxicity among all the tested extracts, and the nymphs mortality exceeded 80% for the highest concentration after 120 h of application. Considering these results, we were able to observe that the seeds extract of A. mucosa may be an alternative for the control of bed bug nymphs T. limbatriventris, especially for small producers.

Physalis angulata L. (Solanaceae): a potential host-plant of stink bugs Edessa meditabunda F. (Hemiptera, Pentatomidae)

Physalis angulata is native to South America. In Brazil is popularly known as camapu, balaozinho, jua-de-capote, bucho-de-ra, camambu, mata-fome, bate-testa and balao-rajado. Even being a species with wide ecological adaptation the studies on pest insects associated with these plants are incipient. Thus, this study reports for the first time the occurrence of stink bugs Edessa meditabunda on plants P. angulata in the Amazon region.

First Record of Helicoverpa armigera (Lepidoptera: Noctuidae) Feeding on Plectranthus neochilus (Lamiales: Lamiaceae) in Brazil

Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) is a polyphagous agricultural pest recorded in Europe, Asia, Africa, Oceania, and recently South America. Larvae of H. armigera are recorded from over 67 host families, including Asteraceae, Fabaceae, Malvaceae, Poaceae, and Solanaceae. This study documents for the first time H. armigera larvae feeding on inflorescences of “boldo-rasteiro” Plectranthus neochilus Schltr. (Lamiales: Lamiaceae). The species was identified according to external and internal characteristics of adults, morphology of eggs, and by molecular characterization. Sumario Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) e uma praga agricola polifaga com distribuicao geografica registrada na Europa, Asia, Africa, Oceania e, recentemente, na America do Sul. Devido a sua distribuicao mundial, suas larvas foram relatados em cerca de 67 familias, incluindo Asteraceae, Fabaceae, Malvaceae, Poaceae e Solanaceae. Com o recente registro de sua ocorrencia no Brasil, novas especies de plantas hospedeiras tem sido registradas. Portanto, este estudo relata a primeira ocorrencia de lagartas de H. armigera atacando inflorescencias de “boldo-rasteiro” Plectranthus neochilus Schltr. (Lamiales: Lamiaceae). A especie foi identificada de acordo com as caracteristicas externas e internas, morfologia dos ovos e tambem por caracterizacao molecular. View this article in BioOne

Oviposition preference of the neotropical brown stink bug "Euschistus heros" on artificial substrates of different colors

This study aimed to evaluate the oviposition preference of the Neotropical brown stink bug, Euschistus heros (F.) on artificial substrates of different colors (felt woven). For this, ten pairs of stink bugs were transferred into plastic pots. Each pot contained seven felts of 6x20 cm (100% polyester-atoxic) of different colors (white, black, blue, green, red, yellow and brown). The pots were evaluated daily for three weeks (21 days) being counted the number of eggs, clutches and eggs per clutch for each color of felt. The choice test was set in a completely randomized design. Data obtained was submitted to the analysis of variance and means were compared by Scott-Knott test at 5% probability. During the evaluation were produced 7074 eggs distributed in 977 clutches, accounting a mean of 7.06±0.67 eggs per clutch. Results indicated that females laid a significantly greater number of eggs (2380 and 1686) and a greater number of clutches (319 and 233) on the yellow and white felts, respectively, than on the remaining substrates. The substrates in color red, black and brown were the least preferred, and the colors blue and green were intermediate when compared with others. Therefore, the substrates colored yellow and white are suggested to be used in rearing E. heros in the laboratory.

First description of the karyotype and Ag-NORs localization of Brachychalcinus retrospina (Pisces: Characidae: Stethaprioninae) from Upper Paraguay Basin, Mato Grosso State, Brazil

Abstract Cytogenetic studies in fish can be used to discuss the evolution and phylogeny of the species, since the chromosomes are the physical basis of the genetic system of an organism. Thus, our objective was to study chromosomally the fish species Brachychalcinus retrospina to enlarge the number of karyotyped species for the Brachychalcinus genus. Specimens of B. retrospina from Angelim River, Nova Olímpia, Mato Grosso State, Brazil, presented 2n = 50 chromosomes: 16 metacentric, 24 submetacentric, six subtelocentric and four acrocentrics. The Nucleolus Organizer Regions (NOR) was detected in one chromosome pair. The results for B. retrospina corroborate those found for other species this subfamily, both in chromosome number and markings of Ag-NORs, indicating some stability chromosomal for this group.

Distribution extension and geographic distribution map of the Brazil-nut poison dart frog Adelphobates castaneoticus (Caldwell & Myers, 1990) (Anura: Dendrobatidae): new record for southwestern Pará State, Brazil

Adelphobates castaneoticus uses the woody husks of Brazil nut trees, Bertholletia excelsa , (without nuts and filled with water) as oviposition sites. Three specimens of A. castaneoticus were found near Brazil nut trees in Novo Progresso, Para State, Brazil. This record increases the distribution this species more than 500 km to the southwest.

Use of artificial substrates of different colors for oviposition by the brown stink bug Euschistus heros (Hemiptera, Pentatomidae)

Aiming to contribute to a rearing methodology for the brown stink bug, Euschistus heros, in the laboratory, we evaluated oviposition on artificial substrates of different colors. During six days, oviposition was evaluated daily, by counting the total number of eggs, number of clutches, and eggs/clutch. Females laid 12,463 eggs, in 1,677 clutches, resulting in an average of 7.28 ± 0.44 eggs/clutch. Black, brown, and green felt had the most eggs and clutches. The results demonstrated that many colors are suitable as oviposition substrate for E. heros, providing information for the mass rearing of this insect.