Raimunda Nonata Santos de Lemos

Ocorrência de Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae) no Maranhão

Aleurocanthus woglumi Ashby in citrus and mango crops in the state of Maranhão, Brazil, is recorded. Samples of 2003 and 2004 from several counties were identified and deposited in the Insect Collection of the Laboratório de Entomologia of the Núcleo de Biotecnologia Agronômica, Universidade Estadual do Maranhão.

Dinâmica populacional da mosca-negra-dos-citros Aleurocanthus woglumi ashby (hemiptera: aleyrodidae) em Citrus spp. no município de São Luís - MA

This paper aims to evaluate the populational dynamics of Aleurocanthus woglumi throughout one year, verifying the season with higher density, its populational peaks and citrus blackfly distribution in Citrus spp. in two orchards, in Sao Luis, Maranhao, Brazil. To study the populational dynamics, 10 plants were selected at random, in each orchard, as well as 20 leaves per plant, from July 2006 to June 2007, and the number of layings, eggs and nymphs was counted. To determine the vertical distribution of A. woglumi, plants were divided into quadrants: North, East, South and West, and 5 leaves/quadrant were removed, totaling 200 leaves per collecting area. Regarding to distribution over the plant, the delineation was entirely randomized adopting a 2 x 4 factorial scheme (dry and rainy seasons x quadrants), with 13 repetitions (number of collections). It accomplished an exploratory analysis of data and averages submitted to Tukey test at a 5% probability rate. It was observed that on the two locations the insect was distributed homogeneous on the tree canopies and that the highest populational levels of A. woglumi occurred in the low precipitation season (from July to December 2006).

Parasitismo de ovos de Tibraca limbativentris Stal (Hemiptera: Pentatomidae) na cultura do arroz no Maranhão

The rice stem bug, Tibraca limbativentris Stal, is an important pest of rice in Brazil. This work evaluated the occurrence of parasitoids in eggs of T.limbativentris egg parasitism in rice crops in the Maranhão State. The eggs collected exhibited an average parasitism of 32%. The parasitoids collected were Telenomus podisi (Ashmead), Trissolcus urichi (Crawford) (Hymenoptera: Scelionidae) and Oencyrtus submetallicus (Howard) (Hymenoptera: Encyrtidae).

Efeito do recipiente e ambiente de cultivo sobre o desenvolvimento de mudas de mamoeiro cv. Sunrise Solo

The present work aimed to evaluate the effect of three containers and three environments of cropping on the development of papaya seedlings (Carica papaya L.) Cv. Sunrise Solo, at the tropical climate of Sao Luis Island, State of Maranhao, Brazil. The used containers were black polyethylene bags of 20 x 32 cm and 15 x 20 cm and polystyrene trays of 72 cells and as environment conditions were used plastic house, black-screen house of 50% sunlight and open sky. The data taken and evaluated were plant height, diameter of stem, and leaf number. In the period of June 14th to July 21st 2004 were monitored precipitation, temperature and relative humidity, using psycrhometers of natural ventilation. According to the results, it was concluded that the seedlings of papaya produced in the polyethylene bag 20 x 32 cm promotes superior performance in all analyzed characters; the polystyrene tray revealed inadequate for the production of papaya seedlings; over 45 days after sowing, the open sky environment, showed more satisfactory conditions to the seedlings development; past 60-days from sowing, the seedlings produced under the black-screen presented a thin and yellowish growing.

Genetic variability of the Bemisia tabaci (Gennadius) biotype B (Hemiptera: Aleyrodidae) in vegetable crops in São Luís, State of Maranhão, Brazil

The RAPD technique is widely used to investigate the distinct genetic characteristics of the complex Bemisia tabaci (Gennadius), which is currently constituted of approximately 41 biotypes. The objective of this research was to characterize populations of whitefly collected in crops of agricultural producing areas in São Luís, MA, like okra, beans and pepper, using RAPD molecular markers. Females from nine whitefly populations were analyzed and compared with B. tabaci biotype B taken from poinsettia culture of Embrapa Genetic Resources and Biotechnology (Brasília, DF). Twelve out of the 20 primers tested produced specific band patterns suitable to confirm that the evaluated specimens belong to the biotype B of B. tabaci, despite the high percentage of detected polymorphism. The analysis of the 96 RAPD molecular markers generated indicated that the populations on okra, beans and pepper were grouped according to the host cultures, sharing 80, 76 and 45% of genetic similarity, respectively, when compared with the control population of B. tabaci biotype B. A lower selective pressure was observed with the population of whitefly collected on pepper and minor genetic variability in the whitefly populations collected on okra and bean, when compared with the control population.

Preferência para oviposição e ciclo de vida de mosca-negra- dos-citros Aleurocanthus woglumi Ashby em espécies frutíferas

Aleurocanthus woglumi Ashby, popularly known as the citrus blackfly is considered A2 quarantine pest in Brazil and causes damage in many fruit crops, especially citrus (orange, lemon and tangerine). Few researches related to biological aspects are carried out in Brazilian environmental conditions. The present research aimed to determine the oviposition preference and duration of the life cycle of A. woglumi on different hosts. The research was carried out in a greenhouse during the period of March 2009 to March 2010. Tests of preference were done with no chance of choice in six hosts, in periods of 48 and 72 hours, beyond the comparative biology in mango and orange trees. A. woglumi showed preference for laying eggs on citrus species (lemon, orange and mandarin), maintaining a pattern of non-preference in cashew and guava trees. The orange and mango hosts did not interfere in the life cycle of the pest.

Occurrence of Purpureocillium lilacinum in citrus black fly nymphs

Black fly is a pest of Asian origin that causes direct and indirect damages to citrus, damaging the development and production of plants. For the development of efficient management strategies of the pest, the integration of control methods is necessary, and biological control is the most appropriate. Among the agents that can be used, entomopathogenic fungi are considered one of the most important and wide-ranging use. This work investigated the occurrence of Purpureocillium lilacinum (Thom.) Luangsa-ard et al. (= Paecilomyces lilacinus), attacking nymphs of citrus black fly, Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae). The fungus was isolated from infected Black fly nymphs, present on Citrus spp leaves in the municipality of Morros, Maranhão. After isolation, purification and morphological and molecular characterization, pathogenicity test was performed with A. woglumi nymphs. Morphological and molecular correspondence was verified between inoculum and the reisolated, proving the pathogenicity of P. lilacinum.

Hymenopteran parasitoids associated with scale insects (Hemiptera: Coccoidea) in tropical fruit trees in the eastern Amazon, Brazil

Abstract Fifteen species of parasitoids emerged from 6 species of scale insects, all are recorded for the first time in Maranhão State, Brazil. A total of 20 coccoid/parasitoid associations were found, 5 of which are new host records for the parasitoid species: Coccus hesperidum (L.) (Hemiptera: Coccidae) with Arrhenophagus chionaspidis (Aurivillius) (Hymenoptera: Encyrtidae); and Praelongorthezia praelonga (Douglas) (Hemiptera: Ortheziidae) with Aenasius sp. (Hymenoptera: Encyrtidae), Encyrtus aurantii (Geoffroy) (Hymenoptera: Encyrtidae), Aprostocetus sp. (Hymenoptera: Eulophidae) and Signiphora sp. (Hymenoptera: Signiphoridae).

Flutuação populacional e dependência espacial de Aleurocanthus woglumi Ashby, 1915 (Hemiptera: Aleyrodidae) em Citrus latifolia

The citrus blackfly, Aleurocanthus woglumi, presents high dispersal ability and adaptability to diverse climatic conditions as well as large reproductive potential. This study aimed to evaluate the populational fluctuation and to characterize the pattern of spatial dependence of citrus blackfly in a commercial orchard of Tahiti lime (Citrus latifolia Tanaka), in Sao Jose de Ribamar county, state of Maranhao. A global positioning system (GPS) and geographic information system (GIS) were used to locate the points of the samples, to characterize the pattern of distribution, calculate the aggregation area and produce distribution maps of the adults of citrus blackfly in the orchard. The average total number of citrus blackflies was higher during the rainy season and there were significant correlations between the variables rainfall, relative humidity and total number of adults. The spatial distribution of A. woglumi in the orchard is aggregated, adjusting the calculated variograms to the spherical model in the dry and rainy seasons. The insects showed an area of mean aggregation of 162,092 m2 in the rainy season and 9,615 m2 in the dry season. Thus, to obtain a reliable estimate of citrus blackfly populations, at least one trap should be used every 17 hectares in the rainy season and one trap per hectare in the dry season.

Fungos e nematóides fitopatogênicos associados ao cultivo de flores tropicais em São Luís - MA

Considerando a importância do cultivo de flores tropicais no contexto nacional e internacional, buscou-se realizar um levantamento da ocorrencia de fungos e nematoides associados as mesmas, em areas de cultivos de flores tropicais em Sao Luis - MA. Foram realizadas visitas periodicas, em intervalos bimestrais, nos locais onde a principal atividade era o cultivo de flores tropicais, para o monitoramento e coleta de plantas ou partes de plantas das especies: Heliconia spp., Alpinia purpurata e Etlingera elatior com sintomatologia tipica de doencas. Realizou-se, ainda, o teste de patogenicidade dos principais fungos detectados como agentes causais das manchas foliares. Os resultados obtidos confirmaram a existencia de fungos associados aos cultivos de flores tropicais em Sao Luis, com destaque para Curvularia eragrostides (78 %), Pestalotiopsis sp. (68 %) e Colletotrichum gloeosporioides (47 %) como agentes causais de manchas foliares em especies da familia Heliconiaceae, e Curvularia eragrostides (75 %), Pestalotiopsis sp. (37 %) em especies da familia Zingiberaceae. Foram registrados oito generos de nematoides, tanto na familia Heliconiaceae, quanto na Zingiberaceae, destacando-se o genero Meloidogyne.