ABSTRACT
We report for the first time the detection of Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) in Brazil and describe the occurrence of the thrips on leaves of ungrafted dwarf-cashew Anacardium occidentale Linnaeus 1753 (Anacardiaceae), maintained into a greenhouse, in the northeastern state of Ceará. This exotic polyphagous species listed as absent quarantine pest in the country is originated in Asia, but since the beginning of this century, it has readily dispersed despite the strict quarantine regulations currently in several countries. Individuals of S. dorsalis identified in Brazil are similar to specimens found in South Africa rather than Asia by virtue of the absence of conspicuous reticulation on the posterior half of the metanotum and the presence of complete lines of microtrichia restricted to the posterior part of the abdominal sternites. Scirtothrips dorsalis is a particularly invasive pest and its introduction represents a potential threat to various crops in Brazil, especially mango.
Subject(s)
Thysanoptera/anatomy & histology , Thysanoptera/classification , Anacardium , Animals , BrazilABSTRACT
Leafminers (Liriomyza sativae) are the main melon (Cucumis melo L.) pests in Northeast Brazil, which is the main region for the production and export of the fruit in Brazil. Of the integrated management strategies available, genetic resistance is the best method of preventing damage by these insects. The aim of this study was to select sources of resistance to leafminers in melon germplasm. Seven experiments were conducted in the laboratory, field, and greenhouse, with and without choice, using 52 melon accessions and 4 commercial hybrids as controls. Genetic variability among the accessions made it possible to select four new sources of resistance: 'CNPH 11-1072' and 'CNPH 11-1077', because they exhibited lower levels of infestation by the insect (antixenosis); and 'CNPH 00-915(R)' and 'BAGMEL 56(R)', because the pest larvae died soon after beginning to feed on the leaf mesophyll (antibiosis).
Subject(s)
Cucumis melo/genetics , Cucumis melo/parasitology , Diptera/physiology , Animals , Antibiosis , Brazil , Genetic Variation , Insect Repellents , Larva , Pest Control, BiologicalABSTRACT
Objetivou-se testar a atividade inseticida de pós vegetais em Sitophilus zeamais. Foram testados os pós de Anadenanthera colubrina (folhas); Annona muricata (sementes); Azadirachta inidica (folhas e flores); Caesalpinia pyramidalis (folhas), Chenopodium ambrosioides (folhas e flores); Cymbopogon sp.(folhas); Cymbopogon citratus (folhas); Momordica charantia (folhas e frutos); Piper nigrum (sementes); e Ricinus communis (folhas). Além disso, avaliou-se o potencial inseticida de folhas e flores de C. ambrosioides em diferentes dosagens. Na avaliação de repelência foi estabelecido um índice de preferência, e utilizado o teste t para comparação das médias das espécies vegetais. Também foi realizada a comparação das médias das plantas que foram classificadas como repelentes. Para avaliação da mortalidade, procedeu-se a análise de variância e a comparação das médias pelo teste de Tukey e também o teste t para comparação das médias dos tratamentos C. ambrosioides e P. nigrum. Os dados de emergência foram analisados pelo teste de Tukey. Para avaliar os dados de mortalidade, ocasionados por C. ambrosioides, determinou-se a CL50 utilizando a análise de Probit. Os dados de emergência foram verificados pela análise de regressão. As plantas que provocaram repelência foram Cymbopogon sp., C. citratus e C. ambrosioides. A planta que mais afetou a sobrevivência da praga foi C. ambrosioides, que provocou mortalidade total dos insetos infestantes e nenhuma emergência. Adultos de S. zeamais são mais suscetíveis a concentração de 0,125 g do pó de C. ambrosioides.
Effect of plant powders on Sitophilus zeamais (Mots., 1855) (Coleoptera: Curculionidae). The objective of the present study was to test the insecticidal activity of vegetable powders on Sitophilus zeamais. Powders of Anadenanthera colubrina (leaves); Annona muricata (seed); Azadirachta inidica(leaves and flowers);Caesalpinia pyramidalis(leaves);Chenopodium ambrosioides (leaves and flowers);Cymbopogon sp. (leaves);Cymbopogon citratus (leaves); Momordica charantia (leaves and fruits);Piper nigrum (seed); andRicinus communis (leaves) were evaluated. In addition, we evaluated the insecticidal potential of leaves and flowers of C. ambrosioidesat different dosages. In the evaluation of repellency a preference index was established, and the t test was used to compare the means of plant species. The means of plants that were classified as repellent were also compared. To assess mortality, we proceeded with the analysis of variance and comparison of means by Tukey test and also the t test for comparing the means of the C. ambrosioides and P. nigrum treatments. The emergence data were analyzed by Tukey test. To evaluate the data on mortality caused by C. ambrosioides, the CL50 was determined using Probit analysis. The emergence data were verified by regression analysis. Plants that caused repellency were Cymbopogon sp., C. citratusand C. ambrosioides. The plant that most affected the survival of the pest wasC. ambrosioides, which caused total mortality of insect infestations and no adult emergence. Adults of S. zeamaisare most susceptible to the concentration of 0.125 g ofC. ambrosioides powder.
