Performance of the pineapple sweet orange on different rootstocks / Desempenho da laranja doce abacaxi em diferentes porta-enxertos

This study aimed at evaluating the agronomical performance of 'Pineapple' sweet orange grafted on ten rootstocks, in 2011-2017 harvests, so as to recommend the best combinations to be commercially explored in citrus growing regions in Bahia and Sergipe states, Brazil. An experiment wasinstalled to test ten rootstock for 'pineapple' sweet orange: 'Santa Cruz' Rangpur lime, 'Red Rough' Lemon, 'Orlando' Tangelo, 'Sunki Tropical' Mandarin, 'Swingle' citrumelo, the citrandarins 'Indio' and 'Riverside' and the hybrids HTR-051, LVKxLCR-010 and TSKxCTTR-002. The trial was installed in 2008 in the municipalityof Umbauba in Sergipe. The experimental design was complete randomized blocks with four replications and two plants per plot. Plant spacing was 6 x 4 m which corresponds to 416 plants per hectare and the orchard was rainfed and followed conventional management. The following agronomical parameters were evaluated: vegetative growth, drought tolerance, yield and physico-chemical quality of fruits as well as the abundance of phytophagous mites. Both hybrids LVK x LCR ­ 010 and TSKC x CTTR-002 and the 'Santa Cruz' rangpur lime bestowed higher tolerance to the dry period on the 'Pineapple' orange tree, by comparison with higher water deficit susceptibility conferred by the 'Orlando' tangelo and the 'Swingle' citrumelo. Rootstocks HTR-051, 'Riverside' citrandarin, 'Swingle' citrumelo and TSKC x CTTR-02 induced plants to remain small and, thus, showed aptitude for culture densification. Cumulative yield of the 'Pineapple' orange was higher on rootstocks 'Red Rough' lemon and 'Santa Cruz' Rangpur lime, the hybrid LVK x LCR-010 and 'Sunki Tropical'. Yield efficiency was not influenced by the rootstocks. Physico-chemical quality of fruits of 'Pineapple' orange is affected by the rootstocks and meets the requirements of juice industries. Regarding plant resistance, the rootstocks did not influence the population density of mites P. oleivora, E. banksi and T. mexicanus on 'Pineapple' oranges. Results show that both rootstocks 'Red Rough' lemon and 'Santa Cruz' rangpur lime conferred high regularity to 'Pineapple' orange trees in citrus growing regions in Bahia and Sergipe states

O objetivo deste trabalho foi avaliar o desempenho agronômico da laranjeira 'Pineapple' em combinação com dez porta-enxertos, nas safras 2011-2017, com vistas à recomendação das melhores combinações para exploração comercial na região citrícola dos estados da Bahia e de Sergipe. O experimento consistiu de laranja doce 'pineapple' enxertado nos porta-enxertos limoeiros 'Cravo Santa Cruz', limoeiro 'Rugoso Vermelho', tangeleiro Orlando, tangerineira 'Sunki' Tropical, citrumelo 'Swingle', citrandarins 'Indio', 'Riverside', além dos híbridos HTR ­ 051 e LVK x LCR ­ 010 e 'TSKC x CTTR ­ 002'. O trabalho foi instalado em 2008, no município de Umbaúba, em Sergipe, no delineamento experimental de blocos ao acaso, com quatro repetições, duas plantas por parcela, no espaçamento de 6m x 4m, correspondendo a uma população de 416 plantas· ha-1, com manejo em sistema de produção convencional, sem o uso de irrigação. Os seguintes parâmetros agronômicos foram avaliados: crescimento vegetativo, tolerância à seca, produção e qualidade físico-química de frutos, além da abundância de ácaros fitófagos. Os híbridos LVK x LCR - 010 e TSKC x CTTR - 002, assim como o limoeiro 'Cravo Santa Cruz', conferiram um maior nível de tolerância ao período seco, em contraste com maior suscetibilidade à seca relacionada ao tangelo 'Orlando' e ao citrumelo 'Swingle'. Os porta-enxertos HTR - 051, citrandarin 'Riversidade', citrumelo 'Swingle' e TSKC x CTTR - 002 induziram menor porte às plantas, demonstrando aptidão ao adensamento de plantio. A produção acumulada da laranjeira 'Pineapple' foi maior sobre os porta-enxertos limoeiros 'Rugoso Vermelho' e 'Cravo Santa Cruz', híbrido LVK x LCR - 010 e tangerineira 'Sunki Tropical'. A eficiência produtiva não foi influenciada pelos porta-enxertos. A qualidade física e química de frutos da laranjeira 'Pineapple' foi afetada pelos porta-enxertos e atendeu aos padrões exigidos pela indústria de sucos. Os porta-enxertos estudados não causaram variações nos níveis de populações dos ácaros Phyllocptruta oleivora, Eutetranychus banksi e Tetranychus mexicanus. Com base nos resultados conclui-se que os limoeiros 'Rugoso Vermelho' e 'Cravo Santa Cruz' determinam maior regularidade de produção de frutos à laranjeira 'Pineapple' nas regiões produtoras da Bahia e de Sergipe

Spatial-temporal distribution of phytophagous and predatory mites in the canopy of Jatropha curcas L / Distribuição espaço-temporal de ácaros fitófagos e predadores no dossel de plantas de pinhão-manso

The aim of the present study was to evaluate the spatial-temporal distribution of phytophagous and predatory mites in the canopy of Jatropha curcas L. Mite richness, diversity, and abundance were determined, and higher values were observed primarily in the top stratum. Mite population in J. curcas was higher during the rainy season. Phytophagous mites were mostly concentrated in the top stratum, and Brevipalpus sp. was the most abundant. Predatory mites from the family Phytoseiidae presented the highest richness and diversity, and Amblydromalus zannoui was the most abundant species. The present results indicate seasonal population dynamics for both predatory and phytophagous mites on J. curcas.(AU)

O presente estudo teve por objetivo avaliar a distribuição espaço-temporal de ácaros fitófagos e predadores no dossel de plantas de pinhão-manso. Parâmetros de riqueza, diversidade e abundância de ácaros foram determinados. Os resultados deste estudo demonstram que maiores valores de riqueza, diversidade e abundância de ácaros foram observados principalmente no estrato apical e que os níveis populacionais desses artrópodes em plantas de pinhão-manso são mais expressivos na estação chuvosa. Os ácaros fitófagos concentram-se distribuídos principalmente no estrato apical, sendo Brevipalpus sp. a espécie mais abundante. Ácaros predadores da família Phytoseiidae foram aqueles de maior riqueza e diversidade, sendo o ácaro predador Amblydromalus zannoui o mais abundante. Os resultados obtidos neste trabalho sugerem uma dinâmica sazonal tanto para populações de ácaros predadores quanto para ácaros fitófagos em pinhão-manso.(AU)

No evidence of coconut stem bleeding disease transmission by bark beetles in Brazil / Não evidência de transmissão da doença resinose do coqueiro por escolitíneos no Brasil

ABSTRACT: Stem bleeding disease, caused by the fungus Thielaviopsis paradoxa is one of the most important diseases of coconut palm Cocos nucifera worldwide and some insect species have been found in association with T. paradoxa infected coconut palms. The present research investigated whether coconut palm-infesting bark beetles (Coleoptera: Curculionidae: Scolytinae) could disseminate stem bleeding disease. Adult bark beetles collected from coconut palms presenting stem bleeding symptoms were inoculated in PDA culture medium. Results showed no germination of the fungus T. paradoxa from either cuticle or digestive tract of bark beetles. Thus, we found no evidence that bark beetles carry viable spores of T. paradoxa that could infect healthy coconut palms and disseminate stem bleeding disease.

RESUMO: A resinose, causada pelo fungo Thielaviopsis paradoxa, é uma das doenças mais importantes do coqueiro Cocos nucifera em todo o mundo, e algumas espécies de insetos têm sido encontradas em associação com coqueiros infectados por T. paradoxa. O presente trabalho investigou se os besouros escolitíneos (Coleoptera: Curculionidae: Scolytinae) poderiam disseminar a resinose a partir de coqueiros infectados. Escolitíneos adultos coletados de coqueiros com sintomas da resinose foram inoculados em meio de cultura BDA. Os resultados mostraram que não houve germinação do fungo T. paradoxa da cutícula ou do trato digestivo dos insetos. Assim, não encontramos evidências de que besouros escolitíneos carreguem esporos viáveis de T. paradoxa que pudessem infectar coqueiros e disseminar a doença resinose.

Glyphosate sub-lethal toxicity to non-target organisms occurring in Jatropha curcas plantations in Brazil.

Weed management in physic nut plantations has generally been performed by spraying the herbicide glyphosate. However, the effects of glyphosate on non-target organisms present in the crop system are unknown. Here, we evaluated the toxicity of glyphosate (Roundup Transorb(®)) against the pest species Polyphagotarsonemus latus (Acari: Tarsonemidae) and Tetranychus bastosi (Acari: Tetranychidae) which can be exposed by drift. These mites are considered pests of the physic nut; however, they can also feed and reside on weeds associated with the crop, serving as food sources for predatory mites. When subjected to residue (by ingestion of sap of treated plants), and direct contact to glyphosate, P. latus reproduction was affected but T. bastosi was affected only by the residual effect. Although the herbicide caused a reduction in the number of eggs laid by the females of both pest mites, it is suggested that sublethal effects of glyphosate stimulates oviposition of P. latus and T. bastosi: both species displayed higher reproductive rates when exposed to 0.36 kg ha(-1) of the herbicide. We conclude that glyphosate negatively affects the arthropod herbivores studied and we discuss possible implications on their biological control in Jatropha curcas plantations.

Seasonal population abundance of the assembly of solitary wasps and bees (Hymenoptera) according to land-use in Maranhão state, Brazil

ABSTRACT Solitary wasps and bees (Hymenoptera) play a key role in ecosystem and agroecosystem functioning. Crops may benefit from biological pest control and pollination carried out by predatory solitary wasps and solitary bees, respectively. Here, we aimed at evaluating the abundance and faunistic compositions of solitary wasps and bees in respect to land-use (pasture, alley cropping, young fallow and old fallow) over an entire year using trap nests in the Brazilian northeastern state of Maranhão. Land-use did not influence the abundance of solitary wasps and bees, however, levels of dominance, abundance and frequency of the species Pachodynerus guadulpensis Saussure, Isodontia sp. 1, Isodontia sp. 2, Trypoxylon nitidum Smith and Megachile cfr. framea Schrottky varied with land-use. The abundance of wasps and bees varied over the period of the year with populations peeking in January (bees), and June and July (wasps). Relative humidity explained most of the variation for the abundance of wasps while temperature explained higher portions of the variance for the abundance of bees. There was an interaction between period of the year and land-use for the abundance of wasps (but not for bees). We concluded that total population abundance of solitary wasps and bees were not affected by the land-use however, levels of dominance, abundance and frequency of some species of these hymenopterans changed according to land-use. Also, relative humidity and temperature were important environmental variables explaining the abundances of wasps and bees.

Citrus rootstocks influence the population densities of pest mites / Porta-enxertos cítricos influenciam a densidade populacional de ácaros fitófagos

Citrus are attacked by pest mites such as the citrus rust mite Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae) and the spider mite Tetranychus mexicanus (McGregor) (Acari: Tetranychidae). However, little is known on citrus rootstocks influencing pest mites. We aimed to evaluate the influence of rootstocks on population densities of pest mites on the sweet oranges 'Pera CNPMF D-6' and 'Valencia Tuxpan' throughout time. Adults of both mite species were monthly counted during 19 months from June 2011 to February 2013. Rootstocks influenced the populations of pest mites, since lower densities of P. oleivora were found on 'Pera CNPMF D-6' sweet orange grafted on the hybrid TSKC × CTTR - 002 and on 'Swingle' citrumelo in comparison with the hybrid LVK × LCR - 010, 'Red' rough lime and 'Santa Cruz' rangpur lime as rootstocks. Similarly, lower densities of T. mexicanus were found on 'Valencia Tuxpan' sweet orange grafted on the hybrid HTR-051 in comparison to 'Indio' citrandarin, 'Sunki Tropical' mandarin and LVK × LCR - 010 as rootstocks. We concluded that densities of the mites P. oleivora and T. mexicanus on the sweet oranges 'Pera CNPMF D-6' and 'Valencia Tuxpan' were affected in some periods of the year by some rootstocks, suggesting influence of some genotypes on these pests.

Os citros são atacados por ácaros-praga como o ácaro-da-falsa-ferrugem Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae) e Tetranychus mexicanus (McGregor) (Acari: Tetranychidae). No entanto, pouco é conhecido sobre o efeito de porta-enxertos sobre populações de pragas. O objetivo deste trabalho foi avaliar a influência de porta-enxertos nas densidades populacionais de ácaros-praga nas laranjeiras 'Pera CNPMF D-6' e 'Valência Tuxpan' ao longo do tempo. Adultos das espécies de ácaro citadas foram quantificados mensalmente, durante 19 meses, de junho de 2011 a fevereiro de 2013. Os porta-enxertos influenciaram as populações dos ácaros-praga, uma vez que menores densidades de P. oleivora foram encontradas em laranjeira 'Pera CNPMF D-6', enxertada no híbrido TSKC × CTTR - 002 e no citrumelo 'Swingle', em comparação com o que se observou em relação aos porta-enxertos LVK × LCR - 010, limoeiro 'Rugoso vermelho' e limoeiro 'Cravo Santa Cruz'. Similarmente, menores densidades de T. mexicanus ocorreram em laranjeira 'Valência Tuxpan' enxertada no híbrido HTR-051, em comparação com o que se deu em relação aos porta-enxertos citrandarin 'Indio', tangerineira 'Sunki Tropical' e LVK × LCR - 010. Concluiu-se que as densidades dos ácaros P. oleivora e T. mexicanus nas laranjeiras 'Pera CNPMF D-6' e 'Valencia Tuxpan' foram afetadas pelo porta-enxerto em determinados períodos do ano, sugerindo influência de alguns genótipos sobre essas pragas.

Forest fragments' contribution to the natural biological control of Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in Maize

The present work evaluated the influence of forest distance on predatory solitary wasps' abundance and richness and its relation to the natural biological control of the fall armyworm (Spodoptera frugiperda Smith - Lepidoptera: Noctuidae) in maize. The study consisted of two parallel lines of six experimental maize plots located at an increasing distance from a forest edge. Four trap-nests were placed in the vertices of each plot of the first line to evaluate the abundance and species richness of predatory solitary wasps. The larvae of the fall armyworm were sampled weekly by inspecting ten randomly chosen plants per plot. Predatory solitary wasp abundance (but not species richness) decreased whilst the fall armyworm abundance increased with the distance from the forest. Moreover, population densities of predatory solitary wasps and the fall armyworm were negatively correlated. Results suggested that the crop plantations located near forest fragments might benefit from the reduced pest problems as a result of increased natural biological control.