Entomopathogenic nematodes (EPNs) (Steinernematidae and Heterorhabditidae) can control pests due to the mutualistic association with bacteria that kill the host by septicemia and make the environment favorable for EPNs development and reproduction. The diversity of EPNs in Brazilian soils requires further study. The identification of EPNs, adapted to environmental and climatic conditions of cultivated areas is important for sustainable pest suppression in integrated management programs in agricultural areas of Brazil. The objective was to identify EPNs isolated from agricultural soils with annual, fruit and forest crops in Brazil. Soil samples were collected and stored in 250 ml glass vials. The nematodes were isolated from these samples with live bait traps ([Galleria mellonella L. (Lepidoptera: Pyralidae) larvae]. Infective juveniles were collected with White traps and identified by DNA barcoding procedures by sequencing the D2/D3 expansion of the 28S rDNA region by PCR. EPNs identified in agricultural areas in Brazil were Heterorhabditis amazonensis, Metarhabditis rainai, Oscheios tipulae and Steinernema rarum. These species should be considered pest biocontrol agents in Brazilian agricultural areas.
resumo-o Brasil é o maior produtor, consumidor e exportador de acerola (Malpighia emarginata d.c.) do mundo. Por conter altos teores de vitamina c, tornou-se uma fruta altamente requisitada no mercado mundial para o preparo de sucos e no consumo in natura. nos últimos anos, as lavouras desta fruta vêm apresentando um decréscimo nas produções em razão da ocorrência de nematoides de galhas (Meloidogyne spp.), um dos principais problemas que afetam a cultura. o objetivo deste trabalho foi avaliar a resistência de genótipos de aceroleira frente à Meloidogyne enterolobii. o experimento foi conduzido em casa de vegetação do departamento de Proteção Vegetal, da Faculdade de ciências agronômicas/UneSP -câmpus de Botucatu (SP). Foram utilizados cinco clones: cereja-Brs-236; Fruta cor-Brs-238; Roxinha-Brs-237; Mirandópolis; Japi, e três variedades: okinawa; olivier e Waldy-caTi. cada planta foi inoculada com 2.500 ovos e eventuais juvenis de segundo estádio (Pi) de M. enterolobii. após 60 dias, a parte área de cada planta foi descartada, e o sistema radicular lavado, submetido à coloração com floxina-B e examinado para a obtenção dos índices de galhas (iG) e massa de ovos (iMo), e processados pelo método de trituração em liquidificador, peneiramento e centrifugação com sacarose para a obtenção do número total de ovos (Pf), que foi utilizado para o cálculo do fator de reprodução (Pf/Pi). Todos os clones e as variedades foram considerados suscetíveis à Meloidogyne enterolobii apresentando os fatores de reprodução variando de 4,1 a 18,3. termos de indexação: acerola, nematoide de galha, resistência. reactIon In BarBados cherry (Malpighia emarginata d.c.)to Meloidogyne enterolobii aBstract-Brazil is the biggest producer, consumer and exporter of acerola (Malpighia emarginata d.c.). it has become a highly requested fruit in the world market for preparing juices and consumption in nature because it contains high levels of vitamin c. nowadays brazilian acerola orchards have shown decrease in production due to the occurrence of root-knot nematodes, one of the main problem affecting the culture. The aim of this study was to evaluate the resistance of acerola genotypes to Meloidogyne enterolobii. The experiment was conducted in greenhouse of the department of Plant Protection of agronomic Science college -Fca/UneSP -Botucatu, SP. Five clones, cherry-Brs-236; Fruit color-Brs-238; Roxinha-Brs-237; Mirandópolis; Japi, and three varieties, okinawa; olivier and Waldy-caTi, were studied. each plant was inoculated with 2,500 M. enterolobii eggs and second stage juveniles (Pi). after 60 days the roots of each plant was washed, staining with phloxine-B and examined for obtaining gall and egg mass indices (Gi; eMi), and processed by blender, sieving and centrifugation method to obtain the total number of eggs (Pf), which was used to calculate the reproduction factor (Pf / Pi). all acerola clones and varieties were considered susceptible to Meloidogyne enterolobii, with RF ranging from 4.1 to 18.3. Index terms: acerola, root-knot nematode, re...
The Mediterranean fruit fly Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) is among the main pests of fruit crops worldwide. Biological control using entomopathogenic nematodes (EPNs) may be an alternative to suppress populations of this pest. Thus, the aim of this study was to evaluate the pathogenicity and virulence of six EPN isolates (Heterorhabditis bacteriophora HB, H. amazonensis IBCB-n24, Steinernema carpocapsae IBCB-n02, S. rarum PAM-25, S. glaseri IBCB-n47, and S. brazilense IBCB-n06) against C. capitata pupae. The compatibility of EPNs with different chemical insecticides that are registered for management of C. capitata was also assessed. Isolates of H. bacteriophora HB and S. brazilense IBCB-n06 at a concentration of 1,000 infective juveniles (IJ)/ml proved to be most pathogenic to C. capitata (70 and 80% mortality, respectively). In contrast, the isolates H. amazonensis IBCB-n24, Steinernema carpocapsae IBCB-n02, S. rarum PAM-25, S. glaseri IBCB-n47 provided pupal mortality of less than 60%. Bioassays to determine lethal concentrations indicated that concentrations of 600 IJ/ml (H. bacteriophora HB) and 1,000 IJ/ml (S. brazilense IBCB-n06) showed the highest virulence against C. capitata pupae. In contrast, the highest numbers of IJs emerged at concentrations of 1,200 and 200 IJ/ml. In compatibility bioassays, malathion, spinetoram, phosmet, acetamiprid, and novaluron were considered compatible with and harmless (Class 1) to H. bacteriophora HB and S. brazilense IBCB-n06, according to IOBC/WPRS. This information is important for implementing integrated management programs for C. capitata, using biological control with EPNs, whether alone or in combination with chemical insecticides.
Anastrepha fraterculus (Diptera: Tephritidae) is among the most important fruit pests in South America, and the use of entomopathogenic fungi is considered a promising alternative for its control. The objective of this work was to evaluate the pathogenicity of Beauveria bassiana (Balsamo) Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin on larvae and pupae of A. fraterculus, along with fungal effects on adult fly longevity. Fungal inoculations, fly larvae or pupae were placed in Petri dishes with 1 mL/plate, and the concentrations of 10, 15, 20 and 25 grams of commercial product/liter of water. Controls received water only. To evaluate the residual effect on adult flies, emerging adults were transferred to clean arenas and the adult longevity was monitored. Beauveria bassiana and M. anisopliae caused 93.3 and 96.7% larval mortality and 14.0 and 15.0% pupal mortality, respectively. The estimated LC50 and LC90 values were 22.56 and 40.87 g/L for B. bassiana, and of 23.45 and 42.02 g/L for M. anisopliae. Infected adult insects had shorter longevity than non-infected insects, with mean survival of 8.0 and 83.5 days for B. bassiana and M. anisopliae, respectively.
Meloidogyne enterolobii, reported in different regions of Brazil, is a polyphagous nematode parasitising plants resistant to other root-knot nematode species. This study evaluated the resistance of six cultivars of Avena sativa, seven cultivars of Triticum aestivum and 13 hybrids of Sorghum bicolor to M. enterolobii. The experiment was conducted in a glasshouse. The soil was autoclaved and infested with 5000 eggs of M. enterolobii. The tomato ‘Rutgers’ was used as the susceptible standard to this nematode. The indices of galls, egg masses, and reproduction factor of M. enterolobii were evaluated 60 days after inoculation. This nematode did not reproduce in any of the genotypes considered resistant. The oat, wheat and sorghum cultivars studied may be recommended for crop rotation in areas infested with M. enterolobii.
Meloidogyne spp. are the most economically important species of plant-pathogenic nematodes. Plant resistance and crop rotation are the main nematode management methods. Thus, the objective was to evaluate the resistance of seven wheat genotypes, five oat genotypes, ten sorghum hybrids, and three sorghum-sudangrass genotypes to Meloidogyne incognita and Meloidogyne javanica. The crops were sowed in pots with an autoclaved substrate. A single plant/pot was left after thinning. The soil was infested with 5,000 eggs of the studied nematodes. Tomato (cv. Rutgers) plants were used as the standard for nematode susceptibility. The evaluations were conducted 60 d after inoculation. Gall and egg-mass indexes were obtained according to a 0-5 scale. Plants with a reproduction factor higher than 1.0 were classified as susceptible (S) and lower than 1.0 as resistant (R). Wheat and oat genotypes did not allow M. incognita and M. javanica reproduction, proving resistance to these organisms. Sorghum genotypes had different reactions to M. incognita and M. javanica. The tomato (cv. Rutgers) plants demonstrated the viability of the nematode inoculum for the three crops. The wheat and oat genotypes and the sorghum hybrids 'BRS-610', 'BRS-800', and '307.343' can be used in crop rotation systems for M. incognita and M. javanica management.
A soja é considerada uma das mais importantes culturas do agronegócio no Brasil. Os levantamentos populacionais de fitoparasitos, é uma ferramenta importante na presença de nematoides e na detecçao dos prejuizos. O presente estudo teve como objetivo, utilizando como ferramenta, a geoestatística, verificar a variabilidade espacial de Meloidogyne javanica em duas lavouras de soja, uma apresentando plantas com sintomas característicos do parasitismo do nematoide e outra área com plantas sem sintomas. O estudo foi realizado no município de Araruna, estado do Paraná, ambas cultivadas com soja cultivar BMX Potência RR. Coletaram-se solo e raiz seguindo malha irregular de 50 pontos georreferenciados. Para verificar a existência e estimar o grau de dependência espacial entre as populações, utilizou-se a análise geoestatística. Após o ajuste do variograma foi realizado a krigagem e sequencialmente o mapa de distribuição espacial de nematoides nas áreas. Palavras-chave: distribuição horizontal, nematoide das galhas, geoestatística. RESUMOde solo, e em baixo nível populacional, por isso, tais dados não foram analisados com a geoestatística. Na área apresentando plantas amareladas e com tamanho reduzido, em 60% das amostras foi detectado a presença de M. javanica, sendo que a população obtida variou de 0 a 70.992 nematoides em 10g de raiz, com média de 3.807. O variograma ajustou-se ao modelo esférico, com alcance de 30,80 m e dependência espacial de 86%, nesse caso seria necessária a coleta de nove subamostras para representar um hectare de forma satisfatória. Na área onde não foram observadas plantas com sintomas visíveis, 38% das amostras estavam com M. javanica, e com baixo nível populacional. A população obtida variou de 0 a 2.184 nematoides em 10g de raiz, com media de 262. O alcance obtido foi de 11,60 m, com dependência espacial de 99% e ajuste ao modelo gaussiano, já nesse caso, seria necessária a coleta de 74 subamostras para a representação satisfatória de um hectare. A análise geoestatística mostrou-se eficiente para estudos de distribuição espacial de nematoides fitoparasitas. ABSTRACTSoybean is considered one of the most important crops for agribusiness in Brazil. Surveys of plant parasitic populations constitute an important tool to detect the presence of nematodes and losses. This study aimed to use geostatistics as a tool to check the spatial variability of Meloidogyne javanica in two soybean crops, one of which presented plants with symptoms characteristic of nematode parasitism and the other area had plants without symptoms. The study was conducted in the city of Araruna, Paraná State, and both areas were cultivated with soybean cultivars BMX Power RR. Soil and root were collected by following irregular grid of 50 georeferenced points. To check and estimate the degree of spatial dependence among the populations, geostatistical analysis was used. After adjusting the variogram, kriging and sequentially the spatial distribution map of nematodes in the areas were obtained. The whole geostatistical process was...
The objective of this study was to evaluate the reproduction of Meloidogyne graminicola in 22 cultivars of rice used in the southern region of Brazil according to the irrigation management. The design was completely randomized in a factorial scheme, being the factor A: rice cultivars and factor B: irrigation management (dry and flooded). The rice cultivars were kept individually in pot with sterilized substrate and inoculated with 5,000 eggs and juveniles (second stage-J2) of the nematode. Plants to rice cultivate BRS IRGA 410 was inoculated with M. graminicola and were used as controls. At 60 days after inoculation, the root system of each plant was evaluated number of galls (NG), number of nematodes per gram root (NNGR) and the reproduction factor (RF). The results demonstrate that M. graminicola can parasitize and develop in different rice cultivars that are commonly used in commercial crops in the Southern region of Brazil, and all cultivars evaluated were classified as susceptible to this nematode (FR> 1.00). The cultivation system under flood conditions showed significantly lower values for the NG, NNGR and RF. Highlighted Conclusions 1. The cultivars BRS Firmeza, IRGA 421, IRGA 423, IRGA 424, IRGA 436, IRGA 428 CL, IRGA 429, Inov CL, Avaxi CL, BRS Catiana and SCS121 CL showed the lowest RF in the flooded crop. 2. The use of cultivars with lower nematode RF in early flood cropping systems is a strategy indicated to reduce the population and the potential for damage caused by M. graminicola
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