Management of Soybean Cyst Nematode and Sudden Death Syndrome with Nematode-Protectant Seed Treatments Across Multiple Environments in Soybean.

As soybean (Glycine max) production continues to expand in the United States and Canada, so do pathogens and pests that directly threaten soybean yield potential and economic returns for farmers. One such pathogen is the soybean cyst nematode (SCN; Heterodera glycines). SCN has traditionally been managed using SCN-resistant cultivars and rotation with nonhost crops, but the interaction of SCN with sudden death syndrome (SDS; caused by Fusarium virguliforme) in the field makes management more difficult. Nematode-protectant seed treatments have become options for SCN and SDS management. The objectives of this study were to evaluate nematode-protectant seed treatments for their effects on (i) early and full season SCN reproduction, (ii) foliar symptoms and root-rot caused by SDS, and (iii) soybean yield across environments accounting for the above factors. Using a standard protocol, field trials were implemented in 13 states and one Canadian province from 2019 to 2021 constituting 51 site-years. Six nematode-protectant seed treatment products were compared with a fungicide + insecticide base treatment and a nontreated check. Initial (at soybean planting) and final (at soybean harvest) SCN egg populations were enumerated, and SCN females were extracted from roots and counted at 30 to 35 days postplanting. Foliar disease index (FDX) and root rot caused by the SDS pathogen were evaluated, and yield data were collected for each plot. No seed treatment offered significant nematode control versus the nontreated check for in-season and full-season nematode response, no matter the initial SCN population or FDX level. Of all treatments, ILEVO (fluopyram) and Saltro (pydiflumetofen) provided more consistent increases in yield over the nontreated check in a broader range of SCN environments, even when FDX level was high.

HO-CR and HOLL-CR: new forms of winter oilseed rape (Brassica napus L.) with altered fatty acid composition and resistance to selected pathotypes of Plasmodiophora brassicae (clubroot).

The priority in oilseed rape (Brassica napus L.) research and breeding programs worldwide is to combine different features to develop cultivars tailored to specific applications of this crop. In this study, forms with a modified fatty acid composition of seed oil were successfully combined with a source of resistance to Plasmodiophora brassicae Wor., a harmful protist-causing clubroot. Three HO-type recombinants in F6-F12 generations with oleic acid content of 80.2-82.1% and one HOLL-type F6 inbred mutant recombinant (HOmut × LLmut), with a high oleic acid content (80.9%) and reduced linolenic acid content (2.3%), were crossed with the cultivar Tosca, resistant to several pathotypes of P. brassicae. The work involved genotyping with the use of DNA markers specific for allelic variants of desaturase genes responsible for the synthesis of oleic and linolenic fatty acids, CAPS (FAD2 desaturase, C18:1), and SNaPshot (FAD3 desaturase, C18:3), respectively. Of 350 progenies in the F3 generation, 192 (55%) were selected for further studies. Among them, 80 HO (≥ 72%) lines were identified, 10 of which showed resistance to at least one up to four P. brassicae pathotypes. Thirty lines in the selected progeny contained high oleic acid and less than 5% linolenic acid; eight of them belonged to the HOLL type conferring resistance to at least one pathotype. Two HO lines and two HOLL lines were resistant to four pathotypes. The resulting HO-CR and HOLL-CR inbred lines with altered seed oil fatty acid composition and resistance to P. brassicae represent unique oilseed rape material with the desired combination of valuable traits.

Identificación molecular y diversidad genética de las especies de nematodos Globodera rostochiensis y G. pallida en regiones productoras de papa de Guatemala / Molecular identification and genetic diversity of the species of nematodesGlobodera rostochiensisandG. pallidain potato growing regions of Guatemala

En Guatemala, la producción del cultivo de papa se ve afectada por los nematodos Globodera rostochiensis y Globo-dera pallida. La capacidad de ambas especies para formar quistes complica su control y provoca el aumento de sus poblaciones. En Guatemala se reporta la presencia de ambas especies de nematodos por identificación morfológica, sin embargo, no se ha realizado una confirmación molecular. Este es el primer estudio para validar la presencia de ambas especies de nematodos por PCR múltiple y la determinación de la diversidad y estructura genética de las poblaciones utilizando marcadores moleculares. Se realizaron muestreos en cuatro departamentos productores de papa del país. La identificación por PCR se realizó con el cebador común ITS5 y los cebadores PITSr3 específico para G. rostochiensisy PITSp4 para G. pallida. La caracterización molecular se realizó con el marcador AFLP. Se confirmó la presencia de las dos especies de nematodos en los cuatro departamentos. Los índices de diversidad Shannon y heterocigosidad esperada revelaron mayor diversidad genética en G. rostochiensis (H = 0.311, He = 0.301) que en G. pallida (H = 0.035, He = 0.223). Los métodos NJ, DAPC y PCA exhibieron una débil estructura entre las poblaciones de ambas especies de nematodos. Los resultados sugieren un patrón de dispersión desde Quetzaltenango hacia el resto del país, atribuido a la comercialización de semilla contaminada con nematodos. Se sugiere promover programas de socialización sobre los beneficios del uso de semilla certificada, además de constantes monitoreos moleculares para un diagnóstico certero de ambas especies de nematodos.

In Guatemala, potato crop production is affected by the nematodes Globodera rostochiensis and Globodera pallida. The ability of both species to form cysts complicates their control and causes an increase in their populations. In Guatemala, both species of nematodes have been reported by morphological identification; however, molecular confirmation has not been carried out. It is the first study to validate the presence of both nematode species by multiplex PCR and determine the diversity and genetic structure of the populations using molecular markers. Sampling was carried out in four pota-to-producing departments of the country. PCR identification was performed with the common primer ITS5 and the primers PITSr3 specific for G. rostochiensis and PITSp4 for G. pallida. We performed molecular characterization with the AFLP marker. We confirmed the presence of the two nematode species in the four departments. Shannon diversity and expected heterozygosity indices revealed higher genetic diversity in G. rostochiensis (H = 0.311, He = 0.301) than in G. pallida (H = 0.035, He = 0.223). The NJ, DAPC, and PCA methods exhibited weak structure among populations of both nematode species. The results suggest a dispersal pattern from Quetzaltenango to the rest of the country, attributed to the commer-cialization of seed contaminated with nematodes. We suggest promoting socialization programs on the benefits of using certified seeds and constant molecular monitoring for an accurate diagnosis of both species of nematodes.

Controle alternativo de helmintos de Astyanax cf. zonatus utilizando fitoterapia com sementes de abóbora (Cucurbita maxima) e mamão (Carica papaya) / Alternative control of helminthes, parasites of Astyanax cf. zonatus, using phytotherapy with seeds of Cucurbita maxima and Carica papaya

O objetivo do trabalho foi avaliar a eficácia de sementes de abóbora e mamão desidratadas e moídas, no controle de helmintos parasitos de Astyanax cf. zonatus. Sessenta peixes foram distribuídos em doze recipientes, um peixe/litro. O experimento constituiu de quatro tratamentos e três repetições: TJ = peixes deixados em jejum; TRC = peixes alimentados com ração comercial; TSA = peixes alimentados ad libitum com abóbora, e TSM = peixes alimentados ad libitum com mamão. Após sete dias de alimentação, todos os peixes foram pesados, e o sangue foi retirado para extensão sanguínea. A eficácia foi determinada, verificando a presença de parasitos nas brânquias, no estômago e no intestino. Os peixes do TJ e TSM apresentaram perda de peso (39 por cento e 25 por cento, respectivamente). O TSA apresentou melhor eficácia no controle de nematóides do intestino e do estômago (95,26 por cento e 92,48 por cento). No controle de monogenéticos TSM promoveu 72 por cento de eficácia. Na hematologia observou-se aumento de monócitos nos peixes do TSM e os valores de eosinofilos diminuíram nos tratamentos TSA, TSM e TRC. Assim pode-se concluir que a alimentação com abóbora pode ser utilizado como um controle alternativo eficaz de nematóides intestinais do lambari.

The objective of this study was to evaluate the effectiveness of an alternative method with pumpkin and papaya seeds, dried and ground, for control of helminth parasites of Astyanax cf. zonatus. Sixty fish were distributed into twelve containers, with one fish/liter. The experiment consisted of four treatments and three replications: TJ = fish in fasting; TRC = fish fed with commercial diet; TSA = fish fed ad libitum with pumpkin seed, and TSM = fish fed ad libitum with papaya seeds. After seven days of feeding, all fish were weighed and blood was taken for blood smears. Efficacy was determined by checking the presence of parasites in the gills, stomach and intestine, in 40 percent of fishes per treatment (n=6). TJ and TSM showed 39 percent and 25 percent of weight loss respectively. The TSA showed better efficacy against the nematode in intestine and stomach (95.26 percent and 92.48 percent). The TSM promoted 72 percent of efficiency on monogeneans control. Hematology revealed an increase of monocyte values to treatment TSM. A decrease of eosinophil values was observed in treatments TSA, TSM and TRC. Thus, feeding fishes with pumpkin is a effective alternative method of low cost for control of nematodes in Astianax cf. zonatus.

Duration of feeding and superficial and in-depth damage to soybean seed by selected species of stink bugs (Heteroptera: Pentatomidae)

Laboratory studies were conducted to compare duration of feeding and superficial and in-depth damage to soybean (Glycine max) seeds by the Southern green stink bug, Nezara viridula (L.), the Neotropical brown stink bug, Euschistus heros (F.), the red-banded stink bug, Piezodorus guildinii (Westwood), and the green-belly stink bug, Dichelops melacanthus (Dallas). Results indicated that feeding time was significantly longer for N. viridula (≈ 133 min) compared to E. heros and D. melacanthus (≈ 70 min), but not different from P. guildinii (≈ 103 min). There was a positive correlation between feeding time and the resulting damage for E. heros, N. viridula and P. guildinii (R² > 0.80, P < 0.0001), but not for D. melacanthus (R² = 0.1011, P = 0.1493). The deepest seed damage (2.0 mm) was made by P. guildinii and the shallowest (0.5 mm) by D. melacanthus. The depth of the seed damage by E. heros and N. viridula (0.8, 1.2 mm, respectively) was intermediate in comparison to the other species studied. Feeding damage to the seed endosperm caused variable cell disruption and protein body dissolution, particularly when P. guildinii fed on seeds, suggesting that the deleterious action of salivary enzymes was greater for this bug compared to the others.

Utilização de sementes de Syagrus romanzoffiana (Arecaceae) por formigas em floresta secundária no Sul do Brasil / Syagrus romanzoffiana (Arecaceae) seed utilization by ants in a secondary forest in South Brazil

Ants can nest in a wide variety of substracts. This paper shows Syagrus romanzoffiana seed utilization by ants in an Atlantic secondary forest. We report 29 seeds occupied by small-bodied ants, with 27 of them showing at least two ant development stages. Although a large number of seeds were sampled, a low level of ant occupation was observed.

As formigas podem nidificar em uma ampla variedade de substratos. Este estudo relata o uso das sementes de Syagrus romanzoffiana em floresta atlântica secundária, como local para nidificação de formigas. Foram encontradas 29 sementes ocupadas por formigas de pequeno porte, sendo que 27 delas apresentaram pelo menos dois estágios de desenvolvimento de formigas. A taxa de ocupação foi baixa apesar de as sementes serem abundantes.

Depredación pre-dispersiva de semillas en tres poblaciones del árbol Enterolobium contortisiliquum (Fabaceae)

Pre-dispersal seed predation in three populations of the tree Enterolobium contortisiliquum (Fabaceae). Predation is an important selective force that has shaped different strategies related to size, quantity and production time of fruits, seeds and seed reserves. The seeds of E. contortisiliqum are predated by the bruchid Merobruchus bicoloripes. We collected 1 300 fruits from 26 trees in San Salvador de Jujuy (Jujuy province), Castañares, and San Lorenzo (Salta province) Argentina. San Lorenzo is the wettest and highest site, while Castañares is the driest and lowest site. Jujuy is in the middle. In the laboratory, the fruits from each site were weighted and divided in three groups (small, medium and big). We counted the mature and predated seeds per fruit. In San Lorenzo, seed predation was higher in medium sized fruits while in Castañares and Jujuy seed predation was higher in both medium and bigger fruits. However, only in San Lorenzo we found a significant difference in preference for medium size fruits. Rev. Biol. Trop. 57 (3): 781-788. Epub 2009 September 30.

La depredación se ha postulado como una importante fuerza selectiva que ha moldeado distintas estrategias relacionadas con el tamaño, la cantidad y el tiempo de producción de semillas, frutos y el contenido de reservas. Las semillas de Enterolobium contortisiliqum son depredadas por el brúquido Merobruchus bicoloripes. Se estudiaron tres poblaciones de E. contortisiliquum en relación al tamaño de los frutos, a la producción de semillas por fruto, y a la depredación de semillas, comparando la variabilidad dentro y entre poblaciones. Se recolectaron 1300 frutos de 26 árboles en San Salvador de Jujuy (Jujuy), Castañares y San Lorenzo (Salta). Los frutos se pesaron y se contaron las semillas viables y depredadas. San Lorenzo es el sitio más húmedo y de mayor altitud, y Castañares el de menor altitud y más seco. En San Lorenzo encontramos una mayor preferencia de depredación en frutos medianos. En Castañares y San Salvador de Jujuy, a pesar de que los frutos medianos y grandes presentaron mayores niveles de depredación, no encontramos diferencias en la preferencia por alguna clase de tamaño. Los mayores niveles de depredación se encontraron en Castañares y S. S. de Jujuy.

Effects of the seed predator Acanthoscelides schrankiae on viability of its host plant Mimosa bimucronata

Seeds of Mimosa bimucronata are heavily infested (pre-dispersal predation) by the bruchid beetle Acanthoscelides schrankiae in Brazil. In this study, firstly we set up experiments to assess seed germination under seven and six different light and temperature regimes, respectively, and then we evaluated the ability of seeds to germinate after predation. We tested the hypothesis that the non-predated seeds from infested fruits may respond differently when set for germination than those seeds of non-infested fruits. We also hypothesized that predation may increase the production of unviable seeds. Seeds under 18 hours of light presented the highest percentage of germination, and the alternating temperature 20-30 °C was considered as optimum for germination (abnormal seedlings were not considered as a successful germination). Germination of seeds from non-infested fruits was significantly higher than germination of non-predated seeds from infested fruits, and predation also caused a significant increase in the proportion of dead seeds. Our results also show a positive correlation between proportions of unviable seeds and predated seeds. These results demonstrated that seeds of M. bimucronata are strongly affected by predation because predated seeds did not germinate and non-predated seeds had their viability reduced when located in infested fruits, supporting our hypothesis.

Estudios preclínicos de cucurbita máxima (semilla de zapallo) un antiparasitario intestinal tradicional en zonas urbano rurales / Preclinics studies of Cucurbita maxima (zapallo seed) a traditional intestinal antiparasite in zones urban rural

Estudio experimental realizado en los laboratorios de Parasitología y Química de la Universidad Nacional Jorge Basadre Grohman - Tacna. El proceso involucró dos fases: 1. determinación de la Concentración Mínima Inhibitoria (CMI) de Cucúrbita máxima como antiparasitario, se usó tenias caninas con tiempo 5 a 6 horas de aislamiento intestinal y 2. Determinación de la Reacción adversa de Cucúrbita máxima en ratas albinas expuestas. Se halló que la CMI de semilla de zapallo a razón de 23g. en 100 ml de agua destilada es capaz de producir un efecto antihelmíntico, concentración equivalente a más menos 73 semillas de zapallo (x2 = 5.6, P menor 0.01). Macroscópicamente a dosis de 23 g. a más se hallan alteraciones en la motilidad del helminto, hay un efecto proteolítico con un tiempo promedio de supervivencia de 38.4 minutos. Macroscópicamente los proglótidos maduros presentan destrucción del tegumento con compromiso de la membrana basal. En los proglótidos grávidos hay destrucción de huevos, hallazgos mucho más acentuados a concentraciones de 30 y 32 g. de cucúrbita experimentados. Se halló gastritis no erosiva superficial en ratas weys a dosis de 9 g/kg posterior a las 4 horas de administración.

Experimental research was carried out at the Parasitology and Chemistry laboratories of the Jorge Basadre Grohmann National University, in Tacna.The process involved two phases: (1) determination of the minimum inhibitory concentration (MIC) of Cucurbita Maxima as an antiparasitic agent using canine tapeworms with an intestinalisolation of 5 to 6 hours, and (2) determination of the side-effects of Curbita Maxima on exposed albino rats.It was found that the MIC of 23 gr. of pumpkin seed in 100 ml. of distilled water can produce an antihelminthic effect. This concentration is equivalent to ± 73 pumpkin seeds (x2 = 5.6, p<0.01). Macroscopically, alterations in helminthic motility are present at a dose of > 23 gr. There is a protheolithic effect with an average survival time of 38.4 minutes. Microscopically the mature proglottids present a destruction of the tegument involving the basal membrane. In the gravid proglottids there is egg destruction. These findings are accentuated when experimenting with Cucurbita Maxima in a concentration of 30 and 32 gr. Superficial non-erosive gastritis was found in weys rats after 4 hours of administering 9 gr/kg.

A review of evolution of oviposition guilds in the Bruchidae (Coleoptera)

Uma revisão das guildas de oviposição em Bruchidae (Coleoptera). Os bruquídeos apresentam três guildas de oviposição caracterizadas por períodos e maneiras diferentes de postura. Algumas espécies somente ovipositam nos frutos enquanto presos à planta (Guilda A), outras somente em sementes expostas de frutos enquanto ainda estão na planta (Guilda B) e algumas apenas em sementes livres no substrato (Guilda C). Uma espécie de planta pode ser infestada nas três condições, outras somente por duas e outras por apenas uma condição. Muitos artigos científicos têm sido publicados antes e após o conceito das guildas e, ao que parece, o comportamento primitivo dos bruquídeos provavelmente foi o de ovipositar sobre os frutos, com as larvas penetrando através de sua parede para se alimentarem das sementes (Guilda A). Como a evolução dos frutos foi direcionada para a dispersão das sementes e, possivelmente, fuga da predação por bruquídeos, estes desenvolveram outras maneiras para se alimentar de sementes (Guilda B e C). Os dados indicam que cerca de 78% dos bruquídeos ovipositam em frutos e 22% se incluem nas Guildas B e C. Nesse trabalho são revistos e discutidos os artigos científicos sobre guildas de oviposição e a evolução de bruquídeos, bem como acrescentados novos dados.