Heterorhabditis amazonensis to Control Euschistus heros (Hemiptera: Pentatomidae) in Laboratory and Field Conditions.

This study evaluated the potential of entomopathogenic nematodes (EPNs) to control Euschistus heros (Fabricius) under laboratory and field conditions. Eight isolates of the species Heterorhabditis amazonensis were evaluated on field-collected and laboratory-reared insect populations. The isolates that performed best in the virulence test were evaluated for in vivo production on Galleria mellonella Fabricius larvae. Then, these were evaluated in field conditions on E. heros from the laboratory and field populations. The isolates IBCB-n46, NEPET11, and IBCB-n40 caused the highest mortality in adult E. heros from laboratory rearing (100, 94, and 80%, respectively), and IBCB-n46 and NEPET11 were the best against the field population (71 and 47% mortality, respectively). In the assay to evaluate production, the isolate IBCB-n46 achieved the best result (3.4 × 105 IJs/g per larvae), followed by isolates UEPN05 (1.4 × 105 IJs/g per larvae) finally NEPET11 (7.5 × 104 IJs/g per larvae). In the assay in field conditions, all treatments differed from the control treatment, no significant differences were observed in the evaluated factors (isolates and insect populations), and the highest percentage of mortality was obtained by the UEPN05 isolate when applied to insects from the laboratory (18.57% mortality).

Sequencial passages of the multiple nucleopolyhedrovirus of Anagrapha falcifera (Kirby) (Lepidoptera: Noctuidae) (AfMNPV) in Spodoptera cosmioides (Walker) (Lepidoptera, Noctuidae) / Passagens sequenciais do múltiplo nucleopoliedrovírus de Anagrapha falcifera (Kirby) (Lepidoptera: Noctuidae) (AfMNPV) em Spodoptera cosmioides (Walker) (Lepidoptera, Noctuidae)

The aim of this work was to evaluate the effects of Anagrapha falcifera multiple nucleopolyhedrovirus (AfMNPV) passages in the Spodoptera cosmioides caterpillar's biology at different times of infection and histological changes that the virus could cause in the caterpillar midgut, seeking correlate histopathologic effects to the effectiveness of this virus as a potential biological control of this pest. Larvae were infected with seven days of development, by using three different passages of AfMNPV on S. cosmioides (F1, F4 and F7, which is the first, fourth and seventh passages, respectively) and the control treatment. Compared biology assays with the same treatments for analyzing behavior and mortality of caterpillars were performed concomitantly. The midgut morphology was compared between infected and uninfected larvae. The digestive tubes were collected at 24, 72 and 144 hours of infection (20 tubes/treatment/time of infection). After collection, the digestive tubes were fixed in Karnovsky, processed, stained with Hematoxylin-Eosin, and examined under a light microscope. The biology results of F4 and F7treatments, showed a drastic reduction in locomotion and feeding from the fourth day after infection and higher cumulative mortality rate compared to the control and F1. All treatments caused morphological changes in the midgut of S. cosmioides, in the three times of infection, with the greatest changes occurring at the epithelium. The AfMNPV, in the three passages tested in S. cosmioides, caused behavioral and morphological changes in the midgut, indicating that it can be a promising agent for biological control of this pest.

O objetivo deste trabalho foi avaliar os efeitos de passagens do múltiplo nucleopoliedrovírus de Anagrapha falcifera (AfMNPV) na biologia de lagartas de Spodoptera cosmioides, em diferentes momentos de infecção, e as alterações histológicas que o vírus poderia causar no intestino médio da lagarta, buscando correlacionar os efeitos histopatológicos e a eficácia deste vírus, como um potencial controle biológico desta praga. As lagartas foram infectadas com sete dias de desenvolvimento, utilizando três passagens diferentes do AfMNPV em S. cosmioides (F1, F4 e F7, sendo a primeira, quarta e sétima passagens, respectivamente) e o tratamento controle. Foram realizados, concomitantemente, ensaios de biologia, comparados com os mesmos tratamentos, para analisar o comportamento e mortalidade das lagartas. A morfologia do intestino médio foi comparada entre as lagartas infectadas e as não infectadas. Os tubos digestivos foram coletados com 24, 72 e 144 horas de infecção (20 tubos/tratamento/ tempo de infecção). Após a coleta, os tubos foram fixados em Karnovsky, processados, corados com Hematoxilina-Eosina e analisados ao microscópio de luz. Os resultados da biologia dos tratamentos F4 e F7 mostraram uma redução drástica na locomoção e alimentação das lagartas, a partir do quarto dia pós-infecção e maior taxa de mortalidade cumulativa, em relação ao controle e F1. Morfologicamente, todos os tratamentos causaram alterações no intestino médio das lagartas de S. cosmioides, nos três tempos de infecção, sendo que as maiores alterações ocorreram no epitélio. O AfMNPV, nas três passagens testadas em S. cosmioides, provocou alterações comportamentais e morfológicas no intestino médio, indicando que pode ser um promissor agente de controle biológico desta praga

Macro-elements in the hemolymph of adult Euschistus heros (Fabr.) (Hemiptera: Pentatomidae) treated with pyriproxyfen.

Euschistus heros is an important pest in many crops in Brazil, and different control strategies, mainly involving chemicals, have been evaluated; however, the side effects of these chemicals on the balance of inorganic element levels in the hemolymph are unknown. Thus, the aim of this work was to determine the concentration of inorganic elements (focusing on macro-elements) in the hemolymph of female and male E. heros adults, after applying pyriproxyfen at a sublethal concentration (LC30 = 6.68 mL L-1 diluted in distilled water) to 4th instar nymphs, which were kept in controlled conditions. The hemolymph pool was removed 48 h after adult emergence, centrifuged and placed on an acrylic disk added with Gallium as internal standard for the analysis of total reflection X-ray fluorescence. Most of the elements in the control treatment did not differ between females and males. However, following insecticide application to females and males, respectively, there was a significant increase in sulfur (19 and 51%), chlorine (33 and 137%) and calcium (47 and 82%) in the hemolymph. The significantly higher increase in macro-elements in males' hemolymph indicates that the action of pyriproxyfen may be sex-specific. Phosphorus and potassium concentrations also differed between females and males in the control and treated groups. The observed variation in inorganic elements in the insect's hemolymph may be related to the unknown effects of pyriproxyfen, mainly on immune and reproductive performance.

Euschistus heros (Hemiptera: Pentatomidae) Fitness on Artificial Diets: An Approach to Optimize Mass Rearing of Telenomus podisi (Hymenoptera: Platygastridae) for Augmentative Biological Control.

In order to optimize the mass rearing of Telenomus podisi Ashmead (Hymenoptera: Platygastridae) for augmentative biological control we tested the suitability of different artificial diets with respect to egg production of Euschistus heros (F.) (Hemiptera: Pentatomidae). For this purpose, biological parameters of E. heros and T. podisi were evaluated in experimental trial with these diets. All tested artificial diets supported the rearing of E. heros. However, female and adult life history traits including longevity, total oviposition, nymph developmental time, and fertility were altered, with poorer results than under the natural diet. However, because of the higher economic cost of the natural diet, its replacement with artificial diets could be beneficial. Since stink bug reared on artificial diet has shorter lifespan, an alternative to overcome this issue is to replace earlier the insects in the insect facility what could still be cheaper than insects reared on natural diet. It was also noted the possibility of using artificial diets without lyophilized components what can further reduce the cost of rearing.

The effect of synthetic pesticides and sulfur used in conventional and organically grown strawberry and soybean on Neozygites floridana, a natural enemy of spider mites.

BACKGROUND: The beneficial fungus Neozygites floridana kills the two-spotted spider mite Tetranychus urticae, which is a serious polyphagous plant pest worldwide. Outbreaks of spider mites in strawberry and soybean have been associated with pesticide applications. Pesticides may affect N. floridana and consequently the natural control of T. urticae. N. floridana is a fungus difficult to grow in artificial media, and for this reason, very few studies have been conducted with this fungus, especially regarding the impact of pesticides. The aim of this study was to conduct a laboratory experiment to evaluate the effect of pesticides used in strawberry and soybean crops on N. floridana. RESULTS: Among the pesticides used in strawberry, the fungicides sulfur and cyprodinil + fludioxonil completely inhibited both the sporulation and conidial germination of N. floridana. The fungicide fluazinam affected N. floridana drastically. The application of the fungicide tebuconazole and the insecticides fenpropathrin and abamectin resulted in a less pronounced negative effect on N. floridana. Except for epoxiconazole and cyproconazole, all tested fungicides used in soybean resulted in a complete inhibition of N. floridana. Among the three insecticides used in soybean, lambda-cyhalothrin and deltamethrin resulted in a significant inhibition of N. floridana. CONCLUSION: The insecticides/ acaricides abamectin and lambda-cyhalothrin at half concentrations and fenpropathrin and permethrin and the fungicide tebuconazole at the recommended concentrations resulted in the lowest impact on N. floridana. The fungicides with the active ingredients sulfur, cyprodinil + fludioxonil, azoxystrobin, azoxystrobin + cyproconazole, trifloxystrobin + tebuconazole and pyraclostrobin + epoxiconazole negatively affected N. floridana. © 2015 Society of Chemical Industry.

Populações de plantas e estratégias de manejo de irrigação na cultura da soja / Plant population and irrigation management strategies in the soybean tillage

Este trabalho teve por objetivo verificar o efeito do manejo da irrigação e da população de plantas sobre o rendimento de grãos em soja semeada após a época recomenda. O experimento foi conduzido de janeiro a maio de 2005 na Universidade Federal de Santa Maria. O delineamento experimental utilizado foi blocos ao acaso com parcelas subdivididas e quatro repetições. Nas parcelas principais foram distribuídos três manejos de irrigação: 1) não-irrigado; 2) irrigado todo o ciclo; e 3) irrigado nos períodos críticos. Nas subparcelas foram distribuídas duas populações de plantas (250.000 e 400.000 plantas ha-1). Para as plantas irrigadas todo o ciclo ou somente nos períodos críticos, o rendimento de grãos não diferiu entre as populações testadas. O rendimento de grãos das plantas não-irrigadas teve um incremento de 21 por cento com o aumento da população de plantas para 400.000 plantas ha-1.

The objective of these experiments was to verify the effect of irrigation management and plant population on grain yield of soybean sown after recommends period. The experiment was conducted from January to May 2005 at Federal University of Santa Maria. The experiment design was randomized blocks with subdivided bits in fourth repetitions. In the main bits were distributed three irrigation management: 1) no irrigated; 2) irrigated all cycle; and 3) irrigated in critical periods. In subplot were distributed both plants populations (250.000 and 400.000 plants ha-1). For the irrigated plants ll cycle or only in critical periods, the grain yield did not differ between tried populations. The grain yield of no irrigated plants had an increment of 21 percent with the increase of plant population to 400.000 plants ha-1.

Ácido giberélico e dia curto interrompido em crisântemo de corte (Dendranthema grandiflora, Tzvelev., "Gompier Chá") / Gibberellic acid and short day interrupted in cut chrysanthemum (Dendranthema grandiflora, Tzvelev., 'Gompier Chá')

Algumas cultivares de crisântemo, como a "Gompier Chá", apresentam menor crescimento quando cultivadas no período de inverno. A utilização do ácido giberélico (GA3) e o manejo do fotoperíodo com dia curto interrompido podem ser alternativas para estimular o crescimentodas plantas. Assim, foi realizado um experimento com objetivo de avaliar a resposta do GA3 e do dia curto (DC) interrompido por dias longos (DL) na qualidade de hastes de crisântemo de corte "Gompier Chá", cultivado no inverno no Rio Grande do Sul. O experimento foi conduzido na Universidade Federal de Santa Maria, no período de maio a agosto de 2001. Os tratamentos foram diferentes concentrações de ácido giberélico (50, 100, 200, 300, 500 e 500mg L-1) aplicadas seis, três, duas, duas, uma e duas vezes, respectivamente, e o uso de dia curto interrompido (32DL+9DC+12DL+DC até a colheita). Os tratamentos que proporcionaram a formação de hastes de melhor qualidade foram as dosagens de 100mg L-1 aplicado três vezes e 200mg L-1 aplicado duas vezes. O esquema de dia curto interrompido usado foi ineficiente para a qualidade da cultivar "Gompier Chá", já o uso de ácido giberélico possibilitou melhoria no comprimento dos pedúnculos e na altura das plantas em cultivo de inverno no Rio Grande do Sul.

Some chrysanthemum"s cultivars, as the 'Gompier Chá', have problems of small growth during winter crop. The spraying whit gibberellic acid (GA3) and the control photoperiod with interrupted short day can be options for to stimulate growth. Thus, an experiment was carried out with the objective of evaluating the stems quality of cut chrysanthemum 'Gompier Chá' response of GA3 and short day (DC) interrupted by long day (DL), during winter time in Rio Grande do Sul. The experiment was conducted at the Universidade Federal de Santa Maria, in 2001, from May to August. The treatments consisted of different gibberellic acid concentration (50, 100, 200, 300, 500 e 500mg L-1) sprayed six, three, two, two and one times, respectively, and short day interrupted (32DL+9DC+12DL+DC until the harvest). The best stem quality was obtained whit GA3 dosages: 100mg L-1 sprayed three times and 200mg L-1 sprayed two times. The short day interrupted used was inefficient to the 'Gompier Chá' quality, while the spraying with gibberellic acid improved the length of floral stalks and the plant height during winter time in Rio Grande do Sul.

Capacidade de coleta de dois métodos de amostragem de insetos-praga da soja em diferentes espaçamentos entre linhas / Colleting capacity of two methods of insect sampling in soybean in diferent row spacings

A amostragem é um dos procedimentos básicos indispensáveis ao manejo integrado de pragas. Neste experimento, comparou-se a capacidade de coleta de dois métodos de amostragem da lagarta-da-soja (Anticarsia gemmatalis Hueb., 1818) e do percevejo-verde-pequeno (Piezodorus guildinii Westw., 1837) na cultura da soja semeada em três espaçamentos entre linhas (0,30; 0,40 e 0,50m). Foi utilizado o delineamento inteiramente casualizado, com dez repetições (amostragens), em esquema fatorial 2x3; utilizaram-se dois métodos de amostragem (pano-de-batida e pano-vertical) e três espaçamentos entre linhas. A população de lagarta-da-soja e de percevejo-verde-pequeno foi avaliada nos estádios V8 e R6, respectivamente. Para lagartas, os resultados indicam maior eficiência do pano-vertical em relação pano-de-batida. Nos menores espaçamentos, o pano-vertical não deixou clara sua maior capacidade de coleta de percevejos, como observado para lagartas. Estes resultados demonstram que são necessárias pesquisas visando a aprofundar a avaliação dos métodos de amostragens de pragas da soja cultivada em diferentes espaçamentos.