Bifenthrin Baseline Susceptibility and Evaluation of Simulated Aerial Applications in \u3ci\u3eStriacosta albicosta\u3c/i\u3e (Lepidoptera: Noctuidae)

Striacosta albicosta (Smith) is a maize pest that has recently expanded its geographical range into the eastern United States and southeastern Canada. Aerial application of pyrethroids, such as bifenthrin, has been a major practice adopted to manage this pest. Reports of field failure of pyrethroids have increased since 2013. Striacosta albicosta populations were collected in 2016 and 2017 from maize fields in Nebraska, Kansas, and Canada and screened with bifenthrin active ingredient in larval contact dose-response bioassays. Resistance ratios estimated were generally low in 2016 (1.04- to 1.32-fold) with the highest LC50 in North Platte, NE (66.10 ng/cm2) and lowest in Scottsbluff, NE (50.10 ng/cm2). In 2017, O’Neill, NE showed the highest LC50 (100.66 ng/cm2) and Delhi, Canada exhibited the lowest (6.33 ng/cm2), resulting in a resistance ratio variation of 6.02- to 15.90-fold. Implications of bifenthrin resistance levels were further investigated by aerial application simulations. Experiments were conducted with a spray chamber where representative S. albicosta populations were exposed to labeled rates of a commercial bifenthrin formulation. Experiments resulted in 100% mortality for all populations, instars, insecticide rates, and carrier volumes, suggesting that levels of resistance estimated for bifenthrin active ingredient did not seem to impact the efficacy of the correspondent commercial product under controlled conditions. Results obtained from this research indicate that control failures reported in Nebraska could be associated with factors other than insecticide resistance, such as issues with the application technique, environmental conditions during and/or after application, or the insect’s natural behavior. Data generated will assist future S. albicosta resistance management programs

Immature stages of Spodoptera eridania (Lepidoptera: noctuidae): developmental parameters and host plants.

This study aimed to detail the temporal and morphological parameters of the immature stages of southern armyworm Spodoptera eridania (Stoll, 1782) with larvae feed on artificial diet, under controlled conditions (25?±?1°C, 70?±?10% relative humidity and 14-h photophase) and gather information about their larval host plants. The viability of the egg, larval, pupal, and prepupal stages was 97.82, 93.62, 96.42, and 97.03%, respectively. The average duration of the egg, larval, pupal, and pre-pupal stages was 4.00, 16.18, 1.58, and 9.17 d, respectively. During the larval stage, 43.44% of females passed through seven instars, observing that the female's development was significant slower than males. The female larvae that developed through six and seven instars exhibited a mean growth rate of 1.52 and 1.44, respectively. Female pupae were significantly larger, exhibiting faster development than males. The rearing method proved to be adequate, providing more detailed observations of the biological cycle, especially at the larval stage, and resulting in an overall survival of almost 85%. Two hundred two plant species belonging to 58 families are listed as natural hosts for S. eridania, mainly including Asteraceae, Fabaceae, Solanaceae, Poaceae, Amaranthaceae, and Malvaceae

Immature development of Spodoptera dolichos (Fabricius) (Lepidoptera: noctuidae).

We provide detailed temporal and morphological parameters of the immature stages of Spodoptera dolichos (Fabricius) larvae fed on artificial diet under controlled conditions (25?±?1°C, 70?±?10% RH, and 14 h photophase). The viability of the egg, larval, pupal, and prepupal stages was 97.5%, 97.0%, 93.1%, and 98.9%, respectively. The average duration of the egg, larval, prepupal, and pupal stages was 5.0, 23.4, 3.2, and 21.5 days, respectively. Females took longer at the larval stage than males, with 10.5% of them having seven instars. The growth rate of female larvae that developed through six and seven instars was 1.72 and 1.54, respectively. Female pupae were significantly larger, exhibiting slower development than males

Movement of \u3ci\u3eStriacosta albicosta\u3c/i\u3e (Smith) (Lepidoptera: Noctuidae) Larvae on Transgenic \u3ci\u3eBt\u3c/i\u3e and Non-\u3ci\u3eBt\u3c/i\u3e Maize

Exposure of lepidopteran pests to Bacillus thuringiensis (Bt) proteins has been shown to affect the behavior of larvae, including increased movement and avoidance of Bt-expressing plants or diet. Therefore, we hypothesized that the behavior of western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), an important pest of maize, could be affected when exposed to Bt plants. To test this hypothesis, we conducted a series of artificial arena and on-plant experiments to determine S. albicosta neonate behavior when exposed to Bt and non-Bt plant tissue. Video tracking experiments presented neonate larvae with the choice of Bt or non-Bt pollen in a Petri dish for 15 min while being video recorded for analysis with EthoVision software. This study showed an increase in mean velocity and total time spent moving for larvae in the presence of Cry1F vs. non-Bt when compared with Vip3A vs. non-Bt or Cry1F vs. Vip3A. However, there was no difference in total distance moved or time spent in the food zone for all scenarios. Maize tissue choice experiments allowed neonatal larvae the choice of feeding on Bt or non-Bt tassel or leaves for 9 h in Petri dish arenas. This experiment showed that larvae preferred tassel tissue over leaves but did not indicate that larvae could distinguish between Bt and non-Bt tissue. In contrast, on-plant experiments (including a whole plant neonate dispersal study under controlled conditions and an in-field silking behavior experiment) indicated that the presence of Cry1F and Vip3A Bt toxins increased plant abandonment, suggesting that larvae are able to detect and avoid Bt toxins. The discrepancy of these results is likely due to the on-plant studies providing more field-realistic environmental conditions and a longer duration of exposure to Bt toxins for the behavioral experiments. Our results represent the first steps in understanding the complex behavior of S. albicosta when exposed to Bt plants. A better understanding of the response of larvae when exposed to Bt traits can aid in the management of this pest, particularly for the design of resistance management strategies and refuge design

Efeito do tamanho e de múltiplos casais sobre o potencial reprodutivo de Spodoptera eridania (Stoll, 1782) (Lepidoptera: Noctuidae).

Entre os lepidópteros de importância agrícola, Spodoptera eridania (Stoll, 1782) tem despertado atenção por atingir níveis de dano econômico em culturas de importância como algodão e soja. Entretanto, existem poucos estudos detalhados de biologia, especialmente relacionados a aspectos reprodutivos. Visando determinar a capacidade máxima reprodutiva desta espécie avaliou-se o efeito do tamanho, empregando como parâmetro o peso pupal, e o número de casais por gaiola (um e três) sobre o número de cópulas, fecundidade e fertilidade. Os experimentos foram conduzidos em sala climatizada (25 ± 1ºC, 70 ± 10% UR e fotofase de 14 horas) com observações diárias. Adultos, emergidos no mesmo dia, classificados de acordo com a massa pupal, como pequenos, médios e grandes foram dispostos em gaiolas plásticas, (10 x 15cm), alimentados com dieta artificial e água estéril. Foram formadas 15 gaiolas com um casal cada, todos de tamanho médio, cinco gaiolas com 3 casais de tamanho pequeno e médio e 4 com três casais de tamanho grande. O número médio de cópulas dos casais de tamanho médio mantidos individualmente (1,13) foi significativamente menor do que o dos insetos pequenos (2,58), médios (2,47) e grandes (2,33),mantidos a três por gaiola. A fecundidade média dos casais individuais (1.398,00) também foi significativamente menor que a dos mantidos a três por gaiola, tanto de tamanho pequeno (1.709,07), médio (2.044,27) e grande (2.469,92). Entre estes últimos observou-se efeito positivo entre o tamanho da pupa e a fecundidade, com diferenças significativas entre todos os tamanhos. A fertilidade média dos casais individuais (67,45) foi muito inferior a observada para os casais pequenos (97,32%), médios (96,43%) e grandes (98,91%), mantidos a três por gaiola. Estes resultados indicam que em estudos que estimam o potencial reprodutivo devem ser utilizados pelo menos três casais por gaiola e que sejam descritos os pesos das pupas que originaram os adultos

Parâmetros biológicos dos estágios imaturos de Spodoptera eridania (Stoll, 1782) (Lepidoptera: Noctuidae), em condições controladas.

O gênero Spodoptera (Guenée, 1852) é cosmopolita e abriga grande parte das lagartas de importância agrícola. Spodoptera eridania (Stoll, 1782) é uma espécie polífaga que se alimenta de plantas de 57 famílias, incluindo muitas de importância econômica. Este estudo objetivou detalhar parâmetros biológicos de desenvolvimento dos estágios imaturos de S. eridania, em condições controladas (25 ± 1ºC, 70 ± 10% UR e fotofase de 14 horas). Foram avaliados 4.454 ovos provenientes de 16 posturas e 298 larvas neonatas, individualmente, alimentadas com dieta artificial modificada de Grenee et al. A viabilidade dos ovos, larvas, pré-pupas e pupas foi de 97,82; 93,62; 96,42; 97,03%, com duração de 4,00; 16,18; 1,58 e 9,17 dias, respectivamente. Observou-se que 93% das fêmeas e 100% dos machos passaram por seis e 7% das fêmeas passaram por sete instares larvais. A partir do quinto ínstar observou-se diferenciação no tamanho das cápsulas entre machos e fêmeas de seis instares e, entre fêmeas com as de sete instares, a diferenciação iniciou no quarto ínstar, com razão de crescimento menor que as demais, no entanto o tamanho final foi maior que nas larvas de seis instares, compensado pelo ínstar adicional. O tamanho final das cápsulas foi significativamente diferente entre fêmeas (2,64mm) e machos (2,50mm), bem como entre as fêmeas que passaram por seis (2,64mm) e sete ínstares (2,72mm). Nas larvas femininas e masculinas de seis instares a razão média de crescimento foi de 1,52 e 1,51, respectivamente; nas de sete ínstares foi de 1,44. As pupas femininas das larvas que passaram por seis instares foram significativamente maiores (377,53mg) do que os machos (329,45mg), porém, menores que as provenientes de larvas que passaram por sete ínstares (435,11mg). Tanto a metodologia de criação quanto a dieta larval foram adequadas, pois permitiram 85,87% de sobrevivência e um detalhamento muito maior das observações, especialmente, quando larvas

Spodoptera frugiperda (Lepidoptera: Noctuidae) updated host plants and new records.

Conteúdo do volume 2: Ácaros; Biologia, fisiologia, morfologia; Controle biológico com bactérias entomopatogênicas; Controle biológico com fungos entomopatológicos; Controle biológico com nematoides; Controle biológico com parasitoides; Controle biológico com predadores; Ecologia e biodiversidade; Educação e etnoentomologia; Entomologia florestal; Entomologia Forense; Entomologia médica e veterinária; Entomologia molecular; Manejo integrado de pragas; Organismos geneticamente modificados; Plantas inseticidas; Polinização; Pragas quarentenárias e invasivas; Resistência de insetos a táticas de controle; Resistência de plantas a insetos; Semioquímicos e comportamento; Sistemática e taxonomia; Tecnologia de aplicação; Controle biológico com vírus entomopatogênicos; Controle químico

Bifenthrin Baseline Susceptibility and Evaluation of Simulated Aerial Applications in \u3ci\u3eStriacosta albicosta\u3c/i\u3e (Lepidoptera: Noctuidae)

Striacosta albicosta (Smith) is a maize pest that has recently expanded its geographical range into the eastern United States and southeastern Canada. Aerial application of pyrethroids, such as bifenthrin, has been a major practice adopted to manage this pest. Reports of field failure of pyrethroids have increased since 2013. Striacosta albicosta populations were collected in 2016 and 2017 from maize fields in Nebraska, Kansas, and Canada and screened with bifenthrin active ingredient in larval contact dose-response bioassays. Resistance ratios estimated were generally low in 2016 (1.04- to 1.32-fold) with the highest LC50 in North Platte, NE (66.10 ng/cm2) and lowest in Scottsbluff, NE (50.10 ng/cm2). In 2017, O’Neill, NE showed the highest LC50 (100.66 ng/cm2) and Delhi, Canada exhibited the lowest (6.33 ng/cm2), resulting in a resistance ratio variation of 6.02- to 15.90-fold. Implications of bifenthrin resistance levels were further investigated by aerial application simulations. Experiments were conducted with a spray chamber where representative S. albicosta populations were exposed to labeled rates of a commercial bifenthrin formulation. Experiments resulted in 100% mortality for all populations, instars, insecticide rates, and carrier volumes, suggesting that levels of resistance estimated for bifenthrin active ingredient did not seem to impact the efficacy of the correspondent commercial product under controlled conditions. Results obtained from this research indicate that control failures reported in Nebraska could be associated with factors other than insecticide resistance, such as issues with the application technique, environmental conditions during and/or after application, or the insect’s natural behavior. Data generated will assist future S. albicosta resistance management programs

Spatio-temporal variation of Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) populations in Brazil according to meteorological factors.

Resumo: Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) tem sido reconhecida como uma das principais espécies consumidoras de gramíneas em todo o continente americano. Durante os surtos, as lagartas são capazes de consumir completamente os hospedeiros preferenciais (gramíneas) e, quando os hospedeiros preferenciais são destruídos, podem mover-se para plantas adjacentes não gramíneas e causar danos semelhantes. Variáveis meteorológicas, como temperatura e umidade, são conhecidas por afetar o desenvolvimento e a abundância de suas populações. Este trabalho teve como objetivo descrever e comparar a distribuição espaço-temporal de M. latipes em diferentes localidades do Brasil e avaliar a influência de variáveis meteorológicas sobre suas variações temporais. Foram avaliados 12 locais, em cada ponto de coleta foram instaladas armadilhas luminosas próximas às áreas de cultivo. Para entender a influência das variáveis meteorológicas na abundância de M. latipes, os dados foram analisados pelo Modelo Linear Generalizado, empregando a regressão de Poisson. Uma regressão linear tambémfoi utilizada para verificar a relação entre a abundância e a latitude. Um total de 1.985 mariposas foram coletadas. Os maiores números de indivíduos foram coletados nos biomas Amazônia e Cerrado. Os resultados mostram que a abundância de mariposas está inversamente relacionada ao aumento da latitude. A análise de regressão de Poisson indicou que as principais variáveis meteorológicas foram significativamente relacionadas à abundância em cada local. Este estudo mostra que devido à preferência por gramíneas em estado vegetativo e às altas exigências de temperatura (30°C), M. latipes é uma espécie importante em regiões quentes, especialmente nas épocas de maior umidade. Além disso, mesmo em latitudes elevadas, durante os meses de verão, as populações podem aumentar rapidamente, podendo causar danos econômicos

The Granulate Cutworm (Lepidoptera: Noctuidae): Biological Parameters Under Controlled Conditions, Host Plants, and Distribution in the Americas.

Feltia subterranea (Fabricius), commonly known as the granulate cutworm, is a common species of owlet moths (Noctuidae) of major agricultural importance, widely distributed in Nearctic and Neotropical regions. This study was conducted to determine the species biological parameters, gather information about its larval host plants, and assess the agricultural significance of this species in the Americas. The viability of the egg, larval, pupal stages, and prepupal period was 98, 98, and 100%, respectively, under laboratory conditions. The average duration of the egg, larval, pupal stages, and prepupal period was 3, 17, 4, and 13 d, respectively. All laboratory-reared larvae developed through five instars. The growth ratio was 1.93 for females and 1.85 for males. The duration of the larval stage was significantly longer in females than in males from the fourth instar. The duration of the pupal stage was significantly shorter in females than in males. When larval and pupal stage durations were combined, there were no significant differences in total development time as a function of sex. In total, 159 botanical taxa belonging to 41 families were recorded as host species for F. subterranea. The families with the greatest number of host species were Fabaceae (22), Poaceae (19), Asteraceae (16), Brassicaceae (13), Solanaceae (12), Amaranthaceae (7), Cucurbitaceae (7), and Malvaceae (5). It is noteworthy that the large number of native weeds used by F. subterranea as host plants could represent a significant source of infestation of crops in the agricultural landscape