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The tobacco budworm, Chloridea virescens (F.) (Lepidoptera: Noctuidae), once a major insect pest of tobacco, Nicotiana sp., and cotton, Gossypium hirsutum L., in the Americas, has decreased in abundance, especially in cotton fields, during the past 2 decades. Little is known of the biological factors, crop management techniques, and effect that ample planting of cultivars of cotton expressing Bacillus thuringiensis Berliner (Bt-cotton) might have had on their reduction, nor of changes in the conditions of the ‘source’ areas that produce migrant populations of tobacco budworm. Detailed knowledge of its population dynamics is lacking. This work proposed a mathematical model considering only seasonal changes in temperature as the driving factor to explain variations of tobacco budworm during a 20-year collection of males in pheromone traps in Washington County, MS. Tobacco budworm dynamics according to the model suggested the stability of the population of the geographical area did not depend on immigration and that larvae of the last generation of the year that survive winter temperatures better explain the dynamics, contrary to what was commonly assumed that larvae in the area could not survive prolonged wet and cold winter weather. The Mississippi Delta has planted Bt-cotton in high proportions, however, this might be a more reasonable force behind reduction in abundance of tobacco budworms.
The sugarcane aphid, Melanaphis sacchari (Hemiptera: Aphididae), is an important pest of sorghum (Sorghum bicolor (L.) Moench) and sugarcane, (Saccharum officinarum L.) in the southern United States and in many parts of the world. Recent invasion by this prolific pest has created demand for evaluation of insecticides that also are favorable for conservation of natural enemies. The objective of this study was to compare currently recommended insecticides in combination with predatory lady beetles to develop a strategy to manage sugarcane aphids. The study was done in a laboratory by using field-sprayed sorghum substrate. Two insecticides, flupyradifurone (Sivanto™) and sulfoxaflor (Transform®) were used in combination with the release of predatory lady beetle adults and larvae onto sugarcane aphids and their efficacies were evaluated. Treatments were Sivanto™, Transform®, lady beetle adult, lady beetle larva, Sivanto™ + lady beetle adult, Transform® + adult, Sivanto™ + lady beetle larva, Transform® + larva, and nontreated check. One day after insecticide spray and release of sugarcane aphids and predators, all treatments killed significantly more (48-83%) sugarcane aphids than did the nontreated check. Three days after treatment, all treatments except Sivanto™ and larvae killed significantly more (41-79%) sugarcane aphids than did the nontreated check. Significantly more sugarcane aphids were killed with predators combined with Sivanto™ (82-91%) and Transform® (96-97%) than with Transform® (59%), Sivanto™ (49%), or larvae (46%) alone. Lady beetle adults killed significantly more sugarcane aphids than did larvae. Seven days after treatment, no significant difference in sugarcane aphid mortality was observed between Transform® and Sivanto™. Fourteen days after treatment, abundance of sugarcane aphids increased in Sivanto™ treatments but no significant differences were found in sugarcane aphid mortality between nontreated check and Sivanto™ treatments. Sivanto™ and Transform® were similar, except Transform® displayed slightly longer residual activity in suppressing sugarcane aphids than did Sivanto™. Overall, a combination of lady beetle larva or adult with Transform® or Sivanto™ suppressed sugarcane aphids better than did Sivanto™ or Transform® alone. Sivanto™ and Transform® had no significant negative impact on predatory lady beetles.
Studies in the field and growth chamber evaluated sorghum, Sorghum bicolor (L.) Moench, hybrids for resistance to sugarcane aphid, Melanaphis sacchari (Zehntner). Hybrids were known resistant ATx2752/RTx2783, known susceptible ATx2752/RTx430, and 14 with suspected resistance. The field study was done during 2015 and 2016 at three locations in Louisiana. The study was a split-plot design with hybrids randomized to main plots and insecticidal protection from aphid infestation (sprayed versus non-sprayed) randomized to sub-plots. Seedlings of the hybrids also were evaluated in a growth chamber. In the field, hybrids that seemed susceptible (demonstrated yield benefit after application of insecticide) were ATx2752/RTx430 and DG M756B39. Hybrids with possible tolerance (many cumulative aphid days but no yield benefit from insecticide) were DG M77GB52, DG 765B, and R94153. Hybrids with possible antibiosis (few cumulative aphid days and no benefit from insecticide) were ATx2752/RTx2783, RS84353, RS9813, SP6929, SP73B12, SP7715, SPX760, SP78M30, 83P17, W-844-E, and DKS37-07. Seedlings of ATx2752/RTx2783, DKS37-07, RS9813, RS84353, SP7715, SPX17414, SPX17514, NKX760, and W-844-E were significantly less damaged by aphids feeding than was ATx2752/RTx430. In addition to field and seedling studies, four hybrids were used to evaluate reproductive potential of sugarcane aphids in a growth chamber. Suspected resistant hybrid DKS37-07, suspected susceptible hybrid M75GB39, and two intermediate hybrids P83P17 and W -844-E were used. DKS3707 was the most resistant hybrid evaluated, with reduced intrinsic rate of increase of sugarcane aphids compared to the other hybrids. M75GB39 seemed the most susceptible of the three hybrids.
Cotton (Gossypium hirsutum L.) is a high-value cash crop persistently plagued by insect pests such as stink bugs and related species. Stink bugs vector pathogens that cause necrosis of cotton seed and lint, yet the frequency of pathogen transmission into successive bolls by individual stink bugs is not documented. Individual adults of southern green stink bug, Nezara viridula (L.), (n = 80) were provided green beans (Phaseolus vulgaris L.) infected with the fungus Eremothecium coryli (Peglion) Kurtzman (syn. Nematospora coryli Peglion) and caged sequentially with five bolls of known age to determine potential for infection of consecutive bolls by a single stink bug. Stink bug adults fed on 82.4% of bolls (n = 108), and the pathogen was transmitted to 68.5% of these bolls (n = 89). As expected, insect bacterial flora was detected in all bolls with evidence of insect feeding. Overall, frequency of feeding ranged from one to five bolls per stink bug; frequency of boll infection also ranged from one to five bolls per stink bug. The frequency of infection by E. coryli in bolls did not differ between sexes of stink bugs (Fisher's Exact Test: P = 0.84), and the number of females and males infecting one to five bolls did not differ (Fisher's Exact Test: P = 0.92). The findings can serve as an impetus for determining whether current insect management thresholds should be reconsidered given the potential for infection of multiple bolls by individual southern green stink bugs.
The mealybug Ferrisia dasylirii (Cockerell), found for the first time in the salt-tolerant plant Salicornia bigelovii (Torr.), previously was identified by Cockerell (1896) as Dactylopius dasylirii because it is naturally found in Dasylirion wheeleri, a wild plant known as “sotol” in the Asparagaceae family, and is native to arid zones in the states of Chihuahua and Sonora in northern Mexico. The polyphagous insect was found in 47 genera of plants in 29 families. However, because of its adaptive capacity derived from genetic plasticity, F. dasylirii fed and reproduced in 10% of S. bigelovii in an area adjacent to a multi-trophic shrimp-rearing farm as part of a wetland constructed for phytoremediation at Baja California Sur, Mexico. S. bigelovii is of economic interest for use in gourmet cuisine, industry, and soil remediation in deteriorated environments not suitable for conventional agriculture, a problem in arid and semi-arid regions. The plant also has great potential use in integrated marine aquaculture systems. Strategies for possible-plague management based on good practices should be established, especially when the plant is intended for human consumption.
The study provided information, for the first time, on parasitoid species associated with the American serpentine leafminer, Liriomyza trifolii (Burgess) (Diptera: Agromyzidae), in the State of Baja California Sur, Mexico. During 2017, in the agricultural area of El Comitán (24° 07′ 30″ N, 110° 18′ 15″ W), leafminers were abundant during two consecutive cycles of bell and habanero peppers, Capsicum annuum L. and Capsicum chinense Jacq., protected with mesh-shadow systems. The average was 42.2 adults per trap-week and 3.8 mines per leaf, with peaks of 56 adults per trap and 5.2 mines per leaf at 90 days after transplanting. Fifty percent of plants were mined by 45 days after transplanting. Three species of Hymenoptera in Braconidae and Eulophidae families were parasitoids of L. trifolii. Closterocerus cinctipennis Ashmead (Eulophidae: Entedoninae) appeared first, followed by Chrysocharis sp. Forster (Eulophidae: Entedoninae). The last species was Opius dissitus Muesebeck (Braconidae: Opiinae). The parasitism rate was 29% (~40 insects per week) by eulophids and 9% (~12 insects per week) by braconids. New knowledge was provided on the presence and dispersion of L. trifolii at Baja California Sur, and the three species of associated parasitoids.
Toxicity of essential oil of Mexican oregano (Lippia graveolens H.B.K), obtained by steam distillation, from the states of Chihuahua and Durango, Mexico was bioassayed against larvae of third and fourth instars of Epilachna varivestis Mulsant. Different concentrations (8, 30, 50, 70, and 100 μg μl-1) of essential oil were tested using topical application administered by a microsyringe. Mortality was analyzed by Probit to obtain LD50 values. LD50 values obtained for essential oil were 38.5 μg μl-1 from Durango State and 26.15 μg μl-1 from Chihuahua State. Additionally, Homogeneity Regression coefficients were tested to determine significant differences among regression equations and confidence intervals obtained. Oregano oils from Chihuahua and Durango had no statistically significant differences, and there was a synergistic effect between the metabolites of the oils that increased the insecticidal effect.
Environmental factors that affect Aedes sp. mosquitoes should be considered to optimize control. The study assessed the association between the abundance of Aedes aegypti (L. 1762) (Diptera: Culicidae) and temperature, rainfall, and relative humidity of the State of Baja California Sur, Mexico. Total Mosquito eggs collected each week for 3 years from ovitraps at La Paz and Los Cabos was 3,129,203; mean number of eggs, ovitrap positivity index, and egg density index were calculated, showing the three entomological indices were greater at La Paz than at Los Cabos (P < 0.005). The means of eggs per month differed statistically only at La Paz (P < 0.0001), with less abundance in January and March but more in October. Although monthly differences were not detected from January to December at Los Cabos, increase occurred from September to November during the 3 years. Results showed statistical association between egg abundance and minimum temperature at both locations during the 3 years of study; more activity was observed during the summer and fall when more precipitation and thus greater relative humidity occurred, but they were statistically associated only with precipitation at La Paz (P < 0.01). The number of eggs was statistically significant with minimum temperatures at both locations (P < 0.01) and with rainfall only at La Paz (P < 0.01). Therefore, management should be more intense during winter-spring when insects were less abundant and hence management strategies used would be more effective.
A new species of Diadocidia Ruthe fungus gnat was discovered in a mixed pine and hardwood forest in the eastern Lower Peninsula of Michigan. Diadocidia longivena Taber is the fourth species recorded from North America and the first new species of the genus described from the Nearctic in 63 years. The fly belongs to subgenus Adidocidia Laŝtovka and Matile, as do both of its congeners that were described in North America.
Victor Manuel Gutiérrez-Palomares, Liliana Elizabeth Ronces-Frutos, Johan Rodríguez-Mendoza, José Manuel Cambrón-Crisantos, Claudio Chavarín-Palacio, José Abel López-Buenfil
The spotted wing drosophila, Drosophila suzukii Matsumura, affects berry (Fragaria L., Rubus L., and Vaccinium L.) production and is under official mitigation and surveillance in Mexico. To obtain biological information about the pest, a sample of six adult males and six adult females from CNRF breeding (Colima, Mexico) was studied. PCR was used to amplify regions of the X chromosome. Six markers (FBgn0001083, FBgn0017651, FBgn0026206, FBgn0029789, FBgn0029997, and FBgn0030437) were identified and their sequences were processed with different bioinformatic systems to build a network of haplotypes associated with their geographical distribution. The sequenced markers had similarities with those from populations in the United States (Florida, Georgia, Hawaii, and Massachusetts) and Japan.
Hymenoptera parasitoids Meteorus laphygmae Viereck, 1913 and M. arizonensisMuesebeck, 1923 were analyzed genetically to identify their variability in relation to species similar to them in morphology. Because of complexity in delimitation of the species, they have polymorphisms in color of the body and distinctive color patterns in the mesosome. A fragment of the cytochrome oxidase I (COI) gene was sequenced to learn the genetic distance between individuals. Maximum distribution of variance was found when two groups were formed: Group 1: Meteorus sp. Durango (two species = nine morphotypes) and Group 2: M. laphygmae ("predominant" species in Mexico) compared with external group Homolobus truncator Say, 1829, taxonomically similar to Meteorus (in Durango). The morphotypes of Meteorus sp. at Durango were genetically in a single group (0.0005 genetic distance between them), although taxonomically they belonged to two species (M. laphygmae and M. arizonensis). Group 1 differed from Group 2 of M. laphygmae (0.118) and H. truncator (0.206). This indicated the morphological characters of the two species of Meteorus did not coincide with genetic characters, which resulted in erroneous identification.
Se describe e ilustra el exocorion de Detritivora barnesi con el empleo de las técnicas de tinción de azul de metileno y el estereoscopio, así como del microscopio electrónico de barrido; los caracteres registrados se comparan con los de otros géneros de Riodinidae americanos. El exocorion de Detritivora barnesi es de una forma hemidiscal o cuasiesferoidal deprimida y exhibe una estructura en forma de ‘crochet’ en la región coriónica de transición; muestra retícula hexagonal regular de cuatro hileras, cuyos polígonos presentan proyecciones cilindriformes cortas en sus vértices. Estas características las comparten con Calephelis Grote & Robinson, considerado uno de los géneros más próximos a Detritivora Hall & Harvey. También comparte varios caracteres con el género Caria Hübner, además de la posición de los aerópilos/hidrópilos en el exocorion. No obstante, la trama reticular se asemeja con la del exocorion de Juditha, que pertenece a Lemoniadiina (Nymphidiini); aunque el grosor de las aristas difiere. Se sugiere una mayor exploración del exocorion de otras Riodinidae, con el fin de analizar su utilidad taxonómica y filogenética en esta familia.
La extracción apropiada de ADN en los insectos es un factor limitante debido a la presencia de inhibidores que afectan los estudios genéticos basados en la reacción en cadena de la polimerasa (PCR) y marcadores moleculares, por lo que es importante utilizar métodos que permitan obtener cantidades suficientes de ADN con alta pureza, calidad, y concentración. Se evaluaron cinco protocolos de extracción de ADN, CTAB, H. Guanidina, Buffer STE, Buffer de lisis y kit Qiagen, en larvas de Spodoptera frugiperda (J.E. Smith). A partir del ADN obtenido, se evaluó calidad, pureza, concentración y costo, lo que permitió seleccionar la mejor metodología para identificación de biotipos del insecto plaga mediante PCR-RFLP. Las concentraciones promedio fueron 1158.5, 404, 610, 188.7 y 25.9 ng/μl para los métodos de extracción de ADN, CTAB, H. Guanidina, Buffer STE, Buffer de lisis, y kit Qiagen, respectivamente. El ADN obtenido con el Buffer STE presentó mayor cantidad de impurezas proteicas y restos celulares (A260/A280 = 1.37), seguido de Buffer de lisis, H. Guanidina, kit Qiagen, y CTAB (1.74, 2.13, 1.89, y 1.85). El kit Qiagen fue el mejor método de extracción en cuanto a pureza y calidad, pero mostró una concentración baja, mientras que con el método CTAB se obtuvo una concentración mayor y una pureza confiable, en ambos métodos se obtuvo el 100% en la amplificación de fragmentos de 569 pb del gen COI de S. frugiperda. Los mejores resultados se obtuvieron usando los métodos CTAB y kit Qiagen. El método CTAB es el recomendado en este estudio porque se obtiene una mayor concentración, calidad requerida, y bajo costo en la extracción del ADN, además de lograr la detección e identificación molecular de biotipos de gusano cogollero del maíz Spodoptera frugiperda colectados en Sinaloa, México. Todos los métodos de extracción del ADN evaluados, fueron eficaces para la identificación de los biotipos de gusano cogollero mediante análisis PCR-RFLP.
Diaphorina citri Kuwayama es el vector reconocido de la enfermedad “Huanglongbing” (HLB). Los insecticidas son la base para su manejo dentro de áreas regionales de control (ARCO). El incremento de la presión de selección sobre poblaciones de campo es ahora un riesgo potencial para el desarrollo de resistencia a insecticidas en el vector y para la diseminación del HLB. En este estudio se determinó la susceptibilidad de D. citri a cuatro insecticidas, en tres ARCO de la costa del Golfo de México: Álamo, Cuitláhuac y Martínez de la Torre, estado de Veracruz; y dos en la costa del Pacífico: una en Tecomán, estado de Colima y una en Buenavista, estado de Michoacán. Los resultados indican niveles de resistencia variables entre insecticidas y ARCO. Las poblaciones de Tecomán (PR50 = 12) y Martínez de la Torre (PR50 = 11.5) mostraron niveles similares de resistencia a cipermetrina, aunque pertenecieran a diferentes regiones; una situación parecida ocurrió con las poblaciones de Álamo y Buenavista en relación a clorpirifos y dimetoato. Sin embargo, las poblaciones de Tecomán resultaron susceptibles a clorpirifos (PR50 = 1.85) y dimetoato (PR50 = 1), las de Buenavista (PR50 = 2.72) y Álamo (PR 50 = 1) a cipermetrina. Todas las poblaciones resultaron susceptibles a imidacloprid. El manejo de D. citri es factible con base en grupos toxicológicos. Por ejemplo, rotación de imidacloprid seguido de cipermetrina, suspendiendo el uso de insecticidas organofosforados y carbamatos, además de incorporar insecticidas de menor impacto biológico y ambiental, podría disminuir la tendencia de D. citri a desarrollar resistencia en las ARCO.
Se estudió la preferencia de oviposición y el índice de reproducción de Harmonia axyridis dentro de micro-jaulas con diferentes sustratos de colores bajo condiciones controladas. El sustrato de color azul fue el que mostró el mayor número de posturas, huevos y adultos nuevos de H. axyridis. El índice de reproducción (número de adultos nuevos / número de huevos) no fue diferente entre tratamientos, indicando que las condiciones de los ensayos fueron adecuadas para la reproducción de los insectos y que el único factor que influyó en éstos fue la preferencia de oviposición en los tratamientos. Estos resultados proveen nueva información fundamental para la cría masiva de este insecto.
Alejandra Pérez-Altamirano, Alberto Margarito García-Munguía, Carlos Alberto García-Munguía, Luis Arturo Ibarra-Juárez, Otilio García Munguía, Wendy Karina Gastelum Ferro
Tenebrio molitor y Gromphadorhina portentosa fueron comparados como posibles fuentes alternativas de proteína para consumo animal, con harina de pescado y harina de soya. La proteína cruda de las harinas obtenidas de los insectos fluctuó 51 al 69% (metodología de Dumas), las grasas del 4 al 22% (metodología de Goldfish). La digestibilidad de la materia orgánica fue similar a la de los ingredientes de uso común (metodología de Kesting) y fue superior en el caso de la harina obtenida de Gromphadorhina portentosa con un 90%. El perfil de aminoácidos entre la harina obtenida de larvas de T. molitor es similar al de la harina de pescado y tienen concentraciones más elevadas a las de la harina de soya. En general los insectos tienen mayores concentraciones de aminoácidos esenciales que la harina de soya; si bien la suma de aminoácidos es menor en las harinas de insectos, el total de proteína cruda es mayor y tienen una mejor digestibilidad de la materia orgánica que los ingredientes de uso común como son la harina de pescado y soya. La producción de harinas de insectos es posible, obteniendo productos con un valor nutricional atractivo, es sustentable y tiene una baja huella ecología, lo que las convierte en un futuro ingrediente estándar para la producción de alimentos balanceados para consumo animal.
Phoracantha recurva,_Newman, 1840, is a beetle native to Australia. Adults of this species have a bright body, with dark brown and yellow to cream areas on the elytra, antennae as long or longer than the body, pronotum with discs or protuberances on the back, and lateral spines; elytra with at least one spine or process in the apical margin. P. recurva is an important pest, because it causes severe damage to trees belonging to the Myrtaceae family, such as Eucalyptus and Angophora. The National Commission for the Knowledge and Use of Biodiversity in Mexico (CONABIO) has published the list of high-risk exotic insects and arachnids for Mexico. Of the 20 species of insects associated with eucalyptus trees in México, the genus Phoracantha is not registered, probably because reports of this species are only incidental. Here, we report the occurrence of P. recurva, in Mexico based upon captured and observed specimens.
Adult male and female rice water weevils from fields of rice, Oryza sativa L., in the Mexican state of Morelos were collected for taxonomic identification. Based on morphological characteristics of male and female individuals, the species of rice water weevil in the State of Morelos was Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae) according to taxonomic keys. The male had a tridentate mucro in the posterior tibiae; two outward-facing bifurcated apical teeth, one moderately large apical tooth, acute, facing inward, with two distinct curved submedian setae. Females had a deeply emarginated, VII tergite with a deep indentation or notch in the middle apical part.
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