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This work analyzed the volatiles by obtaining extracts of green leaves of sugar cane in the mature state of eight varieties of sugarcane and of two pasture species by hydrodistillation with a Clevenger trap. The varieties of sugar cane used in this study were: CP 72-2086, MEX 69-290, RD 75-11, ITV 92-1424, MEX 79-431, L 77-50, COLPOS CT MEX 05-223, COLPOS CT MEX 05- 204. The grasses evaluated were: itchgrass (Rottboellia cochinchinensis) and African star grass (Cynodon nlemfuensis). In the evaluated material three main compounds were found, these are: (Z) -3-hexen-1-ol, 1-octen-3-ol and phytol. These compounds were more representative in the varieties CP 72-2086 and MEX 69-290. The compound with greater frequency was (Z) -3-hexen-1-ol, which was present in seven varieties as well as in the two pastures evaluated. The abundance of (Z) -3- hexen-1-ol in the samples of the varieties of sugarcane varies from 20.35% to 57.36%, the greater amount of (Z) -3-hexen-1-ol was detected in African star grass with an abundance of 59.69%. [ABSTRACT FROM AUTHOR]

High populations of the spittlebug (Hemiptera: Cercopidae) may reduce yields on sugar cane. This research was aimed to quantify the effect of biotic, abiotic and agronomic factors on adult populations of the spittlebugs. Data collected was related to the number of adults captured in traps, previous-year infestation level of the sampling plot, nymph counts, weed coverage within and on the border of the plots, sampling time, insecticide and entomopathogen applications, precipitation and temperature. Fifteen plots were sampled from July 2 to October 15, 2014 in Veracruz, Mexico. The data was analyzed as a linear mixed model. Most of the captured adults (98%) were Aeneolamia contigua (Walker, 1851). The analysis showed the following significant effects: a positive relationship between adult populations and spittlebug nymphs and previous-year infestation, and a direct relationship between within-plot weed coverage and spittlebug adult populations. Weed coverage on the borders showed fluctuating effects and had not significant effect on adult populations. Temperature had a positive, significant effect as well, but precipitation and sampling time did not affect adult populations. Results are discussed as related to preventive spittlebug management. [ABSTRACT FROM AUTHOR]

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an introduced pest in Mexico and a vector of huanglongbing, a lethal citrus disease. Estimations of the habitat distribution and population growth rates of D. citri are required to establish regional and areawide management strategies and can be used as a pest risk analysis tools. In this study, the habitat distribution of D. citri in Mexico was computed with MaxEnt, an inductive, machine-learning program that uses bioclimatic layers and point location data. Geographic distributions of development and population growth rates were determined by fitting a temperature-dependent, nonlinear model and projecting the rates over the target area, using the annual mean temperature as the predictor variable. The results showed that the most suitable regions for habitat of D. citri comprise the Gulf of Mexico states, Yucatán Peninsula, and areas scattered throughout the Pacific coastal states. Less suitable areas occurred in northern and central states. The most important predictor variables were related to temperature. Development and growth rates had a distribution wider than habitat, reaching some of the northern states of México. Habitat, development, and population growth rates were correlated to each other and with the citrus producing area. These relationships indicated that citrus producing states are within the most suitable regions for the occurrence, development, and population growth of D. citri, therefore increasing the risk of huanglongbing dispersion. [ABSTRACT FROM AUTHOR]

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Stenoma catenifer Walsingham is a quarantine pest of avocado. Therefore, its detection in avocado-growing regions of Mexico that had been designated pest-free can halt national and international trade. One option for monitoring S. catenifer is the use of synthetic sex pheromone traps. In this study we determined the optimal density of pheromone-baited traps for monitoring S. catenifer. The experiment was conducted in 4 commercial Hass avocado orchards in Colima, Mexico, each with different pest infestation levels. Trap densities were established at 0.5, 1, 2, or 3 traps per ha. The traps were checked every 15 d and the number of moths recorded. The density of 3 traps per ha captured the most moths per trap followed by 1 trap per ha; similar small numbers of moths were captured at densities of 0.5 and 2 traps per ha. In general, there was a linear relationship between trap catch and trap density per ha. The overall default error rate, i.e., the proportion of traps did not detect moths when they were present, was 5.5% at a density of 3 traps per ha and 2.7% at trap densities of 0.5 and 2 traps per ha. Furthermore, at a density of 1 trap per ha all traps captured moths and so there was no default error. Since S. catenifer is a quarantine pest that must be detected promptly to reduce the risk of dispersal and establishment in moth-free areas, it is suggested that a density of 1 trap per ha should be used in avocado orchards to effectively monitor for the presence of this pest. However, this estimate was obtained through the bootstrapping technique, which involves the creation of pseudoreplicate datasets by resampling. Randomized field experiments with true replicates are needed to corroborate this result. La presencia de Stenoma catenifer Walsingham, una plaga cuarentenaria, puede cancelar la comercialización nacional e internacional de aguacate Hass de zonas libres de plagas reglamentadas del aguacatero. Una opción para su oportuna detección es el uso de trampas con feromona sexual sintética. El objetivo del estudio fue determinar la densidad de estas de trampas para el monitoreo de S. catenifer. El experimento se estableció en cuatro huertos comerciales de aguacate Hass, con diferentes niveles de infestación de la plaga, en Colima, México. En los huertos, se establecieron las densidades siguientes: 0.5, 1, 2, y 3 trampas por ha. Las trampas se revisaron cada 15 días para registrar el número de palomillas capturadas. La densidad de 3 trampas por ha capturó el mayor número de palomillas, seguida de la densidad de 1 trampa por ha, mientras que las capturas con 0.5 y 2 trampas por ha fueron las menores, pero muy similares entre sí. En general, las densidades de 0.5, 1, y 2 trampas por ha en relación con la densidad de 3 trampas por ha estuvieron linealmente relacionadas en la mayoría de los casos. La tasa de error global por omisión, i.e., no detectar la palomilla cuando está presente, con referencia a la densidad de 3 trampas por ha fue de 5.5%, y de 2.7% para las densidades de 0.5 y 2 trampas por ha, mientras que en la densidad de 1 trampa por ha siempre se detectaron palomillas y no tuvo omisión de error. Por tratarse de una plaga de importancia cuarentenaria y por el interés de detectarla oportunamente y así reducir el riesgo de dispersión y establecimiento a las áreas libres, se sugiere usar la densidad de una trampa por hectárea de aguacate. Sin embargo, este estimado se obtuvo mediate la técnica de bootstrapping que utiliza pseudor-replicas. Para validar este resultado, se requieren experimentos de campo con repeticiones verdaderas. [ABSTRACT FROM AUTHOR]

The State of Veracruz in Mexico is one of the main cattle producers, and uses several veterinary products for disease and parasite control. For parasite control, ivermectin is one of the most frequently used substances. Nevertheless, even though previous research conducted in other countries has found that this product has negative effects on beneficial coprophagous fauna, no studies have described its effects on coprophagous insects at a local scale in Veracruz, Mexico. This study evaluated Euoniticellus intermedius survival, fecundity, fertility and preimaginal development under laboratory conditions when ivermectin was added to cattle dung at three different concentrations. The design included two controls (spiked dung), and the following product concentrations: 0.01, 1.0 and 100ppm, which were homogenized with wet cattle dung. 20 female-male E. intermedius couples between five and 15 days old were used and kept at 27°C, 70% RH, and 12h light for 10 days. The survival of all specimens, the fertility of 20 females and the gonadal maturity of 17 males were verified. The larval development in 162 pieces of brood-mass was examined, and a total of 974 larvae developed and reached adulthood. The highest ivermectin concentration was toxic at 1.0ppm dose, the survival of adults was reduced to almost the half, and at 100ppm, total mortality was observed. The effects on specimen reproductive systems showed that the ovary was not affected, that the testicle size increased, and that the fecundity and weight of brood-masses were reduced. Pre-imaginal development increased 0.5 times at 0.01ppm concentration, and the width of the cephalic capsule in third instar larvae diminished. The prolonging of development time may cause a phase lag in the field activity cycle, this lag may reduce the number of E. intermedius individuals and the efficiency of the environmental services that they provide [ABSTRACT FROM AUTHOR]

The spatial and temporal distribution of gastrointestinal nematodes of cattle has been little studied in Mexico. Previous studies have described periods of higher larval presence, vertical and horizontal migration in grasslands, and the frequency of adult nematodes; as well as the effect of pasture trichomes on the migration and survival of Haemonchus larvae. The aim of this study was to determine the time-space layout and spread of gastrointestinal nematode larvae on pasture, and to estimate the effect of ivermectin applied to cattle on the time-dependent abundance of their eggs in a ranch in Veracruz. To determine the spatio-temporal arrangement, monthly morning grass samples were obtained from 30 sampling points from July 2008 to June 2009. Third stage larvae (L3) from each point were counted, and aggregation patterns were estimated through variance/mean and negative binomial K indices. Additionally, the number of eggs per gram in cattle feces was determined, from samples with (CI) and without ivermectin (SI), using standard techniques. A total of 20 276 L(3) larvae were recovered in the pasture, of which an 80% corresponded to Haemonchus contortus. The highest nematode density with more than 5 000L(3)/kgDM was detected in October 2008, and the lowest in February and March 2009. The L3 showed an aggregated spatial pattern of varying intensity throughout the year. The number of eggs in the stool was not reduced with the ivermectin application to cattle, which suggested a failure of control. However, the highest parasite loads were observed from July to November 2008. We concluded that the application of ivermectin was not effective to control nematodes eggs, and that L3 populations fluctuated on pasture for ten months, providing an infection source to grazing animals afterwards.

This paper evaluated the risk that Aenolamia postica (Walker) Fennah populations reach the economic threshold in sugar cane fields in Veracruz, México. A risk deductive model was constructed to include the sequence of events leading to damaging populations, considered the top event or critical failure in the crop. Model events were identified and quantified, and model was validated on field conditions. The model components and their state values were identified as: temperature e" 28 degrees C, precipitation e" 45% during June and July, soil clay content e" 40%, infested adjoining fields, deficient weed control, wind dominance, crop phenology and variety, deficient chemical and biological control, and irrigation. Sensitivity analysis showed that the most important events triggering high densities of A. postica were high temperatures and precipitation, previous field infestation, nymph and weed presence. Event probability estimates were combined using Boolean algebra to compute the minimum, mean and maximum probabilities for the top event, yielding values of 0.417, 0.563, y 0.734 respectively. Model was tested in field, by selecting sugar cane fields having the model properties and compared to fields without these features. Fields were sampled in both conditions during 2004 year and high-risk fields had significantly (F = 13, 4, gl = 1, 18, P = 0,0018) higher densities (2.4 adults m(-1)) than low-risk plots (0.4 adults m(-1)) thus agreeing with the model forecast.