The influence of maize, Zea mays L., and pigweed, Amaranthus spp., on the abundance of tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), adults infesting cotton, Gossypium hirsutum L., in the Mississippi Delta was studied using stable-isotope analyses. Cotton fields adjacent to maize and those farther than 1.6 km from maize were identified in four counties of the Mississippi Delta. Tarnished plant bug adults were collected from the cotton fields weekly throughout the growing season and analyzed with stable-carbon and nitrogen isotopes to determine the natal host. The proportion of tarnished plant bug adults collected from cotton that developed as nymphs on plants that used the C4 photosynthetic pathway, primarily maize and pigweed, peaked from 79–92% during 2008–2009. Distance of cotton fields from maize did not influence the peak proportion of tarnished plant bug adults with a C4 signature from cotton fields, the peak time, or peak duration. Time of the C4 peaks occurred from 28 June to 8 July, and the duration was between 13 and 19 days. Stable-nitrogen isotope analyses indicated maize was the major contributor of C4 tarnished plant bugs infesting cotton compared to pigweed. Nevertheless, pigweed produced a significant proportion of tarnished plant bug adults infesting cotton. Improved control of these weed species could potentially reduce abundance of tarnished plant bugs in cotton. Because maize makes up a significant amount of the crop acreage in the Mississippi Delta, this information can be used to estimate the time of mass movement, thus allowing more efficient use of insecticide to control tarnished plant bugs in cotton. It may also allow future targeting of tarnished plant bugs in field corn before movement to cotton.

Controlled field studies using clip cages were used to quantify development, reproduction, and survival, and generate life history characteristics and population growth parameters of the cotton aphid, Aphis gossypii Glover, on irrigated upland cotton, Gossypium hirsutum L. Newly born (<6-hour-old) aphid nymphs were individually placed on the underside of fifth mainstem cotton leaves (n = 30 plants). Aphids were monitored every 24 hours and the developmental stage, fecundity, and mortality recorded until the last aphid from the cohort died. Individual aphids were transferred to a new fifth leaf on the same plant when plants gained a newer leaf. Average daily temperature under the leaf surface was 28.1°C. Nymphal durations were 38, 48, 37, and 34 degree-days above a development threshold of 6.3°C for 1^st, 2^nd, 3^rd, and 4^th instars, respectively. Aphids began dying at 448 degree-days, and the last individual in the cohort died at 907 degree-days, with an average longevity of 674 degree-days. The gross reproductive rate and finite rate of increase were 62.24 and 1.43263, respectively. A complementary study was done by daily monitoring population dynamics and within-plant distribution of the aphid for two growing seasons. Cotton aphids were not typically in the field until mid-July or early August, and the population decreased after mid-September. A fifth mainstem leaf from the top of the plant canopy (T₅) and a leaf from the mid-canopy (M) consistently tracked population activity with whole-plant densities, suggesting that either T₅ or M should serve as a reliable indicator-leaf for monitoring cotton aphid population dynamics in the field.

Fifteen genotypes of maize, Zea mays L., varying from putatively resistant to susceptible to corn earworm, Helicoverpa zea (Boddie), and fall armyworm, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae), based on visual observations in a breeding nursery, were evaluated for leaf and ear injury, yield, and aflatoxin content in an open field experiment. The genotypes were nine nontransgenic inbred lines and six hybrids including a Bt hybrid containing transgene events MON810 and MON88017. Larval development and progressive leaf injury were measured on selected genotypes in companion laboratory larval feeding and field-cage experiments. Resistance to corn earworm was confirmed for one nontransgenic inbred line in the open field as observed by significantly less ear injury with deepest penetration of larval feeding as low as 1.61 cm and total surface area as low as 1.44 cm², compared to injury of susceptible genotypes (e.g., depth of penetration as high as 7.53 cm and surface ear injury as high as 14.16 cm²). The low injury of the putative resistant genotype approached the low ear injury seen in the transgene Bt hybrid. Fall armyworm was not abundant in the open field, and injury scores were not significant different across genotypes, ranging from 1.15 to 3.33 (using the 1–9 leaf injury scale). But putative resistance to fall armyworm was indicated in one genotype in field cages as observed by less leaf injury 7 to 24 days after artificial infestation compared with a susceptible genotype. Related to yield, kernel weight of the inbred genotypes (as low as 205 kg/ha) was significantly less than kernel weight of the hybrids (as high as 2599 kg/ha), but there was no apparent relationship of yield with plant injury. Few differences in aflatoxin content were observed, but variability was great, average 52 to 2838 ppb across genotypes. One genotype resistant to corn earworm was referred for advanced breeding and testing for resistance to multiple stresses, with the aim to include native resistance to the insects into the genetic background of high-yielding maize, including Bt hybrids, grown in the southern U.S. Further observations of three genotypes were recommended before consideration for advanced breeding.

Greenhouse experiments simulated field treatments with Premise® 75 WP imidacloprid insecticide at the highest recommended labeled rate (0.10% AI) for prevention and control of subterranean termites around and within structures. Persistence of imidacloprid was examined in treated sandy loam soil with and without vegetation. Samples from soil substrates and leachates collected 1, 3, 6, 9, and 12 months after treatment during a 1-year post-treatment period were analyzed by high-performance liquid chromatography. The mean concentrations of imidacloprid in the treated soil and leachate immediately after application were 842.6 ± 9.2 µg per gram and 941.5 µl per liter, respectively. Recovery of imidacloprid utilizing high-performance liquid chromatography was 84.2 ± 9.2 and 94.5 ± 10.6%, respectively. No imidacloprid was found in soil or leachate 6 months after treatment. The results indicated that imidacloprid was soluble and leached from the treated soil.

Athel, saltcedar, siempreverde, rompeviento, or pinabete (Tamarix aphylla (L.) Karsten) is an exotic ornamental tree important for shade and wind protection in northern Mexico. There, the tree is defoliated by Diorhabda beetles, especially the subtropical tamarisk beetle, Diorhabda sublineata (Lucas), introduced for biological control of other invasive, shrubby Tamarix spp. The damage is conspicuous in Mexican communities in the Rio Grande and Conchos River basins, in Chihuahua State. To protect athel trees against damage by D. sublineata, we evaluated the effect of insecticide treatment on trees (one drench, 70 g active ingredient of imidacloprid per tree, for trees with approximately 1-m-diameter trunk bases) on foliage consumption by and insect knock-down of Diorhabda beetles at Ojinaga, Chihuahua, Mexico. One hundred sixteen days after treatment, fresh foliage was taken from treated and check trees to feed D. sublineata adults and larvae in a laboratory. The parameters of insecticide performance were: quantities of excrement (droppings) produced (as indicator of foliage consumption) and irreversible knockdown and convulsions of beetles; both were evaluated after insects were exposed to field-treated foliage for 14 hours in the laboratory. After this time, 100% of adult insects on non-treated foliage produced large amounts of droppings and showed no knockdown; on the other hand, when adult insects were fed foliage from the two treated sites, 100 and 86.6% produced few droppings and 33.3 and 42.2% showed knockdown, respectively. When fed foliage from the nontreated tree for 14 hours, 100% of larvae produced large amounts of droppings and showed no knockdown, while 87.5 and 50% of larvae produced few droppings and 47.5 and 28.7% showed knockdown when fed foliage from imidacloprid-treated sites. The amount of droppings and number of knocked-down insects and larvae were significantly different among treated and check trees. Drench application of imidacloprid can be a simple tool to prevent undesirable defoliation of athel trees at Chihuahua.

Aromatic cedar from eastern red cedar trees (Juniperus virginiana L.) contains chemicals that are toxic and repel some insects. In South-central Texas and the Texas Hill Country, Ashe juniper (Juniperus asheii J. Buchholz) is the prominent species in the Cupressaceae family and commonly found in landscaping mulch. This study evaluated the effects of cut and shredded Ashe juniper on abundance of mosquitoes during 5 weeks at Hardberger Park in San Antonio, TX. A total of 55 mosquitoes were collected in nontreated sites, and 76 total mosquitoes in treated sites over the five week period. Fifteen species of mosquitoes were identified. A mean of 4.8 mosquitoes were collected nightly in untreated sites and 4.9 in treated sites. Mosquitoes of various species were not affected by fresh-cut mulch from Ashe juniper over time.

Dengue cases occur frequently at Nuevo Leon, Mexico, where Aedes aegypti (L.) and Ae. albopictus (Skuse) are present. Ae. albopictus is considered the second vector of dengue. Because it bites humans outdoors during the day, the mosquito plays an important role in transmission of dengue virus (DENV). However, no previous studies at Nuevo Leon indicated the role of the mosquito outdoors. To assess Ae. albopictus for dengue virus, mosquitoes were collected from April to October 2010 at five localities at Guadalupe and Santiago, Nuevo Leon, (Northeast) Mexico, by using two methods: engine backpack aspirator and ovitraps. In total, 1,836 Ae. albopictus and 833 Ae. aegypti mosquitoes were collected by ovitrap and engine backpack aspirator methods. Groups of mosquitoes were processed by RT-PCR. Examination for DENV infection of mosquitoes showed one positive group of four female Ae. albopictus from an ovitrap. This research provided information that showed transovarial transmission of dengue virus in Ae. albopictus occurred naturally, maintaining endemic levels of disease at a study site.

Ragweed weevils, Lixus scrobicollis Boheman, were collected from leaves and stems of giant or great ragweed, Ambrosia trifida L., growing at the Trinity River Audubon Center in Dallas, TX. Examination of the external anatomy of the weevils with a scanning electron microscope revealed a bacterial symbiont. The results of biochemical testing suggested the bacterium was Bacillus endophyticus sp. nov.

Indian fig opuntia, Opuntia ficus-indica (L.) Mill., is a cultivated cactus adapted to semiarid conditions that has established complex interactions with insects. Several insect pests feed on and cause economic damage to the crop. The cactus weevil, Cactophagus spinolae Gyllenhal, is a phytophagous beetle that during larval and adult stages feeds on Opuntia plants, despite defensive compounds -- reported as antinutritional factors -- in the plants. Most likely the insect has developed metabolic mechanisms that enable it to use Opuntia cladodes as food, despite antinutritional factors in the plant. The aim of this work was to determine enzymes as auxiliary elements in the digestive process of the insect. The digestive enzymatic profile was described by zymographic techniques, hydrolysis of synthetic substrates, and chemical-specific inhibitors. Amylase activity was detected, represented by only one band of 80 kDa at pH 7. Serine proteinases dependent of calcium as cofactor were active at pH 8 and 9. Cysteine proteinases were active at pH 5 and 6 and found to be part of the proteolytic battery. Assays with specific substrates allowed detection of trypsin, chymotrypsin, and elastase-like proteinase activities, with 694, 1016, and 891 proteolytic activity units per milligram of protein, respectively. An attenuation effect in the activities of proteinases was detected when interacting with a protein crude extract obtained from the cladode of Indian fig opuntia, showing inhibition of the insect serine proteinases and increased cysteine proteinase activities. Interaction between plants and specialist insects is complex, and knowledge of the relationship between Opuntia plants and the insects that attack them, could be an interesting model to understand how strong the interaction is with specialist phytophagous and potentially useful to develop pest management strategies.

To understand the relationship between pathogenicity and enzymatic activity of fungal isolates associated with Diaphorina citri Kuwayama, three isolates of Beauveria bassiana (Bals.) Vuill. and six of Hirsutella citriformis Speare from southeastern and Central Mexico were characterized enzymatically. Pathogenicity against D. citri was evaluated in four of them. They killed >90%, and no differences among isolates were found; however, by the change rate (rL) of the logistic model, a trend of more mortality (1.12) was confirmed in the Bb-Ch isolate of B. bassiana obtained from adult D. citri from Quintana Roo State, while the Y-2 isolate of H. citriformis from Yucatan State resulted in least mortality (0.74). Enzymatic production, both intra and inter-specific, varied, but greatest variability was found in proteases, and there were strains without proteolytic activity. A positive relationship (r = 0.84 to 0.98) was found only between intracellular proteases versus pathogenicity; isolates with more and least production were Bb-Ch (3.15) and Y-2 (0.12), respectively, suggesting this methodology for detecting enzymes might be useful in selecting the most pathogenic isolates. Based on pathogenicity and intracellular enzymatic activity, strains with the greatest potential for managing D. citri were Bb-Ch and Bb-Cat of B. bassiana. Based on enzymatic activity only, Y- 5 and Camp-1 could be the H. citriformis strains more pathogenic to D. citri.

The blackberry, Rubus sp., crop in the state of Michoacán, Mexico is the second-most important crop after avocado, Persea americana Mill., in relation to value of production and employment. In this study was identified a blackberry leafroller, its parasitoids, and population dynamics in two commercial orchards at Michoacán, Mexico, during the growing seasons of 2007 and 2008. Collected rolled leaves containing larvae and pupae where maintained in a laboratory until leafroller adults and their parasitoids emerged. Population dynamics of moths were determined using wing traps containing the sex pheromone of Argyrotaenia citrana (Fernald) (Lepidoptera: Tortricidae). Numbers of males caught peaked in September and November 2007 at the two locations. After these months, numbers gradually decreased to almost zero during the dry season in 2008. Moths that emerged were identified as Argyrotaenia montezumae (Walsingham) (Lepidoptera: Tortricidae). Of the A. montezumae larvae collected in the field, 38% were parasitized by Apanteles near aristoteliea Viereck (Hymenoptera: Braconidae), 9% by Colpoclypeus michoacanensis Sánchez and Figueroa (Hymenoptera: Eulophidae), and 3% by unidentified specimens of the family Ichneumonidae. Males of A. montezumae were attracted to the sex pheromone of A. citrana. The greatest number of moths trapped during the growing season coincided with the periods of intense vegetative growth and harvest.

Parasitoid flies of white cedar sawfly, Monoctenus sanchezi Smith, were identified molecularly and morphologically. Third and fourth instars of sawfly larvae were collected in white cedar trees, Juniperus flaccida Schltdl, at Sierra de Alvarez, San Luis Potosi, in 2011, 2012, and 2013. The material collected was taken to Universidad Autonoma Agraria Antonio Narro and identified to family. Molecular characterization was done at CINVESTAV Campus Irapuato, and DNA sequences were compared with GenBank Blast. Parasitoids obtained were Vibrissina mexicana (Aldrich) and Lespesia postica (Walker) (Diptera: Tachinidae) with 99 and 97% similarity, respectively. Parasitism of white cedar sawfly was 2.6, 4.25, and 5.5% in 2011, 2012, and 2013, respectively.

A new species of Boletina Staeger fungus gnat was discovered in western Michigan and named Boletina ciliata Taber. Two adult males flew to a Malaise trap in an ecotone between swamp and second-growth forest dominated by black ash (Fraxinus nigra Marshall), paper birch (Betula papyrifera Marshall), red maple (Acer rubrum L.), and black cherry (Prunus serotina Ehrhart). Adult females and juveniles of Boletina ciliata remain unknown.

Metanotum characters were used in the determination of species and supra specific groups within Thysanoptera. Collection specimen study of the structure of the metanotum and the presence of sensillae were viewed by light microscopy. Studies using light microscopy, electron microscopy, and laser confocal showed the so-called striations in the metanotum are really keels, while each of the sensillae, considered in the literature as campaniform sensilae, are not well classified and are more likely to be sensilla placodea.

Although the State of Veracruz is a megadiverse entity, it has the highest annual deforestation rates. Protected natural areas are considered strategic to preserve local biodiversity. In this paper, composition and alpha diversity of ant assemblages were analyzed in the natural protected area ‘Metlac’ near Fortin, Veracruz, Mexico. Sampling was conducted at four transects using baited pitfall traps and hand-collection. In total 3,204 ant workers belonging to 36 species, 21 genera, 12 tribes, and seven subfamilies were collected. The average alpha diversity was 16 species and no significant differences between recorded richness in each transect were found. Average sampling completeness was above 80%. Locally, Solenopsis geminata and Nylanderia steinheili dominate the epigeous and shrub strata due probably to their biological, behavioral and ecological plasticity that allows them to easily adapt to disturbed environments. This paper shows that for the small area sampled, the relict of tropical semi-evergreen forest is of great biological value despite heavy human intervention and the space-geographic context in which it is found.

Landscapes are heterogeneous mosaics of habitats. In Yucatan, Mexico, these landscapes have been modified by different historical events, both natural and of human origin, such as the extensive cultivation of hemp mainly distributed in the area where deciduous forest dominated. The aim of this study was to determine the diversity and spatial and temporal structure of an assemblage of cursorial spiders in a fragmented landscape by agroecological management in Yucatan. Samples were collected monthly from March 2008 to February 2009 using pitfall traps in different agroecological management areas in the landscape. More than 224 cursorial spiders belonging to 12 families, 21 genera, and 25 species were recorded. The most abundant families were Lycosidae, Oxyopidae, and Salticidae. The most abundant species in the study was Pardosa vadosa Barnes, 1959 (Lycosidae). There were changes in the spatial and temporal structure of the cursorial spiders among agroecological management areas. This might be because of microclimatic conditions caused by the type of management and by the sampling effort in each habitat.

Population growth curves in three species of Diabrotica in the region of Irapuato, Guanajuato, Mexico, were estimated using multivariate multiple regression techniques through a third-degree polynomial function defined by:

where T is the average monthly standard temperature, PP is the average monthly accumulated rainfall, and Y1, Y2, and Y3 are the numbers of Diabrotica undecimpunctata (Harold), Diabrotica balteata (LeConte), and Diabrotica virgifera (Krysan & Smith) adults, respectively. The Roy criterion was used in the multivariate analysis of variance (MANOVA) of the multivariate multiple regression, which statistical test value was 95.2 with a probability for its corresponding approximation F of 8.548e-05. Consequently, the estimated polynomials for the population growth curves were adequate. Multivariate association measures Wilks (Λ; = 0.9984) and Roy (θ = 0.9896) were calculated, allowing estimation of growth curves as prediction tools. These models of polynomial growth curves were compared to each other through the statistic W = 23171.78, which yielded a probability value P = 0**, concluding that the growth curves were different. The critical points for temperature and rainfall (T, PP), at which the number of individuals of each species reached its maximum, calculated through standard techniques of mathematical programming were (14.0562, 4.5) for D. undecimpunctata, (13.7000, 168.0) for D. balteata, and (14.7020, 4.5) for D. virgifera.

Mortality and growth inhibition effect of Trichiliahavanensis, Annona cherimola, and Carica papaya seed powders were evaluated on Scyphophorus acupunctatus Gyll. (Coleoptera: Curculionidae). Seeds of T. havanensis and C. papayaat 15% were very toxic to S. acupunctatus, causing 100 and 90% larval mortality. Seed powder of A. cherimola killed 63% of the weevils. All powders inhibited the weight of the insect. Annona cherimola was the most effective, decreasing the weight of larvae, pupae, and adults 98.5, 40.6, and 45.0%. These results show that T. havanensis, C. papaya, and A. cherimola seed powders have the potential to control the S. acupunctatus weevil.

With the aim to provide bases to define a regional management strategy of insecticides, the susceptibility of populations of Aedes aegypti from three regions of Guerrero, Mexico, to the insecticides malathion, temefos, chlorpyrifos, pirimiphosmetil, permethrin, lambda-cyhalothrin, propoxur, and spinosin was determinated, using the New Orleans population as a reference. Commercial and technical-grade insecticides were evaluated by residual application in larvae of early fourth instar according to the methodology proposed by the World Health Organization. The mortality was recorded 24 hours after application. Probit analysis was used to determinate the response lines log dose-mortality, LC₅₀ values and the resistant factor for each product. The results indicate that the three populations of A. aegypti were resistant to the insecticide lambda cyhalothrin, and the populations from Acapulco and Costa Chica were moderately resistant to pirimiphos methyl. In contrast, the three field populations were susceptible to malathion, temephos, chlorpyrifos, permethrin, propoxur, and spinosin. However, although some products were found to be effective, it is recommended to use them in rotation combining different modes of action and in conjunction with other alternatives, as removal of breeding sites, to preserve the life of the authorized insecticides. This study provides useful reference information for the development and implementation of strategies for managing and monitoring local insecticide resistance of A. aegypti in Guerrero, Mexico.

Research on entomopathogenic fungi has been conducted to control the potato psyllid, Bactericera cockerelli, to find new strategies and because of its mode of action, that, unlike other entomopathogenic microorganisms, does not require being ingested. Two Beauveria bassiana strains, a wild type (BB42) and a commercial (BB09), and two Metarhizium anisopliae strains (MA25 and MA28) were used at 1×10⁷ spores ml^-1, on B. cockerelli nymphs on chili peppers under greenhouse conditions. Three applications (at 1, 3, and 5 days) killed 36% (MA25) to 47% (BB09), achieving more control than imidacloprid.

To quantify the presence of whitefly (Bemisia tabaci Genny), thrips (Frakliniella occidentalis Pergande), and leaf miners (Liriomiza trifolli Burgess) in the exterior and interior of greenhouses, and the effect of screens as physical barriers on the yield and quality of tomatoes (Solanum lycopersicum L.), five screens with different porosities were installed on the side windows of greenhouses. The amount of the three insects outside the greenhouses was 30% greater than in the interior. Mesh with 39% porosity limited to 30 and 18% the abundance of B. tabaci and F. occidentalis, while L. trifolli decreased 30% using 37.5% or 37.9% porosity meshes. Greater tomato yield was obtained with 39% porosity mesh on the greenhouse side windows.

Current knowledge regarding predatory wasps (Hymenoptera) of the Yucatan Peninsula, an important region of the Mexican Neotropics, was reviewed. The review includes an overview of the richness of predatory wasps at global, regional, and national levels, as well as revision of pedotrophic and nesting behavior of the species. The review showed the known diversity of species in the Yucatan Peninsula, and that information on pedotrophic and nesting behavior is sparse. To date, 78 species have been recorded in the Yucatan Peninsula. The Family Vespidae has the most species (36) followed by Crabronidae (20), Pompilidae (18), and Sphecidae (four). Most species in the Peninsula were recorded in the state of Yucatan, while few species were recorded in Campeche and Quintana Roo. The pedotrophic behavior of the wasps involves use of some species of insects and caterpillars and spiders. Nests of predatory wasps were most often constructed in the soil or of clay. Further studies are recommended to better understand ecological interactions, as well as the origin and evolution of social behavior and the role wasps play as predators of other arthropods in tropical ecosystems.

In Ozuluama region in northern Veracruz, Mexico, 1,888 specimens of the genus Phyllophaga were collected. Six species were recognized from three subgenera and five species groups. The most abundant species was Phyllophaga trichodes (Bates). The numbers of P. crinita (Burmeister), P. xkumuka Morón, and P. temora Saylor are new state records.

Reduviidae (Hemiptera) is a family of polyphagous predators that can be used as biological control agents for one or more pest species. Predator efficiency of Pselliopus latispina over Tetranychus urticae Koch females was evaluated using the functional response at different mite densities. Mites were exposed to predation in Petri dishes under laboratory controlled conditions during 24 hours. Predators consumed an average of 56.3 individuals of 64 adult females of T. urticae, with a type II functional response according to Holling's instant discovery rate model (a') of 1.0597, and a handling time (th) of 0.00442. These results indicated that Pselliopus latispina is a predator with broad perspective that can be used in different crops.