Luis Alberto Aguirre-Uribe

Insecticidal Effect of Plant Extracts on Bactericera cockerelli (Hemiptera: Psyllidae) Nymphs

Abstract. Potato psyllid, Bactericera cockerelli (Sulcen), nymphs were treated with extracts of Annona muricata L., Carica papaya L., Euphorbia dentate Michx, Thuja occidentalis L., Sapindus saponaria L., and Azadirachta indica A. Juss. (neem) as a commercial check in the laboratory. At 72 hours, most potato psyllid nymphs died (98 and 100% mortalities) from A. muricata extract from seeds, at concentrations of 2,500 and 5,000 ppm, respectively, followed by A. indica oil that caused 91 and 100% mortality at concentrations of 2,000 and 2,500 ppm, respectively. A. muricata seed extract was the most effective insecticide in the study.

Population variability of Spodoptera frugiperda (Lepidoptera: Noctuidae) in maize (Poales: Poaceae) associated with the use of chemical insecticides

Summary The objective of this research was to determine the genetic variability of Spodoptera frugiperda Smith & Abbot (Lepidoptera: Noctuidae) larvae from populations collected on maize (Poales: Poaceae) crops from several locations (Sinaloa, Jalisco, Coahuila, and Durango) in Mexico grown under various types of pest management using inter-simple sequence repeats (ISSR) type molecular markers. These ISSR markers amplified 105 loci, with 92.59% being polymorphic, which genetically characterized these populations and related this variability with factors such as pest control management. The most divergent population was from Tlajomulco, Jalisco. This location had the most intense use of chemical insecticides with diverse modes of action, which may account for much of the difference in genetic variability observed among sites in this study.

Biological Activity of Hyphomycete Entomopathogenic Fungi Against Gynaikothrips uzeli (Thysanoptera: Phlaeothripidae)

Weeping fig, Ficus benjamina L. (Moraceae) is an ornamental plant species grown worldwide. In Mexico, it is one of the most widely used ornamentals in urban green areas. Leaves of the tree are damaged by the thrips Gynaikothrips uzeli Zimmerman (Cambero et al. 2010). Thrips feed on leaf terminals and inject toxins causing deformed leaves and gall formation (Held et al. 2005; Retana-Salazar & Sanchez-Chacon 2009). Chemical control of Gynaikothrips spp. is possible (Held & Boyd 2008), but insecticides should be used wisely in order to preserve associated natural enemies (Wheeler et al. 2007). In Mexico, Montandoniola confusa Streito & Matocq and Androthrips ramachandrai (Karny) have been found to be predators of Gynaikothrips spp (Cambero et al. 2010). In North America north of Mexico, A. ramachandrai, Montandoniola moraguesi Puton and Thripastichus gentilei (Del Guercio) are reported natural enemies (Held et al. 2005; Held & Boyd 2008).

Escarabajos de la Savia1 de Coahuila, México y Atrayentes Efectivos Para su Recolecta

Resumen. Especímenes de Nitidulidae fueron recolectados en diferentes localidades de Coahuila, Méx. durante 2011 al 2013. Trece géneros y 27 especies se reportan, 23 son primeros registros para Coahuila y para México y 4 de ellos reportados anteriormente. Aethina tumida Murray es considerada una importante especie invasora de Apis mellifera Linnaeus (Hymenoptera: Apidae); Stelidota geminata Say y Lobiopa insularis Castelnau dañan al fruto maduro de la fresa; Carpophilus lugubris Murray y C. hemipterus Dobson causan daños en mazorcas secas de maíz y en maíz en estado de elote, respectivamente. Se describen los métodos y técnicas utilizadas con los que se recolectaron estos primeros taxones, y el uso específico de los cebos a base de frutos en descomposición como son: frutos secos, bebidas alcohólicas, jugos fermentados, carne descompuesta de puerco, masa de maíz mezclada con azúcar morena, entre otros. Se presenta una lista de las especies de Nitidulidae como primer marco taxonómico para el estado de Coahuila y para México.

New Records of the Genus Encarsia Förster1 and Hosts at Veracruz, Mexico

Abstract. The Mexican state of Veracruz is renowned for biological diversity based on limited studies in the ecoregion. Fifteen species of Encarsia Förster are reported to occur on numerous hosts. Our objective was to intensively survey the Encarsia genus in the northern part of the state to detect new and previously unreported species that might be present, along with their hosts. Whitefly nymphs from a wide range of hosts were collected at Tampico el Alto and Ciudad Cuauhtémoc during 2013 and 2014. Six species of Encarsia not reported for the State of Veracruz, Mexico were identified and recorded: E. andrewi Myartseva & Coronado Blanco, E. nigricephala Dozier, E. pergandiella Howard, E. Sophia (Girault & Dodd), E. tapachula Myartseva, and E. trialeurodis Myartseva, parasitizing: Aleurodicus sp., Bemisia tabaci (Gennadius), Tetraleurodes acacia Quaintance, T. vaporariorum (Westwood), Aleuropleurocelus sp., and Aleurotrachelus sp., respectively. The six species of Encarsia are new records for the State of Veracruz, increasing to 21 the number of species known. In addition, six new Aleyrodidae hosts were recorded for Encarsia species. The Aleyrodid complex includes many agricultural pests, and these findings will aid scientific understanding of tritrophic interactions in nature and agriculture.

Plant Oils to Control Sitophilus zeamais Motschulsky1

Abstract. The maize weevil, Sitophilus zeamais Motschulsky, is the most important pest of stored maize, Zea mays L. The pest causes estimated losses of 5–10% worldwide. Oil extracts from plants show promise to control maize weevil with important advantages over conventional insecticide, such as non-toxicity to humans, biodegradability, and ecosystem safety. The objective of this research on maize weevils in laboratory conditions was to determine the insecticidal effect of 10 plant oils: garlic, Allium sativum L.; cinnamon, Cinnamomum verum J.; hot pepper, Capsicum annuum L.; clove, Syzygium aromaticum L.; mint, Mentha piperita L.; black pepper, Piper nigrum L.; rosemary, Rosmarinus officinalis L.; rue, Ruta graveolens L.; thyme, Thymus vulgaris L. and allyl (commercial product). Residual film was used to test plant oils at five concentrations: 9,000, 7,000, 5,000, 3,000, and 1,000 ppm. The number of weevils killed was counted at 72 hours, and treatment means were compared using a Tukey multiple separation test. PC-Probit analysis determined LC50 and LC95. Most weevils, 52.47 and 60.38%, were killed by garlic and black pepper oils, respectively; at 9,000 ppm; fewer than 50% were killed with the other plant oils. Use of garlic and black pepper oil might be an alternative method to manage this insect pest in stored maize.

First Report of Siphosturmia rafaeli (Townsend)1 as a Parasitoid of Diatraea saccharalis (Crambidae) at Tabasco, México

Abstract. Sugarcane borer, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), is a key insect pest that affects crop yield in Mexico. Immature stages of the pest are naturally attacked by a complex of parasitoids. We identified the parasitoid Siphosturmia rafaeli (Townsend) to be a new record at Tabasco, Mexico, and reported a new host.

Damage by Diatraea sacharalis (Fabricius)1 to Sugarcane at la Chontalpa, Tabasco, México

Abstract. Sugarcane borer (Lepidoptera: Pyralidae) feeds on buds and shoots of young plants and tunnels in stalks, causing yield loss and affecting juice quantity and quality of harvested sugarcane (Saccharum officinarum L.). The objective of this research was to evaluate pest damage and identify borer species at La Chontalpa, Tabasco, Mexico. Samples were collected starting in February during plant growth and before harvest. Stalks were 8.9% infested and 1.9% damaged before harvest based on a damage scale for the pest, and 9.4% of plants had dead growing points. Diatraea saccharalis (Fabricius) was the only borer species found in the region. Infestation by D. saccharalis was low in sugarcane in the area.

Species of Stalk Borers (Lepidoptera: Crambidae) and Damage to Maize in Southeastern Mexico

Abstract. Stalk borers (Diatraea spp.) are important pests of maize, Zea mays L., in the Neotropical region. The objective of this research was to identify the Diatraea species and assess the injury they cause and their effect on yield of maize at Tabasco, Mexico. In total, 199 larvae and 54 pupae were found infesting 319 (62.4%) of 511 plants sampled. Species analyses showed 97.6% were Diatraea lineolata (Dyar) and 2.4% D. saccharalis (F). Despite the great amount of injury, no significant difference between yield and the number of nodes injured per plant was observed (R2 = 0.014, P > 0.05). This is the first report of corn borers injuring maize in this area, and the findings suggest economic damage does not occur when stalk injury is <63% and maize matures before the borers complete development.

Importance of Bactericera cockerelli, Empoasca spp., and Macrosteles spp. for Potato Purple Top Epidemic

Abstract. Incidence of potato purple top, and abundance of its vectors, the potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Psyllidae), and leafhoppers (Empoasca spp. and Macrosteles spp.) were monitored in three production sites and four crop cycles (2004–2007) in the potato, Solanum tubersum L., growing region of Coahuila and Nuevo León, México. There was a linear relationship between the annual incidence of potato purple top, and abundance of potato pyllid and leafhoppers. Results showed the importance of the vectors in dissemination of potato purple top in the region. Potatoes planted before the middle of May are exposed to more abundant vectors. The least risk of disease occurred when the potato plant emerged between June and July, when the insects were scarce. Arrival of vectors to the production site did not always coincide with disease outbreak, which suggests seed potatoes are the main initial source of inoculum for potato purple top.