César Ruiz-Montiel

Aggregation pheromone of the agave weevil, Scyphophorus acupunctatus

The agave weevil, Scyphophorus acupunctatus Gyllenhal (Coleoptera: Curculionidae), is the most important insect pest of wild and cultivated agaves in the world. Combined gas chromatography‐electroantennography (GC‐EAD) analysis of male volatile extracts showed that four peaks elicited antennal responses from males and females. The peaks were identified by GC‐mass spectrometry (GC‐MS) as 2‐methyl‐4‐heptanol (1), 2‐methyl‐4‐octanol (2), 2‐methyl‐4‐heptanone (3), and 2‐methyl‐4‐octanone (4). Electroantennogram (EAG) recordings of both sexes to 0.01‐, 0.1‐, 1‐, and 10‐µg stimulus load of synthetic compounds showed that the dose of the tested compounds and weevil sex significantly influenced the antennal response of S. acupunctatus. However, there was no sexual dimorphism in the antennal responses to the four synthetic compounds evaluated because the EAG profiles revealed no interaction between doses by sex. Antennae of S. acupunctatus were most sensitive to compounds 2 and 4, reaching the threshold at a 0.01‐µg stimulus load. Weevil antennae were less sensitive to compounds 1 and 3, and the threshold response to these compounds was 0.1 µg. Behavioural evaluation of the synthetic compounds showed them to be attractive to both males and females in a Y‐tube olfactometer. Field experiments confirmed the laboratory results, showing that all components, singly or in blends, were attractive to the weevils. In general, traps baited with the quaternary blend of compounds 1–4 captured significantly more weevils than traps baited with males. However, compounds 3 and 4 were sufficient to obtain captures equivalent to those by the quaternary blend. The potential use of the aggregation pheromone in the development of a mass‐trapping programme as a viable pest management alternative for S. acupunctatus is discussed.

Factors Affecting Pheromone Release by Scyphophorus acupunctatus (Coleoptera: Curculionidae)

ABSTRACT Scyphophorus acupuncatus Gyllenhal is considered to be the most significant pest of cultivated agaves in the world. Recent studies on the chemical ecology of this weevil have shown that males release a pheromone that attracts both sexes. In this study, we investigated the effect of feeding, aging, photoperiod, and time of day on pheromone release by S. acupuncatus males under laboratory conditions. The pheromone released by individual males was sampled using solid-phase microextraction and analyzed by gas chromatography—coupled mass spectrometry. Our results show that food is an important factor because weevils deprived of plant material did not release any pheromone. In addition, we found that males fed with apple, a nonhost plant, released less pheromone than weevils fed with agave. Host odor does not seem to be important in stimulating pheromone release. We found that males as young as 1 mo were able to release pheromone, although the numbers of individuals releasing pheromone increased with age. Older males released more pheromone than younger males. We found that S. acupuncatus males released pheromone during the photophase and scotophase; there was, however, no significant peak in pheromone release. Also, the pheromone released by S. acupunctatus was not affected by the length of the photoperiod.

New Distribution Records of the Small Avocado Seed Weevil, Conotrachelus perseae Barber (Coleoptera: Curculionidae), in Mexico and Notes on Its Biology

The genus Conotrachelus Dejean is represented by 93 species in Mexico (O’Brien and Wibmer 1982, 1984; Wibmer and O’Brien 1989). Of these, Conotrachelus dimidiatus Champion, Conotrachelus copalensis Salas and Romero, Conotrachelus eburneus Champion, Conotrachelus crateagi Walsh, Conotrachelus aguacatae Barber, and Conotrachelus perseae Barber (Fig. 1) are documented as important pests in tropical and subtropical fruits in Mexico, including guava (Psidium guajava L.; Myrtaceae), guajocote (Malpighia mexicana A. Juss.; Malpighiaceae), tejocote (Crataegus spp.; Rosaceae), and avocado (Persea americana Mill.; Lauraceae) (Coria-Ávalos 1999; Muñiz-Merino et al. 2012; Salas-Araiza and Romero-Nápoles 2012; Castañeda-Vildózola et al. 2014). The distribution of C. perseae includes Mexico and Central America (Whitehead 1979; O’Brien and Wibmer 1982; Castañeda-Vildózola et al. 2013). The most significant damage to avocado is caused by females when they perforate growing fruits for oviposition (Figs. 2–3). The larvae feed on the pulp and seeds (Fig. 4), causing fruits to drop prematurely. Larvae continue to develop in the fallen fruit and exit to pupate in the soil (Fig. 5) (Coria-Ávalos 1999; Castañeda-Vildózola et al. 2013). Although this is a species of economic

Evidence for Male-Produced Aggregation Pheromone in Sphenophorus incurrens (Coleoptera: Curculionidae)

Abstract Sphenophorus incurrens Gyllenhal (Coleoptera: Curculionidae) is an insect that feeds mainly on plants of the family Poaceae in the Neotropics. In Mexico, this weevil is an emergent pest of sugarcane. In this study, first the behavioral responses of both sexes to conspecifics were evaluated in a Y-tube olfactometer. Second, the volatiles of S. incurrens were sampled by the dynamic headspace technique and analyzed by gas chromatography coupled with electroantennographic detection (GC-EAD). Third, the antennal-active compound was identified by gas chromatography coupled with mass spectrometry. Finally, the biological activity of the identified compound was evaluated in laboratory and field tests. Our results showed that males emitted a pheromone that attracts both sexes. The GC-EAD analysis of the male volatiles showed that one peak elicited antennal responses from male and female weevils. The compound was identified as 2-methyl-4-octanol. Laboratory and field tests showed that the identified compound is attractive to both sexes of this weevil species, confirming its pheromonal activity.

Insects Associated with Soursop (Annona muricata L.) in Veracruz, Mexico

Abstract. Soursop, Annona muricata L., is an economically important tropical crop in America, Asia, and Australia for its fresh pulp and processed products, and is attacked by insects from a variety of families. As many as 199 insects infest fruits of the family Annonaceae. Annona muricata fruits, leaves, and flowers were collected at 11 locations in central Veracruz, Mexico, producing new records for the region, including a fruit borer (Lepidoptera: Pyralidae), Stenoma spp., (Lepidoptera: Oecophoridae), Neosilba spp. (Diptera: Lonchaeidae) in fruits: Acantocephala femorata Fab. (Hemiptera: Coreidae), Euphoria leucographa (Coleoptera: Melolonthidae), Collembola, Aphis gossypii (Hemiptera: Aphididae) in flowers, as well as parasitoids and predators. Of the 15 insects associated with soursop, seven are new records for Mexico and some have the potential to become pests. The two main pests at all locations were Bephratelloides cubensis and Cerconota anonella.

Foraging Behavior of Apis Mellifera (Hymenoptera: Apidae) and Lycastrirhyncha Nitens (Diptera: Syrphidae) on Pontederia sagittata (Commelinales: Pontederiaceae) on a Disturbed Site

Abstract By influencing the exchange of pollen, floral visitor behavior largely promotes the reproductive success of the plants. Pontederia sagittata (C. Presl) (Commelinales: Pontederiaceae) is a tristylous species whose morphs (long-styled L, mid-styled M and short-styled S) differ in the arrangement of reproductive organs and the amounts and accessibility for food for pollinating insects. We evaluated the behavior of 2 common contemporary visitors to inflorescences, the exotic bee Apis mellifera (L.) (Apidae), a not historical pollinator, and the flower fly Lycastrirhyncha nitens (Bigot) (Syrphidae), a frequent visitor already reported on this aquatic plant, based on HD video records of the number of individuals and the frequency and duration of their visits to 300 inflorescences. Both species of insects preferred to visit S-morph inflorescences. Pollen collection and nectar feeding were the most important activities of the bees, whereas flower flies were observed fed only on nectar. Thus, these behaviors could play an important role in reproduction in the study population of P. sagittata.

Actual and Potential Distribution of Five Regulated Avocado Pests Across Mexico, Using the Maximum Entropy Algorithm

Abstract Mexican avocado producers face phytosanitary barriers that limit the ability to ship avocados to foreign markets due to concerns about invasion by unwanted pests. The principal regulated pests are the big avocado seed weevil, Heilipus lauri Boheman; the small avocado seed weevils Conotrachelus aguacatae Barber and C. perseae Barber; the branch borer weevil, Copturus aguacatae Kissinger (all Coleoptera: Curculionidae); and the avocado seed moth, Stenoma catenifer Walsingham (Lepidoptera: Elachistidae). In Mexico, distribution information of these pests is largely based on a slow integration of the geographic data. This study was conducted to determine the potential distribution of these 5 insect pests in Mexican avocadogrowing areas by using the maximum entropy algorithm. Distributional data of these insects were obtained from scientific literature, databases, and field collection, and incorporated into the MaxEnt model using 19 global climatic variables and elevation data. Distributional models for Mexico, and geographic interaction with avocado-growing areas of the country, were calculated. Conoctrachelus aguacatae, C. perseae, Copturus aguacatae, and H. lauri showed similar environmental suitability patterns in Mexico, with a potential distribution from central to southern Mexico. High suitability was projected principally in the Trans-Mexican Volcanic Belt and surrounding biogeographic provinces. Stenoma catenifer exhibited an irregular environmental suitability pattern, with preference for western Mexico. Altitude, isothermality, and seasonality of precipitation were the variables that most influenced potential distribution of analyzed species. Geographic interaction with avocado-growing areas ranged from wider (Conoctrachelus aguacatae, C. perseae, Copturus aguacatae, and S. catenifer) to narrow or irregular (H. lauri), but the last species has the potential to invade new geographic areas. For the first time, the geographic distribution of these 5 insect pests was determined based on environmental suitability and their geographic interaction with avocados. These data could support development of management strategies throughout the country, and help focusing surveys and control tactics.

Efecto de la Trampa y Atrayente sobre Scyphophorus acupunctatus1 en Agave

Resumen. El picudo del agave Schyphophorus acupunctatus Gyllenhal es una plaga importante que se distribuye en varias regiones del mundo. En México causa pérdidas económicas en especies de agaves y en la producción de nardo. Se ha reportado que el tejido de plantas durante la fermentación produce volátiles como el alcohol que sinergia la feromona para capturarlo. Además, el color de las trampas tiene un impacto sobre la efectividad de éstas. Colocamos trampas de color, ausente de color y atrayente alimenticio en combinación con la feromona de agregación en una plantación de Agave salmiana. Los picudos responden significativamente más a las trampas cebadas de color azul, verde, y amarilla con feromona respecto a la trampa color azul sin feromona. Sin embargo, cuando se coloca feromona en todas las trampas no se registran diferencias en la captura de picudo. Las trampas de color azul y verde atraen más picudos que la ausente de color. Los bulbos de Polianthes tuberosa L. fueron más atractivo que los trozos de A. salmiana Otto Salm-Dick y A. angustifolia Haw. Se identificaron tres volátiles que son liberados por el nardo.

Altitudinal Record of Dendroctonus approximatus Dietz (Coleoptera: Curculionidae) in Veracruz, Mexico

Among bark beetles, the genus Dendroctonus Erichson causes the most damage to trees in forests around the world (Six and Bracewell 2015), attacking trees of the genera Pinus L., Picea A. Dietr., Pseudotsuga Carrière, and Larix (Mill.) (all Pinaceae) (Wood 1963; Six and Bracewell 2015). The group comprises 20 species (ArmendárizToledano et al. 2015), of which 13 are found in the forests of Mexico. In Mexico, 40.5% of pest control reports are attributed to damage by Dendroctonus species (Pérez-Camacho et al. 2013). Species in this genus have been classified into two groups according to the order of colonization of the host, with six species (D. mexicanus Hopkins, D. frontalis Zimmermann, D. adjunctus Blandford, D. rhizophagus Thomas and Bright (Salinas-Moreno et al. 2010), D. pseudotsugae Hopkins, and D. ponderosae Hopkins) considered as primary pests and the remaining seven as secondary pests, including D. approximatus Dietz (Ruiz et al. 2009; Salinas-Moreno et al. 2010; Vı́ctor and Zúniga 2016). Dendroctonus approximatus attacks 17 species of Pinus, of which the following species are known to occur in Veracruz: P. ayacahuite C. Ehrenb. ex Schltdl., P. hartwegii Lindl., P. montezumae Lamb., P. patula Schltdl. and Cham., P. pseudostrobus Lindl., and P. teocote Schltdl. and Cham. (Salinas-Moreno et al. 2010), practically all of which are economically important species in Mexico. Dendroctonus approximatus usually has one generation per year but can have two generations in years with warmer conditions. The species’ pheromone system is unknown (Six and Bracewell 2015). This report offers the first geo-referenced data on the altitudinal distribution of D. approximatus in the northwestern region of the volcano Cofre de Perote, Veracruz, Mexico. The specimens were collected by means of eight-cone Lindgren traps baited with generalist bait composed of frontalin, alphaand beta-pinene, and endo-brevicomine (Sistema Injecthor De Mexico) from June 2014 to July 2016 in coniferous ecosystems of the communities of El Conejo and Los Pescados (Perote), El Rosario (Xico), and El Zapotal (Acajete) in Veracruz (Table 1). Four traps (three baited and one unbaited) were placed at intervals of 100 m per site. The sites occurred at altitude intervals of 250 m from 2,000 to 3,500 m elevation (Table 1). Beetles caught in traps were collected and transferred to 70% ethyl alcohol every 15 days. Specimens were identified to genus using Wood (1982), and species identification was made by Thomas Atkinson (University of Texas, Austin, TX). Genitalia of collected insects were compared to those of D. approximatus specimens from the Entomological Collection of the Institute of Plant Health of the Colegio de Postgraduados (CEAM) in Texcoco, Mexico, following Vı́ctor and Zúniga (2016). Genitalia were dissected by separating the abdomen from the rest of the body and immersing it in 10% potassium hydroxide at 80° C for 20 minutes to macerate the tissue. Once extracted, the genitalia were immersed in 70%

New Records of Cherimola Fruit Borer Talponia batesi Heinrich (Lepidoptera: Tortricidae) in Mexico

En la región Neotropical, el principal problema que enfrenta las anonáceas (Magnoliales: Annonaceae) como la guanábana (Annona muricata L.), chirimoya (A. cherimola Mill.), saramuyo (A. squamosa L.), ilama (A. diversifolia Saff.), y anona colorada (A. reticulata L.), es la alta incidencia de insectos barrenadores de frutos que limitan el crecimiento de la superficie de cultivo (Peña et al. 2002). Se tienen identificadas cinco especies de insectos que perforan frutos de anonáceas. La avispa de las anonáceas Bephratelloides cubensis Ashmead (Hymenoptera: Eurytomidae), palomilla de las anonáceas Cerconota anonella (Lepidoptera: Elachistidae), el gusano de la cáscara Oenomaus ortygnus Cramer (Lepidoptera: Lycaenidae), picudo de las anonáceas Optatus palmaris Pascoe (Coleoptera: Curculionidae), y el barrenador de frutos del chirimoyo Talponia batesi Heinrich (Lepidoptera: Tortricidae) (Peña et al. 2002). Las larvas de estos insectos, causan daño directo al alimentarse del endocarpio y semillas, destruyéndolos en su totalidad, además las perforaciones que realizan las larvas y adultos sirven de entrada a hongos como Colletotrichum spp, causante de la antracnosis de frutos de anonáceas (Peña et al. 2002; Boscán y Godoy 2004). En México, el chirimoyo es un árbol frutal cultivado a nivel traspatio y en pequeños huertos comerciales; produce frutos que son muy apreciados por su agradable sabor y alto valor comercial en los mercados locales (Agustín 1999). Esta especie presenta baja producción de frutos, atribuido a una deficiente polinización y la presencia de T. batesi; constituyen la principal limitante para su cultivo (Castañeda-Vildózola et al. 1996). Heinrich (1932), describió al adulto de T. batesi de larvas criadas de frutos de chirimoya provenientes de Antigua, Guatemala. Registros de esta especie han sido documentados en Costa Rica, México y Venezuela (Nava-Díaz et al. 2000, Boscán y Godoy 2004, Castrejón-Gómez y Valdez-Carrasco 2008, Razowski 2011).