El hiperparasitismo dificulta el control biológico de Aphis spiraecola en clementinos

Aphis spiraecola Patch. (Hemiptera: Aphididae) es actualmente una plaga clave en clementinos. A pesar de que este pulgón tiene un rico complejo de enemigos naturales perteneciente a diversos órdenes de insectos, no se ha identificado ningún parasitoide capaz de regular sus poblaciones ni disminuir sus daños. Trabajos recientes desarrollados en nuestro grupo de investigación han arrojado luz sobre algunas de las razones que explican la baja eficacia de los parasitoides en el control de A. spiraecola y que resumimos a continuación. Por una parte, tan solo se encuentra un parasitoide primario, Binodoxys angelicae Haliday (Hymenoptera: Braconidae), el cual presenta una tasa de parasitismo muy baja sobre A. spiraecola. Por otra parte, existe un abundante y diverso complejo de hiperparasitoides que influye negativamente sobre las poblaciones de B. angelicae. La presencia de este complejo de hiperparasitoides en la regulación natural de las poblaciones de A. spiraecola es una de las principales causas que explica la baja eficacia de los parasitoides. Por lo tanto, a partir de estos resultados, recomendaríamos que los futuros programas de control biológico de A. spiraecola en clementinos se centraran en el uso de depredadores en lugar de parasitoidesEsta investigación fue financiada por Ministerio de Ciencia e Innovación (AGL2011-30538-C03) y la Conselleria d'Agricultura, Pesca i Alimentació de la Generalitat Valenciana

Pezothrips kellyanus (Thysanoptera: Thripidae) nymphs on orange fruit: importance of the second generation for its management

Kelly’s citrus thrips Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae) is a new pest of oranges in New Zealand, southern Australia, and the Mediterranean Basin. The nymphs of this thrips can damage the fruit from petal fall up to 6 wk later. Because there is a lack of information on its management, the aims of this study were to determine the number of generations occurring on the fruit and the efficacy of 3 insecticides (chlorpyrifos, spinosad, and spirotetramat) to control this pest. Chlorpyrifos and spinosad displayed a high efficacy against nymphs and reduced significantly the percentage of damaged fruit when a single generation of P. kellyanus attacked the fruit. However, these insecticides did not prevent development of a subsequent generation of P. kellyanus. The percentage of damaged fruit was higher when the 2nd generation was present. Spirotetramat did not display a knockdown effect, and its efficacy was less than that of chlorpyrifos and spinosad. Similar to these insecticides, spirotetramat did not prevent the attack of a 2nd generation when it occurred. Additionally, we analyzed the side effects of these treatments on predatory mites. Spinosad and spirotetramat negatively affected these beneficial species.Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae) es una nueva plaga de cítricos en Nueva Zelanda, el sur de Australia y la Cuenca del Mediterráneo. Las ninfas de estos trips pueden dañar los frutos desde la caída de pétalos hasta sesi semanas después. A pesar de los estudios realizados sobre esta plaga y que hasta ahora sólo es posible su control mediante insecticidas, la información para realizar un adecuado manejo integrado es insuficiente. Por ello, el objetivo de este estudio fue determinar el número de generaciones que pueden encontrarse sobre el fruto y la eficacia de tres insecticidas (clorpirifos, spinosad y spirotetramat) con diferente modo de acción en el control de esta plaga y los efectos secundarios sobre fitoseidos en cítricos. Clorpirifos y spionsad tuvieron una elevada eficacia contra ninfas y redujeron significativamente el porcentaje de frutos dañados cuando fueron atacados por una sola generación. Sin embargo, su actividad no pudo prevenir el ataque de una siguiente generación de P. kellyanus. Además, el pordentaje de frutos dañados aumentó cuando se detectó esta segunda generación. Spirotetramat no tuvo un efecto de choque y su eficacia fue menor que la de clorpirifos y spinosad. Al igual que estos insecticidas, spirotetramat no pudo evitar un segundo ataque cuando se produjo. Los efectos secundarios evaluados de estos tratamientos sobre fitoseidos mostraron que spinosad y spirotetramat les afectaron negativamente

Seasonal Distribution and Movement of the Invasive Pest Delottococcus aberiae (Hemiptera: Pseudococcidae) Within Citrus Tree: Implications for Its Integrated Management

[EN] Delottococcus aberiae (De Lotto) (Hemiptera: Pseudococcidae) is the most recent species of mealybug introduced to Spain that is affecting citrus. The feeding behavior of D. aberiae causes severe direct damage to citrus fruits, distorting their shape and/or causing reduction in size. There is no information available regarding its distribution within the citrus trees. The main objective of this study was to describe the seasonal distribution of D. aberiae within citrus trees and its migration patterns on the plants. Ten citrus orchards from eastern Spain were periodically sampled during 3 yr. In each orchard, the mealybug was sampled in different infested strata (canopy, trunk, and soil) and canopy structures (flower, fruit, leaf, and twig). Results showed that, within the sampled strata, D. aberiae was mostly in the canopy. Within the canopy, the feeding location of D. aberiae changed throughout the year. D. aberiae overwintered in the twigs and moved to the flowers and fruits in spring. Once there, its populations started to increase exponentially until August. From February to September, 5-30% of the mealybugs migrated to the trunk and soil. These results will facilitate an early detection of the pest in the areas where it is spreading and improve sampling protocols and pesticide applications.We thank the owners of the orchards for allowing us to use their plantations, especially Placido Calabuig. We thank Debra Westall (UPV) for English corrections. The authors are also grateful to two anonymous reviewers for helpful comments and corrections. This research was supported by two predoctoral grants (FPU to V.M.-B. and Val I+d to J.P.-R. from the Spanish Ministry of Education, Culture and Sport and Generalitat Valenciana, respectively), a national project provided by Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA) (project no. RTA2014-00067) and the European grants FP7-IAPP #324475 'Colbics' and FP7-IRSES #612566 'Biomodic'.Martínez-Blay, V.; Pérez-Rodríguez, J.; Tena Barreda, A.; Soto Sánchez, AI. (2018). Seasonal Distribution and Movement of the Invasive Pest Delottococcus aberiae (Hemiptera: Pseudococcidae) Within Citrus Tree: Implications for Its Integrated Management. Journal of Economic Entomology. 111(6):2684-2692. https://doi.org/10.1093/jee/toy279S26842692111

Parasitic wasps avoid ant-protected hemipteran hosts via the detection of ant cuticular hydrocarbons

This research was partially funded by Instituto Nacional de Investigaciones Agrarias Project RTA2017-00095 and the Conselleria d'Agricultura, Pesca i Alimentacio de la Generalitat Valenciana. A.M. was a recipient of a MSc scholarship from Bodossaki Foundation (Greece).Mouratidis, A.; Vacas, S.; Herrero, J.; Navarro-Llopis, V.; Dicke, M.; Tena Barreda, A. (2021). Parasitic wasps avoid ant-protected hemipteran hosts via the detection of ant cuticular hydrocarbons. Proceedings of The Royal Society B Biological Sciences. 288(1942):1-10. https://doi.org/10.1098/rspb.2020.1684S110288194

Evaluación de distintas estratégias de manejo químico del piojo rojo de California, Aonidiella aurantii (Maskell)

El piojo rojo de California, Aonidiella aurantii, es una plaga clave en el cultivo de los cítricos. Por lo general, esta plaga se combate realizando una aplicación fitosanitaria en primera generación y, si es necesario, otra en segunda generación alternando los insecticidas clorpirifos y piriproxifén. En este trabajo se han evaluado diversas estrategias de control basadas en la utilización de dos insecticidas, piriproxifén y spirotetramat, aplicados en dos épocas distintas, salida del invierno y primera generación de A. aurantii. El trabajo se ha realizado en un campo de cítricos con un elevado nivel de infestación de A. aurantii en la cosecha anterior. Ambos insecticidas alcanzaron eficacias elevadas en cosecha, tanto cuando se aplicaron en primera generación, como a la salida del invierno. El porcentaje de destrío se redujo hasta un 100 % con spirotetramat y 86 % con piriproxifén en primera generación respecto al año anterior. Por otro lado, las aplicaciones a la salida del invierno también resultaron eficaces y redujeron el porcentaje de destrío en más de un 66 %. Además, la eficacia de spirotetramat aplicado en invierno redujo el número medio de escudos por fruto en un 80 %. Por lo tanto, los tratamientos en invierno aparecen como una alternativa interesante en la gestión de A. aurantii porque además de reducir significativamente sus poblaciones, pueden tener menores efectos secundarios sobre la fauna útil tan abundante y beneficiosa en nuestros cítrico

Novel defenses of Protopulvinaria pyriformis (Hemiptera: Coccidea) against itsmajor parasitoid Metaphycus helvolus (Hymenoptera: Encyrtidae): Implicationsfor biological control of soft scales

Protopulvinaria pyriformis (Cockerell) (Hemiptera: Coccidae), a scale native to South America, is a major pest of laurel, Laurus nobilis L., and a potential pest of other ornamental plants in urban green areas. We evaluated the potential of Metaphycus helvolus (Compere) (Hymenoptera: Encyrtidae), its major parasitoid, as a biological control agent against P. pyriformis. This parasitoid was imported from South Africa to control soft scales in Europe more than 20 years ago. Three factors limited its efficacy: (i) the scale frequently thwart parasitoid attack by removing its stylet and wiggling, a unique defense in soft scales, (ii) scale honeydew extended M. helvolus lifespan little more than water, and (iii) P. pyriformis did not encapsulate Metaphycus spp. eggs but immature parasitoids died during their prepupal stage, which may have been caused by laurel plant secondary compounds from laurel. This parasitoid mortality had not been previously reported in immature parasitoids of genus Metaphycus. These three novel aspects should be considered when choosing a suitable parasitoid in future soft scale biological control programs.We are grateful to Dr. Robert Luck and Dr. Apostolos Kapranas for revising an earlier version of the manuscript and two anonymous reviewers for their constructive comments and suggestions. A. Tena was a recipient of a postdoctoral fellowship from the MCINN (Juan de la Cierva Program). English corrections were carried out by Centro de Lenguas of the Universidad Politecnica de Valencia.Tena Barreda, A.; Beltrà Ivars, A.; Soto Sánchez, AI. (2012). Novel defenses of Protopulvinaria pyriformis (Hemiptera: Coccidea) against itsmajor parasitoid Metaphycus helvolus (Hymenoptera: Encyrtidae): Implicationsfor biological control of soft scales. Biological Control. 62(1):45-52. doi:10.1016/j.biocontrol.2012.03.005S455262

Fortuitous biological control of the invasive mealybug Phenacoccus peruvianus in Southern Europe

Phenacoccus peruvianus Granara de Willink (Hemiptera: Pseudococcidae) is a Neotropical invasive mealybug that has rapidly spread throughout Mediterranean Basin. It has established itself as the principal pest of several ornamental plants, causing considerable problems in nurseries and urban landscapes. The aim of this study was to determine the natural enemy complex of this pest and report the feasibility of its biological control. Six urban green spaces were surveyed in eastern Spain from 2008 to 2010. The most abundant natural enemies of P. peruvianus were found to be the primary parasitoids Acerophagus n. sp. near coccois and Leptomastix epona Walker (Hymenoptera: Encyrtidae). Phenacoccus peruvianus populations were lower during the second and third year of the survey, coinciding with an increase of the parasitoid Acerophagus sp., which displaced the native L. epona. Differential female offspring and resource preemption are discussed as the main reasons for this displacement.This research was supported by one predoctoral grant (FPU) and a postdoctoral fellowship (Juan de la Cierva) from the Spanish Ministry of Economy and Competitiveness. English corrections were funded by the Universitat Politecnica de Valencia, Spain.Beltrà Ivars, A.; Tena Barreda, A.; Soto Sánchez, AI. (2013). Fortuitous biological control of the invasive mealybug Phenacoccus peruvianus in Southern Europe. BioControl. 58(3):309-317. doi:10.1007/s10526-012-9488-5S309317583Agricola U, Agounké D, Fischer HU, Moore D (1989) The control of Rastrococcus invadens Williams (Hemiptera: Pseudococcidae) in Togo by the introduction of Gyranusoidea tebygi Noyes (Hymenoptera: Encyrtidae). Bull Entomol Res 79:671–678Amarasekare KG, Mannion CM, Epsky ND (2009) Efficiency and establishment of three introduced parasitoids of the mealybug Paracoccus marginatus (Hemiptera: Pseudococcidae). 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Entomol Hell 19:137–143Bento JMS, de Moraes GJ, Bellotti AC, Castillo J, Warumby J, Lapointe S (1999) Introduction of parasitoids for the control of the cassava mealybug Phenacoccus herreni (Hemiptera: Pseudococcidae) in north-eastern Brazil. Bull Entomol Res 89:403–410Bogran CE, Heinz KM, Ciomperlik MA (2002) Interspecific competition among insect parasitoids: field experiments with whiteflies as hosts in cotton. Ecology 83:653–668Bokonon-Ganta AH, van Alphen JJM, Neuenschwander P (1996) Competition between Gyranusoidea tebygi and Anagyrus mangicola, parasitoids of the mango mealybug, Rastrococcus invadens: interspecific host discrimination and larval competition. Entomol Exp Appl 79:179–185Bolker BM, Brooks ME, Clark CJ, Geange SW, Poulsen JR, Stevens MHH, White JSS (2009) Generalized linear mixed models: a practical guide for ecology and evolution. 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Wiley, New York, USADaane KM, Cooper ML, Triapitsyn SV, Andrews JW, Ripa R (2008) Parasitoids of obscure mealybug, Pseudococcus viburni (Hem.: Pseudococcidae) in California: establishment of Pseudaphycus flavidulus (Hym.: Encyrtidae) and discussion of related parasitoid species. Biocontrol Sci Technol 18:43–57Díaz-Aranda LM, Monserrat VJ (1990) Larval stages of Iberian Neuropterans. VI: Chrysoperla carnea (Stephens, 1836), Chrysoperla mediterranea (Holzel, 1972) and Chrysoperla ankylopteryformis Monserrat and Díaz-Aranda, 1989 (Insecta, Neuroptera: Chrysopidae). Bol San Veg Plagas 16:675–689Ferragut F, González-Zamora JE (1994) Diagnosis and distribution of peninsular species of Orius Wolff 1811, (Heteroptera, Anthocoridae). Bol San Veg Plagas 20:89–101García-Mercet R (1917) Revisión de los signiforinos de España. 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Blackwell, Oxford, USA, pp 51–70Kairo MTK, Pollard GV, Peterkin DD, Lopez VF (2000) Biological control of the hibiscus mealybug, Maconellicoccus hirsutus Green (Hemiptera: Pseudococcidae) in the Caribbean. Integr Pest Manag Rev 5:241–254Karamaouna F, Copland M (2000) Host suitability, quality and host size preference of Leptomastix epona and Pseudaphycus flavidulus, two endoparasitoids of the mealybug Pseudococcus viburni, and host size effect on parasitoid sex ratio and clutch size. Entomol Exp Appl 96:149–158Miller DR, Miller GL, Watson GW (2002) Invasive species of mealybugs (Hemiptera: Pseudococcidae) and their threat to US agriculture. Proc Entomol Soc Wash 104:825–836Moore D (1988) Agents used for biological control of mealybugs (Pseudococcidae). Biocontrol News Inf 9:209–225Muniappan R, Meyerdirk DE, Sengebau FM, Berringer DD, Reddy GVP (2006) Classical biological control of the papaya mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae) in the Republic of Palau. Fla Entomol 89:212–217Nechols JR (2003) Biological control of the spherical mealybug on Guam and in the Northern Marianas Islands: a classic example of fortuitous biological control. In: van Dreische RG (ed) Proc 1st Int Symp Biological Control of Arthropods. USDA Forest Service, Forest Health Technology Enterprise Team, Washington DC, USA, pp 324–329Neuenschwander P (2001) Biological control of the Cassava Mealybug in Africa: a review. Biol Control 21:214–229Neuenschwander P, Boavida C, Bokonon-Ganta A, Gado A, Herren HR (1994) Establishment and spread of Gyranousoidea tebygi Noyes and Anagyrus mangicola Noyes (Hymenoptera: Encyrtidae), two biological control agents released against the mango mealybug Rastrococcus invades Williams (homoptera: pseudococcidae) in Africa. Biocontrol Sci Technol 4:61–69Noyes JS (1982) Collecting and preserving chalcid wasps (Hymenoptera: Chalcidoidea). 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Phenology and natural parasitoid community of Protopulvinaria pyriformis: influence on the behavioral ecology of its main parasitoid

Three parasitoids and four hyperparasitoids develop on P. pyriformis in laurel. Metaphycus helvolus accounts for 97% of the parasitoids recovered. M. helvolus shows inverse host density dependence. M. helvolus populations decrease in summer and winter when the scale is smaller.Beltrà Ivars, A. (2010). Phenology and natural parasitoid community of Protopulvinaria pyriformis: influence on the behavioral ecology of its main parasitoid. http://hdl.handle.net/10251/11427Archivo delegad

Early arrival of predators controls Aphis spiraecola colonies in citrus clementines

Aphis spiraecola Patch. (Hemiptera: Aphididae) is a key pest of citrus clementines. This aphid colonizes tender clementine shoots in the spring and causes important economic losses. A complex of predators preys on A. spiraecola colonies but does not result in satisfactory control. To disentangle the reasons for this failure, we investigated the effect of predators on A. spiraecola colonies and damage over a 3-year period. A. spiraecola colonies were tracked every 48–72 h from the period of aphid colonization until the colony declined or disappeared. The number of aphids, their stage and the presence of predators were recorded in each colony. Different life parameters of A. spiraecola colonies (maximum number of aphids, longevity and colony phenology) varied among the orchards over 3 years. Predators attacked one-third of the colonies, and this did not significantly differ among orchards for the years studied. The maximum number of aphids and longevity of A. spiraecola colonies were not related to the ratio of colonies attacked by predators but were negatively correlated with the time of their first attack. More importantly, the percentage of shoots occupied by A. spiraecola remained below or close to the intervention threshold when colonies were attacked prior to ~200 degree days from the beginning of the aphid colonization. These results suggest that (1) the presence of predators at the beginning of the season should be considered to develop new intervention thresholds and (2) biological control programs should promote the early presence of predators in clementine orchards.Authors want to thank Pablo Bru, Laura Planes and Jose Catalán for their technical assistance in the field; we also thank Dr. Mollá for the identification of the spiders and Aureli Josep Marco and Francisco Aguilar for allowing us to sample their orchards. F. Gómez-Marco was the recipient of a PhD grant from the Spanish Ministry of Science and Innovation (FPI program). A. Tena was the recipient of a postdoctoral fellowship from the Instituto Nacional de Investigaciones Agrarias (INIA) and an IVIA project. The research leading to these results received funding from the Spanish Ministry of Science and Innovation (AGL2011-30538-C03) and the Conselleria d’Agricultura, Pesca i Alimentació de la Generalitat Valenciana

Effect of mediterranean ants (Hymenoptera, Formicidae) on California Red Scale (Hemiptera, Diaspididae) populations in citrus orchards

[EN] We conducted an ant-exclusion experiment in a citrus orchard to evaluate the overall impact of three ant species native in the Mediterranean, Pheidole pallidula (Nylander), Plagiolepis schmitzii Forel, and Lasius grandis (Forel), on populations of Aonidiella aurantii Maskell (California red scale). The ant-exclusion was carried out in four experimental plots from March 2007 to November 2008. Another subset of four plots, adjacent to the ant-excluded plots, was used as control. We measured scale densities and percent parasitism on fruits at harvest in 2007 and 2008. Additionally, we sampled the seasonal trend of the scale on twigs and fruits in both treatments during 2008. California red scale densities in the ant-excluded treatment began to be signiÞcantly lower than in the antallowed control in May (1 mo after ant activity began), and this difference increased until November. Thus, the effect of the ants on California red scale density seems to be accumulative. At harvest, scale densities on fruits were signiÞcantly lower in the ant-excluded treatment. However, percent parasitism on fruits was similar between treatments. Finally, scale densities on the fruits of the ant-allowed plots were positively correlated with the number of ants that climbed to the citrus canopy. These results suggest that increases of scale densities induced by Mediterranean ants depend on the intensity of the ant-activity on citrus canopies.We thank two anonymous referees for careful review and helpful comments. This work was supported by the Project AGL2005-07155-C03-03 from the Ministerio de Educacio´n y Ciencia of SpainPekas, A.; Tena Barreda, A.; Aguilar Martí, MA.; García Mari, F. (2010). Effect of mediterranean ants (Hymenoptera, Formicidae) on California Red Scale (Hemiptera, Diaspididae) populations in citrus orchards. Environmental Entomology. 39(3):827-834. https://doi.org/10.1603/EN09207S82783439