Bio-ecology and integrated management of the red palm weevil, Rhynchophorus ferrugineus (Coleoptera: Curculionidae), in the region of Valencia (Spain)

The invasive red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae), is one of the most destructive pests of palms in the world. It is widely distributed in all continents and has been reported on 26 palm species belonging to 16 different genera. In the Mediterranean basin, R. ferrugineus has become the major pest of palms, mainly Phoenix canariensis hort. ex Chabaud, an endemic palm to the Canary Islands widely used as ornamental. In this manuscript we summarize the research that the UJI-IVIA Unit has carried out on this pest. The first objective of our work was to determine different bio-ecological parameters of R. ferrugineus under natural conditions in a Mediterranean climate. Washingtonia filifera is the only palm species included in our studies showing mechanisms of complete resistance against R. ferrugineus. Although Chamaerops humilis and Phoenix theophrasti show antixenotic and antibiotic mechanisms of resistance, respectively, they cannot be considered as resistant against R. ferrugineus. Under Mediterranean climate, the preimaginal development of R. ferrugineus in P. canariensis takes 666.5 DD and the weevil can complete 13 larval instars. Based on the results obtained, less than one generation per year can be expected in areas with a mean annual temperature (MAT) below 15ºC and more than two in those with MAT above 19ºC. Oviposition in R. ferrugineus is also strongly affected by temperature. The thresholds for oviposition and egg hatching obtained are very close to MAT registered in most of the northern shore of the Mediterranean basin. Under these circumstances, no new infestations would be expected during most of the winter. The second objective has been to improve chemical and biological control. Both imidacloprid and Steinernema carpocapsae in a chitosan formulation are highly effective against R. ferrugineus in the field. Different timings and product combinations were studied, and high efficacies were obtained in all cases. An indigenous strain of Beauveria bassiana, found naturally infecting pupae of R. ferrugineus, resulted highly virulent against all developmental stages of the weevil in the laboratory. Additionally, adults of either sex inoculated with the fungus efficiently transmitted the disease to healthy adults of the opposite sex and this result confirmed the potential of B. bassiana as a biological control agent against this pest. These results should help developing an integrated management program against this pest.The UJI-IVIA-CIB/CSIC group has received financial support from the Spanish Ministry of Science and Innovation (MCINN projects TRT2006-00016-C07-01 and AGL2008-05287 -C04/AGR) and the Valencian Department of Agriculture, Fisheries and Food (CAPA, project IVIA-5611). Ó. Dembilio was recipient of a predoctoral grant from IVIA

Eficacia y fitotoxicidad a corto y largo plazo del fosfuro de aluminio contra el picudo rojo de las palmeras sobre ejemplares de palmeras canarias vivas

El picudo rojo de las palmeras, Rhynchophorus ferrugineus, es un curculiónido nativo del sureste asiático que se ha extendido por todo el mundo debido, principalmente, al movimiento no intencionado de plantas infestadas. Como resultado, esta especie se ha convertido en la plaga más destructiva de palmeras a nivel mundial. La enorme dificultad que conlleva detectar los primeros síntomas de infestación debido a los hábitos crípticos de esta plaga, ha provocado que muchos paises pongan en práctica estrictas normas cuarentenarias en la pre y post entrada de palmeras con el fin de evitar su propagación. Sin embargo, aún no existen protocolos cuarentenarios que permitan asegurar que las palmeras no estén infestadas por este insecto. El objetivo de este estudio fue determinar la eficacia del fosfuro de aluminio, comno tratamiento cuarentenario seguro, contra diferentes estados de desarrollo de R. ferrugineus y comprobar los posibles efectos fitotóxicos producidos por este gas en palmeras canarias vivas. Nuestros resultados confirman que una dosis de 1,14 g metro/cúbico durante 2 días es suficiente para eliminar todos los estados de desarrollo del picudo en palmeras canarias vivas, no observando efectos fitotóxicos sobre las mismas durante un año después del tratamiento. Este procedimiento, se podría aplicar fácilmente en contenedores cerrados utilizados para la exportación de palmeras, pudiendo reducir drásticamente los riesgos asociados al tránsito de palmeras en todo el mundo

Ground-covers affect the activity density of ground-dwelling predators and their impact on the Mediterranean fruit fly, Ceratitis capitata

Three developmental stages of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), can be found in the soil (late third instar larvae, pupae, and teneral adults). These stages are susceptible to predation by generalist ground-dwelling predators. Our objectives have been to investigate the association between ground cover management (bare soil, a seeded cover of Festuca arundinacea and a mulch of straw), the emergence success of C. capitata, and the activity density of the most important groups of ground-dwelling predators (spiders, beetles, ants and earwigs). As expected, C. capitata emergence was lower in a seeded cover of Festuca arundinacea (FA) and a mulch of straw (M) (10.2%) relative to bare soil (BS) (13.2%). This was related to higher diversity and activity density of ground-dwelling predators in FA and M compared to BS. The contribution of the ground-dwelling predators considered in this study to this reduction highlights the key role of beetles, earwigs and, to a lesser extent, ants, while the contribution of the most abundant group of ground-dwelling predators, spiders, remains unclear. Ground covers appear as a strong and sustainable conservation biological control method that should be taken into consideration for the management of C. capitata populations.Funding for open access charge: CRUE-Universitat Jaume IOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Financial support has been provided by the European Union’s Horizon 2020 Program for Research and Innovation grant number 818184 (FF-IPM) and PRIMA grant number 1812 (PLANT-B).We thank M. Piquer (UJI) and A. Benages (COCALNI, Cooperativa Citrícola de Les Alqueries) for technical support and provision of the experimental orchard, respectively. Financial support has been provided by the European Union’s Horizon 2020 Program for Research and Innovation grant number 818184 (FF-IPM) and PRIMA grant number 1812 (PLANT-B)

Could Plant Hormones Provide a Reliable Tool for Early Detection of Rhynchophorus ferrugineus (Coleóptera: Curculionidae) Infested Palms?

Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) is one of the most important pest of palms worldwide. A serious management problem is the difficulty of detecting early infestation stages, which is critical for successful control. Our main objective has been to characterize the metabolic response of Phoenix canariensis hort. ex Chabaud to R. ferrugineus injury to identify candidate biomarkers for early detection. Mechanical wounding and R. ferrugineus infestation resulted in different patterns of plant hormone and secondary metabolite production: SA and caffeic acid concentrations increased by several orders of magnitude following R. ferrugineus development within the palm 7 days after infestation. These compounds did not change in mechanically wounded palms. Therefore, these substances could be further exploited as early warning signs of infestation

Survey of natural enemies of spider mites (Acari: Tetranychidae) in citrus orchards in eastern Spain

Field surveys were conducted from 2004 to 2007 to determine the species composition and relative abundance of natural enemies associated with colonies of either the citrus red mite, Panonychus citri, or the two spotted spider mite, Tetranychus urticae, in Valencian citrus orchards (eastern Spain). Fourteen species were recorded, six phytoseiid mites and eight insect predators. Two of them are reported for the first time on citrus in Spain and two more are first reports as predators associated with T. urticae. The community of predators associated with T. urticae and P. citri was almost identical, and the Morisita-Horn index of similarity between both natural enemy complexes was close to one, suggesting that predators forage on both pest species. Quantifying the presence of many known spider mites predators in Valencian citrus orchards is an important first step towards spider mite control. A challenge for future studies will be to establish conservation and/or augmentation management strategies for these predators, especially to improve T. urticae biological control

Field efficacy of imidacloprid and Steinernema carpocapsae in a chitosan formulation against the red palm weevil Rhynchophorus ferrugineus (Coleoptera: Curculionidae) in Phoenix canariensis

BACKGROUND: The invasive red palm weevil, Rhynchophorus ferrugineus (Olivier), has become the major pest of palms in the Mediterranean Basin. Chemical control against this species is difficult because of its cryptic habits and is mainly based on the repeated application of large quantities of synthetic insecticides. The aim of this work has been to evaluate in the field the efficacy of imidacloprid (Confidor (R) 240 OD) and Steinernema carpocapsae Weiser with chitosan (Biorend R (R) Palmeras) as soil and stipe treatments respectively, alone or in combination, against this pest. RESULTS: All treatments significantly reduced the mean number of immature stages of R. ferrugineus per palm. However, there were no significant differences among the different treatments considered. Efficacies ranged from 83.8 to 99.7% for the mean number of immature stages found in the palms and resulted in a significant increase in palm survival compared with the untreated control (75.0-90.0% versus 16.5% respectively). CONCLUSION: Both imidacloprid and S. carpocapsae in a chitosan formulation proved highly effective against R. ferrugineus in the field, and their efficacies did not significantly change when used in combination. (C) 2009 Society of Chemical Industr

Remating in Ceratitis capitata sterile males: Implications in sterile insect technique programmes

Sterile insect technique (SIT) is used, among other biological control tools, as a sustainable measure for the management of Ceratitis capitata Wiedemann (Diptera: Tephritidae) in many agricultural regions where this pest can trigger severe economic impacts. The tendency of wild females to remate multiple times has been deeply studied; it has been a common point of controversy when evaluating SIT programmes. Nevertheless, the remating potential of the released sterile males remains unknown. Here, under laboratory conditions, the remating capability of mass-reared sterile males was determined. Wild-type virgin females were offered to sterile males (Vienna-8 strain), which had the opportunity to mate up to four consecutive times. The remating assays were carried out at 24 hr, 48 hr, 4 days and 7 days after the first mating. At the end of each tested time period, males were divided according to their mating response, mated or unmated, and subsequently reused for the next round of mating assays. The frequency of successful remating in each tested time period was obtained. Insemination was confirmed by determining the sperm transfer in mated female spermathecae by quantitative real-time PCR. Our results demonstrate that 73% of the mass-reared sterile males were able to remate 24 hr after the first mating, 55% of which remated again the day after. Close to 25% of the V8 sterile males tended to copulate in all of the four mating opportunities. The qPCR analysis of the spermathecae contents verified an effective transfer of V8 sperm to wild females with every mating; 99% of copulations resulted in sperm transfer. These findings shed light on the remating potential of V8 sterile males, an aspect until now underestimated in many SIT programmes