Guiding Classical Biological Control of an Invasive Mealybug Using Integrative Taxonomy

The analysed sequences were deposited in Genbank under accession numbers KP771926-KP771972. Mealybug slides are available at the Polytechnic University of Valencia (Valencia, Spain). Parasitoid slides are deposited at Università degli Studi di Napoli Federico II (Portici, Italy).[EN] Delottococcus aberiae De Lotto (Hemiptera: Pseudococcidae) is a mealybug of Southern African origin that has recently been introduced into Eastern Spain. It causes severe distortions on young citrus fruits and represents a growing threat to Mediterranean citrus production. So far, biological control has proven unsatisfactory due to the absence of efficient natural enemies in Spain. Hence, the management of this pest currently relies only on chemical control. The introduction of natural enemies of D. aberiae from the native area of the pest represents a sustainable and economically viable alternative to reduce the risks linked to pesticide applications. Since biological control of mealybugs has been traditionally challenged by taxonomic misidentification, an intensive survey of Delottococcus spp. and their associated parasitoids in South Africa was required as a first step towards a classical biological control programme. Combining morphological and molecular characterization (integrative taxonomy) a total of nine mealybug species were identified in this study, including three species of Delottococcus. Different populations of D. aberiae were found on wild olive trees, in citrus orchards and on plants of Chrysanthemoides monilifera, showing intra-specific divergences according to their host plants. Interestingly, the invasive mealybug populations from Spanish orchards clustered together with the population on citrus from Limpopo Province (South Africa), sharing COI haplotypes. This result pointed to an optimum location to collect natural enemies against the invasive mealybug. A total of 14 parasitoid species were recovered from Delottococcus spp. and identified to genus and species level, by integrating morphological and molecular data. A parasitoid belonging to the genus Anagyrus, collected from D. aberiae in citrus orchards in Limpopo, is proposed here as a good biological control agent to be introduced into Spain.This work was supported by the European Union Seventh Framework Programme FP7-IRSES #269196 "IPRABIO" and FP7-IAPP #324475 "COLBICS" and FP7-IRSES #612566 "BIOMODICS". The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.Beltrà Ivars, A.; Addison, P.; Ávalos Masó, JA.; Crochard, D.; García Mari, F.; Guerrieri, E.; Giliomee, JH.... (2015). Guiding Classical Biological Control of an Invasive Mealybug Using Integrative Taxonomy. PLoS ONE. 10(6):1-14. https://doi.org/10.1371/journal.pone.0128685S11410

Factors influencing the mobility of Red Palm Weevil Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) adults

Tesis por compendio[EN] The management of Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae), the worst threat for palm trees worldwide, consists in several preventive and curative techniques, but because of its low efficacy the insect still causes major economic and landscape losses. In order to define aspects that have facilitated its rapid dispersal and contribute to improving its management, the effects of vision and flight, which influence the mobility of R. ferrugineus, have been analysed. The chromatic preference of R. ferrugineus has been studied by analysing their captures in coloured bucket traps. Black traps capture the highest number of insects compared with the other colours studied, both when they contain olfactory attractants, as when these compounds are not used, demonstrating that colour by itself is a crucial attraction factor. Moreover, the spectral reflectance of studied colours and of some P. canariensis tissues has been analysed. The wavelength spectrum of black shows great similarity to that of fibres of P. canariensis, so this may be the reason why R. ferrugineus prefers this colour. Regarding sex ratio of the insect in traps, female captures are significantly greater in those baited with olfactory attractants. However, a higher number of female captures does not always occur when these compounds are not used. On the other hand, the study of sex ratio in natural populations of the insect demonstrates that the proportion is one female per male. Therefore, the greater number of captures of females in commercial traps is due exclusively to their greater attraction towards the olfactory attractants used. Another of the analysed aspects has been the flight potential of R. ferrugineus under laboratory conditions. In order to know more about the mobility of this insect, different parameters have been studied using a computer-monitored flight mill. The selected parameters used to define the R. ferrugineus flight potential have been the number of flights, total distance flown, longest single flight, flight duration, and average and maximum speed. Moreover, the influence of sex, body size, and age of the adults on the aforementioned parameters has been examined. R. ferrugineus sex does not have a significant effect on the compared flight parameters. The body size in females is significantly greater, but this does not influence their flight potential. A higher percentage of flight is observed for adults with an age range of 8-23 days old, compared to the 1-7 day old adults. However, age does not significantly influence their flight potential. By analysing the longest single flight undertaken by each adult, up to 63% of the insects can be classified as short-distance flyers (9% as long-distance flyers (>5000m). Finally, the flight behaviour and dispersal of R. ferrugineus have been analysed under field conditions using the mark-release-recapture method. This test focused on detecting the influence of different factors, such as sex, temperature, relative humidity, and solar radiation, in the take-off and dispersal of the adult insects. Take-off probability of R. ferrugineus adults is significantly greater in males Moreover, this probability increases when temperature and solar radiation rise. Concerning the insect dispersal by flying, the number of recaptures is influenced by temperature, increasing significantly when this factor increases. Likewise, dispersal distances also increase significantly as temperatures rise. The insect tends to fly distances 63% de los insectos se clasifican como voladores de corta distancia (9% de larga distancia (>5000m). Finalmente, se ha analizado en campo el comportamiento de vuelo y dispersión de R. ferrugineus mediante la técnica de marcaje-suelta-recaptura. Este ensayo ha permitido estudiar la influencia del sexo, la temperatura (Tª), la humedad relativa y la radiación solar, en el despegue y dispersión de los adultos. La probabilidad de despegue de R. ferrugineus es significativamente mayor en machos. Además, esta probabilidad se incrementa cuando la Tª y la radiación solar aumentan. Respecto a la dispersión del insecto mediante el vuelo, el nº de recapturas se ve influenciado por la Tª, aumentando significativamente cuando ésta se incrementa. De la misma manera, las distancias de dispersión también se incrementan significativamente a media que lo hace la Tª. El insecto tiende a volar distancias 90% se recapturaron en los 7 primeros días), reduciéndose[CA] El maneig de Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae), una de les pitjors amenaces per a les palmeres en tot el món, es porta a terme mitjançant l'aplicació de diverses tècniques de prevenció i control, però degut a la baixa eficàcia d'aquestes l'insecte continua causant importants pèrdues econòmiques i paisatgístiques. Per a definir els aspectes que han intervingut en la seua dispersió i contribuir a la millora del seu maneig, s'ha analitzat l'efecte que tenen la visió i el vol en la mobilitat dels adults de R. ferrugineus. S'ha estudiat la preferència cromàtica mitjançant l'anàlisi de les seues captures en trampes poal acolorides. Les trampes negres capturen el major nombre d'insectes en comparació amb la resta de colors estudiats, tant quan contenen atraients olfactius com quan no els contenen, demostrant que el color per ell mateix és un factor important d'atracció. A més, s'ha analitzat l'espectre de longitud d'ona dels colors estudiats i de diversos teixits de P. canariensis. L'espectre del color negre mostra gran similitud amb el de les fibres de P. canariensis, és per açò pel que R. ferrugineus podria presentar aquesta preferència. En relació a la proporció de sexes a les trampes que contenen atraients olfactius, les captures de femelles són significativament més elevades. En canvi, sense aquests no sempre es produeix un major nombre de captures d'aquest sexe. Per altra banda, l'estudi de la proporció de sexes en poblacions naturals demostra que la ràtio és d'una femella per mascle. Per tant, les majors captures de femelles en trampes es deuen a una major atracció d'aquestes cap als atraients olfactius utilitzats. Altre aspecte estudiat ha sigut el potencial de vol de R. ferrugineus sota condicions de laboratori. Amb la finalitat de conèixer la mobilitat d'aquest insecte s'han analitzat diversos paràmetres mitjançant la utilització d'un molinet de vol computeritzat. Els paràmetres estudiats han sigut: nombre de vols, distància total volada, vol més llarg, duració del vol i velocitats mitjana i màxima dels vols. A més, s'ha analitzat com influeixen el sexe, el tamany del cos i l'edat dels adults en dits paràmetres de vol. El sexe de R. ferrugineus no mostra un efecte significatiu sobre els paràmetres de vol comparats. El tamany del cos de les femelles és significativament major, però no influeix estadísticament en el seu potencial de vol. En adults amb edats d'entre 8-23 dies s'observa un major percentatge de vol que en aquells amb 1-7 dies d'edat. En canvi, l'edat no influeix significativament sobre el seu potencial de vol. En analitzar el vol més llarg, obtenim que més del 63% dels insectes es classifiquen com voladors de curta distància (9% de llarga distància (>5000m). Finalment, s'ha analitzat en camp el comportament de vol i dispersió de R. ferrugineus mitjançant la tècnica de marcatge-solta-recaptura. Aquest assaig ha permès estudiar la influència del sexe, la temperatura, la humitat relativa i la radiació solar, en l'enlairament i dispersió dels adults. La probabilitat d'enlairament de R. ferrugineus és significativament major en mascles A més, aquesta probabilitat s'incrementa quan la temperatura i la radiació solar augmenten. Respecte a la dispersió de l'insecte mitjançant el vol, el nombre de recaptures es veu influenciat per la temperatura, augmentant significativament quan aquesta s'incrementa. De la mateixa manera, les distàncies de dispersió també s'incrementen significativament a mesura que ho fa la temperatura. L'insecte tendeix a volar distàncies 90% es recapturaren en els 7 primers dieÁvalos Masó, JA. (2015). Factors influencing the mobility of Red Palm Weevil Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) adults [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59394Compendi

Study of chromatic attraction of the Red Palm Weevil, Rhynchophorus ferrugineus using bucket traps

Full text articles are available at http://www.bulletinofinsectology.org/Contents/Contentsbullinsect.htm freely two years after publication[EN] Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae) is at present considered the biggest threat to palm trees worldwide. Due to the current trend towards the use of environmentally-friendly control measures, increasing interest is being shown in trapping as a way of dealing with this pest. The present study assessed the influence of chromatic attraction on the capture of R. ferrugineus adults and identified possible reasons for the better performance of pheromone traps. Two tests were carried out using coloured bucket traps; in the first the traps were baited with male aggregation pheromone and kairomone from R. ferrugineus, while the second involved traps without olfactory attractants. The spectral reflectance of the colours tested and of leaves and external trunk fibres from the Phoenix canariensis (Hort. ex Chabaud) were measured by spectrophotometer. The internal climatic conditions of the coloured traps were also analysed. Black traps, both with and without olfactory attractants, captured significantly more R. ferrugineus adults than red and white traps. The higher efficacy of the black traps was mainly due to chromatic attraction and not only to the possibly higher emission of olfactory attractants. The olfactory attractants used to bait traps are responsible for the female-biased captures, a phenomenon found to occur with all the colours tested. This study provides useful information for improving current management strategies against R. ferrugineus.This research was partially funded by the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) (Project TRT2006-00016-C07-03) and by the Foundation of the Comunidad Valencia for the Agroalimentary Research, Agroalimed, within the project: Study of the flight behaviour and chromatic attraction in Rhynchophorus ferrugineus adults (Coleoptera: Curculionidae).Ávalos Masó, JA.; Soto Sánchez, AI. (2015). Study of chromatic attraction of the Red Palm Weevil, Rhynchophorus ferrugineus using bucket traps. Bulletin of insectology. 68(1):83-90. http://hdl.handle.net/10251/64091S839068