Population dynamics and seasonal trend of California red scale (Aonidiella aurantii Maskell) in citrus in Northern Spain

Abstract

The California red scale, Aonidiella aurantii (Maskell), was first detected in citrus groves in Catalonia, Northern Spain, in 2000, and has since spread slowly and irregularly. New foci of infestation are currently found in citrus-growing areas of southern Tarragona. As Catalonia is the northernmost citrus growing area in Spain, between 2002 and aurantii population dynamics and seasonal trends were studied in two citrus groves and compared with other regions and countries. The population dynamics showed that there were four male flights (including that of the overwintering generation): in May, mid June-mid July, August and October, the most abundant being that of August (over 60% of the males captured during the year). The thermal constant estimated between male flights, using 11.7°C as the lower threshold temperature, was 611.8 ± 35.5 degree-days. Three peaks of 1 st and 2 nd nymph instars were observed: in early June, late July-early August, and late September. The number of crawlers captured on sticky tapes reached a first maximum on 27th May (± 1.85 days). The male flight abundance showed a positive relationship between two consecutive generations, revealing the stability of A. aurantii populations.Additional key words: Aonidiella aurantii; California red scale; Catalonia; Diaspididae; population dynamics. Resumen Dinámica poblacional y estacional del piojo rojo de California (Aonidiella aurantii Maskell) en cítricos del norte de EspañaEl piojo rojo de California, Aonidiella aurantii (Maskell), fue detectado en el año 2000 en Cataluña, y desde entonces hasta la actualidad esta plaga ha experimentado una lenta e irregular expansión; actualmente se pueden encontrar focos de infestación de la plaga en todas las áreas de cultivo citrícolas del sur de Tarragona. En la zona citrícola de Cataluña, que es la más septentrional de España, desde 2002 a 2009, se llevaron a cabo estudios del ciclo biológico y vuelos de machos en dos fincas de cítricos para compararlos con otras regiones y países. De acuerdo con la dinámica poblacional observada, se produjeron cuatro vuelos de machos (incluyendo el de las poblaciones invernantes): en mayo, desde mediados de junio a mediados de julio, en agosto y durante octubre, siendo el tercero el más abundante, que representa alrededor del 60% del total de machos capturados. La constante térmica estimada entre dos vuelos consecutivos, empleando como umbral míni-mo 11,7°C, fue de 611,8 ± 35,5 grados-día. Además se observaron tres máximos de ninfas de primera y segunda edad: a primeros de junio, entre finales de julio y primeros de agosto, y a finales de septiembre. El número de ninfas móviles de primera edad alcanzó un primer máximo el 27 de mayo (± 1,85 días). La abundancia de machos en los vuelos mostró una relación positiva entre vuelos consecutivos, mostrando la estabilidad de las poblaciones de A. aurantii.

Contribution of predation to the biological control of a key herbivorous pest in citrus agroecosystems

“…The predation rate observed in the first A. aurantii generation could be explained by: (a) climatic conditions are optimal for most predator species in the study area at the end of the spring and beginning of the summer; (b) offspring of the first generation or overwintering generation of A. aurantii are usually the least abundant because they are the progeny of specimens that survived the winter; thus, there are less individuals to prey upon (Atkinson, ; Campos‐Rivela, Martínez‐Ferrer, & Fibla‐Queralt, ).…”

“…Stem‐tap sampling revealed a larger number of potential A. aurantii predators present in citrus agroecosystems. Nevertheless, some groups such as phytoseiid mites, dipterans, thrips as well as predator species with nocturnal activity that could also contribute to A. aurantii mortality (Campos‐Rivela et al., ; Sorribas & Garcia‐Marí, ; Vanaclocha et al., ) cannot be accurately sampled with this methodology, and we can therefore not determine the importance of these species.…”

Seasonal trends, sampling plans and parasitoid complex of the Chinese wax scale, Ceroplastes sinensis Del Guercio (Hemiptera: Coccidae), in Mediterranean citrus groves

“…Accordingly, three factors must concur to achieve an optimal efficacy: (1) a maximum of sensitive instars, (2) a maximum of hatched eggs and (3) a minimum presence of new third instars. In Spain, almost every year, Aonidiella aurantii and other dispididae are chemically controlled with sprays in early June, during the maximum presence of sensitive instars of these scales (Campos-Rivela et al , 2012). At this time, the C. sinensis population is mostly composed of females, the most resistant stage, and thus these treatments are inefficient.…”

Revalorización del Complejo de Depredadores Polífagos Asociado al Cultivo de los Cítricos, Como Agentes de Control Biológico de Plagas Claves

“…This strategy allows natural enemy coexistence when depending upon the same prey resource (Hare et al, 1990;Vanaclocha et al, 2011). With the exclusion experiments, we studied the combined effect of the whole predator complex together which may have upon (Atkinson, 1977;Campos-Rivela et al, 2012); iii) as we observed in this study, predator seasonal-activity is highest during this generation (Lundgren, 2009;Hodek et al, 2012;Gómez-Marco et al, 2016 (Riechert & Lockley, 1984;Symondson et al, 2002) progressively increased their numbers throughout the growing season as had been previously observed (Monzó et al, 2014). In contrast to generalist and stenophagous predators, the specialist coccinellid predators of the family Diaspididae, R. lophanthae, C. bipustulatus and C. citricola, presented very low seasonal-activity and were mostly concentrated at the end of the season.…”