IRTA Amposta

Amposta, Spain

IRTA Amposta

Amposta, Spain
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Martinez-Ferrer M.T.,IRTA Amposta | Campos-Rivela J.M.,IRTA Amposta
Entomologia Experimentalis et Applicata | Year: 2017

Ants play important ecological roles, such as predation on other arthropods, seed dispersal, and soil structure maintenance. In citrus agroecosystems, ants are considered a secondary pest. The damage they cause is indirect through the disruption of the biological control of pests, especially honeydew producers. In integrated pest management programs, adequate and precise sampling methods are required to accurately determine the need for chemical ant control to minimize the economic and environmental costs of unnecessary chemical treatments and to reduce the risk of crop loss by pests. In Mediterranean citrus groves, eight ant species that differed in abundance and frequency have been found foraging on citrus trees: Lasius grandis Forel, Pheidole pallidula (Nylander), Plagiolepis pygmaea (Latreille), Formica gerardi Bondroit, Formica rufibarbis Fabricius, Camponotus sylvaticus (Olivier), Linepithema humile (Mayr), and Tapinoma erraticum (Latreille) (all Hymenoptera: Formicidae). The trunk was selected as the most efficient sampling unit to establish the monitoring method. Aggregation indices on the trunk of these species were calculated, and enumerative and binomial sampling methods were developed for the most frequent species, L. grandis and Ph. pallidula. Ant species differed in spatial distributions within citrus orchards, and required different sample sizes to estimate population abundance. The minimum sample size required, taking into account the maximum average abundance found – 44.1 L. humile, 17.3 L. grandis, and 3.5 Ph. pallidula per trunk per min –, would be 28, 25, and 54 trees, respectively. © 2017 The Netherlands Entomological Society

Martinez-Ferrer M.T.,IRTA Amposta | Campos-Rivela J.M.,IRTA Amposta | Verdu M.J.,Instituto Valenciano Of Investigaciones Agrarias Ivia
Bulletin of Entomological Research | Year: 2015

Seasonal trends and the parasitoid complex of Chinese wax scale (Ceroplastes sinensis) was studied from July 2010 to February 2013. Six commercial citrus groves located in northeastern Spain were sampled fortnightly. Chinese wax scale completed a single annual generation. Egg oviposition started in May and continued until mid-July. Egg hatching began in mid-June, and in the first quarter of August, the maximum percentage of hatched eggs was reached. In the same groves, the parasitoid species of C. sinensis were determined together with their seasonal trends, relative abundance and occurrence on C. sinensis. Four hymenoptera were found parasitizing C. sinensis, mainly on third instars and females: Coccophagus ceroplastae (Aphelinidae), Metaphycus helvolus (Encyrtidae), Scutellista caerulea (Pteromalidae) and Aprostocetus ceroplastae (Eulophidae). The most abundant species was A. ceroplastae, corresponding to 54% of the parasitoids emerged. Coccophagus ceroplastae and M. helvolus represented 19%, whereas S. caerulea comprised 8% of the total. This study is the first published record of C. ceroplastae in Spain and the first record of M. helvolus on C. sinensis in Spain. Concerning the economical thresholds normally used, sampling plans developed for the management of C. sinensis in citrus groves should target population densities of around 12-20% of invaded twigs, equivalent to 0.2-0.5 females per twig. The sample size necessary to achieve the desired integrated pest management precision is 90-160 twigs per grove for the enumerative plan and about 160-245 twigs per grove for the binomial plan. © Cambridge University Press 2014.

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 2009, A. 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 27 th May (± 1.85 days). The male flight abundance showed a positive relationship between two consecutive generations, revealing the stability of A. aurantii populations.

Martinez-Ferrer M.T.,IRTA Amposta | Campos J.M.,IRTA Amposta | Fibla J.M.,IRTA Amposta
Journal of Applied Entomology | Year: 2012

Mass trapping is being used in Mediterranean regions to control Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in citrus. The technique is based on placing a high density of traps with an attractant (Ferag CC D TM ®, a three-membrane dispensers of trimethylamine, ammonium acetate and diaminoalkane), and a toxicant, aiming to capture the highest numbers of adults in the grove. From 2006 to 2008, field trials were conducted in commercial Clementine (Citrus reticulata Blanco) groves to evaluate the efficacy against medfly of using different trap densities, 25, 50, 75 and 100 traps per ha. Based on the number of adults captured, fruit maturity parameters and medfly fruit damage, a 25 trap per ha density appears to be a valid stand-alone method to protect mid-season varieties (Clemenules) from the attack of C. capitata, because <0.5% of fruits on average were damaged at harvest. For early-season varieties (Loretina and Marisol), mass trapping technique alone did not offer a satisfactory medfly control, because medfly populations were higher in the warmer months of the early-season variety production, which led to a higher percentage of attacked fruits, even when increasing the trap density from 50 to 100 per ha. However, using 50 traps per ha density combined with chemical treatments only to the perimeter row of the grove gave good results, because <2% of fruits in average were damaged at harvest. © 2011 Blackwell Verlag, GmbH.

Seasonal and annual trends in Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) populations were analyzed to determine the factors that influence population fluctuations in the field. Adult flies were monitored along 2003-07 in two citrus areas in eastern Spain with similar climate, Valencia and Tarragona. Adults were present throughout the study period, even in winter. The initial annual population increase was related to previous winter and spring temperatures. Captures started to increase in April-May and usually reached a peak in July. This peak corresponded to the maximum capture period in Valencia, but not in Tarragona, where there was usually a second peak in autumn, with capture levels similar to the first peak. Gravid females were found throughout the year, even in overwintering populations of medfly. The availability of other host fruit species in the vicinity of the citrus groves may explain the differences in annual abundance and distribution of captures between the two areas studied.

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