Postteneral Protein Feeding may Improve Biological Control Efficiency of Aphytis lingnanensis and Aphytis melinus

The augmentative releases of mass-reared Aphytis spp. (Hymenoptera: Aphelinidae) parasitoids are widely used against armored scales. The nutritional status and the initial egg load of Aphytis spp. females are key to their success as biological control agents. For these reasons, this work focuses on the study of providing a protein feed to Aphytis lingnanensis (Compere) and A. melinus DeBach to improve the egg load before their release. The addition of protein to a honey diet during the first 2 d after the adult parasitoid emergence increased the initial egg load in both species of parasitoids by more than five eggs. Furthermore, the addition of protein increased the total number of eggs laid by A. lingnanensis on oleander scale, Aspidiotus nerii Bouche (Hemiptera: Diaspididae). In contrast, this effect was not observed on A. melinus probably because A. nerii is considered a suboptimal host for this parasitoid. The host-feeding activities of the two Aphytis species were differentially affected by the addition of protein to their diets. These results may have direct implications for augmentative biological control programs, especially during transportation from insectaries to the field, a period of time when parasitoids are deprived of hosts

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

Placement density and longevity of pheromone traps for monitoring of the citrus leafminer (Lepidoptera: Gracillariidae)

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is an important pest of all citrus varieties. Larvae damage young leaves, thereby reducing photosynthesis and tree vigor, and may impact yield. Wounds opened by P. citrella larvae may also increase susceptibility to citrus canker disease caused by the bacterium Xanthomonas axonopodis pv. citri (Xanthomonadales: Xanthomonadaceae). Sex pheromones coupled with appropriate traps are used as monitoring tools for this and other lepidopteran pests. Information compiled from trap captures is indicative of seasonal population fluctuations and may be used to guide management practices. Trap density and pheromone dispenser longevity are factors affecting the accuracy of trapping data. Our objectives were to evaluate capture of P. citrella in relation to trap density and duration under field conditions. Almost 2 yr of citrus leafminer monitoring demonstrated that a density of 1 trap per approximately 2 ha yielded similar results to the higher recommended density of 1 trap per 0.4 to 1.6 ha. Trap catch with the 2 pheromone brands tested declined by 25% after 3 to 6 wk and 50% after 6 to 10 wk during the spring through fall growing season in Florida. Therefore, correction factors are required if traps are replaced at 8 to 13 wk intervals. Results of the present study will help optimize monitoring programs that can serve as early warning of potential damaging populations of P. citrella

Intra-guild interactions between the parasitoid Aphytis lingnanensis and the predator Chilocorus circumdatus: Implications for the biological control of armoured scales

The parasitoid Aphytis lingnanensis and the predator Chilocorus circumdatus are released in different crops to control armoured scales. Both natural enemies compete, to some extent, for the same resource and therefore they can induce intraguild predation interactions (IGP). In the present work, the consequences of these interactions on the parasitism and predatory efficiency of these natural enemies were assessed under laboratory conditions by studying potential changes in their functional responses. A type II functional response to host/prey density was observed in A. lingnanensis and C. circumdatus when acting alone. The predatory efficiency of C. circumdatus was not affected by the presence of A. lingnanensis in the same arena. Conversely, the parasitism efficiency of A. lingnanensis was affected by the presence of the predator. Due to IGP at low host densities there was a shift from functional response type II to type III. No changes in the handling time when the predator was present suggested that parasitism behavior was not influenced by the presence of the predator. C circumdatus did not discriminate between parasitised and unparasitised scales. A recommended strategy in biological control programs could be the use of one of the two natural enemies at low infestation levels and to reinforce these releases with the other one at high densities of the pest. (C) 2013 Elsevier Inc. All rights reserved

Pest survey card on Citrus leprosis viruses

This pest survey card was prepared in the context of the EFSA mandate on plant pest surveillance (M-2020-0114), at the request of the European Commission. Its purpose is to guide the Member States in preparing data and information for surveys of citrus leprosis viruses. These are required to design statistically sound and risk-based pest surveys, in line with current international standards. Six of the seven viruses that cause citrus leprosis (CiLV-C, CiLV-C2, HGSV-2, OFV, CiLV-N sensu novo and CiCSV) are clearly defined taxonomic entities, while the status of CiBSV is unclear. CiLV-C, CiLV-C2, HGSV-2, the citrus strain of OFV, CiLV-N sensu novo and CiCSV are Union quarantine pests. Citrus leprosis viruses do not cause systemic infections and they are all exclusively transmitted by mites of the genus Brevipalpus. Brevipalpus mites associated with the transmission of the leprosis disease are present in some regions of EU territory. The commercial citrus species most relevant to the EU are considered susceptible to citrus leprosis disease. There are no ecoclimatic constrains known for the citrus leprosis viruses, except for those affecting their host plants and their mite vectors. Therefore, due to the wide availability of host species and the presence of Brevipalpus mites, all citrus-growing areas in the EU are considered potentially suitable for the viruses to become established. Long-distance spread is likely to occur through movement of viruliferous mites phoretically associated with commodities. Detection of citrus leprosis viruses in the field should be performed by visual examination of symptoms followed by sampling and molecular identification in the laboratory. Visual examination should be preferably conducted in late summer / early autumn. Based on the analyses of the information on the pest-host plant system, the various units that are needed to design a survey should be defined and tailored to the situation in each Member State

Risk-based regionalization approach for area-wide management of HLB vectors in the Mediterranean Basin

Huanglongbing (HLB) is one of the most devastating citrus diseases worldwide. It is associated with the non-culture bacteria Candidatus Liberibacter spp., which can be transmitted by grafting and/or the psyllid vectors Diaphorina citri (ACP) and Trioza erytreae (AfCP). Although HLB has not been reported in the Mediterranean Basin to date, both vectors are present, and thus represent a serious threat to the citrus industry in this region. Resistant citrus cultivars or effective therapeutic treatments are not currently available for HLB. Nevertheless, area-wide pest management via coordinated management efforts over large areas has been implemented in Brazil, China and the USA for HLB control. This study proposes an open access flexible methodology to address area-wide management of both HLB vectors in the Mediterranean Basin. Based on a risk-based approach which considers climatic information and other variables that may influence vector introduction and spread, such as conventional, organic, abandoned and residential citrus areas as well as transportation corridors, an area-wide management division in pest management areas (PMAs) is proposed. The size and location of these PMAs were estimated by means of a hierarchical clustering algorithm with spatial constraints whose performance was assessed under different configuration scenarios. This proposal may assist policymakers and the citrus industry of the citrus-growing areas of the Mediterranean Basin in risk management planning in the case of the spread of HLB vectors or a possible introduction of the disease. Additionally, it may be a valuable resource to inform opinion dynamic models, enabling the identification of pivotal factors for the success of control measures

Influence of ground predators on the survival of the Mediterranean fruit fly pupae, Ceratitis capitata, in Spanish citrus orchards

A survey of predaceous ground arthropods was conducted in two citrus orchards in Valencia, Spain, and their role as predators of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) pupae was evaluated under field and laboratory conditions. A total of 2959 predaceous arthropods were collected in pitfall traps in the two orchards from July 2003 to September 2004. Ants (Hymenoptera) were the most abundant group (83.61%), followed by Staphylinidae (7.77%), Araneae (5.24%), Dermaptera (2.13%), Carabidae (0.64%) and Cicindelidae (0.61). Pupae disappearance rates were higher during the warmer months of the year, from May to October, and in the orchard with the largest ant population. In the warm season, the mean survival of C. capitata pupae was 35.7±6.2% and 14.3±6.7%, respectively, in both orchards. Patterns of predation, inferred from broken or abnormal pupae, were more frequently observed in the colder months, from November to April, when spiders, Staphylinidae and other predators were present. In the cold season, the combined effect of predation and low temperature led to an adult emergence rate of 26.7±9.9% and 13.0±7.5% in both orchards. In no-choice laboratory trials, all predator species tested fed at significantly different rates on C. capitata pupae. Preliminary data show that the Carabids, Pseudophonus rufipes (Duftschmid) and Harpalus distinguendus (Degeer), were the most voracious species, consuming more than one pupa per day. © 2006 International Organization for Biological Control (IOBC)