Impact of natural control agents of the citrus leafminer Phyllocnistis citrella on lemon trees varies among seasons

Studies on insect natural enemies and their effects on host populations are of immense practical value in pest management. Predation and parasitism on a citrus pest, the leafminer Phyllocnistis citrella Stainton, were evaluated by sampling over 3 years in four locations within a world leading lemon producing area in Northwest Argentina. Both mortality factors showed seasonal trends consistent across locations, with predation exerting earlier and more sustained pressure than parasitism, which showed wider seasonal variations. The dominant parasitoids, native Cirrospilus neotropicus and introduced Ageniaspis citricola, showed different seasonal trends: C. neotropicus was dominant in spring whereas A. citricola superseded it in autumn and winter. Although parasitism rates were relatively low, the native C. neotropicus revealed favourable features as potential control agent, by showing density-dependence, parasitism rates comparable with those of the specific A. citricola during part of the cycle, and earlier synchronization with the host. The study provides highly relevant information for a sustainable management of this worldwide pest, for which biological control is considered the best long-term option.Fil: Goane, Lucía. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Casmuz, A.. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Salas, H.. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Willink, E.. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; ArgentinaFil: Mangeaud, A.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Valladares, Graciela Rosa. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentin

Communication interference in sympatrically occurring moth species

Inmoth species, females emit a species-specific sex pheromone that is perceived over long distance by conspecific males. The species-specificity in the chemical communication channel is achieved by a combination of unique components in specific ratios and sometimes also by interspecific behavioural antagonists to deter sympatrically occurring heterospecificmales. In this study, we determined possible antagonistic effects in Helicoverpa gelotopoeon Dyar (Lepidoptera: Noctuidae) males to the major sex pheromone component of sympatrically occurring heliothine moths, Z11-16:Ald, as well as to the sex pheromone of the sympatrically occurring Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) (Z11-16:Ald and Z9-14:Ald). We also explored whether other co-occurring species are attracted to these pheromone blends. Our field experiments showed that the addition of Z11-16:Ald alone or in combination with Z9-14:Ald inhibited trap catches of H. gelotopoeon males and that this inhibition depended on the concentration of these compounds. In addition, other moth species were attracted to the blends. Together, our results confirm the antagonistic effect of heterospecific sex pheromone compounds of H. virescens toH. gelotopoeon

Yeast derivatives and wheat germ in the adult diet modulates fecundity in a tephritid pest

Anastrepha fraterculus (Wiedemann), a pest of great economic importance in South America, needs urgently to be controlled by environmentally friendly methods such as the sterile insect technique for which mass rearing of insects is required. Because oogenesis takes place during the adult stage, mass-rearing facilities should provide the females a diet that maximizes egg production at the lowest cost. Accordingly, we investigated the effect of artificial protein sources in the adult diet (yeast derivatives of different cost but with similar amino acids profiles, and the addition of wheat germ) on fecundity. Additionally, we evaluated different ratios of yeast derivatives or wheat germ on ovary maturation, fecundity, and fertility as well as their association with the nutrient content of females. Females fed hydrolyzed yeast and yeast extract attained the highest fecundity level, and those fed brewer's yeast the lowest. Reducing the amount of hydrolyzed yeast, an expensive protein source, in the diet negatively affected fecundity and ovary maturation. Increasing the amount of brewer's yeast, a low-cost protein source, did not favor fecundity. The addition of wheat germ in the adult diet improved fecundity regardless of the yeast derivate considered. Percentage of egg hatch was not affected by the diet. Nutrient content of A. fraterculus females varied according to the adult diet provided and mating status. Our findings provide novel baseline information to understand the role of nutrition on reproductive performance of A. fraterculus females and are discussed in the context of resource allocation. They also provide valuable advances in the search for cost-effective adult diets at fruit fly mass rearing facilities.Instituto de GenéticaFil: Goane, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Pereyra, P. M. Fundación Miguel Lillo. Instituto de Fisiología Animal; ArgentinaFil: Castro, F. Fundación Miguel Lillo. Instituto de Fisiología Animal; ArgentinaFil: Ruiz, María Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Juárez, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Segura, Diego Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética. Laboratorio de Insectos de Importancia Agronómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vera, María Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentin

Lemon and Schinus polygama essential oils enhance male mating success of Anastrepha fraterculus

The sterile insect technique (SIT) is an environmentally friendly pest control method that relies on the introduction of sterility into the pest population by the release of sterile males. Many Tephritidae fruit fly pests are currently being controlled with SIT. Sterile insect technique efficacy can be increased if the sexual success of mass-reared sterile males is enhanced. Phytochemicals influence the sexual behaviour of many species of phytophagous insects. Here, we evaluated the possibility of using essential oils to enhance male sexual success of the highly polyphagous fruit fly pest Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae), also known as the South American fruit fly. In laboratory tests, we determined the effect of exposing males to volatiles from seven essential oils [Baccharis spartioides (Hook. & Arn) Cabrera (Asteraceae), Schinus polygama (Cav.) Cabrera, Schinus areira (L.) (Anacardiaceae), Zingiber officinale (Roscoe) (Zingiberaceae), Citrus limon (L.) Burm. F., Citrus paradisi Macfad., and Citrus sinensis (L.) Osbeck (Rutaceae)] and two monoterpenes (limonene and citral) that are present at high proportions in some of the oils we evaluated. One exposed and one non-exposed (control) male were placed in a mating arena with one virgin female. We recorded the type of male chosen as mating partner, copula start time, and copula duration. Laboratory males exposed to the volatiles of C. limon and S. polygama essential oils achieved more matings than non-exposed males. The rest of the oils had no effect on male mating success. In addition, limonene-exposed males obtained significantly more matings than non-exposed males, and citral induced a detrimental effect. Exposure to the volatiles of the various essential oils and monoterpenes did not impact on copula start time and copula duration. We discuss the role of essential-oil volatiles on A. fraterculus males’ sexual behaviour and its implications for SITEEA San JuanFil: Ruiz, María Josefina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Jofré Barud, Flavia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Goane, Lucía. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Goane, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Valladares, Gabriela A. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Valladares, Gabriela A. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Bachmann, Guillermo E. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Bachmann, Guillermo E. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina.Fil: Belliard, Silvina A. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Belliard, Silvina A. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina.Fil: Páez Jerez, Paula. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Páez Jerez, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Zamora Belli, Ana Lucía. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: García Méndez, F. Daniela. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Segura, Diego F. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Segura, Diego F. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina.Fil: López, María Liza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: López, María Liza. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Juan; Argentina.Fil: Vera, María T. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina.Fil: Vera, María T. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina