Understanding important aspects of the adaptation of a biological control agent population to different abiotic conditions (e.g., temperature) is essential to ensure its success once it is released in the field . In this context, we assessed different biological parameters of three Argentinian populations of Pseudapanteles dignus (from Salta, Buenos Aires and Rio Negro provinces), a larval endoparasitoid of the South American tomato pinworm, Tuta absoluta, a key pest of tomato crops worldwide, under various regimes of temperature (25, 28 and 30 degrees C). All local populations of P. dignus showed density-independent parasitism at the temperatures tested , and sex ratios did not deviate from 1:1 except for Salta population at 30 degrees C. Intra and inter-population comparisons revealed differences in pre-imaginal development times according to the temperature regimes. These results may be exploited to improve mass rearing of P. dignus and to implement biological control programs of T. absoluta in Argentina.

En el presente artículo se analizan las tensiones existentes en torno al modelo agrícola industrial de la Argentina. Para ello se aborda desde un enfoque interdisciplinario, la gestación y desarrollo de dicho modelo, sus características y sus consecuencias socioambientales. En particular, nos centramos en el conflicto por la reglamentación de agrotóxicos desarrollado en el partido de Pergamino (Buenos Aires, Argentina) a partir del año 2013, identificando los actores que se enfrentaron, sus argumentos y las acciones que llevaron a cabo.

Ecologists study how populations are regulated, while scientists studying biological pest control apply population regulation processes to reduce numbers of harmful organisms: an organism (a natural enemy) is used to reduce the population density of another organism (a pest). Finding an effective biological control agent among the tens to hundreds of natural enemies of a pest is a daunting task. Evaluation criteria help in a first selection to remove clearly ineffective or risky species from the list of candidates. Next, we propose to use an aggregate evaluation criterion, the pest kill rate, to compare the pest population reduction capacity of species not eliminated during the first selection. The pest kill rate is the average daily lifetime killing of the pest by the natural enemy under consideration. Pest kill rates of six species of predators and seven species of parasitoids of Tuta absoluta were calculated and compared. Several natural enemies had pest kill rates that were too low to be able to theoretically reduce the pest population below crop damaging densities. Other species showed a high pest reduction capacity and their potential for practical application can now be tested under commercial crop production conditions.

Fil: Luna, Maria Gabriela. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata. Centro de Estudios Parasitologicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitologicos y de Vectores; Argentina

In hymenopteran parasitoids, isolated geographic populations can show morphological variation and reproductive incompatibility that may lead to failures in biological control programs when they are intended to be used as biocontrol agents. Through a classical morphometric approach we confirm the specific identity of three local populations of the larval arrhenotokous endoparasitoid Pseudapanteles dignus (Muesebeck) (Hymenoptera: Braconidae) of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), from three main tomato producing areas of Argentina. Moreover, we examined reproductive compatibility by outcrossing the three populations. Morphometric differences among P. dignus biotypes were found but no evidences of mating incompatibility among them existed. This laboratory study contributes with relevant information to the original description of the species P. dignus and has significant implications for T. absoluta biological control using this parasitoid in tomato crops from different regions of Argentina.

Argentina has over 100 years of experience in classical biological control, mostly based on the importation of biological control agents (BCAs) against arthropod pests. We present the state-of-the-art of the importation regulatory framework from the last 30 years to date. We also applied a part of a recent developed environmental risk assessment (ERA) methodology to analyze retrospectively the potential negative effects on non-target species of 15 BCAs (12 parasitoids and three predators) imported since 1996 in Argentina, supported by the published literature (Tier 1 Scoping Assessment and Tier 2 Screening Assessment). We demonstrated that the previously imported species could have negative effects on non-target species [Adverse Effect risk characterization > 5 for ERA categories 2 (Reduction of native natural enemies), 3 (Reduction in herbivory) and 4 (Reduction in valued species)], which would be worth evaluating with a Definitive Assessment (Tier 3) and field research to determine if any were actually occurring. We discuss some suggestions for government organizations, state officials and decision makers, scientific researchers, and biological control practitioners to improve the current evaluation for the introduction of new BCAs into Argentina.

Augmentative biocontrol implemented through inoculative seasonal releases of one or more biological control agents has proven to be a reliable crop protection approach in greenhouse and open field crops. The South American tomato pinworm, Tura absoluta, is a key tomato pest worldwide. In this context, the effectiveness of the American-native larval endoparasitoid Pseudapantales dignus in reducing T. absoluta populations, in a semi-field set-up under greenhouse crop conditions, was assessed. In individual plants enclosed in cages, five host (T. absoluta):parasitoid (P. dignus) relative densities (2:1; 4:1; 4:2; 10:3 and 10:5) were evaluated through inclusion techniques. Controls for each treatment were included. Parasitization was allowed for 48 h; then leaves with signs of moth injury were removed and taken to the laboratory for rearing the host larvae until its pupation or the formation of P. dignus cocoons. Percentages of parasitism were calculated for each treatment and compared using a generalized linear model (GLM) with binomial link function. Pseudapanteles dignus females failed to parasitize at a host density of 2 larvae per plant; meanwhile at the other host densities tested, it reached from 23 to 61% parasitism. The greater percentage of parasitism was observed at host:parasitoid relative densities of 10:3. This field experiment showed evidence that the efficiency of this biocontrol agent decreases at low host densities, probably influenced by a reduction in host localization stimuli. Besides, at higher P. dignus release rates, parasitism decreased due to self-limitation of adult females by mutual interference when searching for hosts. Pseudapantales dignus has a significant potential for use in biological control programs.

The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) represents a global threat to commercial tomato (Solanum lycopersicum L.) production, both in open field and greenhouse. Native to South America, it spread over the Mediterranean Basin, Europe, Africa and part of Asia in only 12 years, and currently it is reported in over 80 countries. Biological control is one of the options for its control and a large number of natural enemies has been reported in association with the pest, both in the areas of origin and of introduction. The egg parasitoid Trichogramma pretiosum, in South America, and the mirid predators Macrolophus pygmaeus and Nesidiocoris tenuis, in Europe and the Mediterranean basin, are used as commercial biocontrol agents. Even if several natural enemies might be promising candidates for biocontrol, their potential role in quantitative pest reduction has been seldom established under practical tomato production conditions.Since climatic suitability indices predict a high probability for continued invasion by T. absoluta, mainly in China and the USA, there is an urgent need for new control options. In order to minimise the use of broad spectrum insecticides, biocontrol techniques should be considered. As tomato is produced seasonally, augmentative biocontrol seems to be the most effective control option, but pest reduction might be optimised by adding conservation biocontrol, and by combining biocontrol within IPM programmes.Here, an overview of predators and parasitoids of T. absoluta in South American and Euro-Mediterranean regions, and their biological control efficacy under laboratory, semi-field and field conditions is provided.

Pseudapanteles dignus (Muesebeck; Hymenoptera: Braconidae) is an American endoparasitoid that attacks the South American tomato leafminer Tuta absoluta (Meyrick; Lepidoptera: Gelechiidae). The interaction between P. dignus and T. absoluta in tomato (Solanum lycopersicum L.; Solanales: Solanaceae) crops has demonstrated that this enemy exhibits some desirable ecological traits as an effective biological control agent of this pest. With the aim of extending the use of P. dignus to other solanaceous crops, laboratory experiments were carried out to assess some life history traits and the parasitism efficiency when parasitizing T. absoluta larvae fed on eggplant (Solanum melongena L.; Solanales: Solanaceae). Rearings and experiments were conducted at 25 ± 2°C, ≈70% RH, and 14:10 (L:D) h photoperiod, and T. absoluta was fed with eggplant. P. dignus developmental times of immature stages were lower (~ 5 d) on S. melongena than on S. lycopersicum. The female did not exhibit a pre-reproductive period, and its oviposition period lasted longer (~ 4 d) than that determined in tomato plants. Adult longevity was ca. 24 d for both sexes. Females produced ca. 61 cocoons during their lives and the maximum daily percentage of parasitism was 50% at the first day of adult emergence. Functional response of P. dignus on eggplant was density-independent of the host density offered, as in tomato plant, and the instantaneous attack rate (a') was 0.24 attacked larvae/ available larvae, in 24 h. Our results indicate that although there are differences, P. dignus would have a similar performance in eggplant and tomato in terms of its efficacy in the control of T. absoluta.

Los acridios estan frecuentemente asociados a plantas que sufren estres hidrico y termico, en pastizales con sequias estacionales marcadas. El objetivo de este trabajo fue evaluar el efecto de hojas de maiz, Zea mays, sometidas a marchitamiento artificial, en el comportamiento alimentario, la supervivencia y la fecundidad de Dichroplus pratensls en laboratorio. Se utilizaron hojas turgentes y hojas marchitas para evaluar la preferencia alimentaria, tasas de consumo, crecimiento y eficiencia de conversion de alimento. Se computo la supervivencia diaria, la duracion del 5to estadio ninfal, el periodo de preoviposicion y la fecundidad en hembras criadas con ambos tipos de alimentos. Tanto ninfas de 5to estadio como adultos mostraron una marcada preferencia por el alimento marchito. Las ninfas alimentadas con hojas marchitas crecieron y consumieron mas que las alimentadas con hojas turgentes. En los adultos, hubo una mayor tendencia al consumo de alimento marchito, sin embargo, no se hallaron diferencias entre alimentos para la tasa de crecimiento relativo. No hubo tampoco diferencias entre tratamientos en la supervivencia, duracion del 5to estadio ninfal, periodo de preoviposicion y fecundidad.

Cannibalism ( CANN ) and intraguild predation ( IGP ) may provide energy and nutrients to individuals and eliminate potential competitors. These negative competitive interactions could also affect the coexistence of predatory species. The co‐occurrence of aphidophagous ladybird species in crops creates opportunities for CANN and IGP , especially when aphids become scarce. The Lotka–Volterra model predicts the coexistence of two species if intraspecific competition is stronger than interspecific interference interactions. C ycloneda sanguinea L. and E riopis connexa ( G ermar) (both C oleoptera: C occinellidae) coexist in sweet pepper crops in La Plata (Argentina) consuming mainly M yzus persicae ( S ulzer) ( H emiptera: A phididae). The present study used laboratory experiments to estimate levels of CANN and IGP by adults and larvae on eggs, and by adults on larvae, in both the presence and absence of prey (i.e., M . persicae ), to explain the effect of prey on coexistence of these two predators. Levels of CANN by C . sanguinea and E . connexa were high in the absence of aphids, and decreased when prey was present. Intraguild predation was bidirectional and asymmetric. Adults and larvae of E . connexa were more voracious IG predators of C . sanguinea than vice versa, the former being the stronger IG predator and interference competitor. E riopis connexa always won when larvae of the same instar were compared, whereas the larger larva always won when larvae were of different instars, regardless of species. In the presence of prey, CANN by both species decreased, but IGP by E . connexa on C . sanguinea remained high, suggesting that E . connexa could displace C . sanguinea via interspecific interference competition. Other factors potentially affecting the coexistence of C . sanguinea and E . connexa in sweet pepper crops are discussed.