Nontarget Effects Of Biological Control Research Articles

Insights from Population Genomics to Enhance and Sustain Biological Control of Insect Pests.

Biological control—the use of organisms (e.g., nematodes, arthropods, bacteria, fungi, viruses) for the suppression of insect pest species—is a well-established, ecologically sound and economically profitable tactic for crop protection. This approach has served as a sustainable solution for many insect pest problems for over a century in North America. However, all pest management tactics have associated risks. Specifically, the ecological non-target effects of biological control have been examined in numerous systems. In contrast, the need to understand the short- and long-term evolutionary consequences of human-mediated manipulation of biological control organisms for importation, augmentation and conservation biological control has only recently been acknowledged. Particularly, population genomics presents exceptional opportunities to study adaptive evolution and invasiveness of pests and biological control organisms. Population genomics also provides insights into (1) long-term biological consequences of releases, (2) the ecological success and sustainability of this pest management tactic and (3) non-target effects on native species, populations and ecosystems. Recent advances in genomic sequencing technology and model-based statistical methods to analyze population-scale genomic data provide a much needed impetus for biological control programs to benefit by incorporating a consideration of evolutionary consequences. Here, we review current technology and methods in population genomics and their applications to biological control and include basic guidelines for biological control researchers for implementing genomic technology and statistical modeling.

Interaction between Torymus sinensis (Hymenoptera: Torymidae) and T. beneficus, Introduced and Indigenous Parasitoids of the Chestnut Gall Wasp Dryocosmus kuriphilus (Hymenoptera: Cynipidae)

Torymus sinensis is a parasitoid wasp that was introduced from China to Japan to control the invasive chestnut gall wasp Dryocosmus kuriphilus. Interaction between T. sinensis and the indigenous parasitoid T. beneficus has been of interest since T. sinensis was first released in chestnut orchards, as hybridization between them might impede the success of biological control by the introduced parasitoid. Such apprehensions disappeared with the drastic decrease in damage caused by D. kuriphilus. However, the emergence of morphologically intermediate individuals between them after the introduction of the parasitoid has triggered renewed interest in hybridization, specifically on the non-target effects of biological control. In this review, the interaction between both species, specifically hybridization, species composition and species displacement, is surveyed. Molecular markers are used, not only because T. sinensis and T. beneficus are similar morphologically, but also because the latter has two emergence strains (early- and late-spring). Surveys show that 1) T. sinensis has displaced both emergence strains of T. beneficus; 2) hybridization between T. sinensis and early-spring T. beneficus occurs at a low frequency (≤ 1%); but that 3), hybrid F 1 s between T. sinensis and late-spring T. beneficus occur at a much higher frequency (≤ 20%). A study of phylogenetic relationships indicates that the late-spring T. beneficus is closer to the different species T. sinensis than the early-spring T. beneficus. This can partly explain why T. sinensis hybridizes more readily with the late-spring T. beneficus than with the early-spring T. beneficus.

Non-Target Effects of Dalaca pallens Blanchard Control Examined Through Principal Response Curves: A Guild Approach in Southern Chile

A B S T R A C T The non-target effects of biological control are a complex matter requiring a multi-approach analysis. A fungal biopesticide is under research to control the larval stages of the ghost moth Dalaca pallens Blanchard (Lepidoptera: Hepialidae) in southern Chile. A field experiment was conducted to compare the effects of the biological control agent Beauveria bassiana (Balsamo) Vuillemin (10 12 spores ha -1 ) and the insecticide lambdacyhalothrin (7.5 g active ingredient ha -1 ) on non-target invertebrate species belonging to different guilds. The soil invertebrates were collected by using pitfall trapping and soil coring before and after spraying the biocontrol agent or the insecticide. Caught individuals were assigned to predator, herbivore or decomposer guilds and then a relatively new multivariate technique called principal response curves (PRC) was adopted to track the potential treatment effects over time in the abundance or activity of the non-target guilds. The products targeting D. pallens caused different effects on guilds: lambda-cyhalothrin decreased the activity-density of the predator guild but not herbivore or decomposer guilds, while the biological control agent caused no reduction in the activity-density of the three examined guilds. The negative effects of the insecticide were present from 1 to 60 days after treatment.

Physical and ant-mediated refuges from parasitism: Implications for non-target effects in biological control

Abstract A promising natural enemy for release against the Asian soybean aphid, Aphis glycines Matsumura, in North America is the aphidiine braconid wasp Binodoxys communis (Gahan). The aphid Aphis monardae Oestlund, a native of North America’s tall-grass prairies, is a non-target species that may be at risk from releases of B. communis . This paper describes ecological facets of A. monardae populations in their native habitat that could protect them from attack by this exotic biological control agent. In prairie habitats, A. monardae populations aggregate in flower heads of their host plant, Monarda fistulosa L. On this host plant, aphids are also commonly tended by four ant species, and ant-tended colonies are larger than un-attended colonies. Laboratory studies showed that parasitism rates of A. monardae by B. communis are significantly higher on vegetative M. fistulosa than on M. fistulosa flower heads. In addition, attendance of A. monardae by the ant Lasius neoniger Emery significantly decreased parasitism by B. communis . Ants attacked and killed host-seeking adult parasitoids, and preyed upon B. communis mummies. No evidence was found that B. communis reared from A. monardae are less susceptible to attack by ants than parasitoids reared from A. glycines . M. fistulosa flower heads and attendance by L. neoniger may act as refuges for A. monardae against B. communis . Our work describes spatial refuges as ecological filters that separate non-target organisms from exotic natural enemies. Implications for classical biological control of A. glycines are discussed.

Kairomone involvement in the host specificity of the egg parasitoid Trissolcus basalis (Hymenoptera: Scelionidae)

This paper reports the results of a comparative laboratory analysis of the behavioural responses of the egg parasitoid Tris- solcus basalis (Wollaston) (Hymenoptera: Scelionidae) to semiochemical cues from four species of pentatomid bugs, Nezara viridula (L.), Eurydema ventrale Klt., Murgantia histrionica Hahn. and Graphosoma semipunctatum F. (Heteroptera: Pentatomidae). In a Y-tube olfactometer, T. basalis was attracted by volatile chemicals from N. viridula, but not from other pentatomid species. In an open arena, the parasitoid reacted to chemical trails left on filter paper by all the species but most intensely to those left by N. viridula. However, upon encountering pentatomid eggs, T. basalis examined more intensely and probed more frequently the eggs of G. semipunctatum than those of the other species. The parasitoid only parasitized and emerged from eggs of G. semipunctatum and N. viridula; those of the other species were unsuitable. Therefore N. viridula is semiochemically confirmed to be a coevolved host (old association) of T. basalis, whereas G. semipunctatum may be a potential non-coevolved host (new association). The utility of these tests for defining a parasitoids' host specificity and in assessing the risk of non-target effects in biological control is discussed.

Methods Used to Assess Non-target Effects of Invertebrate Biological Control Agents of Arthropod Pests

The number of concerns regarding potential non-target effects of invertebrate biological control agents of arthropods has risen over the last decade and an increasing number of studies have since dealt with this topic. Despite some recent international initiatives aimed at providing guidance for risk assessment of biological control agents, detailed methods on how tests should be designed and conducted to assess for potential non-target effects still need to be provided. It is believed that this review comes at an ideal time, giving an overview of methods currently applied in the study of non-target effects in biological control of arthropod pests. It provides the first step towards the ultimate goal of devising guidelines for the appropriate methods that should be universally applied for the assessment and minimisation of potential non-target effects. The main topics that are reviewed here include host specificity (including field surveys, selection of non-target test species and testing protocols), post-release studies, competition, overwintering and dispersal. Finally, a number of conclusions that have emerged from this comprehensive compilation of studies are drawn, addressing potential non-target effects in arthropod biological control.

COMPETITION BETWEEN NATIVE AND INTRODUCED PARASITOIDS OF APHIDS: NONTARGET EFFECTS AND BIOLOGICAL CONTROL

Little attention has been given to indirect nontarget effects of classical biological control, those effects that do not involve control agents directly attacking nontarget species. We combined experiments, theory, and historical information to show that the decline of a native parasitoid, Praon pequodorum Viereck (Braconidae: Hymenoptera), in alfalfa cropping systems may be caused by competition with Aphidius ervi Haliday (Braconidae: Hymenoptera), an exotic parasitoid introduced as a biological control agent of pea aphids. We conducted studies to examine competition for hosts at the population and plant levels, compare parasitoid searching behaviors, and model the interactions between two parasitoids on their single host. At the population level, P. pequodorum achieved relatively higher parasitism than A. ervi when the overall level of parasitism (and hence competition) was higher; this is explained by P. pequodorum's superior within-host competitive ability. A negative correlation between A. ervi and P. pequodorum parasitism per plant suggested strong competition by larvae within hosts or behavioral avoidance of previously parasitized hosts by P. pequodorum. Comparison of searching behavior revealed that A. ervi is a superior among-host competitor, searching longer on a plant after an aphid is encountered, moving more rapidly within plants, and attacking and parasitizing more aphids per unit time than P. pequodorum. Using a simple model, we show that high searching efficiency such as that exhibited by A. ervi could lead it to extirpate a superior larval competitor such as P. pequodorum. This competitive exclusion is facilitated by severe or frequent disturbances (such as regular harvesting of alfalfa) that cause mortality of both hosts and parasitoids. Disturbances place a premium on searching efficiency that allows rapid parasitoid population growth. These findings suggest that indirect nontarget effects of biological control may depend on agricultural practices and the consequent disturbance regime of human-dominated systems.

The Conflicting Values and Differing Priorities of Biological Control

The Conflicting Values and Differing Priorities of Biological Control

Non-Target Effects of Biological Control

Non-Target Effects of Biological Control

Non-target Effects of Biological Control

Non-target Effects of Biological Control