Natural Enemies Of Agricultural Pests Research Articles

Effects of agricultural intensification on ability of natural enemies to control aphids

Agricultural intensification through increasing fertilization input and cropland expansion has caused rapid loss of semi-natural habitats and the subsequent loss of natural enemies of agricultural pests. It is however extremely difficult to disentangle the effects of agricultural intensification on arthropod communities at multiple spatial scales. Based on a two-year study of seventeen 1500 m-radius sites, we analyzed the relative importance of nitrogen input and cropland expansion on cereal aphids and their natural enemies. Both the input of nitrogen fertilizer and cropland expansion benefited cereal aphids more than primary parasitoids and leaf-dwelling predators, while suppressing ground-dwelling predators, leading to an disturbance of the interspecific relationship. The responses of natural enemies to cropland expansion were asymmetric and species-specific, with an increase of primary parasitism but a decline of predator/pest ratio with the increasing nitrogen input. As such, agricultural intensification (increasing nitrogen fertilizer and cropland expansion) can destabilize the interspecific relationship and lead to biodiversity loss. To this end, sustainable pest management needs to balance the benefit and cost of agricultural intensification and restore biocontrol service through proliferating the role of natural enemies at multiple scales.

Provisioning Floral Resources to Attract Aphidophagous Hoverflies (Diptera: Syrphidae) Useful for Pest Management in Central Spain

Noncrop plant communities present on the boundaries or within crop fields are essential for the maintenance of functional biodiversity, affecting beneficial insect numbers and ecological fitness. Habitat manipulation is an increasingly studied strategy aimed at enhancing natural enemies of agricultural pests by providing feeding and shelter resources. In this study, six plant species selected from preliminary work were tested for their potential attractiveness to four common aphidophagous hoverflies species. Potential attractiveness was evaluated through observation of hoverfly feeding visits to replicated flower plots distributed in a randomized design. The combination of the selected species covered a 2-mo full-bloom period. Sphaerophoria scripta L. and Sphaerophoria rueppellii (Wiedeman) were the dominant hoverflies present throughout the sampling period, whereas Eupeodes corollae (F.) and Episyrphus balteatus (DeGeer) visits were less abundant and appeared only in the early season. Potential attractiveness varied among plant species. Calendula arvensis L. and Coriandrum sativum L. were the most visited species. C. arvensis received a high number of visits throughout a long period, whereas the visits to Co. sativum were concentrated in a short blooming period. These results suggest that habitat management by using these plant species may increase the abundance of hoverflies and could improve the biological control of aphid pests typical of spring-summer crops in open Mediterranean environments.

Detecting pest control services across spatial and temporal scales

Natural habitat may deliver ecosystem services to agriculture through the provision of natural enemies of agricultural pests. Natural or non-crop habitat has strongly positive effects on natural enemies in cropland, but the resulting impact on pests is not as well established. This study measured weekly natural enemy (syrphid fly larvae) and pest (cabbage aphid) abundances in Central California broccoli fields for three years. Abundance of syrphid fly larvae increased strongly with the proportion of natural habitat surrounding the farm. As the density of syrphid fly larvae increased, weekly aphid population growth rates slowed, such that aphid densities just prior to harvest were lowest in farms with natural habitat. These landscape-mediated impacts of syrphids on aphids were not evident when data were aggregated into annual averages, a common metric in research on pest control services. We suggest that higher temporal resolution of data for natural enemy and pest abundance can reveal top–down control that is otherwise masked by seasonal and interannual variation in environmental factors.

Effects of position within wheat field and adjacent habitats on the density and diversity of cereal aphids and their natural enemies

The spatial structure of agricultural landscapes can have a strong impact on the distribution and diversity of insects. Here we studied the effects of within-field position (edge or center) as well as adjacent habitats on the community structure of the natural enemies of cereal aphids. Twelve agricultural sites were included in the study, with two spring wheat fields selected for each site (one adjacent to an alfalfa field, the other adjacent to a corn field). We sampled two rows per field (1 and 20 m from the edge) using pitfall trapping for ground-dwelling predators, sweep netting for leaf-dwelling predators and hand collecting of aphid mummies for parasitoids. Adjacent alfalfa areas, as opposed to corn fields, can significantly increase the abundance and diversity of leaf-dwelling predators and parasitoids near the field edges. Abundance and diversity were found significantly higher near the edges than in the centers of fields adjacent to alfalfa areas. In contrast, no significant differences were found between edges and centers of fields adjacent to corn fields. Of the fifteen most abundant species, Aphidius avenae (Haliday), A. gifuensis (Ashmead), Hippodamia variegata (Goeze) and Chrysopa sinica (Tjeder) were significantly more abundant near the edge than in the center. Being adjacent to alfalfa habitats could enhance parasitism and predator/prey ratios of leaf-dwelling predators at the edges, but has no effects on ground-dwelling predators. In conclusion, the effect of within-field position and adjacent habitats on natural enemies of agricultural pests was species specific. This should be considered for designing efficient plans of biological control.

Zamorano y sus Contribuciones a la Agricultura Sostenible a Través del Control Biológico de Plagas

El Centro para el Control Biológico en Centro América (CCBCA) fue creado en 1989 por la Escuela Agrícola Panamericana, financiado por la United States Agency for International Development (USAID) en Honduras. El CCBCA se enfocó en el control biológico clásico, el aumento y la conservación de enemigos naturales. En el 2000 cambió el nombre de Laboratorio de Control Biológico y se enfocó en el aprender haciendo de los estudiantes de la Escuela Agrícola Panamericana y la producción y comercialización de enemigos naturales de plagas agrícolas. El único parasitoide conocido que ataca al picudo de las bromelias (Metamasius quadrilineatus), fue encontrado en las investigaciones del CCBCA; resultó una especie nueva nombrada Lixadmontia franki que fue liberada en Florida en el 2007 para el control biológico del picudo mejicano de las bromelias (Metamasius callizona). Se determinaron los organismos parasíticos de las plagas Plutella xylostella, Mocis latipes, Spodoptera frugiperda, Leptophobia aripa y Liriomyza spp. Cuatro especies de avispas parasíticas exóticas, un baculovirus, un hongo y tres picudos fueron introducidos a Honduras para control biológico clásico: Cotesia plutellae (parasitoide asiático de P. xylostella); Diadromus collaris (parasitoide pupal de P. xylostella); Telenomus remus (parasitoide que ataca a los huevos de 30 especies de lepidópteros); una especie de Eretmocerus (originaria de India, para controlar Bemisia tabaci); los picudos Neochetina bruchi y Neochetina eichhorniae y el hongo Cercospora piaropi (para el control de la maleza acuática lirio de agua (Eichhornia crassipes); y el picudo Neohydronomous affinis (controlador biológico de la maleza acuática lechuga de agua (Pistia stratiotes). En el 2000, Zamorano cambió la estrategia del uso de control biológico y empezó a incursionar en la producción comercial de microrganismos para el control de plagas, debido a una demanda no satisfecha. Los controladores biológicos que ha producido son el hongo antagonista Trichoderma harzianum (Trichozam™) para combatir hongos en el suelo, Beauveria bassiana (Bazam™) para controlar lepidópteros y coleópteros, Lecanicillium lecanii (Verzam™) para el control de áfidos y mosca blanca, Metarhizium anisopliae (Metazam™) para el control de salivazo (Aeneolamia spp.) y larvas de coleópteros en caña de azúcar, y Purpureocillium lilacinum (Pazam™) para controlar nematodos. Además, ha reproducido y vendido la chinche depredadora Orius insidiosus para el control de trips, áfidos y mosca blanca, el ácaro depredador Neoseiulus longispinosus para el control de la arañita roja (Tetranychus spp.) y el nematodo entomófago Heterorhabditis bacteriophora para el control de insectos del suelo, especialmente contra Phyllophaga spp., Cosmopolitus sordidus, larvas de lepidóptera, picudo del camote (Cylas formicarius) y termitas en el suelo. Posiblemente, el mayor aporte es en la enseñanza de las técnicas y tecnologías del control biológico de plagas que se han distribuido por América Latina a través de los graduados de Zamorano que estudiaron y fueron entrenados en Zamorano.DOI: http://dx.doi.org/10.5377/ceiba.v52i1.966

Compatibility of Two Systemic Neonicotinoids, Imidacloprid and Thiamethoxam, With Various Natural Enemies of Agricultural Pests

Two systemic neonicotinoids, imidacloprid and thiamethoxam, are widely used for residual control of several insect pests in cotton (Gossypium spp.), vegetables, and citrus (Citrus spp.). We evaluated their impact on six species of beneficial arthropods, including four parasitoid species--Aphytis melinus Debach, Gonatocerus ashmeadi Girault, Eretmocerus eremicus Rose & Zolnerowich, and Encarsia formosa Gahan--and two generalist predators--Geocoris punctipes (Say) and Orius insidiosus (Say)--in the laboratory by using a systemic uptake bioassay. Exposure to systemically treated leaves of both neonicotinoids had negative effects on adult survival in all four parasitoids, with higher potency against A. melinus as indicated by a low LC50. Mortality was also high for G. ashmeadi, E. eremicus, and E. formosa after exposure to both compounds but only after 48 h posttreatment. The two predators G. punctipes and O. insidiosus were variably susceptible to imidacloprid and thiamethoxam after 96-h exposure. However, toxicity to these predators may be related to their feeding on foliage and not just contact with surface residues. Our laboratory results contradict suggestions of little impact of these systemic neonicotinoids on parasitoids or predators but field studies will be needed to better quantify the levels of such impacts under natural conditions.

Enhancing Biological Control: Habitat Management to Promote Natural Enemies of Agricultural Pests. Charles H. Pickett , Robert L. Bugg

Previous articleNext article No AccessNew Biological BooksEnhancing Biological Control: Habitat Management to Promote Natural Enemies of Agricultural Pests. Charles H. Pickett , Robert L. Bugg Daniel M. PavukDaniel M. Pavuk Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 74, Number 4Dec., 1999 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/394188 Views: 3Total views on this site Citations: 1Citations are reported from Crossref Copyright 1999 The University of ChicagoPDF download Crossref reports the following articles citing this article:Nirina Ratsimba, Olivier Therond, Hazel Parry, Claude Monteil, Aude Vialatte Inconsistent responses of conservation biocontrol to landscape structure: new insights from a network‐based review, Ecological Applications 32, no.22 (Dec 2021).https://doi.org/10.1002/eap.2456

Ecology and behavior of ground beetles (Coleoptera: Carabidae).

The ground beetles from the speciose beetle family Carabidae and, since their emergence in the Tertiary, have populated all habitats except deserts. Our knowledge about carabids is biased toward species living in north-temperate regions. Most carabids are predatory, consume a wide range of food types, and experience food shortages in the field. Feeding on both plant and animal material and scavenging are probably more significant than currently acknowledged. The most important mortality sources are abiotic factors and predators; pathogens and parasites can be important for some developmental stages. Although competition among larvae and adults does occur, the importance of competition as a community organization is not proven. Carabids are abundant in agricultural fields all over the world and may be important natural enemies of agricultural pests.

The Ecology and Behavior of Ground Beetles

The ground beetles form the speciose beetle family Carabidae and, since their emergence in the Tertiary, have populated all habitats except deserts. Our knowledge about carabids is biased toward species living in north-temperate regions. Most carabids are predatory, consume a wide range of food types, and experience food shortages in the field. Feeding on both plant and animal material and scavenging are probably more significant than currently acknowledged. The most important mortality sources are abiotic factors and predators; pathogens and parasites can be important for some developmental stages. Although competition among larvae and adults does occur, the importance of competition as a community organization is not proven. Carabids are abundant in agricultural fields all over the world and may be important natural enemies of agricultural pests.

Predatory Ants of Diaprepes abbreviatus (Coleoptera: Curculionidae) in Citrus Groves in Martinique and Guadeloupe, F.W.I.

Although ants were used as biocontrol agents by different ancient cultures, few works on the possible use of ants as natural enemies of agricultural pests are known. The role of ants in protecting forests against hervibores in the northern hemisphere is well documented (Pavan 1961, Gosswald et al. 1968). Several studies, evaluating ants as possible predators of pests, have been carried out on cocoa plantations in Africa (Leston 1972, 1973, Majer 1972, Room 1971) and in South America (Jaffe et al. 1987). Also, ants may interfere with control agents for tuliptree aphids (Dreistadt et al. 1986). Tryon (1986) and Fowler (1988) showed that ants have an untrapped potential in biological control, including citrus grove pests. Among the 23 species of 5 genera of Curculionidae known to attack citrus in Martinique and Guadeloupe, Diaprepes abbreviatus (L.), D. famelicus (Oliver), D. marginatus (Fabrcius) and Litostylus pudens (Boheman) are common pests since 1973, though D. marginatus is absent in Martinique (Mauleon & Marival 1986). Although it is not the primary problem affecting production, they remain an important insect pest on citrus. Whitcomb et al. (1982) reported two Pheidole species, Tetramorium similluni and Paratrechina bournonica as possible control agents for D. abbreviatus in Florida, though different live stages of these curculionids may be affected by various predators (Whitcomb et al. 1982, Mauleon & Marival 1986, Tryon 1986). Diaprepes spp deposit their eggs between leaves that are glued together with a genital secretion. Once the larvae emerge, they drop to the ground and penetrate into the soil where they spend all their larval stages. The insect pupates in the soil. Life stages that might be succeptible to ant predation are, the eggs, first instar (before burying), and recently emerged adults. To evaluate the possibility of using ants for biological control of Diaprepes pests in the French Antilles, a search was made for the most promissing autoctonous ant species. Ant species in citrus groves were collected from October 1986 to April 1987 on trees and on the ground, during a minimum of 4 h at each site following the hand collecting method described elsewhere (Romero & Jaffe 1989). Collections were made only during the day. Sites visited were: Guadeloupe: Vieux-Habitants (1), Capesterre (2) and Duportail (3); and Martinique: Riviere Lezarde-Saint Joseph (1), Habitation Moulin a Eau-Le Robert (2), Hab. Belle Vue-Marigot (3), Hab. Concorde-Sainte Marie (4), Hab. Grand Case-Le Precheur (5) and Morne Rouge (6). In Table 1, only species that were collected in more than two trees at each location were reported. Groups of at least 10 eggs, first or last D. abbreviatus instars or 1 adult were offered to workers of at least 3 different colonies on the ground around citrus trees, in Riviere Lezarde, Martinique, in Vieux Habitantes and in Capesterre, Guadeloupe. Ant species collecting all eggs or larvae 10 min after a scout ant discovered the food, or attacking