Biological control of insect pests in apple orchards in China

Abstract

Apple is one of the most important fruits in China, and both yield and quality are greatly affected by insect pests. According to surveys, there are more than 200 species of natural enemies in apple orchards. Few, however, have been closely studied. Major natural enemies including parasitoids, predators and pathogens are briefly described in this review, especially focusing on two parasitoids of Trichogramma dendrolimi Matsumura and Aphelinus mali Haldeman, predatory mites and a pathogenic fungus of Beauveria bassiana (Balsamo) Vuillemin as case studies. Augmentation, one important strategy of biological control, supplements the natural control provided by the existing natural enemy community in apple orchards, and greatly increases their efficiency in controlling pests. Conservation biological control is also widely applied in four major apple-producing areas. Based on habitat manipulation, the ground cover planting system helps regulate the microclimate and enhance the biodiversity of apple orchards, effectively conserving the richness and diversity of beneficial insect species. Certain achievements have been made in the main biological control strategies including successful introduction of some exotic natural enemies such as A. mali and Typhlodromus occidentalis Nesbitt, augmentative production and application of biological control agents such as T. dendrolimi, B. bassiana and Bacillus thuringiensis, and further research in conservation of establishing adaptive ground cover planting patterns to local environment. Challenges, however, still exist. Biological control of insect pests in apple orchards is an important part of integrated pest management programs, requiring more research and application in China.