There is a critical need in the southern U.S. and globally for new insect, disease and weed biological control to manage native and non-native organisms. This need is even greater as climate change continues to disrupt ecological interactions such as herbivory, predation, and parasitism. Biological control contributes to food security and safety by reducing pesticide applications and losses due to species that consume or destroy agricultural commodities. Biological control is also valuable in reducing pesticide applications in ornamental plant production and in urban and suburban landscapes. This increases the safety of those landscapes for people, pets, and biodiversity. Additionally, biological control is needed to manage arthropod pests, diseases, and weeds in natural areas without harming non-target and beneficial organisms. Biological control is critical to protecting pollinators, monarchs, and other species of concern in agricultural, ornamental, and natural ecosystems. This proposal aims to continue the important work of the past eight Southern Region biological control research projects (S-192, S-238, S-267, SDC-319, SDC-351, S-1034, S-1058, and S-1073) and expand the effort to develop novel pest management approaches. Coordinated regional collaboration is fundamental for the success of these efforts. The southern U.S is the entry point and incubator of many non-native species and native sleeper species due to global entry points and warm climate. The proposed project aims to build on the many collaborations and accomplishments of this regional network of scientists engaged in biological control research. This project also aims to attract new members and foster the careers of early-career scientists and students to preserve continuity in biological control research and advancement. 

Biological control is the practice of releasing or promoting natural enemies of pests to reduce the pest populations and economic damage. Natural enemies in this context can be arthropod herbivores of plants, arthropod predators or parasitoids of arthropod pests, or disease agents, including nematodes, bacteria, fungus, or viruses, or plant or arthropod pests. Biological control consists of three primary areas of research and practice. Classical biological control entails the discovery and release of foreign natural enemies to manage foreign pests. Augmentative biological control entails the culture and release of native natural enemies to manage native or non-native pests. Conservation biological control is the practice of making pest prone habitats more hospitable to native natural enemies and less hospitable to pests. This increases natural enemy abundance without the expense of rearing and releasing them. All three components of biological control are covered by scientists in this project.

Global changes, including climate, urbanization, population growth, global nitrogen balance, invasive species, and other factors all influence production of food crops and ornamental plants. Global change also affects the biology, persistence, and spread of weeds. Global change factors, particularly climate, affect arthropod development, geographic range, voltinism, survival, and pest status. Climate also affects trophic interactions among arthropods and between arthropods and plants which is the very thing biological control seeks to exploit. Members of our regional group are dedicated to tackling this new frontier in biological control research to maintain past progress and adjust practices to new environmental situations. Understanding the interactions of global change factors and biological control is a new objective for our group.

Specialist and generalist natural enemies can play important roles in biological control. Specialist natural enemies have the advantage of specific adaptations to the pest and host specificity but they can be inflexible. Generalist natural enemies can often adjust to environmental conditions and take advantage of many prey or food resources. However, this ability to use alternate prey may disturb an unrelated food web. To develop sustainable biological control strategies, this project will assess individuals and communities of natural enemies and how they function in food webs to suppress pests of interest.

Cultural practices that enhance the action of existing natural enemies have gained grower acceptance. These cultural practices alter habitat complexity or resource availability and are important aspects of conservation biological control. Among the most prominent of these are conservation tillage, cover and trap crops, multiple cropping, and crop rotation. All of these practices affect the efficacy of natural enemies, as well as the abundance, timing and distribution of pest species within a field. Understanding how cultural practices interact with biological control also may yield opportunities to manipulate habitats to increase their suitability for natural enemies. However, the effective use of natural enemies in integrated pest management (IPM) programs is contingent on understanding their ecology and that of their targets, and their interactions with production and management practices.

Invasive species produce continuous new threats to agricultural production and natural resources. Members of our group will work on classical biological control in which non-native natural enemies approved for field release by USDA-APHIS will be released in the southern U.S. Ongoing release programs will build on new and previous evaluation studies on non-native, invasive weeds. Biological control programs targeting important non-native insect pests across the Southern Region will also be pursued for existing invasive species (e.g. emerald ash borer, red imported fire ant, hemlock woolly adelgid) and for relatively recent invasives such as spotted lanternfly and boxtree moth. 

Pesticides, plant-based insect resistance, and transgenic crops are common methods of insect management that can be integrated with biological control for more resilient pest suppression. Pest management will be most effective and economical if a variety of compatible technologies are developed and employed, rather than attempting to use a single option. Plant traits that result from breeding or genetic manipulation are important mechanisms that can hinder or enhance biological control. Members of our group will continue evaluating new crop varieties and phenotypes, and transgenic crops for their compatibility with biological control. 

Development and implementation of successful biological control programs are dependent on effective communication and coordination across the region. This multi-state research project will enhance biological control of arthropod pests and weeds in the Southeastern Region of the U.S. through collaboration among practitioners. This multi-state project provides a framework for target pest selection and coordinated research that focuses on pest-natural enemy complexes, addressing both entomology and weed science. Arthropod pest and weed biological control are based on many of the same ecological principles, and researchers from the two fields benefit greatly from information exchange and research collaboration. Although the methodologies for controlling arthropod pests and weeds may differ, the two fields share some of the same scientific issues (e.g., introduction strategies, genetics of colonization, evaluation of natural enemy impact, etc.). Further evidence of the conceptual similarities between these two fields is illustrated by the fact that some individuals involved in this project conduct research in both arthropod pest and weed systems.

Biological control is among the most selective, cost-effective and environmentally sustainable pest management practices for managing arthropod pests and weeds. It is increasingly important in IPM as concern grows about the effects of many insecticides, miticides, and herbicides on ecosystems and non-target organisms, including people. A fundamental principle in biological control is to select an appropriate agent or combination of agents that will bring about the desired level of pest suppression with minimal impact on non-target species. Reductions in insecticide and herbicide applications may allow farmers and ranchers to reduce and natural resource managers to reduce pest management costs. This should also provide benefits to the environment, biodiversity, and human health.