Entomopathogenic Viruses: Molecular, Cellular and Biotechnological Insights That Enhance Their Potential Application as Biopesticides

Dear Colleagues,

Insect pest resistance to pesticides is an ongoing concern, and the rising cost of registering new chemistries or the development of transgenic crops that meet extensive environmental regulations is leading to an appreciation and wider uptake of biopesticides to help make food production more sustainable and safer for human consumption. Entomopathogenic viruses, in particular baculoviruses that target many of the most damaging lepidopteran pests globally are important in this regard.

Entomopathogenic viruses are often highly specific in relation to the insects they target, and can be highly virulent. For these reasons, many baculovirus products are relatively easy and inexpensive to register due to their well-established safety profile in relation to non-target species. Of particular interest, baculoviruses were recently formally acknowledged as a new mode of action (Group 31) by the Insecticide Resistance Action Committee (IRAC) which focuses on the preservation of the use of insecticides through effective resistance management to promote sustainable agriculture. This inclusion was fueled by the increase in natural products and biologics now used as control options, and places these alternatives as a valid control to use with chemical insecticides and transgenic plants to manage resistance.

Despite some spectacular successes over the past 20 years, particularly in Brazil, the use of virus biopesticides requires extensive research in a number of areas if their full potential in aiding sustainable food production is to be realized. The slow kill rate of many viruses and their instability in the field compared to chemical pesticides, along with quality control/cost issues during the in vivo production of baculoviruses, still need attention. The in vitro production of baculovirus biopesticides using animal cell technology (ACT) holds great promise for improving the manufacture of these products by eliminating the need to maintain large insect colonies required for in vivo production. While many challenges remain to make the in vitro production of baculoviruses cost effective, ACT has developed enormously over the past 30 years, resulting in a 100-fold reduction in the cost of producing a gram of recombinant protein. It now supplies more than 25% of the global pharmaceutical market, with biotherapeutics worth USD 275 billion. In addition, our knowledge of how viruses interact with cells will improve rapidly now that a few key insect genomes are available, which combined with progress in genomics and metabolomics should deliver rapid progress for the in vitro production of viruses. If these issues can be addressed, some virus products could access very large markets.

Regardless, the most significant contribution of entomopathogenic viruses in the long term is their different, complex and often species-specific mode of killing insect pests compared to single-molecule pesticides or single-gene-based transgenic plants which provides them with significant advantages. Many viruses targeting many pests could over time play a key role in integrated pest management (IPM) programs to prevent/delay insects developing resistance against chemical pesticides and transgenic plants. Indeed, roles of virus biopesticides can be envisaged for applications other than food production, particularly in some areas of human and animal health. For example, insect viruses for controlling mosquitoes or other insect vectors could play a role in reducing the spread of animal and human pathogens such as malaria and dengue.

To realize the use of many viruses against many insect pests, more virus isolates need to be found and assessed. Ultimately, the commercial success of the use of virus biopesticides will be enhanced if companies have the capacity to produce multiple viruses using frozen stocks of appropriate cell lines rather than depending on the maintenance of multiple insect colonies.

Hence, in this Special Issue we will be happy to consider both original research and review articles dealing with any aspect relevant to the use of entomopathogenic viruses:

• Baculoviruses (nucleopolyhedroviruses and granuloviruses);
• Viruses other than baculoviruses (nudiviruses, cypoviruses, poxviruses, reoviruses, etc.);
• Molecular insights into entomopathogenic viruses and how insect host cells respond to infection by these viruses;
• Molecular enhancements of entomopathogenic activities;
• In vivo production, industrial scale;
• In vitro production;
• Formulation;
• Field trial application data;
• Market size;
• Commercialization issues/successes;
• World view—Europe, Americas, Africa, China, India, S.E. Asia etc.;
• Use in IPM applications;
• Regulatory issues—wild-type viruses in countries where the virus is not present already;
• Regulatory issues with recombinant viruses delivering insect specific toxins;
• Resistance problems;
• Baculoviruses or densoviruses to control mosquitoes.

Dr. Steve Reid
Dr. Juan Claus
Dr. Gabriel Visnovsky
Guest Editors

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• entomopathogenic viruses
• baculoviruses
• resistance management
• integrated pest management
• production process development and optimization
• field efficacy
• formulation
• strain variation
• virus–cell interactions