In vivo production of Agrotis ipsilon nucleopolyhedrovirus for quantity and quality

Authors: Behle, Robert

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2017
Publication Date: 12/20/2017
Citation: Behle, R.W. 2017. In vivo production of Agrotis ipsilon nucleopolyhedrovirus for quantity and quality. Journal of Economic Entomology. 111(1):101-107. doi: 10.1093/jee/tox315.
DOI: https://doi.org/10.1093/jee/tox315

Interpretive Summary: The high production cost of insect pathogens for biological pesticides is a major factor limiting their development as environmentally friendly pest control products. For a baculovirus to control the black cutworm, three major in vivo production parameters were evaluated simultaneously and identified the levels necessary to optimize quantity (number of virus particles) and quality (insecticidal activity) of the resulting product. Optimized production is an important first step toward commercializing this baculovirus as a biological product to provide safe and effective control of an important insect pest of many crop, vegetable and urban turf environments.

Technical Abstract: The black cutworm, Agrotis ipsilon (Hüfnagel), is a pest causing damage to a variety plants from urban turf environments to farming row crops. A recently discovered baculovirus has the potential to be developed as a microbial-based biological pesticide to provide targeted control of this insect pest. In an effort to develop this baculovirus as a biological pesticide, experiments were conducted to determine parameters necessary to maximize in vivo production using cutworm larvae. Treatment combinations including three larval diets, larval age at infection (6 to 10 day-old), and dosage of virus exposure (1 × 10**5 to 1 × 10**8 occlusion bodies ml-1) were evaluated. Production quantity and quality were measured as number of occlusion bodies produced and insecticidal activity of the virus, respectively. Generally speaking, insect diets that maximized larval growth resulted in a greater quantity of virus occlusion bodies. Less virus was produced when small larvae were exposed to higher dosages of virus resulting in rapid mortality and when large larvae were exposed to low dosages of virus resulting in low levels of infection. Virus quality was measured as insecticidal activity (low LC50 representing high activity) and was highest for larger larvae exposed to minimal virus concentrations needed to initiate infections. When considering both quantity and quality measurements, maximum production was achieved for 8-9 d-old larvae fed a general purpose lepidoptera diet. These results will support the development of this baculovirus as an additional tool for the integrated control of the black cutworm.