Control of Eastern Tent Caterpillars with an insect virus

Scientific Importance: Eastern Tent Caterpillars caused Mare Reproductive Loss Syndrome in 2001 and 2002 because of their exceptionally high abundance in this region in those years. Tent caterpillar populations have declined since 2001 and our studies indicate that an insect virus is the most likely cause for this decline in tent caterpillar numbers in our region. Viruses are common organisms that cause diseases of essentially all plants and animals. Many important insect pest species are naturally controlled by viruses, predators and other pathogens. The virus we have identified as a likely cause of the decline in tent caterpillar populations in our region is a baculovirus. Closely related baculoviruses have been studied worldwide because they cause frequent and dramatic declines in pest populations in many cropping and landscape systems. Baculoviruses have been intensively studied in university, commercial and government laboratories as non-chemical pesticides but, with some notable exceptions, have not been commercially successful. A major reason for the lack of commercial success is that baculoviruses are relatively expensive to produce as compared to chemical pesticides. However, there is an important success story that underlies and supports this project. That is the example of a baculovirus that attacks the Velvet bean caterpillar which is currently used on about 5 million acres of soybeans in Brazil. This virus is successful because it is effective and production systems enable this virus to be produced cheaply, in quantity making it less expensive than competing chemical pesticides. Here we propose to take advantage of the life cycle of tent caterpillars to enable inexpensive production of baculoviruses for use in controlling tent caterpillars. The life cycle of tent caterpillars synchronously generates large numbers of insects in the spring and this is a direct cause of MRLS as experienced in Kentucky. The high population density and colonial behavior of tent caterpillars make them particularly susceptible to viruses and a virus epidemic in tent caterpillar populations has been important to the decline of tent caterpillars since 2001/2002. Data that has been collected since 2002 suggest that this virus is important in minimizing tent caterpillar populations as it acts as a brake on increasing populations. We propose to investigate this system with the objective of using the tent caterpillars to produce virus in quantity, testing its efficacy in the field and investigating the transmission of this virus. Development and testing of methods for production use and transmission of the tent caterpillar baculovirus may support production of an environmentally sensitive insecticide that is cost-competitive with chemical pesticides for use in controlling tent caterpillars in central Kentucky. Importance to the Equine Industry: In 2001 and 2002, central Kentucky and the Ohio valley experienced an outbreak of equine abortions known as Mare Reproductive Loss Syndrome that resulted in direct losses estimated at $500 million. We were involved in experimentally demonstrating that ingestion of the eastern tent caterpillar (ETC) by pregnant mares caused these abortions. Control of these insects has become a major concern for horse owners and breeders to prevent any future tragedies. Individual horse farms have spent thousands of dollars since 2001 in an effort to control these caterpillars, often using chemical insects that may be harmful to the environment and may kill all or most insects that they come in contact with, whether beneficial or not. The development of a production system to grow a naturally occuring virus that attacts ETC may eliminate the need for horse owners to use chemical insecticides This system will not only benefit the environment but may prove less expensive than chemical insecticides. Development of effective, environmentally sensitive and sustainable methods for controlling import~nt pests of horses is important to the long term viability and success of the equine industry in Kentucky.