Activity level of NPV following application and characteristics of infected Helicoverpa zea

Monday, November 14, 2022

8:00 AM – 8:12 AM PT

Location: Vancouver Convention Centre, Meeting Room 217/218/219

Presenting Author(s)

JF

Judge T. Fortenberry

Graduate Research Assistant
Mississippi State University
Starkville, Mississippi

Co-Author(s)

AC

Angus Catchot

Mississippi State University
Mississippi State, Mississippi
DC

Don Cook

Entomologist
Mississippi State University
Stoneville, Mississippi
WC

Whitney Crow

Mississippi State University
Cleveland, Mississippi
JG

Jeffrey Gore

Mississippi State University
Stoneville, Mississippi
BC

Beverly Catchot

Mississippi State University
Mississippi State, Mississippi

The cotton bollworm, Helicoverpa zea (Boddie), is a yield limiting insect pest of cotton and soybean in the Mid-southern U.S. In Mississippi during the 2020 growing season, yield losses exceeding 1.68 million bushels of soybeans resulted from bollworm infestations. Nuclear Polyhedrosis Virus (NPV) is a baculovirus used as a form of biological control targeting lepidopteran larvae in many agricultural production systems. Heligen^® is a Heliothis NPV that has been formulated to provide control of bollworm infestations in certain crops. We conducted two studies to determine the residual of Heligen and the feeding habits of bollworms after virus ingestion. To evaluate residual time, we applied Heligen to a soybean field and evaluated its efficacy at different time intervals (0, 12, 24, 36, 48, and 72 hours) after application in laboratory bioassays with treated leaves. Preliminary results indicated that Heligen remained viable for up to 48 hours in the field. To evaluate the feeding habits of bollworms at the ½’’ and ¼’’ life stages, Heligen exposed larvae and untreated larvae were weighed at 0 (before diet exposure), 4, and 7 days. At 4 days after exposure, body weight was reduced anywhere from 56 to 86% for larvae exposed to Heligen compared to control larvae. Together, these studies suggest that Heligen can be an effective form of biological control when larvae are exposed between 0-48 hours of application at the ½’’ and ¼’’ life stage.