Caterpillar feeding (IMAGE) Penn State Caption The researchers found that the glucose oxidase (GOX), secreted by tomato hornworm caterpillars onto leaves, causes stomatal closure in tomato plants within five minutes, and in both tomato and soybean plants for at least 48 hours. This prevents the plants from alerting neighboring plants to the presence of herbivores nearby. Credit Po-An Lin, Penn State Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.