Aphids in Growth Chamber (IMAGE) American Society of Agronomy Caption Graduate student Anthony Hanson checks for aphids in a growth chamber aphid bioassay to test for varietal resistance. Credit Robert Koch Usage Restrictions Please use with story only 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.