FARGO (AP) - Thieves have been raiding test plots of tomatoes, onions and peppers at North Dakota State University.

School officials say it happened at least twice this summer.

NSDU spokesman Dave Wahlberg said extra campus patrols may be used to watch the fields, but he said putting up a fence would be expensive.

Wahlberg said the thieves may not realize that their actions can seriously hurt research projects.