What: No, farmers aren't being replaced with robots, but California growers can soon take advantage of the latest in video and computer technology to control weeds without using chemical pesticides. David C. Slaughter, an associate professor of biological and agricultural engineering, has developed a robotic, vision-guided vegetable cultivator. Video cameras mounted on the frame of the cultivator capture a ground-level view of the crop row. That image is instantaneously flashed to the tractor's computer, which automatically centers the disc or other cultivating tool to cut out all weeds within one-third inch of the crop. The new cultivator will be field tested during a nighttime demonstration for growers and agricultural industry representatives. The ability to cultivate at night means the farmer can run the tractor for three shifts in a 24-hour period, increasing the efficiency of the operation. When: Tuesday, June 27, 8:15 p.m. Where: UC Davis tomato field west of the main campus. Visuals: The tractor and cultivator, complete with video camera, computer and lights, will be cultivating a 1-acre tomato field. Directions: Take Interstate 80 to Highway 113. Head north toward Woodland, exiting at the first opportunity onto Hutchison Drive. Turn left onto Hutchison, crossing Hwy. 113, and go west for six-tenths mile. You will have passed Campbell Road and one dirt road on the left. Turn left onto the second dirt road (unnamed) that is just before the first buildings you see. Continue down the dirt road about one-third mile. The tomato field to be cultivated is on the left.