Theo works weekdays, weekends, and nights. He checks Dutch tulip fields for sick flowers. For a regular farm hand, this would be backbreaking work. But Theo never complains of a sore spine. He’s a robot!

On a windy spring morning, the robot trundles along rows of yellow and red tulips. It checks each plant. When necessary, the ’bot kills diseased bulbs. This stops a tulip-breaking virus in its tracks.

The virus stunts growth in tulips. The flowers stay smaller and weaker. It also weakens the bulbs each tulip grows from. Eventually, bulbs can’t flower at all.

Now 45 robots patrol tulip fields across the Netherlands as the weather warms. They’re just in time. Tulip crops are about to bloom into giant patchworks of color. Tourists from all over the world will come to see them.

Once, people did Theo’s job. They were called “sickness spotters.”

Allan Visser is a tulip farmer. He says the ’bots aren’t cheap. For the price of the robot, he says, “You could also buy a very nice sports car.” The robots cost around $200,000 each.

“But I prefer to have the robot because a sports car doesn’t take out the sick tulips from our field,” Mr. Visser adds. And he says that there are fewer people who can do the job these days.

The robots are a lot slower than a sports car though. They roll through fields, covering about a half-mile per hour. They hunt for red stripes on leaves, which show a flower is infected.

Cameras on the front take thousands of pictures of the tulips. The ’bots use artificial intelligence to tell whether a flower is sick.

“The robot has learned to recognize this and to treat it,” Mr. Visser says.

Theo the robot is named after Theo van der Voort. He spent 52 years hunting for sick flowers. “It’s fantastic,” the real Theo says. “It sees just as much as I see.”

The grass withers, the flower fades, but the word of our God will stand forever. — Isaiah 40:8