MERCEDES – A quarantine on citrus trees in the Rio Grande Valley is growing. More than 400 square miles in Cameron and Willacy counties combined are under quarantine because of the Mexican fruit fly.

According to the U.S. Department of Agriculture, a quarantine area is triggered when five flies are found within a three mile radius.

The USDA told CHANNEL 5 NEWS, this week there are new detentions of the Mexican fruit fly in the Valley.

Dale Murden, president of the Texas Citrus Mutual, says it’s bad news for growers. Costing them thousands of dollars.

View the USDA quarantine maps for the Mexican fruit fly.

Watch the video above for the full report.