Hot-water immersions were tested for control of mealybug Planococcus ficus (Signoret), on dormant grape cuttings used for nursery stock. A range of hot-water temperatures (47–58°C) were evaluated at immersion periods of 2, 5, 10, or 20 min, by using a total of 353,720 mealybugs across all treatments. A 5-min immersion at 51°C is effective in killing >99% of P. ficus. At or above this immersion period and temperature, there was no difference in mealybug stage mortality. We evaluated a commercial operation, which used a 5-min immersion in each of three water tanks: preheating (30.0 ± 3°C), hot-water (52.8 ± 0.3°C), and cooling (23 ± 3°C). The commercial procedure provided 99.8–100% mealybug control in each of three separate trials.