Sanitizing Equipment and Personnel to Prevent the Spread of Hibiscus Mealybug [Nipaecoccus viridis (Hemiptera: Pseudococcidae)] in Florida Citrus

Abstract

Hibiscus mealybug (Nipaecoccus viridis, Newstead) is an emerging and serious pest of citrus in Florida. Preventing the spread of hibiscus mealybug by sanitizing personnel and equipment such as individual protective covers can help limit new infestations. Two mealybug life stages, first instars (crawlers) and eggs inside ovisacs, were tested as they are the most likely to be accidentally transported on people and tools. Isopropanol sprays in 3 commercially available concentrations (50%, 70%, and 90%) were tested against crawlers and ovisacs, and steam treatments and hot water immersion were tested against ovisacs. All concentrations of isopropanol resulted in >90% incapacitation of mealybug crawlers, especially when two sprays of isopropanol were applied. However, no concentration of isopropanol reliably killed all mealybug eggs within ovisacs. Steam treatments and hot water immersion for 10 min or longer at 49°C and for 5 min or longer at 54.5°C resulted in 100% mortality of mealybug adults and eggs inside ovisacs. However, adults and ovisacs insulated inside of individual protective covers did not experience 100% mortality until 30 min or longer at 49°C, 10 min or longer at 54.5°C, and 5 min or longer at 60°C for steam treatments. Isopropanol sprays can effectively incapacitate the majority of hibiscus mealybug crawlers on personnel and tools, but are not effective against ovisacs. Steam treatments and hot water immersion can reliably lead to 100% mortality of ovisacs, but longer times and higher temperatures must be used for steam treatments if ovisacs are insulated by equipment.