Development of a species-level field diagnostic kit for Nipaecoccus viridis (Newstead) (Hemiptera: Pseudococcidae), an invasive and regulatory pest in the United States

Abstract

Nipaecoccus viridis (Newstead) is an exotic pest currently limited to Florida and Texas in the continental USA. In a previous study, we tested 57 mealybug species in Florida and showed only N. viridis turned green in a potassium hydroxide solution (10% KOH), providing a rapid species confirmation test for all life stages. The unanswered question was whether the potassium in 10% KOH or its pH turned the mealybug's haemolymph green. We tested alternative solutions with different pHs in the laboratory and field conditions. We discovered that pH, not potassium, was turning the haemolymph green. A 5% sodium hydroxide (NaOH) solution with a pH of 14 turned N. viridis haemolymph green in less than a minute. We discussed replacing 10% KOH with 5% NaOH in the field test and slide-mounting to avoid potential hazards associated with KOH. In addition, we incorporated this solution into a field diagnostic kit and developed and tested the kit for commercial production systems in citrus and ornamental plant industries. This kit will aid in controlling N. viridis in the field and contribute to efforts to halt its further spread in Florida and the United States.