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

Authors: Ahmed, Muhammad; Dorado, Christina; ELLENRIEDER, NATALIA - California Department Of Food And Agriculture; QUINN, NICOLE - University Of Florida; RODA, AMY - Animal And Plant Health Inspection Service (APHIS); SCHOELLER, ERICH - University Of Florida; McKenzie, Cindy; OSBORNE, LANCE - University Of Florida; DIEPENBROCK, LAUREN - University Of Florida

Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2023
Publication Date: 8/22/2023
Citation: Ahmed, M.Z., Dorado, C., Ellenrieder, N.V., Quinn, N., Roda, A., Schoeller, E.N., Mckenzie, C.L., Osborne, L.S., Diepenbrock, L.M. 2023. Development of a species-level field diagnostic kit for Nipaecoccus viridis (Newstead) (Hemiptera: Pseudococcidae), an invasive and regulatory pest in the United States. Journal of Applied Entomology. 1-9. https://doi.org/10.1111/jen.13177.
DOI: https://doi.org/10.1111/jen.13177

Interpretive Summary: Nipaecoccus viridis (Newstead) is an exotic pest in the USA, currently limited to Florida. Most of the records of N. viridis associated with the major damage in the last few years were from citrus in Florida. It can potentially cause severe damage to citrus by distorting fruits and leaves, leading to branch dieback and even tree death in young and recently planted trees. Premature fruit drop has been documented to cause up to 50% of crop losses in citrus orchards. Citrus orchards were burned to eradicate N. viridis in Jordan. This pest can be easily misidentified at low populations or as individuals since its species based on eggs, first instars, and other immature stages are hard to distinguish from those of other mealybugs. Besides citrus, several commercially grown agricultural and ornamental plant species are potential hosts in Florida, including asparagus, avocado, blueberries, chrysanthemums, cotton, gardenia, grape, hemp, hibiscus, honeysuckle, jasmine, mangos, oleander, pagoda flower, palms, papaya and roses. It is most likely that N. viridis will eventually be introduced to other locations, including leading citrus-growing states: California, Arizona, Texas, and the leading blueberry-growing state: Georgia. Implementing control, quarantine, and regulatory measures requires regular scouting and inspection of citrus orchards and nurseries for N. viridis. These scouting and inspection would be facilitated with onsite species confirmation tests. This study will help develop the species-level field diagnostic kit for growers and nurseries.

Technical Abstract: Nipaecoccus viridis (Newstead) is an exotic pest in the USA, currently limited to Florida. In a previous study, we tested over 57 mealybug species and revealed N. viridis hemolymph 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 turns hemolymph green. We tested alternative solutions with different pHs in the laboratory. In laboratory and field conditions, we discovered that pH, not potassium, was turning hemolymph green, and 5% of Pure Lye solution (sodium hydroxide, NaOH) with a pH of 14 turns N. viridis hemolymph green in less than 1 minute. We tested two other mealybug species from another genus belonging to the blue-green mealybugs, Amonostherium hymenocleae and Amonostherium lichtensioides. In addition, we also tested Paracoccus hakeae, which was recently reported to turn green in the KOH. We confirmed that 5% NaOH with pH 14 also turns other species green. We discussed replacing 10% KOH with 5% NaOH in the field test to avoid potential hazards associated with KOH. This study will help develop the species-level field diagnostic kit for growers and nurseries.