INSECT HOT TOPICS: Lobate lac scale

by James A. Bethke

First, I want to give a little update. In the last "Insect Hot Topics" article I concentrated on the problems that my colleagues across the country were having with the daylily leafminer. Unfortunately, soon after the article was published, I learned of the first confirmed detection in the landscape in Orange County, California. No, I did not bring them in, but it makes me wonder whether I should continue writing this article due to karma or some other related phenomenon.

As such, I hesitate to write about our next potential pest invasion of the lobate lac scale insect, Paratachardina pseudolobata Kondo & Gullan (fig. 1). Many of the articles and alerts I have read about this insect mentions that the invasion of the lobate lac scale into the subtropical regions of Texas, California, Hawaii, the West Indies and Mexico will undoubtedly affect local crop production, the urban landscape and natural areas. Why? It has been known to attack over 160 ornamental and agricultural plant species in 49 families.

Lobate lac scale originates from India and Sri Lanka, and it was first found in the United States in Florida on hibiscus in 1999 and in 2000 on Ficus benjamina. In 2012, it was again found on F. benjamina, but this time in Hawaii. Some notable hosts are hibiscus, gardenia, hopseed bush, Ficus spp., wax myrtle, olive and avocado.

Lobate lac scale prefers to infest the twigs or branches of host plants, and the types of damage typically observed are the dieback of twigs and branches, leaf drop, honeydew and sooty mold, and plant death of some species. Immature stages are flat, thin, elongated and bright red, but in later stages, members of the scale insect family Kerriidae produce lac, a thick resinous secretion. When mature, the convex body of the lobate lac scale has four distinct lobes in an x-shape and is covered in dark red or brown resin (fig. 2). This insect is parthenogenetic, which means that the population consists of reproductive females; no males are known to exist. They will reproduce very fast and mating disruption is not an option.

Be on the lookout for this pest. Make sure you are isolating incoming stock from other states, especially from Florida and Hawaii. This is one insect that would be great to exclude.

Web pages of interest with lots of photos:

http://www.dontmovefirewood.org/gallery-of-pests/lobate-lac-scale.html

http://hdoa.hawaii.gov/pi/files/2013/01/3-27-2013-Lobate-lac-scale-NPA.pdf

http://www.fcla.edu/FlaEnt/fe91p674.pdf or http://journals.fcla.edu/flaent/article/view/75878/73536

http://www.fngla.org/education-and-research/research/reports/177/finalreport.pdf

http://entomology.ifas.ufl.edu/creatures/orn/scales/lobate_lac.htm

http://www.reportapest.org/pestlist/parpse.htm

http://edis.ifas.ufl.edu/in471

http://www.alohaarborist.com/index.php/lobate-lac-scale-a-most-unwanted-pest-article-by-carol-kwan/

James Bethke is Farm Advisor for Nurseries and Floriculture, UC Cooperative Extension, San Diego and Riverside Counties.