Developing a potential biological control measure for a new exotic soft scale insect on croton

A new species of soft scale [Phalacrococcus howertoni (Hemiptera: Coccidae)] was first collected in April 2008 in south Florida.  This pest continues to spread throughout the state and is at high risk to spread to new areas. Phalacrococcus howertoni is particularly problematic on crotons in production and in the landscape but has also been reported on approximately 100 host plants. Due to its polyphagous nature and high reproductive ability, it is a potentially serious pest of numerous tropical and subtropical ornamental and fruit host plants and environmentally important mangroves. Currently, there are no recommended biological control measures for this pest and little is known of its biology and population dynamics. A predatory beetle, Thalassa montezumae (Coleoptera: Coccinellidae), has been identified feeding on the scale and is reportedly very specific on this scale. Caged and laboratory studies were conducted to determine the life cycle, longevity, and fecundity of Thalassa montezumae.  Average developmental time was 24.7 and 26.5 days for females and males, respectively with 4 instars each.  Lifetime fecundity was 165 ± 15 eggs per female.  Eggs were typically laid near or around scales and hatched 7 to 9 days after being laid.  Adult females lived longer (37.5 ± 5 days) than adult males (29.8 ± 3.7 days). Adult beetles fed on all stages of the scale.  These findings provide useful insights about the biology of this predatory beetle which will aid in future studies, rearing and releasing as a biological control agent of Phalacrococcus howertoni.