Efficacy of a horticultural oil + insect growth regulator mix (SuffOil-X + Molt-X) and two imidacloprid formulations (Bayer Tree and Shrub; Fertilome Tree & Shrub Systemic Insect Drench) were tested for control of bark scale (Eriococcus lagerostroemia) on crapemyrtles at LeTourneau University. There was a trend towards decreasing alive scales and decreasing alive:dead scale ratio with time, especially by the fifth week in all treatments (including the control). The systemic insecticides (imidacloprid) demonstrated a decrease in alive:dead scale ratio two weeks after treatment, whereas contact treatments showed a decrease one week after treatment (horticultural oil + insect growth regulator). Since the control also showed decrease in scale populations, in some cases before other treatments, the efficacy of the insecticides studied here are inconclusive.
On June 24th and 25th (2014), a number of Texas A&M AgriLife personnel set out to McKinney to collect data on susceptibility of different varieties of crape myrtles to the new invasive pest, crape myrtle bark scale (CMBS). McKinney is home to over 114 varieties of crape myrtles from all over the world, making it a great site to investigate the preference of CMBS for certain cultivars and varieties. Follow the gallery below to see how the research was carried out.
A new invasive scale of crape myrtles has recently been detected. Current evidences suggest that the species is Eriococcus lagerostroemia, a native to the plant host to Lagerostroemia sp., also found in China, Japan, Korea, India, Mongolia, South Korea and United Kingdom.