Articles
An assessment of mechanical pest control methods in an urban landscape
Article number
1345_41
Pages
309 – 314
Language
English
Abstract
Pests in urban environments offer many control challenges, especially when managers need to balance effective control methods while having minimal impact on non-target arthropods.
In the southern US, crepe myrtle bark scale (CMBS) (Acanthococcus lagerstroemiae) has become an important pest of crepe myrtle (CM) (Lagerstroemia indica). CMBS is best controlled using insecticidal drenches.
Unfortunately, CM is a major pollen source for honeybees, and plants translocate sufficient active ingredient to the pollen to cause acute and chronic effects to individual bees and the hive.
In 2019 and 2020, 24 existing CM, all with confirmed CMBS infestations, were divided into four blocks and assigned to one of four treatments: no treatment, dinotefuran drench, power wash, and scrub with a soft bristled brush and soapy water.
Mechanical cleanings were conducted in February, and dinotefuran drench was applied in March 2019 and May 2020. Plants were scored from June to September using a 0-10 scale for both CMBS and sooty mold, with 0 indicating the complete absence of CMBS or sooty mold and 10 a complete infestation.
During year one, treated and untreated plants had similar CMBS and sooty mold scores, likely due to natural bark loss and abundance of predatory insects.
In year two, dinotefuran, brush, and power wash treated plants had lower CMBS (1.0, 0.1, and 1.3) and sooty mold scores (0.8, 0.0, and 0.6) than the untreated control (4.0, 2.8) in July.
In September, the dinotefuran treatment scores remained better than the untreated control, but the mechanical treatment benefits had lessened, and scores could not be separated from either the chemical treatment or the untreated control.
Mechanical controls appear to provide immediate benefits, and the control provided may be satisfactory.
However, the efficacy and longevity of control is dependent upon the fecundity of the target pest.
In the southern US, crepe myrtle bark scale (CMBS) (Acanthococcus lagerstroemiae) has become an important pest of crepe myrtle (CM) (Lagerstroemia indica). CMBS is best controlled using insecticidal drenches.
Unfortunately, CM is a major pollen source for honeybees, and plants translocate sufficient active ingredient to the pollen to cause acute and chronic effects to individual bees and the hive.
In 2019 and 2020, 24 existing CM, all with confirmed CMBS infestations, were divided into four blocks and assigned to one of four treatments: no treatment, dinotefuran drench, power wash, and scrub with a soft bristled brush and soapy water.
Mechanical cleanings were conducted in February, and dinotefuran drench was applied in March 2019 and May 2020. Plants were scored from June to September using a 0-10 scale for both CMBS and sooty mold, with 0 indicating the complete absence of CMBS or sooty mold and 10 a complete infestation.
During year one, treated and untreated plants had similar CMBS and sooty mold scores, likely due to natural bark loss and abundance of predatory insects.
In year two, dinotefuran, brush, and power wash treated plants had lower CMBS (1.0, 0.1, and 1.3) and sooty mold scores (0.8, 0.0, and 0.6) than the untreated control (4.0, 2.8) in July.
In September, the dinotefuran treatment scores remained better than the untreated control, but the mechanical treatment benefits had lessened, and scores could not be separated from either the chemical treatment or the untreated control.
Mechanical controls appear to provide immediate benefits, and the control provided may be satisfactory.
However, the efficacy and longevity of control is dependent upon the fecundity of the target pest.
Authors
D.A. Harp, M. Bledsoe, B. Ruiz, T. Bazhaw, M. Mendietta, C. Sutton, P. Castillo
Keywords
crepe myrtle, Lagerstroemia indica, crepe myrtle bark scale, Acanthococcus lagerstroemiae
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