[et_pb_section fb_built=”1″ admin_label=”section” _builder_version=”4.16″ global_colors_info=”{}”][et_pb_row column_structure=”1_2,1_2″ admin_label=”row” _builder_version=”4.16″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” width=”100%” global_colors_info=”{}”][et_pb_column type=”1_2″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_text admin_label=”squiggle-left” _builder_version=”4.24.1″ _module_preset=”default” header_font=”||||||||” header_text_align=”left” header_font_size=”22px” width=”75%” module_alignment=”left” custom_margin=”||||false|false” custom_padding=”||||false|false” global_module=”23371″ saved_tabs=”all” global_colors_info=”{}”]<\/p>\n
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Order: Hemiptera
Family: Pseudococcidae<\/p>\n
The hawthorn mealybug\u00a0is an introduced species in Colorado. It feeds on twigs and small branches of hawthorn (Crataegus<\/em> spp.), mountain ash (Sorbus<\/em> spp.), juneberry (Amelanchier<\/em> spp.), and other plants in the family Rosaceae. This pest produces copious amounts of honeydew and has piercing-sucking mouthparts for piercing plant tissues and extracting plant fluids. Adult females measure about 3.2 mm (1\/8 inch) and have globular, red bodies covered with secretions of white wax, while adult males are smaller, have wings, and are typically present during the spring as individuals migrate from overwintering sites to twigs. The red or brown nymphs (crawlers) are generally smaller and more elongated than adult females.<\/p>\n [\/et_pb_text][et_pb_blurb title=”Quick Facts” use_icon=”on” font_icon=”||fa||900″ icon_color=”#F15625″ image_icon_width=”36px” _builder_version=”4.24.2″ _module_preset=”default” header_level=”h3″ header_font=”|||on|||||” header_text_align=”center” header_font_size=”26px” background_color=”#FEBD3B” custom_margin=”|4%||4%|false|true” custom_padding=”4%|4%|4%|4%|true|true” global_colors_info=”{}”]<\/p>\n [\/et_pb_blurb][et_pb_blurb image=”https:\/\/agsci.colostate.edu\/agbio\/wp-content\/uploads\/sites\/127\/2024\/03\/adults-crawlers-hawthorn-mealybug-1080×700-min.jpg” alt=”Adults and crawlers of hawthorn mealybug” _builder_version=”4.24.2″ _module_preset=”default” body_line_height=”1.4em” image_icon_custom_margin=”||-22px||false|false” global_colors_info=”{}”]<\/p>\n Adults and crawlers of hawthorn mealybug. Notice the red bodies of adults covered in wax, while the nymphs are smaller and have a tan or light brown color. Image credits: Whitney Cranshaw, Colorado State University, Bugwood.org<\/em><\/p>\n [\/et_pb_blurb][\/et_pb_column][et_pb_column type=”1_2″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_blurb image=”https:\/\/agsci.colostate.edu\/agbio\/wp-content\/uploads\/sites\/127\/2024\/03\/nymph-hawthorn-mealybug-1080×700-min.jpg” alt=”nymph of hawthorn mealybug” _builder_version=”4.24.2″ _module_preset=”default” body_line_height=”1.4em” image_icon_custom_margin=”||-22px||false|false” global_colors_info=”{}”]<\/p>\n Nymph of hawthorn mealybug on a hawthorn leaf. Note the elongated, oval-shaped body. Image credits: Whitney Cranshaw, Colorado State University, Bugwood.org<\/em><\/p>\n [\/et_pb_blurb][et_pb_blurb image=”https:\/\/agsci.colostate.edu\/agbio\/wp-content\/uploads\/sites\/127\/2024\/03\/overwintering-nymphs-hawthorn-mealybug-1080×700-min.jpg” alt=”Overwintering nymphs of hawthorn mealybug” _builder_version=”4.24.2″ _module_preset=”default” body_line_height=”1.4em” image_icon_custom_margin=”||-22px||false|false” global_colors_info=”{}”]<\/p>\n Nymphs of hawthorn mealybug overwintering in bark crevices. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org<\/em><\/p>\n [\/et_pb_blurb][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.24.2″ _module_preset=”default” background_color=”#F1F1F1″ global_colors_info=”{}”][et_pb_row _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.24.2″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n\t\t The hawthorn mealybug overwinters as a late-stage nymph within bark crevices on the trunk and larger branches. Females migrate to twigs in the spring and continue developing until reaching maturity in late May or early June. Males remain near their overwintering sites on the trunk until they molt into their final winged form and begin mating. After mating, the adult female swells with hundreds of eggs. The newly emerged nymphs briefly feed on leaves before moving to protected areas on twigs where they remain for much of the summer. The peak abundance of nymphs typically occurs in late May and June, although wet, cool weather tends to delay dispersal of nymphs. After feeding and developing on twigs and within leaf folds through the summer, late-stage nymphs migrate to overwintering sites on trunks and larger branches during September and October.<\/p>\n Populations of hawthorn mealybug tend to be high late in the summer, and trees in landscapes tend to be more susceptible to attack than native stands. It is believed that one generation is produced each growing season in Colorado. However, egg producing females and egg hatch have been observed in late September, which suggests that this pest can either produce a second generation or has an extended egg-laying period.<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.24.2″ _module_preset=”default” background_color=”#FFFFFF” global_colors_info=”{}”][et_pb_row _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text admin_label=”Squiggle” _builder_version=”4.17.4″ _module_preset=”default” header_font=”||||||||” header_text_align=”left” header_font_size=”22px” custom_padding=”||||false|false” saved_tabs=”all” locked=”off” global_colors_info=”{}”]\t\t Heavy infestations of hawthorn mealybug can lead to severe defoliation, twig dieback, and weakened plants. The production of honeydew can lead to the growth of black sooty mold, which can give the tree an unattractive appearance. The severity of feeding injuries inflicted by hawthorn mealybug differs among hawthorn cultivars, with English hawthorn, Arnold hawthorn, and Thornless cockspur hawthorn appearing to be most susceptible.<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.24.2″ _module_preset=”default” background_color=”#F1F1F1″ global_colors_info=”{}”][et_pb_row _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text admin_label=”Squiggle” _builder_version=”4.17.4″ _module_preset=”default” header_font=”||||||||” header_text_align=”left” header_font_size=”22px” custom_padding=”||||false|false” saved_tabs=”all” locked=”off” global_colors_info=”{}”]\t\t Green lacewing larvae and certain lady beetles are predators of hawthorn mealybugs. The presence of predators can often limit the density of hawthorn mealybug to acceptable levels, eliminating the need for insecticides.<\/p>\n Chemical control of hawthorn mealybug is challenging due to the insect\u2019s waxy covering and habit of occupying cracks and crevices in bark. Insect growth regulators are relatively safe for beneficial insects and can be applied when crawlers migrate from overwintering sites to twigs in the spring. Late summer or early fall applications can also provide some control against hawthorn mealybug. Dormant oils can be effective when applied to trunks and undersides of branches where hawthorn mealybug overwinters.<\/p>\n While systemic insecticides can control hawthorn mealybug, the toxin can accumulate in nectar and poses a risk to pollinators. Furthermore, hawthorn flowers are attractive to foraging honeybees in Colorado, which further puts these beneficial insects at risk. Given this, systemic insecticides should only be applied after bloom.<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.24.2″ _module_preset=”default” background_color=”#FFFFFF” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″][et_pb_row _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.24.2″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n\t\t CSU. (n.d.).<\/strong> Hawthorn Mealybug. Colorado State University \u2013 Colorado Insect of Interest. Available https:\/\/webdoc.agsci.colostate.edu\/bspm\/Hexapoda%20(Insects)\/Hawthorn%20Mealybug%20December%202014%20Revision.pdf<\/a><\/p>\n CSU. (n.d.).<\/strong> Hawthorn Mealybug. Colorado State University \u2013 Plant Talk Colorado. Available https:\/\/planttalk.colostate.edu\/topics\/insects-diseases\/1457-hawthorn-mealybug\/<\/a><\/p>\n UMN. (n.d.).<\/strong> Hawthorn mealybug. University of Minnesota \u2013 Extension. Available https:\/\/apps.extension.umn.edu\/garden\/diagnose\/insect\/trees-shrubs\/not-obvious\/hawthornmealybug.html<\/a><\/p>\n\n
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Life history and habits<\/h2>\n
\n[\/et_pb_text][et_pb_text _builder_version=”4.24.2″ _module_preset=”default” global_colors_info=”{}”]<\/p>\nInjury<\/h2>\n
\n[\/et_pb_text][et_pb_text _builder_version=”4.24.2″ _module_preset=”default” global_colors_info=”{}”]<\/p>\nBiological control<\/h2>\n
Chemical control<\/h2>\n
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References<\/h2>\n