How to recognize Boisduval scale

The shield of female Boisduval scalesare round to oval-shaped and aretranslucent white with a light brown center. Males have a smaller cover, which is more elongated and whiteof color with longitudinal ridges. White wooly threads are often present, which is the reason that this scale is sometimes identified as a mealybug. A big difference is that the Boisduval scale doesnot produce honeydew. Males and females of the Boisduval scale are usually found in separate groups on the crop. Femalesproduce 20 to 400 eggs continuously throughout the season until their death. Eggs are laid underneath the scaleand develop into crawlers, which emerge from underneath the mother’s cover and spread throughout the plant. During several hours to days, they will search for suitable settling locations. After the first moltthey lose their legs. After the second molt, theold females’skin sticks to the existing skin,forming the beginning of cover development.

Boisduval scale damage

DirectBoisduval scale damage is caused by sap-feeding. Upon withdrawal of large amounts of plant saps, plant growth and development are hampered. This can, in extreme situations, cause leaf-, flower-, or fruit fall, but also twig, branch or sometimes even total plant death. During feeding the scales inject saliva which contains toxic substances, causing yellow, red, or brown spots on leaves and fruits, which can also lead to leaf death. Scales donot produce honeydew. Crawlers can spread actively by walking to other parts of the plant or passively by wind.

  • Life cycle Boisduval scale

    200 eggs per female
    eggs hatch after 5-7 days at 25°C
    crawlers establish within 2 days
    egg to adult in 50 days (females)
    several generations per year in heated greenhouses

  • Host plants Boisduval scale

    pineapple, banana, coconut
    orchids e.g. Bulbophyllum, Cattleya, Cymbidium, Anguloa
    palms, Phoenix, Microcoelum, Livistona, Chamaerops
    Staelitzia, Vriesea

  • Boisduval scale male

  • Boisduval scale female