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Publication #ENY-2039

Citrus Pest Quick Guide: Brown Soft Scale (Coccus hesperidum Linnaeus)1

Lauren M. Diepenbrock and Jamie D. Burrow2

Life Cycle

Immature brown soft scale hatch as crawlers, then settle to feed. Young soft scales can relocate when disturbed.

Brown soft scale is flat and oval during larval and adult stages with color ranging from yellowish to light brown. Color becomes darker as the scale ages, and its outer covering becomes tougher.

Populations of brown soft scale are generally found on leaves and twigs with occasional infestation on fruit. Brown soft scale populations tend to be clumped together due to their high reproductive capacity. Three to five overlapping generations have been recorded in citrus.

Figure 1. 

Brown soft scale.


Credit:

L. Buss, UF/IFAS


[Click thumbnail to enlarge.]

Figure 2. 

Brown soft scale on citrus.


Credit:

L. M. Diepenbrock, UF/IFAS


[Click thumbnail to enlarge.]

Figure 3. 

Darker scales are parasitized.


Credit:

L. Buss, UF/IFAS


[Click thumbnail to enlarge.]

Figure 4. 

Parasitized brown soft scale. Holes indicate where a parasitoid has emerged.


Credit:

L. Buss, UF/ IFAS


[Click thumbnail to enlarge.]

Damage

Brown soft scale excretes large quantities of honeydew (sugary solution) while feeding, which provides a substrate for sooty mold to develop. Sooty mold can cover leaves and fruit, reducing photosynthetic capabilities of trees. In older plantings, this feeding can result in reduced tree vigor, twig dieback, and reduced fruit quality and/or yield. In younger plantings and nursery stock, these scales and the resulting honeydew accumulation can sometimes cause tree death.

Figure 5. 

Colony of brown soft scale with crawlers, adults, and parasitized adults present.


Credit:

L. Buss, UF/IFAS


[Click thumbnail to enlarge.]

Figure 6. 

Sooty mold growing on honeydew excreted by scales.


Credit:

M. E. Rogers, UF/IFAS


[Click thumbnail to enlarge.]

Footnotes

1.

This document is ENY-2039, one of a series of the Entomology and Nematology Department, UF/IFAS Extension. Original publication date February 2020. Visit the EDIS website at https://edis.ifas.ufl.edu for the currently supported version of this publication.

2.

Lauren M. Diepenbrock, assistant professor, Entomology and Nematology Department; and Jamie D. Burrow, Extension program manager; UF/IFAS Citrus Research and Education Center, Lake Alfred, FL 33850.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.