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Pseudaulacaspis pentagona

White peach scale. Photo: John A. Davidson, Univ. Md, College Pk, Bugwood.
Scientific Name: 
Pseudaulacaspis pentagona
Common Name: 
White Peach Scale
Growing Degree Days (GDD's): 
None available at this time.
Host Plant(s) Common Name (Scientific Name): 
Catalpa (Catalpa spp.)
Cherry (Prunus spp.) *Preferred host. (Johnson and Lyon, 1991)
Chinese elm (Ulmus parvifolia)
Dogwood (Cornus spp.)
Golden raintree (Koelreuteria paniculata)
Hibiscus (Hibiscus spp.)
Honeysuckle (Lonicera spp.)
Lilac (Syringa spp.)
Mulberry (Morus spp.) *Preferred host. (Johnson and Lyon, 1991)
Oleander (Nerium spp.)
Peach (Prunus spp.) *Preferred host. (Johnson and Lyon, 1991)
Persimmon (Diospyros spp.)
Plum (Prunus spp.)
Privet (Ligustrum spp.)
Redbud (Cercis spp.)
Spirea (Spiraea spp.)
Walnut (Juglans spp.)
Insect Description: 

The white peach scale was first identified by science in 1886 in Italy. However, it is thought to have originated from either Japan or China. It is an armored scale. Since approximately the early 1900's, it has been a serious pest of fruits, especially peach and cherry, in the United States. It is now considered a common pest found in the eastern coastal states of the US, particularly from Maryland southward but it has been previously detected in Massachusetts (Cooley, 1898a). It is also considered a worldwide pest, mainly in tropical and subtropical locations. ScaleNet lists host plants in 90 plant Families, from 253 plant genera. Adult female white peach scales overwinter. In North Carolina, the female will begin egg laying by early April with each female producing over 100 eggs. The number of eggs laid is influenced by the host plant on which the scales are feeding. Egg laying may not begin until late April or May in Massachusetts, depending upon temperature. In points south of Massachusetts, peak egg laying and hatch occurs by the first week in May. This is for the first generation eggs in these locations. Second generation egg laying and hatch can occur in August. If there is a third generation, egg laying and peak hatch occurs in September. Eggs may be laid over a period of approximately 30 days, and subsequently crawler emergence can occur over a similar length of time. Eggs that develop into females are coral colored; those that develop into males are whitish pink. Crawlers, through the end of the first instar, maintain this color difference in males and females. Depending upon their sex, the crawlers undergo 2 (female) to 5 (male) molts or instars. Adult male covers are bright white in color and approximately 2.0-2.5 mm long and elongated. Female adult scale covers are gray, circular, and slightly larger than the males, but often blend in better on the bark of their host plants. When males mature, the bright white coloration may make the infestation appear larger as the scales become easier to see. Males also secrete masses of a cottony substance, which may apear to blanket the host plant bark in snow (Johnson and Lyon, 1991). Females secrete a sex pheromone in order to attract the males to mate. In northern states, there may only be two generations per year. In southern states, there may be up to four generations per year. The white peach scale may be confused with the white prunicola scale (Pseudaulacaspis prunicola), discussed elsewhere in this Guide. In fact, in Massachusetts and other states north of Maryland, it may be more likely that P. prunicola or the white prunicola scale is what is being detected (Miller and Davidson, 2005). The white prunicola scale is a temperate species.

Damage to Host: 

The white peach scale can be a particularly damaging stone fruit pest. Severe damage in agricultural fruit production has been reported in the past in Florida, Virginia, and the Carolinas (Johnson and Lyon, 1991). Scales feed primarily on the bark of the host plant trunk and that of the larger limbs or branches. The bark of an entire tree may become covered in these scales. Populations of this scale can rapidly increase, which historically has led to the death of large branches and sometimes entire trees. Mulberry is a commonly reported host plant.


Search the trunk and larger branches of susceptible host plants for layers of white peach scales. It may be easiest to spot this scale when the adult males are present. The timing of this for Massachusetts is not fully understood, as areas north of Maryland are assumed to more likely have P. prunicola or the white prunicola scale. 

Cultural Management: 

These armored scales are difficult to manage, especially since they tend to colonize the trunk and larger branches of their host plants. This makes pruning out infested branches very difficult if not impossible. If practical, an attempt can be made to wipe off these scales (using a soft brush) on smaller host plant trunks. This may help with a population of these scales on an individual ornamental planting. 

Natural Enemies & Biological Control: 

In North Carolina, research has shown significant mortality of the first and second generations of the white peach scale. This may be due to the influence of natural enemies or other natural factors that regulate their populations. In North Carolina, it is the third generation (in the fall) that allows the scale to spread the most rapidly. ScaleNet reports natural enemies from 18 insect Families and 60 different genera. Some (but not all) of these include: parasitoid wasps, parasitic midges, green lacewings, lady beetles, and insect-killing fungi. In particular, parasitoid wasps in the genus Encarsia have been effective at reducing white peach scale populations (ScaleNet).

Chemical Management: 

Abamectin (NL)

Acephate (NL)

Acetamprid (L)

Azadirachtin (NL)

Buprofezin (NL)

Carbaryl (L)

Chlorpyrifos (N)

Chromobacterium subtsugae (NL)

Clothianidin (NL)

Cyantraniliprole (NL)

Cyfluthrin (NL)

Dinotefuran (NL)

Gamma-cyhalothrin (L)

Horticultural oil (L)

Imidacloprid (L)

Insecticidal soap (NL)

Lambda-cyhalothrin (L)

Neem oil (NL)

Pyrethrin + sulfur (NL)

Pyriproxyfen (L)

Spinetoram + sulfoxaflor (N)


Dormant oil applications have been reported to be successful at managing this insect (Robert Childs, UMass Extension, Personal Communication).

Active ingredients that may be applied systemically include: abamectin (injection), acephate (injection), acetamprid (injection), azadirachtin (injection, soil drench), clothianidin (soil drench), cyantraniliprole (soil drench, soil injection), dinotefuran (soil drench), imidacloprid (soil drench), and neem oil (soil drench).

Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.

Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.

Read and follow all label instructions for safety and proper use. If this guide contradicts language on the label, follow the most up-to-date instructions on the product label. Always confirm that the site you wish to treat and the pest you wish to manage are on the label before using any pesticide. Read the full disclaimer. Active ingredients labeled "L" indicate some products containing the active ingredient are labeled for landscape uses on trees or shrubs. Active ingredients labeled "N" indicate some products containing the active ingredient are labeled for use in nurseries. Always confirm allowable uses on product labels. This active ingredient list is based on what was registered for use in Massachusetts at the time of publication. This information changes rapidly and may not be up to date. If you are viewing this information from another state, check with your local Extension Service and State Pesticide Program for local uses and regulations. Active ingredient lists were last updated: January 2024. To check current product registrations in Massachusetts, please visit: .