San Jose scale
Encyclopedia
San Jose scale is a hemipterous
insect (Quadraspidiotus perniciosus) in the family Diaspididae
. It is an agricultural pest as it causes damage and crop losses to many fruit crops.
where Comstock
discovered and named it in 1881. It has been considered the most pernicious scale insect in the United States
. It was probably introduced at San Jose about 1870 on trees imported from China
by James Lick
. By 1890 it had spread over the greater part of California, but was not recognized east of the Rocky Mountains
until August, 1893, when it was found by Howard
on a pear received from Charlottesville, Virginia
. Soon afterward it was discovered that infested stock had been brought from California in 1887 or 1888 by two New Jersey
nurseries
and distributed widely. By 1895 the pest had become established in many nurseries and orchard
s in the majority of the Eastern States. Marlatt
made entomological investigations in China, Japan
, and Java in 1901-02. He introduced the ladybird
to the United States
in order to control the San Jose scale.
e. The development of the male involves three moults. The male nymph is more elongate than the female and the adult male is orange coloured and has wings. It lives only for a few hours.
trees and bushes. It is found on the trunks, branches, twigs, leaves and fruits of the plant. Females predominate on the leaf stalks and fruit while males predominate on the leaves. There may be several generations each year in warm climates but in cooler regions there is a single generation. The first and second instar
s may overwinter in cracks in the bark and the hibernating nymphs
can survive temperatures as low as -42°C. The emergence of the nymphs in the spring coincides with bud burst.
, C. L. Marlatt
, A. L. Quaintance, and others, published by the United States Bureau of Entomology
(Washington, 1896 et seq.); W. G. Johnson, Fumigation
Methods (New York, 1902); United States Department of Agriculture
, The Farmer's Bulletin, No. 650 (Washington, 1915), and the publications of the State agricultural experiment station
s.
Hemiptera
Hemiptera is an order of insects most often known as the true bugs , comprising around 50,000–80,000 species of cicadas, aphids, planthoppers, leafhoppers, shield bugs, and others...
insect (Quadraspidiotus perniciosus) in the family Diaspididae
Diaspididae
Diaspididae is the largest family of scale insects with over 2650 described species in around 400 genera. As with all scale insects, the female produces a waxy protective scale beneath which it feeds on its host plant...
. It is an agricultural pest as it causes damage and crop losses to many fruit crops.
Distribution
This species originated in Siberia, north east China and the northern part of the Korean peninsula. It has spread to every continent except Antarctica and is a major pest of fruit trees.Arrival in the United States
The San Jose Scale derives its popular name from San Jose, CaliforniaSan Jose, California
San Jose is the third-largest city in California, the tenth-largest in the U.S., and the county seat of Santa Clara County which is located at the southern end of San Francisco Bay...
where Comstock
John Henry Comstock
John Henry Comstock was an eminent researcher in entomology and arachnology and a leading educator. His work provided the basis for classification of butterflies, moths, and scale insects.-Early life and education:...
discovered and named it in 1881. It has been considered the most pernicious scale insect in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It was probably introduced at San Jose about 1870 on trees imported from China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
by James Lick
James Lick
James Lick was an American carpenter, piano builder, land baron, and patron of the sciences. At the time of his death, he was the wealthiest man in California, and left the majority of his estate to social and scientific causes.-Early years:James Lick was born in Stumpstown Pennsylvania on August...
. By 1890 it had spread over the greater part of California, but was not recognized east of the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
until August, 1893, when it was found by Howard
Leland Ossian Howard
Leland Ossian Howard, Ph.D., M.D. , was an American entomologist.-Biography:He graduated from Cornell University in 1877. He was later employed by the Department of Agriculture, and became chief of the Bureau of Entomology in 1894...
on a pear received from Charlottesville, Virginia
Charlottesville, Virginia
Charlottesville is an independent city geographically surrounded by but separate from Albemarle County in the Commonwealth of Virginia, United States, and named after Charlotte of Mecklenburg-Strelitz, the queen consort of King George III of the United Kingdom.The official population estimate for...
. Soon afterward it was discovered that infested stock had been brought from California in 1887 or 1888 by two New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
nurseries
Nursery (horticulture)
A nursery is a place where plants are propagated and grown to usable size. They include retail nurseries which sell to the general public, wholesale nurseries which sell only to businesses such as other nurseries and to commercial gardeners, and private nurseries which supply the needs of...
and distributed widely. By 1895 the pest had become established in many nurseries and orchard
Orchard
An orchard is an intentional planting of trees or shrubs that is maintained for food production. Orchards comprise fruit or nut-producing trees which are grown for commercial production. Orchards are also sometimes a feature of large gardens, where they serve an aesthetic as well as a productive...
s in the majority of the Eastern States. Marlatt
Charles Lester Marlatt
Charles Lester Marlatt was an American entomologist. Born in 1863 at Atchison, Kansas, he was educated at Kansas State Agricultural College , where he was assistant professor for two years...
made entomological investigations in China, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, and Java in 1901-02. He introduced the ladybird
Coccinellidae
Coccinellidae is a family of beetles, known variously as ladybirds , or ladybugs . Scientists increasingly prefer the names ladybird beetles or lady beetles as these insects are not true bugs...
to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in order to control the San Jose scale.
Description
The body of adult female is yellow and is covered with a rounded dark gray scale up to two millimetres in diameter. Over the course of two months, yellow crawlers are born viviparously and emerge from the back of the test at the rate of two or three a day. In bad weather they gather under their mother's scale. The crawlers disperse to other parts of the plant and start feeding. They moult after about ten days and begin to lose their eyes, legs and antennae. The adult female appears after the next moult and the scale develops, incorporating the larval exuviaExuvia
Exuviae is a term used in biology to describe the remains of an exoskeleton and related structures that are left after ecdysozoans have moulted...
e. The development of the male involves three moults. The male nymph is more elongate than the female and the adult male is orange coloured and has wings. It lives only for a few hours.
Ecology
This species is found in both temperate and subtropical climates. It infests about two hundred different species of host plant, mostly deciduousDeciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
trees and bushes. It is found on the trunks, branches, twigs, leaves and fruits of the plant. Females predominate on the leaf stalks and fruit while males predominate on the leaves. There may be several generations each year in warm climates but in cooler regions there is a single generation. The first and second instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...
s may overwinter in cracks in the bark and the hibernating nymphs
Nymph (biology)
In biology, a nymph is the immature form of some invertebrates, particularly insects, which undergoes gradual metamorphosis before reaching its adult stage. Unlike a typical larva, a nymph's overall form already resembles that of the adult. In addition, while a nymph moults it never enters a...
can survive temperatures as low as -42°C. The emergence of the nymphs in the spring coincides with bud burst.
Literature
Numerous articles by L. O. HowardLeland Ossian Howard
Leland Ossian Howard, Ph.D., M.D. , was an American entomologist.-Biography:He graduated from Cornell University in 1877. He was later employed by the Department of Agriculture, and became chief of the Bureau of Entomology in 1894...
, C. L. Marlatt
Charles Lester Marlatt
Charles Lester Marlatt was an American entomologist. Born in 1863 at Atchison, Kansas, he was educated at Kansas State Agricultural College , where he was assistant professor for two years...
, A. L. Quaintance, and others, published by the United States Bureau of Entomology
Bureau of Entomology
The Bureau of Entomology was a unit within the Federal government of the United States from 1894 to 1934. It developed from a section of the Department of Agriculture which had been working on entomological researches and allied issues relating to insects....
(Washington, 1896 et seq.); W. G. Johnson, Fumigation
Fumigation
Fumigation is a method of pest control that completely fills an area with gaseous pesticides—or fumigants—to suffocate or poison the pests within. It is utilized for control of pests in buildings , soil, grain, and produce, and is also used during processing of goods to be imported or...
Methods (New York, 1902); United States Department of Agriculture
United States Department of Agriculture
The United States Department of Agriculture is the United States federal executive department responsible for developing and executing U.S. federal government policy on farming, agriculture, and food...
, The Farmer's Bulletin, No. 650 (Washington, 1915), and the publications of the State agricultural experiment station
Agricultural experiment station
An agricultural experiment station is a research center that conducts scientific investigations to solve problems and suggest improvements in the food and agriculture industry...
s.