Brevicoryne brassicae
Encyclopedia
Brevicoryne brassicae, commonly known as the cabbage aphid, cabbage aphis or turnip aphid, is a destructive aphid
(plant louse) native to Europe
that is now found in many other areas of the world. The aphids feed on many varieties of produce, including cabbage
, broccoli
, Brussels sprouts, cauliflower
and many other members of the genus Brassica
, but do not feed on plants outside of the Cruciferae family.
Cabbage aphids, from the genus
Brevicoryne
of the family
Aphididae
, are grayish-green, but a waxy covering gives them a grayish-white to powdery blue appearance.
(beta-thioglucoside glucohydrolase) enzyme
in head and thoracic muscle
s; the aphids also uptake glucosinolate
s, particularly sinigrin
, from the plants on which they feed, storing the glucosinolates in their haemolymph. (Glucosinolates are natural defenses for plants in the order
Brassicales
against pests and herbivore
s.) The combination of the glucosinolates and the myrosinase enzyme produces a violent chemical reaction that releases the mustard oil
chemical allyl isothiocyanate
. The defense mechanism has a dramatic negative effect on the survival of the larva
l ladybird predator Adalia bipunctata. The chemical defence of the aphids has been likened to a "walking mustard oil bomb".
The myrosinase from Brevicoryne brassicae appears to have evolved
separately from myrosinases found in plants, possibly a case of convergent evolution
. Aphid myrosinase appears to have greater similarity to animal beta-O-glucosidases than to plant myrosinases.
s have varying resistance to Brevicoryne brassicae.
Diaeretiella rapae
is a common wasp
parasite
of cabbage aphids. Other controlling insects include ladybird beetles, syrphid fly larvae, and lacewing larvae. Some insecticidal soap
s may be effective in treating aphid infestations.
Aphid
Aphids, also known as plant lice and in Britain and the Commonwealth as greenflies, blackflies or whiteflies, are small sap sucking insects, and members of the superfamily Aphidoidea. Aphids are among the most destructive insect pests on cultivated plants in temperate regions...
(plant louse) native to Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
that is now found in many other areas of the world. The aphids feed on many varieties of produce, including cabbage
Cabbage
Cabbage is a popular cultivar of the species Brassica oleracea Linne of the Family Brassicaceae and is a leafy green vegetable...
, broccoli
Broccoli
Broccoli is a plant in the cabbage family, whose large flower head is used as a vegetable.-General:The word broccoli, from the Italian plural of , refers to "the flowering top of a cabbage"....
, Brussels sprouts, cauliflower
Cauliflower
Cauliflower is one of several vegetables in the species Brassica oleracea, in the family Brassicaceae. It is an annual plant that reproduces by seed...
and many other members of the genus Brassica
Brassica
Brassica is a genus of plants in the mustard family . The members of the genus may be collectively known either as cabbages, or as mustards...
, but do not feed on plants outside of the Cruciferae family.
Cabbage aphids, from the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Brevicoryne
Brevicoryne
Brevicoryne is a genus of aphid insect that contains many insects which are agricultural pests.-Hosts:This genus parasitizes a wide range of hosts, with many members of the Brassicaceae included.-Adults:...
of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Aphididae
Aphididae
Aphididae is a very large insect family in the aphid superfamily , of the order Hemiptera. There are several thousand species in this family, many of which are well known for being serious plant pests...
, are grayish-green, but a waxy covering gives them a grayish-white to powdery blue appearance.
Predator defense mechanism
Cabbage aphids have a unique defense mechanism against predators. The aphids produce a myrosinaseMyrosinase
Myrosinase is a family of enzymes involved in plant defense against herbivores. Their structure has been elucidated and is available.-Myrosinase activity:...
(beta-thioglucoside glucohydrolase) enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
in head and thoracic muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
s; the aphids also uptake glucosinolate
Glucosinolate
The glucosinolates are a class of organic compounds that contain sulfur and nitrogen and are derived from glucose and an amino acid. They occur as secondary metabolites of almost all plants of the order Brassicales , but also in the genus Drypetes .-Chemistry:Glucosinolates are water-soluble...
s, particularly sinigrin
Sinigrin
Sinigrin is a glucosinolate that belongs to the family of glucosides found in some plants of the Brassicaceae family such as Brussels sprouts, broccoli, and the seeds of black mustard to name but a few...
, from the plants on which they feed, storing the glucosinolates in their haemolymph. (Glucosinolates are natural defenses for plants in the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Brassicales
Brassicales
The Brassicales are an order of flowering plants, belonging to the eurosids II group of dicotyledons under the APG II system. One character common to many members of the order is the production of glucosinolate compounds...
against pests and herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
s.) The combination of the glucosinolates and the myrosinase enzyme produces a violent chemical reaction that releases the mustard oil
Mustard oil
The term mustard oil is used for three different oils that are made from mustard seeds:*A fatty vegetable oil resulting from pressing the seeds,...
chemical allyl isothiocyanate
Allyl isothiocyanate
Allyl isothiocyanate is the organosulfur compound with the formula CH2CHCH2NCS. This colorless oil is responsible for the pungent taste of mustard, horseradish, and wasabi. This pungency and the lachrymatory effect of AITC is mediated through the TRPA1 and TRPV1 ion channels...
. The defense mechanism has a dramatic negative effect on the survival of the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
l ladybird predator Adalia bipunctata. The chemical defence of the aphids has been likened to a "walking mustard oil bomb".
The myrosinase from Brevicoryne brassicae appears to have evolved
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
separately from myrosinases found in plants, possibly a case of convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
. Aphid myrosinase appears to have greater similarity to animal beta-O-glucosidases than to plant myrosinases.
Pest control
Different varieties of cultivarCultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s have varying resistance to Brevicoryne brassicae.
Diaeretiella rapae
Diaeretiella rapae
Diaeretiella rapae is a cosmopolitan parasitoid of many species of aphids, but especially the cabbage aphid, Brevicoryne brassicae. It is the only species in the genus Diaeretiella...
is a common wasp
Wasp
The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...
parasite
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
of cabbage aphids. Other controlling insects include ladybird beetles, syrphid fly larvae, and lacewing larvae. Some insecticidal soap
Insecticidal soap
Insecticidal soap is defined as any of the potassium fatty acid soaps used to control many plant pests. Insecticidal soap is typically sprayed on plants in the same manner as other insecticides. Insecticidal soap works only on direct contact with the pests. The fatty acids disrupt the structure and...
s may be effective in treating aphid infestations.