''Coccus viridis'' is a soft

scale insect Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than the ...

in the family

Coccidae The Coccidae are a family of scale insects belonging to the superfamily Coccoidea. They are commonly known as soft scales, wax scales or tortoise scales. The females are flat with elongated oval bodies and a smooth integument which may be cover ...

with a wide host range. It is commonly known as green scale or sometimes coffee green scale because it is a major

pest Pest or The Pest may refer to: Science and medicine * Pest (organism), an animal or plant deemed to be detrimental to humans or human concerns ** Weed, a plant considered undesirable * Infectious disease, an illness resulting from an infection ** ...

coffee Coffee is a drink prepared from roasted coffee beans. Darkly colored, bitter, and slightly acidic, coffee has a stimulant, stimulating effect on humans, primarily due to its caffeine content. It is the most popular hot drink in the world. S ...

crops throughout the world.

Description

The adult scale insect is a glossy pale green colour with black internal markings that are visible through the

chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

ous body wall. It has a flattish elongated oval dome shape and is about three millimetres in width. The front end is rounded while the rear end has a distinctive groove. Adults retain their legs and antennae but mostly remain sedentary. The

nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are typ ...

are a flattish oval shape, yellowish green, with six short legs. The nymphs shed their skin three times and each

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...

is larger and more convex than the previous one.Fredrick, J. M. 1943. Some Preliminary Investigations of the Green Scale, ''Coccus viridis'' (Green), in South Florida. Florida Ent. 26(1): 12-15; 26(2): 25-29.

Biology

Males have not been recorded for this species so the populations are composed entirely of females. A mature female lays whitish oval

eggs Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...

and keeps them underneath her body to protect them. She usually chooses the underside of a leaf and adult scales may often be seen in a line on both sides of the midrib and beside the lateral

veins Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...

. Eggs hatch in anything between a few minutes and a few hours. The newly hatched crawlers wander off to find somewhere suitable to settle on a leaf or near the tip of a green shoot. Both nymphs and adults suck sap from the

phloem Phloem (, ) is the living biological tissue, tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This tran ...

of the host plant. When a large number of scale insects are present, their collective feeding causes a yellowing of the leaves which may later fall, a loss of plant vigour and a reduction in crop yield. The scale insects excrete honeydew on which bees, wasps, ants and other insects feed.

Sooty mould Sooty mold (also spelled sooty mould) is a collective term for different Ascomycete fungi, which includes many genera, commonly ''Cladosporium'' and ''Alternaria''. It grows on plants and their fruit, but also environmental objects, like fences, ...

fungus often grows on the honeydew and this decreases the area of leaf available for

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

, spoils the appearance of the plant and reduces the marketability of fruit. It is especially damaging to young trees after transplanting.LePelley, R. H. 1968. ''Coccus viridis'' (Green) - The Green Scale. pp. 353-355. In Pests of Coffee. Longmans, Green & Co., Ltd., London and Harlow. 590 pages.

Hosts

This scale is believed to be of Brazilian or African origin but is now widely distributed throughout the

tropics The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

.http://scalenet.info The host range includes vegetable, fruit and ornamental crops as well as many native plants. Economically important crops include ''

Anthurium ''Anthurium'' (; Schott, 1829) is a genus of about 1,000Mantovani, A. and T. E. Pereira. (2005)''Anthurium'' (section ''Urospadix''; subsection ''Flavescentiviridia'').''Rodriguesia'' 56(88), 145–60. species of flowering plants, the largest g ...

'',

atemoya The atemoya, ''Annona × atemoya'', or ''Annona squamosa × Annona cherimola'' is a hybrid of two fruits – the sugar-apple (''Annona squamosa'') and the cherimoya (''Annona cherimola'') – which are both native to the American tropics. This ...

avocado The avocado (''Persea americana'') is a medium-sized, evergreen tree in the laurel family (Lauraceae). It is native to the Americas and was first domesticated by Mesoamerican tribes more than 5,000 years ago. Then as now it was prized for i ...

cacao Cacao is the seed from which cocoa and chocolate are made, from Spanish cacao, an adaptation of Nahuatl cacaua, the root form of cacahuatl ("bean of the cocoa-tree"). It may also refer to: Plants *''Theobroma cacao'', a tropical evergreen tree ** ...

celery Celery (''Apium graveolens'') is a marshland plant in the family Apiaceae that has been cultivated as a vegetable since antiquity. Celery has a long fibrous stalk tapering into leaves. Depending on location and cultivar, either its stalks, lea ...

cherimoya The cherimoya (''Annona cherimola''), also spelled chirimoya and called chirimuya by the Inca people, is a species of edible fruit-bearing plant in the genus '' Annona'', from the family Annonaceae, which includes the closely related sweetsop a ...

custard apple Custard apple is a common name for a fruit and for the tree that bears it, ''Annona reticulata.'' The tree’s fruits vary in shape; they may be heart-shaped, spherical, oblong or irregular. Their size ranges from 7 to 12 cm (2.8 to 4.7 i ...

, flowering

ginger Ginger (''Zingiber officinale'') is a flowering plant whose rhizome, ginger root or ginger, is widely used as a spice A spice is a seed, fruit, root, bark, or other plant substance primarily used for flavoring or coloring food. Spices ...

guava Guava () is a common tropical fruit cultivated in many tropical and subtropical regions. The common guava ''Psidium guajava'' (lemon guava, apple guava) is a small tree in the myrtle family ( Myrtaceae), native to Mexico, Central America, the ...

lime Lime commonly refers to: * Lime (fruit), a green citrus fruit * Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide * Lime (color), a color between yellow and green Lime may also refer to: Botany ...

, ''

Macadamia ''Macadamia'' is a genus of four species of trees in the flowering plant family Proteaceae. They are indigenous to Australia, native to northeastern New South Wales and central and southeastern Queensland specifically. Two species of the genus ...

'',

orange Orange most often refers to: *Orange (fruit), the fruit of the tree species '' Citrus'' × ''sinensis'' ** Orange blossom, its fragrant flower *Orange (colour), from the color of an orange, occurs between red and yellow in the visible spectrum * ...

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

, ''

Plumeria ''Plumeria'' (), known as frangipani, is a genus of flowering plants in the subfamily Rauvolfioideae, of the family Apocynaceae. Most species are deciduous shrubs or small trees. The species variously are endemic to Mexico, Central America, and ...

'' and

sugar apple The sugar-apple or sweet-sop is the edible fruit of ''Annona squamosa'', the most widely grown species of '' Annona'' and a native of tropical climate in the Americas and West Indies. Spanish traders aboard the Manila galleons docking in the ...

. It is a serious pest of coffee in many countries causing so much damage that in some areas, coffee production ceased.

Management

Green scale is transported to new areas on infected plants. There should be a thorough inspection of planting material for scale and other insects before it is introduced into a greenhouse. Certain

entomopathogenic fungi An entomopathogenic fungus is a fungus that can kill or seriously disable insects. Typical life cycle These fungi usually attach to the external body surface of insects in the form of microscopic spores (usually asexual, mitosporic spores als ...

have been shown to affect green scale but attempts to infect healthy insects with these fungi have been unsuccessful. Controlling ant colonies will assist in reducing levels of attack by green scale (see below). This scale is susceptible to a number of pesticides including

carbaryl Carbaryl (1-naphthyl methylcarbamate) is a chemical in the carbamate family used chiefly as an insecticide. It is a white crystalline solid previously sold under the brand name Sevin, which was a trademark of the Bayer Company. The Sevin tradem ...

malathion Malathion is an organophosphate insecticide which acts as an acetylcholinesterase inhibitor. In the USSR, it was known as carbophos, in New Zealand and Australia as maldison and in South Africa as mercaptothion. Pesticide use Malathion is a pesti ...

methomyl Methomyl is a carbamate insecticide introduced in 1966. It is highly toxic to humans, livestock, pets, and wildlife. The EU and UK imposed a pesticide residue limit of 20 µg/kg for apples and oranges. Methomyl is a common active ingredient in c ...

and volck oil. Consideration should be given to the harmful effects of these chemicals on beneficial insects.

Research

This scale is often associated with ants which feed on the honeydew excreted and defend the insects from attack by

predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

such as

lady beetles Coccinellidae () is a widespread family (biology), family of small beetles ranging in size from . They are commonly known as ladybugs in North America and ladybirds in Great Britain. Some Entomology, entomologists prefer the names ladybird be ...

. The relationship between ''

Pheidole ''Pheidole'' is a genus of ants that belongs to the ant subfamily Myrmicinae. The genus is widespread and ecologically dominant. It probably includes more than 1000 species. The genus first evolved in the Americas, eventually spreading across th ...

'' ants and ''Coccus viridis'' in Hawaii is mutualistic. In trials involving adding lady beetle larvae and carnivorous

lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...

n larvae to plants infested with green scale with or without ants being present, it was found that the ants actively removed both kinds of larvae, usually within an hour of introduction. The direct effect of this was an increase in scale reproductive success and the indirect effect was a decrease in scale mortality resulting from the removal of predators and a decrease in parasitism rates. Another research study conducted in the field found a positive correlation between the presence of ants on host plants and the success of green scale insects. On coffee trees from which ants had been excluded the number of scale insects had declined after fifty days and after seventy days, none remained, whereas scales had thrived on ant-infested trees. A study found that the entomopathogenic fungus, '' Cephalosporium lecanii'', was highly effective in controlling coffee green scale. A study examined the effect of the fungus on coffee green scale in combination with lower than normal applications of either of two insecticides,

fenthion Fenthion is an organothiophosphate insecticide, avicide, and acaricide. Like most other organophosphates, its mode of action is via cholinesterase inhibition. Due to its relatively low toxicity towards humans and mammals, fenthion is listed as ...

and

phosphamidon Phosphamidon is an organophosphate insecticide first reported in 1960. It acts as a cholinesterase inhibitor. The commercial product typically exists as a mixture of 70% (''Z'')-isomer and 30% (''E'')-isomer. Toxicity and regulation Phosphami ...

. The use of fenthion resulted in the highest percentage mortality of the scales at the lowest dosages of insecticide. The results from the use of phosamidon were inconclusive, with the results differing in the laboratory and the field.

References

{{Taxonbar, from=Q10456205 Coccidae Agricultural pest insects Insects described in 1889 Hemiptera of Central America