''Amrasca biguttula'', commonly known as the cotton jassid,
[ is a subspecies of ]leafhopper
Leafhopper is the common name for any species from the family (biology), family Cicadellidae: based on the type genus ''Cicadella''. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or ...
belonging to the subfamily Typhlocybinae
Typhlocybinae is a subfamily of insects in the leafhopper, leafhopper family, Cicadellidae. This is currently the second largest leafhopper subfamily based on the number of described species, but researchers believe there are so many taxa yet und ...
of family Cicadellidae. It is a pest of cotton
Cotton (), first recorded in ancient India, is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure ...
, okra
Okra (, ), ''Abelmoschus esculentus'', known in some English-speaking countries as lady's fingers, is a flowering plant in the Malvaceae, mallow family native to East Africa. Cultivated in tropical, subtropical, and warm temperate regions aro ...
, and other crops in southern Asia and West Africa.
Description
The adult cotton jassid is a long and slender insect about in length. It is yellowish-green, with a conspicuous black spot on either side of the head and another near the tip of the fore wing. The head is pale green and the membranous wings transparent and iridescent. On leaf surfaces, the insect tends to move about diagonally,[ and when disturbed it immediately jumps and flies away.]
Life cycle
Leafhoppers undergo direct development from nymph
A nymph (; ; sometimes spelled nymphe) is a minor female nature deity in ancient Greek folklore. Distinct from other Greek goddesses, nymphs are generally regarded as personifications of nature; they are typically tied to a specific place, land ...
to adult without undergoing metamorphosis
Metamorphosis is a biological process by which an animal physically develops including birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and different ...
. On okra, eggs are mainly oviposited inside the tissue of leaf blades, but may also be laid in leaf stalks or in soft twigs. The eggs hatch in six or seven days. There are five nymphal instar
An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...
s, developing over a period of about seven days. Nymphs are wingless. Total lifespan is about one month, with females living a little longer than males. The fecundity
Fecundity is defined in two ways; in human demography, it is the potential for reproduction of a recorded population as opposed to a sole organism, while in population biology, it is considered similar to fertility, the capability to produc ...
of females is about fifteen eggs. Adults are attracted to light, females more than males.
Ecology
Leafhoppers have mouthparts designed for piercing and sucking, enabling them to feed on plant sap
Sap is a fluid transported in the xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant.
Sap is distinct from latex, resin, or cell sap; it is a s ...
. In India, this jassid feeds on sap from a wide range of plants including cotton
Cotton (), first recorded in ancient India, is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure ...
, okra
Okra (, ), ''Abelmoschus esculentus'', known in some English-speaking countries as lady's fingers, is a flowering plant in the Malvaceae, mallow family native to East Africa. Cultivated in tropical, subtropical, and warm temperate regions aro ...
, eggplant
Eggplant (American English, US, Canadian English, CA, Australian English, AU, Philippine English, PH), aubergine (British English, UK, Hiberno English, IE, New Zealand English, NZ), brinjal (Indian English, IN, Singapore English, SG, Malays ...
, ''Hibiscus rosa-sinensis
''Hibiscus'' is a genus of flowering plants in the Malva, mallow family, Malvaceae. The genus is quite large, comprising List of Hibiscus species, several hundred species that are Native plant, native to warm temperate, Subtropics, subtropical ...
'', and sunflower
The common sunflower (''Helianthus annuus'') is a species of large annual forb of the daisy family Asteraceae. The common sunflower is harvested for its edible oily seeds, which are often eaten as a snack food. They are also used in the pr ...
throughout the year, and on pigeon pea
The pigeon pea (''Cajanus cajan'') or toor dal is a perennial legume from the family (biology), family Fabaceae native to the Eastern Hemisphere. The pigeon pea is widely cultivated in tropical and semitropical regions around the world, being com ...
and cowpea
The cowpea (''Vigna unguiculata'') is an annual herbaceous legume from the genus '' Vigna''. Its tolerance for sandy soil and low rainfall have made it an important crop in the semiarid regions across Africa and Asia. It requires very few inpu ...
during the monsoon
A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in Atmosphere of Earth, atmospheric circulation and precipitation associated with annu ...
season. In Burkina Faso, this jassid attacks cotton, okra, eggplant and hibiscus during the rainy season. It also occurs on various grass
Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and spe ...
es, including lawns of Bermuda grass
''Cynodon dactylon'', commonly known as Bermuda grass, also known as couch grass in Australia and New Zealand, is a grass found worldwide. It is native to Europe, Africa, Australia and much of Asia. It has been introduced to the Americas. Contra ...
.
Damage
Heavy infestations on cotton, okra, and sunflower make the leaves turn yellow, curl up and fall off. The insects also secrete honeydew, and 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, ...
often grows on this, restricting the amount of light reaching the plant's photosynthetic
Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...
surfaces and reducing the yield.[ In many areas, this pest regularly occurs on cotton in epidemic numbers. A number of natural enemies help to control populations including ]ladybirds
Coccinellidae () is a widespread family of small beetles. They are commonly known as ladybugs in North America and ladybirds in the United Kingdom; "lady" refers to mother Mary. Entomologists use the names ladybird beetles or lady beetles t ...
, predatory lygaeid bugs, and several species of mantis
Mantises are an order (Mantodea) of insects that contains over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids"). Mantises are distributed worldwide in temperate a ...
. Neem oil
Neem oil, also known as margosa oil, is a vegetable oil pressed from the fruits and seeds of the neem (''Azadirachta indica''), a tree which is indigenous to the Indian subcontinent and has been introduced to many other areas in the tropics. It ...
can be used as a biopesticide
A biopesticide is a biological substance or organism that damages, kills, or repels organisms seens as pests. Biological pest management intervention involves predatory, parasitic, or chemical relationships.
They are obtained from organisms incl ...
.
Control
On cotton, it has been found that growing a cultivar with hairs on the undersides of the leaves reduces infestation, and that long hairs are better at deterring the insect from laying than are short hairs; this seems to be due to the hairs preventing the insect from getting close enough to the leaf surface to deposit its eggs.
The Entomophthoraceae fungus '' Batkoa amrascae'' is known to infect (and also kill) the cotton leafhopper, ''Amrasca biguttula'' in the Philippines.[Philippine Association of Entomologists ]
References
{{Taxonbar, from=Q10409298
Empoascini
Insects described in 1912
Hemiptera of Asia