COMBATING THE MOSQUITO According Dr Nor Azah the best move to curb the breeding of the mosquito is to destroy its larva or through the use of insect repellents."At the moment, the control of the mosquito vectors depends on the chemical-based and synthetic repellents like dimethyl phthalate, malathion and dimethyl-m-toluamide (DEET).She said even though the chemicals are effective, some could be hazardous apart from being ozone-depleting and continuous use could turn the mosquito vectors resistant to insecticides.POTENTIAL OF HERBS AND SPICESDr Nor Azah suggested the possibility of using herbs and spices, whose essential oils are able to repel insects, be used in insecticides,This is due to the presence of monoterpenoids like limonene, citronellol, geraniol and citronellal that have been reported as having insect repellant properties."As aroma play an important role towards controlling the insects behaviour, essential oils can be used as insect repellents", she said.From FRIM's research, a number of essential oils such as Cymbopogon nardus, Litsea eliptica, Melaleuca cajuputi and Cinnamomum spp demonstrates repellent properties against the Aedes agyptii mosquito.She said essential oils from other plants, reported to be able to repel insects are that from geranium (Pelargonium citrosum), sandalwood (Aquilaria malaccensis) and Sweet Basil (Ocimum spp)."There are other aromatic species that can be found in the Malaysian forest or that cultivated in parks for their medicinal properties and culinary reasons. Essential oils from these species are also preferred by the essential oil industry," said Dr Nor Azah, who has been with FRIM since 1987.FRIMS RESEARCHSince the early 1990s, FRIM has carried out research on the potential for their extracts to be used for various purposes."Our research is focused on the extraction process. We also make trips to the jungle for random sampling of plants that contain essential oils."FRIM's efforts are among the earliest research work on essential oils in Malaysia," she said.According to Dr Nor Azah, since 1994, the research centred on the production of essential oils that emit strong aroma."We found out that essential oils contain natural therapeutic properties that can be used to repel insects apart from being used as deodorants," she said.When FRIM set up its medicinal plants division in 1995, the research work is geared towards bioactivity work. Then, dengue was a frequent occurrence, she said.Dr Nor Azah said the use of various repellents to kill Aedes mosquito could inevitably turn the insect to be resistant to such chemicals.She said the study conducted was on more than 30 plant extracts including that from serai wangi (Cymbopogon nardus), citrus fruits, medang, sandalwood, kemoyang and betel plant.DUAL FUNCTIONDr Nor Azah said further research work is needed on scent-producing plants, which can be utilised for the making of insect repellents and aromatic agents.She said from studies held at FRIM, it was found that aroma-producing plants like citrus, selasih (Ocimum), serai (Cymbopogon) and medang (Cinnamomum) exhibited their potential in repelling mosquito when tested on Aedes aegyptii via the American Society Testing and Materials (ASTM) standard E951-85.Dr Nor Azah said the most effective essential oils discovered so far are that from the citrus plants."Mosquito is repelled by certain aromas from essential oils. Our aim now is to find the essential oils that can kill or knock down this insect," she said.She said the research conducted at FRIM is to also know more about these therapeutic effects on, among others, the human skin."All ingredients, no matter how natural they are, would have side effects if excessively used. Essential oils are not ideal for direct use (and) they should be blended in the form of creams or lotions.Dr Nor Azah also cautioned that some essential oils might cause allergies to pregnant women.
Dr Nor Azah is a senior researcher with medicinal plants programme at FRIM's Forest Biotechnology Division
mosquito control
Importance of water surface during egg-larva-pupa stages
Thursday, September 25, 2008
Sunday, September 7, 2008
Mosquito Life-cycle
http://www.mosquitoes.org/LifeCycle.html
A mosquito may lay a raft of eggs every third night during its life span. Tiny mosquito larvae emerge from a raft of from 200- 300 eggs eggs within 24 hours.
Notes: Anopheles mosquitoes lay their eggs singly on the water, not in rafts. Aedes mosquitoes lay their eggs singly on damp soil. Aedes eggs hatch only when flooded with water (salt water high tides, irrigated pastures, treeholes, flooded stream bottoms, etc.).
Mosquito larvae must live in water from 7 to 14 days depending on water temperature. Larvae must come to the surface at frequent intervals to obtain oxygen through a breathing tube called a siphon. The larva eats algae and small organisms which live in the water. During growth, the larva molts (sheds its skin) four times.before it becomes a pupa.
Note : Anopheles are unlike Culex and Aedes larvae since they do not have a breathing tube, they must lie parallel to the water surface in order to get a supply of oxygen through a breathing opening.
Mosquito pupae must live in water from 1 to 4 days, depending upon species and temperature.The pupa is lighter than water and therefore floats at the surface. It takes oxygen through two breathing tubes called "trumpets". When it is disturbed it dives in a jerking, tumbling motion and then floats back to the surface. The pupa does not eat. The metamorphosis of the mosquito into an adult is completed within the pupal case.The adult mosquito splits the pupal case and emerges to the surface of the water where it rests until its body can dry and harden.
Only female mosquitoes bite animals and drink blood. Male mosquitoes do not bite, but feed on the nectar of flowers.
Aedes mosquitoes are painful and persistent biters, attacking during daylight hours (not at night). Aedes mosquitoes are strong fliers and are known to fly many miles from their breeding sources.
Culex mosquitoes are painful and persistent biters also, but prefer to attack at dusk and after dark, and readily enter dwellings for blood meals. Domestic and wild birds are preferred over man, cows, and horses. Culex tarsalis is known to transmit encephalitis (sleeping sickness) to man and horses. Culex are generally weak fliers and do not move far from home, although they have been known to fly up to two miles. Culex usually live only a few weeks during the warm summer months. Those females which emerge in late summer search for sheltered areas where they "hibernate" until spring. Warm weather brings her out in search of water on which to lay her eggs.
Culiseta mosquitoes are moderately aggressive biters, attacking in the evening hours or in shade during the day.
Anopheles mosquitoes are the only mosquito which transmits malaria to man.
The average life span of a female mosquito is 3 to 100 days. the male lives 10 to 20 days. One female mosquito may lay 100 to 300 eggs at a time and may average 1,000 to 3,000 offsprings during her life span. http://control-mosquitoes.com/#mf6
A mosquito may lay a raft of eggs every third night during its life span. Tiny mosquito larvae emerge from a raft of from 200- 300 eggs eggs within 24 hours.
Notes: Anopheles mosquitoes lay their eggs singly on the water, not in rafts. Aedes mosquitoes lay their eggs singly on damp soil. Aedes eggs hatch only when flooded with water (salt water high tides, irrigated pastures, treeholes, flooded stream bottoms, etc.).
Mosquito larvae must live in water from 7 to 14 days depending on water temperature. Larvae must come to the surface at frequent intervals to obtain oxygen through a breathing tube called a siphon. The larva eats algae and small organisms which live in the water. During growth, the larva molts (sheds its skin) four times.before it becomes a pupa.
Note : Anopheles are unlike Culex and Aedes larvae since they do not have a breathing tube, they must lie parallel to the water surface in order to get a supply of oxygen through a breathing opening.
Mosquito pupae must live in water from 1 to 4 days, depending upon species and temperature.The pupa is lighter than water and therefore floats at the surface. It takes oxygen through two breathing tubes called "trumpets". When it is disturbed it dives in a jerking, tumbling motion and then floats back to the surface. The pupa does not eat. The metamorphosis of the mosquito into an adult is completed within the pupal case.The adult mosquito splits the pupal case and emerges to the surface of the water where it rests until its body can dry and harden.
Only female mosquitoes bite animals and drink blood. Male mosquitoes do not bite, but feed on the nectar of flowers.
Aedes mosquitoes are painful and persistent biters, attacking during daylight hours (not at night). Aedes mosquitoes are strong fliers and are known to fly many miles from their breeding sources.
Culex mosquitoes are painful and persistent biters also, but prefer to attack at dusk and after dark, and readily enter dwellings for blood meals. Domestic and wild birds are preferred over man, cows, and horses. Culex tarsalis is known to transmit encephalitis (sleeping sickness) to man and horses. Culex are generally weak fliers and do not move far from home, although they have been known to fly up to two miles. Culex usually live only a few weeks during the warm summer months. Those females which emerge in late summer search for sheltered areas where they "hibernate" until spring. Warm weather brings her out in search of water on which to lay her eggs.
Culiseta mosquitoes are moderately aggressive biters, attacking in the evening hours or in shade during the day.
Anopheles mosquitoes are the only mosquito which transmits malaria to man.
The average life span of a female mosquito is 3 to 100 days. the male lives 10 to 20 days. One female mosquito may lay 100 to 300 eggs at a time and may average 1,000 to 3,000 offsprings during her life span. http://control-mosquitoes.com/#mf6
Thursday, September 4, 2008
mosquitoes breeding ground
Mosquitoes are difficult to be controlled once they start flying. Various ways and means to killing them physically or chemically have created more tension and stress for mankind. Anyway the mosquitoes need to make love and propagate offsprings.
Mosquitoes with mothers' instinct can easily source breeding ground and then float upon water surface lovingly laying eggs. The eggs will harch into larvae and then into pupae before transforming into adult mosquitoes.
With all the advance scientific method of eradication, mosquitoes still survive. However we can reduce the mosquitoes reproduction process by cutting down the area of water surface within the breeding ground with recycled styrofoam (which has been an enviroment problem) .
Styrofoam could float up and down during raining and drought season at the mosquito breeding ground and it could be tailor-shaped accordingly --- be it a drain, pond or well. Mama mosquitoes would then look elsewhere with good water surface for its larvae and pupae.
Incidentally the newly transformed adult mosquitoe will be trapped within the floating styrofoam which has been caved at its side in contact with the water surface. With such a device, exponential reproduction of mosquitoes would be controlled without disturbing mosquitoes' instinct of lovemaking.
Mosquitoes with mothers' instinct can easily source breeding ground and then float upon water surface lovingly laying eggs. The eggs will harch into larvae and then into pupae before transforming into adult mosquitoes.
With all the advance scientific method of eradication, mosquitoes still survive. However we can reduce the mosquitoes reproduction process by cutting down the area of water surface within the breeding ground with recycled styrofoam (which has been an enviroment problem) .
Styrofoam could float up and down during raining and drought season at the mosquito breeding ground and it could be tailor-shaped accordingly --- be it a drain, pond or well. Mama mosquitoes would then look elsewhere with good water surface for its larvae and pupae.
Incidentally the newly transformed adult mosquitoe will be trapped within the floating styrofoam which has been caved at its side in contact with the water surface. With such a device, exponential reproduction of mosquitoes would be controlled without disturbing mosquitoes' instinct of lovemaking.
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