Friday 30 March 2012

INSECTS AS SOURCE OF FOOD



Eating Insects in the Past...

It is no surprise that certain insect groups can be consumed as a diet...as insects contain lot of proteins, easy to find, take up less space than cows, etc.
Let us have a look at the various insect sources used as food in different regions of the world.....



Algeria - The natives of Algeria would collect large numbers of desert locusts to use as food. They were a valuable resource for the poor population. The locusts were cooked in salt water and dried in the sun. Not only were they collected for personal use, but the locusts were traded in the markets as well.

Australia - Australian natives, known as Aborigines, have eaten many different insects throughout history. Hundreds of Aborigines would come together at the Bogong mountains to feast on Bogong moths. These moths would gather in large numbers on the cave floors and in rock crevices. They were harvested, cooked in sand and stirred in hot ashes. This would burn off the wings and legs. The moths were then sifted through a net to remove their heads before they were eaten by the Aborigines. Some of the moths were ground into paste and made into cakes.

Another important insect in the Aboriginal diet was the witchety grub. This was a moth larva that lived in the roots of the acacia bush, also known as the witchety bush. The grubs were eaten raw or cooked in ashes. Cooked grubs supposedly taste like almonds. The grubs were a valued food source in the Australian desert, especially to women and children.

Some of the insects eaten by the Aborigines were very sweet. The natives would dig into the ground looking for the nests of honeypot ants. The workers of these ants collect honeydew from scales and psyllids and feed it to other worker ants, which would become storage containers for the sweet liquid. The "storage" workers could be found in the nests.

The "honeybag" bee, a stingless native bee, also provided sweet treats for the Aborigines. The "honeybag" was actually the bees' hive. In order to find the "honeybag," the Aborigines would catch a bee that was feeding on nectar, use sticky plant juice to stick a leaf or flower petal to it, and set it loose. The bee would fly straight home. The attached leaf or petal would slow down the bee and make it easier to see and follow.
GIANT WATER BUGS-FRIED

... and Present!


Japan - The Japanese have used insects as human food since ancient times. The practice probably started in the Japanese Alps, where many aquatic insects are captured and eaten. Thousands of years ago, this region had a large human population but a shortage of animal protein. Since the area had an abundance of aquatic insects, this food source became very important for human survival.

The Japanese still use insects in many recipes. If you were to go to a restaurant in Tokyo, you might have the opportunity to sample some of these insect-based dishes

  • hachi-no-ko - boiled wasp larvae
  • zaza-mushi - aquatic insect larvae
  • inago - fried rice-field grasshoppers
  • semi - fried cicada
  • sangi - fried silk moth pupae

Most of these insects are caught wild except for silk moth pupae. They are by-products of the silk industry. Silk moths are raised in mass for their ability to produce silk. The larvae, the young silk moths, produce the silk. Once they pupate, they can no longer produce silk and are then used as food.

Kwara State, Nigeria, West Africa - People from this area have been known to feast on termites, crickets, grasshoppers, caterpillars, palm weevil larvae, and compost beetle larvae. Termites are collected by placing a bowl of water under a light source. The termites are attracted to the light and will then fall into the water. If large numbers of termites are gathered, they are sold at local markets. People of all ages eat the winged reproductive termites, but the queen termites are considered a delicacy and are only eaten by adults. The termites are roasted over a fire or hot coals or fried in a pot. After cooking, the wings are removed and salt is added to taste.

Crickets are collected from soil tunnels which they build. The crickets are roasted over a fire or hot coals. The guts are removed before eating. Several taboos surround eating crickets. Members of the Yoruba tribes do not generally eat crickets. Many worship Ogun, the iron god, and he forbids animals that have no blood. Others believe that eating crickets is childish.

Grasshoppers are prepared and eaten in a manner similar to that for crickets, but there are more grasshoppers than crickets. They are eaten by people of all ages and there are no taboos associated with them. Some farmers will eat uncooked grasshoppers after they remove the grasshoppers' guts.

In some parts of Nigeria, the Cirina forda Westwood larva is reported to be the most important and widely eaten insect. This insect, often called Kanni, is a caterpillar that is collected from the sheabutter tree. It is boiled and dried in the sun before it is eaten. Kanni is widely used as an ingredient in vegetable soup in this region.

A very large edible insect is the palm weevil larva. It can be four inches long and more than two inches wide. The mature larvae are fleshy and grublike with a high fat content. These insects are collected from the trunks of palm trees. They are fried in a pot or frying pan. They are reported to be very delicious.

The compost beetle larvae are even larger than the palm weevil larvae. They live in garbage or manure piles or swampy areas. The end of the abdomen, which contains the guts, is removed before the larvae are washed and fried. Some people refuse to eat this insect because it is found in such "dirty" places.

Bali - Dragonfly and damselfly adults are hunted in Bali. Dragonflies are extremely difficult to catch but several interesting techniques have been used successfully. Latex, sticky plant juice, from the jackfruit tree is applied to the end of a slender stick. This stick is tied to a longer, sturdier stick. The stick is lower to a resting dragonfly and with a quick tap, the dragonfly is stuck to the plant juice. Dragonflies are also captured by hand, but one must be very quiet and quick. If latex is used to catch the insects, it is removed with cooking oil before the dragonflies are cooked. Sometimes the dragonflies are placed directly on the grate of a charcoal grilled for cooking. Another method involves boiling them with ginger, garlic, shallots, chili pepper and coconut milk. The wings are removed before cooking unless they are charcoal roasted.
CHINESE RECIPE

INSECT LOLLIES
REFERENCE:
 http://www.ca.uky.edu/entomology/dept/bugfood2.asp

Saturday 24 March 2012

SPODOPTERA LITURA(armyworm) AND S.EXIGUA(cutworm)----- polyphagous pests



Scientific name: Spodoptera litura Fabricius
Common name: Armyworm/ cluster caterpillar
Scientific name: Spodoptera exigua
Common name: Common cutworm/beet army worm


Class
Insecta
Order
Lepidoptera
Family
Noctuidae


Cutworms and armyworms attack a number of crops and may cause significant damage depending on severity of infestation.


Worldwide.
On hatching, clusters of young larvae feed gregariously by initially scraping the surface of the leaf. Later instars disburse and move on to other leaves and feed voraciously, producing large irregular holes and may leave only the veins. High infestation causes severe defoliation. Army worms quickly skeletonise leaves as they attack in clusters.
Armyworm
Egg. The eggs are laid in mass on the surface of the leaves and covered with whitish scales. The egg stage lasts for 3 days.
Larva. The larvae undergo several  colour phases from green to almost black.  The larval stage lasts for about 9-14 days and usually has six instars.
PupaPupation occurs in the soil and lasts for about 10 days.
AdultsAdults are smaller than other members of the cutworm-armyworm group, about 12 mm long with a wing spread of 25 to 40 mm. Body and wings range from silvery-grey to greyish-brown. Forewings have a lighter spot near the centre. Hindwings are paler with darker borders, with a light band at the wing edges.
Cutworm
Egg. The eggs are round, pearl-white, laid in mass on the ground or on the surface of the leaves and covered with yellowish brown hairs. An egg mass contains about 100 to 300 hundred eggs.  Egg hatches in 3-6 days.
Larva. The newly hatched larvae are greenish with a dark longitudinal band on each side. The larvae are pale greenish brown with dark markings and the body may have rows of dark spots or may have transverse and longitudinal grey and yellow bands. They gradually turn brownish black as they  mature. The fully grown larva  is stout and cylindrical measuring 30-50 mm in length.
Pupa. The pupae are reddish dark brown.  Their legs and appendages are not capable of free movement. Pupal stage lasts for about 12 days.
AdultThe adults are brown moths with greyish brown forewings patterned with wavy markings and the hindwings are transparent with a brown narrow band along the outer margins.
The eggs hatch after 3 days from egg deposition and take about two weeks to reach the pupal stage. The larvae prefer moist sites. The larvae hide during the day in the crevices found in the soil and plant residues and become active during dusk to dawn. Pupation takes place in the soil in an earthen cell. Pupation lasts for a week. The development of the armyworm/cutworm from egg to adult takes about 3.5 to 4 weeks. The female S. exigua lays up to 1,000 eggs while S. litura lays as many as 2,000-2,600.
Apart from sweetpotato, armyworms attack asparagus, banana, cacao, corn, citrus, garlic, jute, kenaf, mulberry, onion, passion fruit, sesame, sorghum, soybean, tobacco, rice, tomato, sugarcane, cotton, beans, peanuts, castor oil plants, taro, wheat, white potato, a number of crops under Cruciferae and Cucurbitaceae, grasses, and some broad leaf weeds.
Aside from the symptoms of damage, the plant can also be inspected for the presence of eggs and feeding larvae. 
Management Options
Biological  control
S. exigua and S. litura have several natural enemies which can be used in biological control. 
One effective control for S. exigua is the use of a solution containing the virus nuclear polyhedrosis virus (NPV).  This can be applied to plants using the common backpack sprayer. There are also predators that prey on this insect.
S. litura is preyed on by a number of predators like ants, earwigs, pentatomid bugs and predaceous beetles.  Telenomus spodopterae Dodd and Telenomus remus Nixon can parasitise the eggs and reduce its population. A species of entomogenous fungus, Nomuraea rileyi infects some larvae in the field. Caterpillars are susceptible to the biopesticide Bt which at severe infestation could be used for spot application.
Chemical  control
Azinphosethyl, carbaryl, chlorphyriphos, monocrotophous phenthoate are recommended for armyworm control.



LARVA of S.litura

PUPA



ADULT


LEAF DEFOLIATION BY Spodoptera
S.exigua larva
PUPA
ADULT

References

Amalin, D.M. and Vasquez, E. A. 1993. A handbook on Philippine sweetpotato pests and their natural enemies. International Potato Center (CIP), Los Baños, Philippines. 82 p.

Ames, T., Smit, N.E.J.M., Braun, A.R., O’Sullivan, J.N., and Skoglund, L.G. 1996. Sweetpotato: Major pests diseases, and nutritional disorders. International Potato Center (CIP). Lima, Perú. 152 p.