eChapters

The hind limb (Fig. 6-1) is termed as pelvic limb and it consists of four segments-the pelvic or hip region, thigh, leg and the pes region. The skeleton of pelvic region is formed by the pelvic girdle (os coxae). The skeleton of thigh region is mainly formed by a long bone (thigh bone) the femur and at its lower extremity is a short sesamoid bone, the patella. The leg region is formed by two long bones, the larger one the tibia and the smaller one the fibula. The last segment, the pes has three subdivisions as tarsus, metatarsus and digits. The tarsus has five short bones arranged in two rows on par with the carpus of fore limb. The metatarsus is constituted by two bones of which one is a long bone called the large metatarsal and the other a short small rudimentary bone the small metatarsal bone. The last part of the hind limb is the digits which are constituted by six phalanges and six sesamoids like those of the forelimb.

Horse

The femur of horse is more massive than that in ox. The proximal third of the caudal surface of shaft of femur presents a rough eminence for attachment of biceps femoris muscle. The trochanter minor is a rough ridge like structure. The proximal third of the lateral border of shaft presents trochanter tertius for attachment of superficial gluteus muscle. The trochanter major is comprised of a convexity, a summit and a crest. The trochanteric ridge is vertical and it connects the trochanter major with the third trochanter. The lateral supracondyloid crest and the supracondyloid fossa are better developed in horse than that in ox. The patella of horse is wider and longer than that of ox.

The tibia in horse is relatively longer than that in ox. The popliteal line is prominent. It extends from the proximal third of the medial border, obliquely crosses the caudal surface and ends at the middle of the lateral border of the shaft of tibia. The medial border in its proximal third bears a small popliteal tubercle for attachment of popliteus muscle. The lateral border is attached to the shaft of the fibula and encloses an interosseous tibiofibular arch with the fibula. At the proximal extremity, the cranial tuberosity is vertically grooved. The lateral condyle on its lateral side presents facet for articulation with the proximal extremity of fibula. At the distal extremity, the grooves are oblique. The lateral malleolus is fused with the distal extremity of tibia, The medial malleolus is more prominent than the lateral one.

The articulations of hind limb (pelvic limb) comprises the joints of pelvic region which include the sacro-iliac articulation, pelvic symphysis and the hip joint; the articulation of thigh region named as stifle joint; the articulation of tarsal or hock joint and the articulations of digits which include the metatarso-phalangeal joint (fetlock) joint, the proximal interphalangeal joint (pastern joint) and the distal interphalangeal joint (coffin joint). The joints of pelvic region especially the sacro-iliac joint and the pelvic symphysis have been described with the articulations of abdomen and pelvis.

Horse

The hip joint has an additional ligament called the pubio-femoral ligament. It arises from the prepubic tendon, passes dorsally and laterally and then caudally and lodges into the subpubic (pubio-femoral) groove, penetrates the capsular ligament, passes through the acetabular notch and is inserted into the fovea capitis behind the round ligament on the head of femur. This ligament is peculiar to solipeds and it prevents the side kicking. The absence of this ligament in ruminants allows them abduction freely and that is how the ruminants can kick sideways. As against this, the equines can kick only back way. The other difference about the hip joint in horse is that the cotyloid ligament is narrower because of the deeper acetabulum.

The stifle joint of horse in general resembles that of ox except that the middle patellar ligament is not so prominent as that in ox.

The tibio-fibular articulation in horse is a diarthrosis and an amphiarthrosis. The diarthrosis is formed between the lateral condyle of tibia and the head of the fibula. It has intimate capsular ligament. The amphiarthrosis is formed between the shafts of the tibia and the fibula. The shafts of the two bones are binded by the proximal and distal interosseous ligaments.

The hock joint of horse has minor differences with those of ox owing to the difference in the number of tarsal bones and their arrangement. The synovial membrane is supported everywhere except at the dorsomedial (craniomedial) aspect where it bulges out in the cases of bog-spavin. If there is a distension of tarsal sheath, it bulges out as two rounded swellings on either sides of the tendon of deep digital flexor. The movements at the hock joint are very limited.

The fascia covering the hind limb is the superficial and deep fascia. The superficial fascia is very scanty lies beneath the skin. It has the same general disposition as in other regions of the body. The deep fascia is in the form of a thick strong sheet covering the superficial layer of muscles over the medial aspect of the hind limb. From this sheet extend several septa that pass between different muscles or muscle groups in the thigh region. The deep fascia of the leg region continues cranially with the fascia of the thoracolumbar region. Caudally it is attached to the aponeurotic tendon of insertion of sartorius and gracilis muscles. The part of the deep fascia that continues on the lateral aspect of the thigh is the fascia lata which is continuous with the gluteal fascia dorsally.

The muscles of the hind limb (Fig. 6-3 A and B) are arranged into different regional, positional as well as functional groups. The muscles of hip and thigh region are arranged in the lateral, medial and cranial groups. The muscles of leg and foot are arranged in dorsolateral and plantar groups. The dorsolateral muscles are generally the extensors of tarsus and digits while the plantar muscles are the flexors of tarsus and digits.

Horse

The tensor fasciae latae is less extensive.

The superficial gluteus exists separately. It is ‘V’ shaped. It originates from the lateral angle of ilium (tuber coxae) and gluteal fascia and is inserted to the third trochanter. The middle gluteus is the largest of the three gluteal muscles and is very extensive. It originates from the aponeurosis of the longissimus dorsi, extends as far forwards up to first lumbar vertebra and is inserted in three heads, to the trochanter major, the crest ventral to trochanter major and the trochanteric ridge. The deep gluteus is smaller than the middle gluteus and is inserted to the convexity of the trochanter major.

The biceps femoris has an additional insertion to the femur on the rough surface near the trochanter tertius.

The semitendinosus arises from the transverse processes of the first two or three coccygeal vertebrae. The semimembranosus is larger and arises from the sacrosciatic ligament also.

The sartorius does not arise from the shaft of the ilium. The gracilis is not so extensively fused to its fellow at the origin.

The obturator internus has an iliac part- the pisiformis. Its tendon passes through the lesser sciatic foramen and hence does not unite with that of the obturator externus.

Articularis genu is absent

The main arterial trunk that supplies blood to the hind limb is the external iliac artery. As this trunk passes down through different segments (regions) of the limb it is differently named according to that segment or the region. In the abdomen it is named as iliac, in the thigh region as femoral, in the leg region as tibial and popliteal and down that the metatarsal artery and lastly the digital.

External iliac artery

The external iliac artery arises from the abdominal aorta ventral to the fifth or sixth lumbar vertebra. It descends at the side of the pelvic inlet ventrally and caudally along the tendon of psoas minor, crosses the tendon, reaches the cranial border of the pubis, gains the space between the sartorius and pectineus muscles and then continues in the thigh (femoral region) as the femoral artery. In this course it is covered by peritoneum and is related laterally to the psoas minor, sartorius and iliacus muscles, medially to the common iliac vein and caudally to the external iliac vein. The following are the collateral branches of the external iliac artery.

The venous drainage of hind limb begins from two digital venous plexuses, one for each digit, situated in the corium of the foot. From each of these plexuses extend three digital veins namely the dorsal common digital vein, the medial digital vein and the lateral digital vein. The digital veins in their upward course converge and form the metatarsal veins which in their turn continue upward in the leg region as tibial and popliteal veins and then in the thigh region as femoral vein which finally joins the external iliac vein as the chief vein of the hind limb.

Digital veins

The dorsal common digital vein arises from the corresponding digital plexus in the form of proper digital vein.The two proper digital veins ascend along the medial face of the corresponding digit and unite at about the middle of the interdigital space below the metatarso-phalangeal articulation (fetlock joint) and form the dorsal common digital vein. The later, thus formed, ascends through the interdigital space, crosses vertically the metatarso-phalangeal articulation and after reaching the distal extremity of the metatarsal bone continues upward as dorsal metatarsal vein.

The medial digital vein after arising from the digital venous plexus ascends along the caudomedial aspect of the medial digit in company with the satellite artery, shares a branch each from the dorsal common digital and lateral digital veins, ascends the medial face of the fetlock joint and is then continued up as the medial plantar metatarsal vein.

The lateral digital vein after arising from the digital venous plexus of the lateral digit passes upward in the interdigital space, communicates a branch to the dorsal common digital and medial digital veins and then ascends the lateral face of the fetlock joint and then is continued up as the lateral plantar metatarsal vein.

The lymphatics of hind limb is comprised of four lymph nodes namely the deep inguinal, epigastric, coxal and popliteal lymph nodes and the afferents and efferent ducts joining and leaving these lymph nodes.

Deep inguinal lymph node

The deep inguinal lymph node is located in the region of deep femoral artery near the origin of the caudal epigastric and the pudic branches from it. The lymph node receives afferents from the muscles in the prepubic and the thigh regions. The efferent vessel from this lymph node joins and opens in the medial iliac lymph node.

Epigastric lymph node

The epigastric lymph node is inconstant. When present, it is located on the course of the caudal epigastric artery near the pubis on the medial surface of the rectus abdominis muscle. The afferents for this lymph node are received from the abdominal muscles and the peritoneum in the vicinity. The efferent vessel of this lymph node joins the medial iliac lymph node.

Horse

The arteries of the hind limb of horse have in general similar architecture as that of ox except the special features mentioned below.

The deep circumflex iliac artery which is a branch of the external iliac artery in ox has a variable origin in horse. It may originate directly from the aorta or the common iliac trunk just prior to the origin of the external iliac artery. The prepubic and deep femoral arteries arise either by a common trunk or separately from the femoral artery. The obturator artery is a well developed independent branch of the femoral artery in horse as against its origin as a branch of deep femoral artery in ox. The saphenous artery is a small branch of femoral artery and it supplies the skin on the medial aspect of the thigh and leg. The popliteal artery terminates by its division into cranial and caudal tibial arteries at a lower level in horse than that in ox. The caudal tibial artery is larger and longer in horse than that in ox. From the proximal plantar arch extend four caudal metatarsal arteries instead of four, two of them are superficial and the other two deep branches. The large metatarsal artery descends along the groove between the large and lateral small metatarsal bone and divides just above the fetlock into lateral and medial digital arteries. Each digital artery divides at the middle of the wing of the third phalanx into preplantar and plantar digital arteries. The preplantar digital arteries supply the sensitive laminae of the sole. The plantar digital arteries of the opposite sides form anastomosis. Small laminar branches from the anastomosis form the circumflex artery of the toe which supplies branches to the sole.

Pelvic (Lumbosacral) plexus

The hind limb is supplied by the nerve branches extending from the Pelvic (lumbosacral) plexus (Fig. 6-4 A and B) which is formed by the convergence of the ventral divisions of the last three lumbar and first two sacral nerves. It is formed in two parts, the cranial and caudal. The two parts are connected by anastomotic branches. The cranial (lumbar) part is formed by the fourth and fifth lumbar nerves and lies between the psoas major and psoas minor muscles while the caudal (sacral) part is formed by the sixth lumbar and first and second sacral nerves. Some times a root from third sacral also joins this part. It lies on the pelvic surface of the sacrosciatic (ischial) ligament. The nerves extending from the cranial part of the plexus are the lateral cutaneous femoral, the femoral and the obturator. The nerves extending from the caudal part are the cranial gluteal, caudal gluteal and the sciatic (ischiatic).

Lateral cutaneous femoral nerve

The lateral cutaneous femoral nerve while leaving the cranial part of the plexus, receives fibres from the fourth lumbar nerve, passes caudally between the psoas major and psoas minor muscles and reaches the tuber coxae. Here it perforates the obliquus abdominis externus muscle in company with the circumflex iliac artery and reaches the skin of the lateral aspect of the thigh. In this course, the nerve supplies the psoas major, psoas minor, iliacus and external oblique muscles of the abdomen and the skin and cutaneous muscle on the lateral face of the thigh.

Horse

The lumbosacral plexus in horse is formed by last three lumbar and first two sacral nerves, similar to that in ox. The caudal gluteal nerve divides into two branches. The medial branch supplies the superficial gluteal muscle in addition to the middle and deep gluteal and biceps femoris muscles. The lateral branch reaches the level of tuber ischii and terminates into the semitendinosus muscle at the perineal region. The sciatic nerve is almost similar to that of ox in the disposition and distribution of its branches. The superficial and deep peroneal nerves are also similar to those of ox. The tibial nerve divides at the distal third of the leg into medial and lateral plantar nerves. Each plantar nerve divides at the fetlock into cranial, middle and caudal digital nerves.

Dog

The lumbosacral plexus in dog is formed by the last four or five lumbar and first two or three sacral nerves. The cranial gluteal nerve receives fibres from sixth and seventh lumbar and first and second sacral nerves. The caudal gluteal nerve arises from sixth and seventh lumbar and first sacral nerves. The sciatic nerve derives fibres from sixth and seventh lumbar and first and second sacral nerves. The lateral cutaneous nerve arises either from sciatic or from the peroneal nerve. The peroneal nerve divides into superficial and deep branches, similar to those of ox. The tibial nerve divides into medial and lateral plantar nerves at the level of distal third of the leg. The medial plantar nerve divides at the metatarsus into medial and lateral branches. The medial branch becomes the first plantar common digital nerve. It divides to form the plantar proper digital nerves of the first and second digits. The lateral branch divides into three plantar metatarsal nerves which unite, in the intermetatarsal space with the three plantar common digital nerves of the lateral plantar nerve. Each of these united plantar common digital nerves descends and after reaching at the metatarso-phalangeal articulation into three plantar proper digital nerves. The lateral plantar nerve, divides into three plantar common digital nerves which join the three plantar metatarsal nerves and form the plantar (caudal) proper digital nerves. The united proper digital nerves supply the second to fifth digit and terminate into the corresponding intermetatarsal space.

Sites for surgical interventions

Luxation of patella in cattle and horses

The luxation of patella is a condition wherein the patella of the stifle joint (femoropatellar articulation) is locked above the medial ridge of the trochlea of the femur.

Anatomy of femoropatellar articulation of the stifle joint

The stifle joint is a composite joint formed in two parts. One of these is an articulation between the condyles of distal extremity of femur and the condyles of the proximal extremity of tibia (femoro-tibial articulation) and the other is the articulation between the trochlea of the distal extremity of the femur and the articular surface of the patella (femoro-patellar articulation).

The trochlea of the femur consists of two asymmetrical ridges separated by a groove. The medial ridge is more prominent, wider and a little more extended dorsally than the lateral ridge. The two ridges converge ventrally. The articular surface of the patella is more or less quadrilateral or triangular with the base above and apex below. It has a vertical ridge in the middle and it separates the two concave areas of which the medial one is larger than the lateral. The patella is fastened against the trochlea with the help of three types of ligaments. One of these is the capsular ligament which is attached to the periphery of the articular areas of the two segments of the joint. The other one is the medial and lateral collateral ligaments. The third set of ligaments is the patellar (straight) ligaments.

A forest is a large area dominated by trees. Many definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function. Although a forest is usually defined by the presence of trees, under many definitions an area completely lacking trees may still be considered a forest if it grew trees in the past, will grow trees in the future, or was legally designated as a forest regardless of vegetation type. According to the Food and Agriculture Organization, forests covered 4 billion hectares or approximately 30% of the world’s land area in 2006. Forests are the dominant terrestrial ecosystem of earth, and are distributed around the globe. Forests account for 75% of the gross primary production of the earth’s biosphere, and contain 80% of the earth’s plant biomass.

DEVELOPMENT OF MODERN FORESTRY

Systematic management of forests for a sustainable yield of timber began in Portugal in the 13th century when Afonso III, the king of Portugal planted the trees to prevent coastal erosion and soil degradation, and as a sustainable source for timber used in naval construction. His successor Dom Dinis continued the practice and the forest exists still today. Forest management also started in German in the 14th century and in Japan in the 16th century. The practice of establishing tree plantations in the British Isles was promoted by John Evelyn during second half of the 17th century.

During the late 19th and early 20th centuries, forest preservation programmes were established in British India, the United States, and Europe. Sir Dietrich Brandis is considered the father of tropical forestry. He brought European concepts and practices to the tropical and semi arid climate zones. The enactment and evolution of forest laws and binding regulations occurred in most Western nations in the 20th century in response to growing conservation concerns. Tropical forestry is a separate branch of forestry which deals mainly with equatorial forests that yield woods such as teak and mahogany. One of the applications of modern forestry is reforestation, in which trees are planted and tended in a given area.

The Indian ancient texts have some mention of the forest and the activities that were performed in the forests. Forests were revered by the people and a large number of religious ceremonies centred on trees and plants. Ancient Hindu culture is said to have evolved in the forest. The epics Ramayana and Mahabharata give an attractive description of forests. The Agni Purana, written about 4000 years ago, stated that man should protect trees to have material gains and religious blessings. Around 2500 years ago, Gautama Buddha preached to his followers to plant trees. There is enough evidence to show that dense forests once covered India. But the growing population and man’s dependence on the forest for infrastructural developments caused the depletion of forests.

HISTORY OF INDIAN FORESTS

The earliest indication of forestry administration in India is found in 300 BC. It was during the reign of Chandragupta Maurya. He realized the importance of the forests and appointed a Superintendent of Forests who looked after forests and wildlife. Later Ashoka continued the process. He launched programmes to plant trees on a large scale. Much importance was also given for planting trees along roadsides and temple premises. These rules continued even during the Gupta period.

The process of replacing the existing mature forest with a new generation of the forest trees is called forest regeneration. It can also be defined as process by which new tree seedlings become established after forest trees have been harvested or have died from fire, insects, or diseases. Forest regeneration is one of the basic tasks of foresters. Regeneration plays such a prominent role in silviculture that most silvicultural systems are named for their method of regeneration.

Silviculture is the branch of forestry dealing with the establishment, development, care and reproduction of trees. Forestry is anything done in the forest and silviculture is anything done to forests. ‘Silva’ is the Latin word for forest and ‘culture’ for cultivation. Silviculture is narrower than forestry, being concerned only with forest plants, but is often used synonymously with forestry.

The Society of American Foresters defines silviculture as theory and practice of establishment, composition, constitution and growth of forests. Thus, silviculture refers to art and science of raising forest crops, methods of raising tree crops, their growth and aftercare up to the time of final harvesting. In simple words, silviculture is the growing and tending stands of trees. Silviculture is also used to manage forests for wildlife, water, recreation, aesthetics, or any combination of these or other forest uses.

Tending is the term applied to pre-harvest silvicultural treatment of forest tree crops at any stage after initial planting or seeding. In other words, tending is the intermediate treatments that forest vegetation receives after establishment of regeneration and prior to final harvest of the stand. These tending operations can occur throughout the life of the forest stand, but do not include efforts directed at establishing regeneration. Tending operations play a fundamental role in the improvement of quality and stability of forest stands. Tending the trees after planting creates favourable conditions for both the plants’ survival and to stimulate a healthy, vigorous growth. Tending operations keep the plants from being suppressed by natural vegetation. It essentially covers operation on the crop itself and competing vegetation. Weeding, cleaning and thinning are important tending operations. Even improvement felling comes under tending operations but regeneration felling is not a tending operation. The major objectives of tending are to maintain sanitation, provide sufficient growing space, and more light, water, nutrients, etc. to the tree crops.

Mensuration is derived from Latin word mensura which means measure. It means measurement of length, mass, time, etc. It is an art and science of locating, measuring and calculating the length of lines, areas of planes, and volumes of solids.

Forest mensuration is one of the most fundamental disciplines within forest and related sciences. It concentrates on trees and forests or potentially forested locations and deals with the measurement of trees and stands and the analysis of the resultant information. Forest mensuration also includes measuring or calculating growth and change in trees and forests. Forest mensuration thus may be defined as the art and science of providing the quantitative information about trees and forest stands necessary for forest management, planning and research. Chaturvedi and Khanna (1986) defined forest mensuration as a branch of forestry which deals with the determination of dimensions (diameter, height, volume, etc.), form, age and increment of single trees, stands or whole woods, either standing or after felling. According to the Society of American Foresters, forest mensuration is the determination of dimensions, form, weight, growth, and age of trees individually or collectively, and of the dimensions of their products (Helms, 1998). It is a tool that provides facts about the forest crops or individual trees to sellers, buyers, planners, managers and researchers.

Forest mensuration provides quantitative information regarding forest resources that will allow making reasonable decisions on its density, use and management. Forest mensuration serves the following objects

Agroforestry is a new name for a set of old practices. The farmers have been practicing agroforestry since ancient times. The general concept of agroforestry is to integrate trees and agriculture so as to create a more diversified landscape, while providing the producers with new environmental and economic benefits. In other words, agroforestry is a method of farming that allows trees and shrubs to grow along with crops and/or livestock, therefore blending agriculture and forestry in the same production system. This relatively young science was brought from the realm of indigenous knowledge into the forefront of agricultural research four decades ago and was promoted widely as a sustainability-enhancing practice that combines the best attributes of both forestry and agriculture.

Multipurpose trees and shrubs are defined as all woody perennials that are purposefully grown to provide more than one significant contribution to the production and/or service functions of a land-use system that they occupy. In agroforestry systems, different species of trees and shrubs can be planted with many types of crops in a variety of patterns. Thus, it is required to know about the methods of propagation and nursery raising, planting and other silvicultural management practices along with the diverse uses of multipurpose trees and shrubs of tropical and subtropical areas before their selection for forestry and agroforestry activities. It is important to select the most suitable tree species since it is not easy to replace them once they have been planted.

MANGIUM (Acacia mangium)

Acacia mangium is a single-stemmed evergreen tree that grows to 25-35 m in height and up to 60 cm in diameter. The bole is usually straight, often fluted near the base, free of branches for up to half its height. Mangium is native to Australia, Indonesia and Papua New Guinea. However, it tolerates varied site conditions and has adaptability to different planting objectives. Mangium shows most vigorous growth on well-drained, fertile soils in high rainfall areas in the humid tropics. It is valued for its rapid growth and has been planted throughout the humid tropics and is a major plantation species in the Asia-Pacific. Provenances from Papua New Guinea consistently show better growth in height and diameter.

A series of efforts have been made to initiate the work on post-harvest grain technology in India. H.M. Lefroy, the 1^st Imperial Entomologist appointed by the British Government in India in 1905 had given a tentative list of storage insects in 1906. This list of storage insects was further supplemented by T.B. Fletcher in 1914. The problems of grain storage were discussed at Pusa, Bihar at the Entomological meetings held during the years 1917, 1919 and 1923.

The Department of Food was established in 1942 by the Government of India. The executive wing of the Food Department was responsible for the purchase, movement, transport and distribution of food grains. Central Food Technology Research Institute (CFTRI) at Mysore was established in 1950 with a mandate to train personnel and evolve technology relating to food processing and preservation. The Central Warehousing Corporation was set up on 2^nd March, 1957 under Agricultural Produce (Warehousing and Development) Act 1956. On 1^st January, 1965 Food Corporation of India was established.

In 1958, the Department of Food started a centre at Hapur known as Grain Storage Research and Training Centre with the main objective to train the personnel of State Government engaged in food procurement, storage and distribution. This centre was upgraded during 1968-1973 with the technical and financial assistance of UNDP and this centre was redesignated as Indian Grain Storage Institute (IGSI). Two field stations at Ludhiana and Bapatla (later shifted to Hyderabad in March 1979) were established in 1968-69. Subsequently, three stations of IGSI at Jabalpur (October, 1980), Udaipur (February, 1981) and Jorhat (May, 1981) were also established. The overall objective was to minimize losses of food grains by development of modernized grain storage practices for the farmers, traders, cooperatives and large storage of food grains in the country and also to evolve the methodology to be adopted by the Save Grain Compaign which has its headquarters in the Department of Food.

Insect infestation occurs in stored grains and grain products to variable extent depending upon the storage conditions in developing countries. The losses of nutritional compounds are proportional to the extent of insect infestation, nature of insect feeding and distribution of nutritional chemicals in different seed components.

1. Sources of Insect Infestation

There are many sources that leads to infestation in storage, viz., left over seed from bins or stores or spilled seeds under the stacks, cleanings, sweepings of storage structure, processing plants, old infested stores, old gunny bags, insect infested transport vehicles, storing insect infested seeds with fresh stock or vice-versa, entry of insects from neighbouring stores and carry over of field infestation

The damage to food grains in the storage may be caused due to insect attack, mould, fungi, bacteria, rodents, heat and moisture. The value of grain for milling purposes and human food is directly correlated with the amount of insect contamination present. The immature stages of rice and granary weevils, lesser grain borer, Angoumois grain moth and occasionally the flat grain beetle, cadelle, rust red flour beetle and saw toothed grain beetle live inside the kernels where they are hidden from view until they emerge.

Grain from casual inspection appears to be in good condition but may contain enough internal infestation which render it unfit for human food or unfit for purchase for future sale as milling stock. In general, millers have found that wheat with more than 0.5 per cent of infested kernels is unfit for milling. The need for a rapid and accurate method of estimating insect contamination in grain offered for sale has become more and more important to both grain dealers and millers.

Methods for Estimation of Damage

In order to assess the damage caused to food grains due to any one or combination of various factors; physical, chemical and micro-analytical methods are employed according to the necessity and information required. Various methods have been employed by field workers as well as by laboratory technicians in estimating damaged grains in food grains with particular reference to detection of insect infestation which alone cause maximum damage. These methods have been described below.

A number of insects infest seeds in storage. These insects infest seeds to fulfill their feed and shelter requirements, which result into qualitative as well as quantitative loss of seeds. Indian climate is very favourable for their multiplication and growth throughout the year. Storage pests move along with commercial products from one area to another and even to different countries in the world. Some adult insects are strong fliers and may spread from one to another place of storage or from source of infestation. Generally, all insects infesting seeds in storage belongs to insect order Coleoptera and Lepidoptera (Table 4.1). Some minor species belong to Pscoptera. These pests cause losses to man by destroying large quantities of grain, corn, legumes (beans, lentils and peas), milled cereal products, flour, bran, macaroni and other paste products, dried fruits, dried vegetables, cheese, nuts, candy and other food materials. They contaminate and thus eliminate for human consumption, far more food than they eat and either cause direct loss or transmit diseases to man and his domestic animals. These insects can be categorized as major or minor pests according to the loss of seeds caused by them. Similarly, on the basis of their feeding behavior, they can be grouped as follows:

There are several species in this cosmopolitan family that are of importance chiefly as pests of stored foods, flour, grain, seeds and bulbs, feeding on these products or the fungi that develop on them. These mites are mostly very minute, almost colourless, with the body bearing a few long setae, and with the legs terminating in one claw and usually a sucker. When very abundant the mites and their cast skins form a buff-colored dust and give rise to a characteristic odour. The living mites move slowly away from a source of light. An interesting characteristic of these mites is a nymphal resting stage (hypopus) during which they take no food but attach themselves to other mites, insects and humans by means of suckers and are thereby transported to other suitable places for development, where they drop off, moult, feed, and develop into adult stage. The hypopus may be resistant to fumigants. However, the cheese mites, Tyrophagus casei do not have a hypopial stage. Prolonged storage of products subject to infestation without cleaning of pantries and shelves where such materials are placed. These mites can subsist on organic debris in cracks, crevices and corners and are readily spread to other areas.

It is interesting to note that only 25 of about 1200 species of birds found in India have been reported to inflict damage to crops, vegetables and fruits. The exact ecological causes for population increase of individual species have yet to be studied. It would appear that, in general, the granivorous birds became abundant with the increase in area under grain crops and the subsequent storage of grain in godowns and bulk storage. The details of important bird pests are given below:

Economic Importance of Rodent Pests

• They consume and damage foods in the fields and in stores. In addition, they spoil it in store by urine and droppings reducing the sale values.
• Due to their gnawing and burrowing habit they destroy many articles (packing, clothes and furniture) and structures (floors, buildings, bridges, etc). By gnawing the electrical cables they can cause fires.
• They are responsible for transmitting diseases dangerous to human and domestic animals.

Among many pests of agricultural crops and stored grain products, rodents are the major pests which do the great damage. Rodents including rats, mice and squirrels are gnawing animals having chisel like teeth. They have highly developed sense of smell, taste and hearing. They are omnivorous and feed on grains, vegetables, fruits, meat and other products in the houses or in the fields. Rats daily consume food equal to about 10 per cent of their body weight and the figure may go up to 30 per cent in case of mice. Rats are among the most destructive pests of paddy in the field causing about 5-10 percent damage. It is estimated that these animals destroy 30 per cent of the total world’s cereal production. In India, 10 million tonnes of food grains are lost every year. It is often said that if rodent ravages could be controlled, a huge amount of food grains can be saved.

Of the 84 species of order Rodentia in India, 50 belong to family Muridae. The important ones belong to two sub-families, viz., Murinae and Gerbillinae. Murinae has 18 species of genus Rattus, 2 of Bandicota, 7 of Mus, 2 of Apodemus and a few each under eight other genera. The sub-family Gerbillinae has 2 species of Gerbillus, one each of Tatera and Meriones. Family Sciuridae has 10 species of flying squirrels and 13 species of tree squirrels in India.

As the name indicates, micro-organisms are very minute, cellular, living organisms which cannot be seen with the naked eyes (however, large colonies of fungi can be seen). Micro-organisms affecting stored grain can be divided into the following groups in order of their significance:

1. Fungi
2. Actinomycetes
3. Yeast
4. Bacteria
5. Protozoa (not found in sound food grains)

Fungi, bacteria and actinomycetes are grouped under the Thallophyta of the plant kingdom. The most important factors for their normal development are: (i) Nature of Food, (ii) Moisture, (iii) Oxygen and (iv) Temperature.

In the past several insect pests had entered India and are causing economically perceptible damage to native crops. The Government of India, in line with the International Standards on Phytosanitary Measures (ISPM), notified ‘Plant Quarantine Order, 2003’ to reduce the risk of introduction of exotic insect pests in India. The storage insect pests of quarantine concern for India have been listed in Table 9.1.

Since commencement of the settlement of world, the search for food had been uppermost, thereby, practising the conservation of food is a basic need for ensuring its ample supply to human being. The problem of food storage is growing fast day by day with the increase in the population. The existing shortage of protein and caloric requirements will not only be solved by growing more food and resorting to family planning measures but also by saving the produce from deterioration and wastage, and its efficient allocation to meet the growing requirement of population. In countries with varied climatic conditions, it is a steady struggle of man with insects, mites, rodents and microbes in getting the food stuff.

Need and Objectives of Storage

Since times immemorial, man adopted a particular system of storage and certain produce storage standards. Some of the storage methods are still in use in several regions, in the capacity varying from one kg to several hundred quintals, like hollowed gourds, skin bags, mud bins, excavated stones, woven baskets, underground pits etc., particularly in the tropics. The problems of storage in developing countries are more acute than that in well developed countries and a considerable disparity seems to be there in food availability. All need a food supply that should be nutritious, clean; free from insects, rodents, birds, other animal filth and harmful chemical residues. There are two types of needs, one immediately after harvest and the other in off season. There is no need of storing the produce for immediate requirement but for the latter case, the need to conserve produce properly is inevitable. Further, the need for storage has always arisen for one reason to distribute commodity in deficit production areas and the other based on improved quality standards. In all the way, therefore; growers, processors, transporters and warehouse owner must assist to comply with these requirements.

A series of efforts have been made to initiate the work on post harvest grain technology in India. The history of post harvest grain technology in India goes back as early as 1888 when COATS published several papers from Calcutta related to biology of stored grain pests. The first professional was appointed in the year 1905, known as Imperial Entomologist, Harold Maxwell Lefroy adorned with this post. Lefroy (1906) for the first time gave a tentative list of storage insects, which was further supplemented by Fletcher (1914). The problems of grain storage were discussed at the entomological meetings held at Pusa, Bihar in the years 1917, 1919 and 1923. The first step towards establishing an Institute in India was in the year 1950 when Central Food Technology Research Institute (CFTRI) was established at Mysore (Karnataka) with a mandate to train personnel and evolve technology related to food processing and preservation. The Central Warehousing Corporation was set up on 2^nd March 1957 under the Agricultural Produce (Warehousing and Development) Act 1956. The Food Corporation of India was established on 1^st January 1965.

In India, the farmers in traditional bulk and bag storage for food, feed and seed stored about 65-70 per cent of the total food grains and seed purposes till next harvest. Rest 30-35 per cent are procured and stored by food grain organizations, like Food Corporation of India (FCI), Central Warehousing Corporation (CWC), State Warehousing Corporations (SWCs), cooperatives, rural godowns and other state government agencies. In 1958, the Department of Food established a centre at Hapur known as Grain Storage Research and Training Centre (GSRTC) with the main objective to train the personnel of state government engaged in food procurement, storage and distribution. This centre was upgraded during 1968-1973 with the technical and financial assistance of UNDP and GSRTC and redesigned as Indian Grain Storage Institute (IGSI). The field stations at Ludhiana and Bapatla (later shifted to Hyderabad in March, 1979) were established in 1968-69. Subsequently, three stations were also established at Jabalpur (1980), Udaipur (1981) and Jorhat (1981).

Introduction

The increase in agricultural production, particularly food grain is one of the major problems of national planners to achieve the target in the food production. Our farmers have been utilized more and more the modern methods of agriculture including the use of chemicals for protection of crop and stored products against the pests. A successful farmer knows that what pests to expect on his crops and stored products, when and under what conditions their attack will be possible. But due to insufficient knowledge of chemicals and their application, our farmers use them without care and injudicious manner, therefore, these chemicals not only give poor kill of insects but also cause the hazards to man and domestic animals. Success in pest control operations depends on many factors such as correct identification of pest, proper timing of insecticidal application, right choice of chemicals and their formulations, doses and method of application.

Fumigants are still widely used for the control of insects and other pest organisms. Because of their unique characteristics and the great adaptability of fumigation technique, fumigants can often provide effective and economical control where other forms of pest control are not feasible. The development of light weight plastic sheets to enclose spaces or materials requiring fumigation has extended its use and made control procedures easier and much more adaptable. Among the fumigants, aluminum phosphide, ethylene dibromide (EDB), Ethylene dibromide- carbon tetrachloride (EDCT) etc. are most common in tropical and sub-tropical while methyl bromide is prevalent in temperate regions. Modern technology and research have also brought to notice certain problems with fumigants that are previously unknown. Among these, adverse effects on seed quality are most important. Thus, fumigants used in seed stores should not affect the viability of the seeds, should not be persistent, non-corrosive and highly diffusible.

All due precautions have to be exercised in handling pesticides because many of these leave toxic residues on treated food materials and plants which accumulate in higher concentrations in animals which consume these.

General Precautions

Read the precautions given by the manufacturer of the pesticides carefully. Store the pesticides under lock and key; prevent access of children to these; empty containers must be disposed off safely.

Blood and skin contaminations must be avoided.

The godown for fumigation must be made airtight by closing the doors, windows, ventilators, crevices etc.

In case of fumigation, the operator must use a suitable gas mask. It is a face-piece connected to a canister containing an absorbent material for the vapours of the fumigants by means of a flexible non-kinking breathing tube and provided with valves so that all air inhaled by the user passes through the canister and the exhausted air passes directly to the outside atmosphere through a non-return valve. The absorbent canister carries instructions indicating the number of hours for which it is effective in an atmosphere charged with the fumigant.

After the required exposure period, aerate the godown thoroughly. First open the entrance door, keep it open for 6-7 hours, then only enter and open other doors or windows.

Insecticide resistance to both fumigants and contact insecticides is an increasing problem in controlling stored grain and grain product insects throughout the world (Table 14.1). Hence, persons engaged in food commodity storage and preservation world over are concerned about the resistance of stored product insects to contact insecticides and fumigants. It is, therefore, necessary to work out strategies to delay or minimize the probability of resistance evolution. Resistance to pesticides is the ability of a strain of insects to tolerate doses of toxicants which would prove lethal to a normal population of insects of the same species. Resistance results when occasional resistant individuals arise in a population and survive the pesticidal treatment. These survivors then reproduce and confer the resistance to their offspring in succeeding generations. Resistance is the ability of a population (of insects) to survive a dose (of insecticide) that would normally kill 100 per cent of a susceptible population. Insecticide resistance is a dynamic phenomenon dependent on biochemical, physiological, genetic and ecological factors.

The chances of development of insecticide resistance in stored grain insect pest are more because of their life style, i.e., to remain confined in limited area. This results in more common inbreeding of the homozygous resistant strain resulting into homozygous resistant progeny. At the same time their management, once detected, can be easily achieved with the application of sufficiently acceptable sufficiently higher dose of the most appropriate insecticide to eliminate all the resistant survivors

The insect pest of stored grains can be conveniently divided into two groups, i.e., coleopterous and lepidopterous, therefore, the subject on these two groups has been pooled accordingly.

The produced food grains have to be stored either for short or long duration for utilization in the coming times for food, feed and seed. In storage, these undergo 9.33 per cent losses due to various agencies such as rodents, insects and mites, microorganism and moisture in India, whereas, in other developing countries, the losses are as high as 30 to 50 per cent. Therefore, with an urge to produce more, there is still urgent need to protect the produce in the storage to meet the challenge. As a result of improved storage technology, the losses in Government Warehouses could be reduced to minimum but at farmers’ level, where 60-70 per cent of the produce is retained, the losses are still too high.

The management of insects in stored products is in transition from a dependence on regular applications of chemical insecticides to the use of integrated pest management (IPM). IPM involves understanding interactions between stored product environment and insects associated with stored products, and replacing all or most of the chemical applications with cost effective non chemical alternatives. The increased emphasis in adopting IPM strategies for stored product insects is primarily due to consumers’ demand for food free from pesticide residues. The transition from a heavy reliance on chemicals to little or no chemical input and increased use of non chemical approaches requires a thorough understanding of stored product insects, their identification, monitoring, biology, ecology and response to chemical and non chemical management options. The current scenario of stored grain protection in India depends totally and judicious use of IPM strategies. For safe storage of food grains, both the preventive and curative measures are required: