eChapters

Weed

Weed in orchards reduce crop yields by competing for moisture, nutrients, light and space. They also harbour insect pests and diseases. When they become large they interfere with orchard operations. Some of weeds climb on the trees and shade the foliage. There are some weeds which are parasitic partially or completely on the host tree e.g. Striga and loranthes on mango.

Site-specific weed control technologies practiced in precision farming are defined as machinery or equipment embedded with technologies that detect weeds growing in a crop and take action to maximise the chances of successfully controlling them taking into account predefined factors such as economics.Some of the commercial hardware and software developed for precision agriculture practices comprise tools for weed mapping and control software that adapts spraying to local weed occurrence. However, few farmers have adopted sitespecific weed management, although several studies have shown that weed occurrence and density varies significantly within a farm or a field. Site-specific weed control techniques have gained interest in the precision farming community over the years. Managing weeds on a subfield level requires measuring the varying density of weeds within a field. Decision models aid in the selection and adjustment of the treatments, depending on the weed infestation. The weed control can be done either with herbicides or mechanically. A site-specific herbicide application technology can save large amounts of herbicides. Mechanical weed control techniques adapting to the weed situation in the field are applicable to a wide spectrum of crops.

A system for the discrimination of different weed species and crops from images is done which generates weed maps automatically. Models for the yield effect of weeds are developed and applied in on-farm-research experimental setups. Economic weed thresholds are derived and used for an herbicide application with a patch sprayer.Herbicide use has not eliminated weed problems in agriculture and the need for manual weed removal is still an issue within specialty crop systems, particularly during the first several weeks of crop emergence when competition for resources is greatest.

Precision agriculture is a powerful technology with potentially important applications to weed management. However, growers should remember good agronomic practices, including preventing weed infestations, managing herbicides wisely to prevent resistance, and minimizing environmental impact associated with weed management. Weeds, and methods used to control weeds, can have negative economic and environmental impacts. With precision agriculture, growers can take advantage of the patchy nature of weeds by targeting management efforts only where they are needed instead of wasting expensive and potentially hazardous inputs where weeds are not present. Weeds are patchy because weed spread, survival, and reproduction are variable within a field and over time. Weed patches stay in about the same place from year to year, even though weed density within a patch may vary

Weed

Definition: “Weed is an unwanted plant growing where it is not desired.” – Jethro Tull

Commonly noticed weed species in fruit orchard:

• There are more than 30,000 species of weeds distributed world over, out of which 18,000 are noxious and cause serious losses.
• Around 250 species are causing serious economic losses.
• Monocot weeds (Narrow leaf/Grasses): Cyprus, Cynodon, Poagrass, Rye grass, Quackgrass etc.
• Dicot weeds (Broad leaf weeds): Dandelion, Chenopodium spp., Parthenium, Solanum, Euphrobia spp., Ground ivy etc

Different crops are grown in a field. Any plant growing in a place where it is not desired competing with the main crops, has to be weeded out and such plants are called ‘weed’.

Effect of weed menace The weeds

Reduce crop yield and production efficiency. It competes with the main economical crop for space, water and nutrients.

Reduce crop quality.

Hamper intercultural operations.

Reduce crop quality.

Obstruct the flow of water in the irrigation channels.

Exert allelopathic effect on crops.

Harbour insect and pests, which affect the main crop of interest.

Increase the cost of production.

13.1 INTRODUCTION

Weed is defined as an unwanted plant growing at a place where it is not desired. Weeds are unwanted and undeserved plants that interfere with the utilization of the land and water resources and thus adversely affect crop production and human welfare. Thus, a plant out of its place or a plant growing where it is not desired at that time is a weed. Weed has no species, but name was suggested as a useless and harmful plant that persistently grows where it is quite unwanted. According to Jethro Tull, the father of Weed Science, weed is defined as the unwanted, undesirable plant, growing out of their proper place, which interfere with the utilization of natural resources, prolific, persistent, competitive, harmful and even poisonous in nature and can grow in adverse climatic conditions. Of the total losses caused by pests, weeds have a major share (30%). They reduce the crop yield and decrease the quality of produce and hence reduce the market value of the turnout. Weeds are a major problem to horticultural production as they take advantage of their initial slow growth rate. Weeds reduce crop yield, lower their quality, act as alternate host of many pests/diseases and also have allelopathic effects on crops. Weeds also interfere with vital farm operations like weeding, fertilizer application, herbicide application and harvesting. Both annual and perennial weeds are common in their actions reducing the productivity of fruit trees. Weeds also provide shelter to various pathogens by becoming an alternate or collateral host of invaded crops by a number of fungal, bacterial and viral diseases.

The worst weeds found in the world are Cyperus rotundus, Cynodon dactylon, Echinochloa crusgalli, Echinochloa colona, Eleusine indica, Sorghum halepense, Imperata cylinderica, Eichhornia crassipes, Portulaca oleracia, Chenopodium album, Digitaria sanguinalis, Convolvulus arvensis, Avena fatua, Amaranthus hybridus, Amaranthus spinosus, Cyperus esculentus, Paspalum cojugatum, Rottboelia exaltata (Rana and Rana, 2016). All of these weeds are found in India. It has been reported that about 36-42% losses may occur due to inadequate management of weeds in apple (El- Metwally and Hafez, 2007). Therefore, management of weeds in all agro-ecosystems is crucial to sustain our crop productivity and to ensure the food security to the rapidly increasing population.

Introduction

In a research laboratory, we frequently need weigh chemicals and prepare different solutions of varying strength, as per the requirements. Accuracy in weighing and preparation of solution, with respect to weight/volume and strength, determines the success of experiment. In turn, the accuracy depends on weighing of solid chemical and/or measuring the volume of liquid chemical/making up the volume. In this Chapter, weighing of chemicals using appropriate weighing balance, preparation of solutions of different strength, their dilution, and precautions while preparing will be discuss in brief.

Weighing of Chemical

The primary method to determine the amount of chemicals to be used is weighing the chemical by using a balance.

In general, there are two types of balances to weigh chemicals in a laboratory:

1. Standard laboratory balance

2. Analytical balance

Standard Laboratory Balance

Generally, a standard laboratory balance is used for weighing a chemical when an error of ±0.02 g is acceptable. It is also used for pre-weighing, where approximate mass needs to be determined. Precise mass of the chemical is then determined using an analytical balance. Following are the steps in using a weighing balance in a laboratory.

West Indian Cherry is a nutritive fruit mainly grown in semi dry and tropical parts of the country. It is native to West Indies and Central and South America and distributed in Southern Florida, Hawaii and other tropical and sub tropical regions of the world. West Indian Cherry received considerable attention in the 1950’s in its area of distribution because of its extremely high vitamin C content (2000-4600 mg / 100 gm of edible matter). It has been considered to be far superior to guava (Psidium guajava L.) as a potential source of vitamin c and it is richer than even the Indian gooseberry (Phyllanthus emblica L.), which is reported to contain roughly 800 mg of ascorbic acid per 100 g of edible matter. One fruit the size of a large cherry can furnish a man’s daily requirement of this vitamin. Thus the fruit of West Indian Cherry can rightly be called as the “pill of nature’s vitamin”. The fruit can be utilized for the production of crystalline vitamin C. The fruit is also rich in vitamin A, iron and can be consumed fresh or can be used in preparation of sherbet, ice cream, jelly and baby foods, fruit nectars and soft drinks. The juice can also be used to fortify ascorbic acid content of various other products and fruit juices to improve their nutritive value. It can withstand mild frost and drought. Fruits are good source of vitamin C and bark yields tannin (Chadha, 2001).

Rust
The rust of wheat has been studied more than any other disease in the world. K.C. Mehta and colleagues conducted exceptional research on the disease in India. There are three recognized wheat rusts. These include Puccinia graminis tritici, which causes black stem rust; Puccinia recondita, which causes brown rust (leaf rust); and P. striiformis, which causes yellow rust. Considering their later seasonal arrival, brown and yellow rusts inflict more damages than black rust.
1. Black or Stem Rust
Diagnostic Symptoms
• Symptoms are produced on almost all aerial parts of the wheat plant but are most common on stem, leaf sheaths.
• Brown pustules of uredina appear on lower surface of the leaves, leaf sheaths and the stems, and on the spikes. which give them a rusty appearance.
• Uredina form urediniospores , which are the repeating spores.
• Uredina gradually start producing teliospores and finally transform into telia.

Loose smut of wheat occurs worldwide but is more abundant and serious in humid and sub – humid regions. In India, this disease is found in all wheat growing areas but the incidence is generally more in comparatively cooler and moist parts of north India than south India. The yield loss may go up to 30% due to this disease.

White yams are food plants belonging to genus Dioscorea and family Dioscoreaceae with about 600 species. White yams are among the 10 species of edible yam and belong to species rotundata (D. rotundata Poir). It originated in West Africa.

White yams are herbaceous annual climbers. Its vine arises from large underground stem that is technically called tuber rather than root (Armstrong, 1996). The underground stem thickens to produce one or more tubers which vary in size and shape. The plant bears green flowers that turn brown on maturity and when dry. The aerial stem may be smooth or thorny which could be round/cylindrical (O’ Hair, 1984). Vines can grow to sizeable lengths if provided with a rigid support. Vine length varies within and among species. The leaves could be alternate or opposite, usually heart shaped and may be smooth or hairy. In some varieties, bulbils are formed but this is real in white yam.

24.1 Introduction

When crosses are made between two different species of a genus or between two different genera, they are known as distant hybridization (also called wide hybridization). It includes both interspecific and intergeneric hybridization. Thomas Fairchild (1717) was the first man to do distant hybridization. He produced a hybrid between two species of Dianthus, viz., D. caryophyllus and D. barbatus (Carnation and Sweet William). Intergeneric hybrid produced by Karpechenko, a Russian scientist, in 1928 is Raphanobarssica. It is the amphidiploid of cross between radish (Raphanus sativus) and cabbage (Brassica oleracea var. capitata). Unfortunately, it had roots like cabbage and leaves like radish. Triticale was produced by Rimpau in 1890 itself. It is an amphidiploid obtained from a cross between wheat and rye (Triticum and Secale). Another example is Saccharum nobilisation involving Saccharum officinarum, S. barberi, S. sinensis, S. spontaneum. Wide hybridization has been used in the genetic improvement of some crops. It is an effective means of transferring desirable genes into cultivated plants from related species and genera.

1. INTRODUCTION

Wine is the alcoholic product obtained by fermentation of fruits like grape, plum, peach, pear, apple and apricot (see chapter 25). Different types of wine which can be made from various fruits are:

• Table wines
• Fortified wines
• Sparkling wines

In preparation of table, fortified and sparkling wine many steps are common. It is out of scope of this text to discuss these specialized wines. But the general steps involved to in wine making are described here.

Equatorial Asia is home to winged beans (Geneva). On atrip to Thailand, Baker Creek’s founder, Jere Gettle, first observed flying beans. Because the winged bean is a tropical crop from the tropics, it takes a long time to flower, setting pods right before frost in our Missouri environment. The winged bean (Psophocarpus tetragonolobus) is a tropical herbaceous legume plant also known as cigarillas, goa bean, four-angled bean, four-cornered bean, manila bean, princess bean, asparagus bean, and dragon bean. From the Philippines and Indonesia to India, Burma, Thailand, Vietnam, and Sri Lanka, winged bean thrives in hot, humid equatorial climates. It’s well-known, yet it’s only farmed in limited quantities in Southeast Asia and Papua New Guinea.

Edible legumes are excellent sources of dietary protein and oils. Winged bean, otherwise known as Goa bean, Manila bean, princess pea, asparagus pea or four angled bean is becoming popular as a tropical legume vegetable. It is a multivitamin and multimineral packed legume. This wonder vegetable was considered as the vegetable of the twentieth century. It is also known as ‘soya’s rival’ or ‘God sent vegetable’. All parts of the plant are edible namely leaves, flowers, immature pods, immature seeds, mature seeds and tubers. It is also named as ‘a supermarket on a stalk’ because the plant combines the desirable characteristics of common bean, pea, spinach, mushroom, soya bean and potato. Its vernacular names are:  Bengali, Chara-koni-sem or lakar-sem; Tamil, Morisuavarai; Kannada, Shambe kayi; Malayalam, Chaturapayar or irachipayar and Marathi, Chavdhari ghevda.

Wood apple (Feronia limonia (L.) Swingle) is also called kainth, elephant apple, monkey fruit, curd fruit, kath bel and other dialectal names in India. It is drought hardy, medium to tall sized, under utilized fruit tree. In Malaya, it is gelinggi or belinggi, in Thailand, Ma-khwit, in Cambodia, Kromsang and in Laos, Ma-fit. In French, it is pomm-d-elephant, pomm de bois, or citron des mois (Morton and Miami, 1987). It is one of the most highly valued fruit plant grown in drier region of the country. Its plants are deciduous, glabrous, tree with thorny branches. Limited work has been done on its post harvest utilization.

The wood apple is native to India and common in the wild form in dry plains of India and Sri Lanka. It is also found growing throughout South East Asia, in Northern Malaya and on Penang Island. In India, the fruit was traditionally a “Poor man’s food” until processing techniques were developed in the mid-1950’s. It occurs, wild or cultivated, up to an elevation of 1500 ft, in Western Himalayas, but more common in the Deccan; Thane and Chandrapur districts of Maharashtra. It is also reported to occur in parts of Hazaribagh, Palamau and Chota Nagpur in Jharkhand, in forest of Vidhyan hills of Uttar Pradesh and Chattishgarh. It is often cultivated on borders of fields and as a roadside tree near villages and sometimes planted in the orchards. It is grown in the states of Odisha, Karnataka, M.P., A. P.  and Tamil Nadu.

Wood apple (Feronia limonia (L) Swingle) is a thorny tree commonly found in dry deciduous forests. In India, it is known by several common names like elephant apple, curd apple, monkey fruit, kavat, curd fruit and kath bel. In Malaysia, it is known as gelinggai or belinggai; in Thailand, ma-khwit; in Cambodia, kramsang; in Laos, ma-fit; in French, pommed’ elephant, pomme de bois or citron des mois. The tree is very hardy and has tolerance to drought and salinity. Its cultivation as a fruit tree is rare, but fruits of naturally occurring trees in community lands, forests and on roadsides are  used for chutney and pickle making. Fruits being rich in pectin, minerals and vitamins offer unique opportunity to utilize them extensively for processing. Extensive root system and synchronization of its reproductive phase with high moisture availability make it a suitable crop for arid zones.

Origin and Distribution
The wood-apple is native and common in  wild in dry plains of India and SriLanka and cultivated along roads and edges of fields and occasionally in orchards. It is also grown throughout Southeast Asia, in Northern Malaysia and on Penang Island. In India, the fruit was traditionally a “poor man’s food” until processing techniques were developed in the mid-1950’s. It is one of the very hardy trees  growing all over the plains of India, especially in the semi-arid and arid regions. It is more common in Deccan, Maharashtra, Madhya Pradesh, Uttar Pradesh, Chhatishgarh, Bihar and Jharkhand. Iit also occurs in the Western Himalayas upto an elevation of about 500 m amol.

The World Vegetable Center (previously called as Asian Vegetable Research and Development Centre, AVRDC) with headquarter at Shanhua, Taiwan conducts research, builds networks, and carries out training and promotion activities to raise awareness of the role of vegetables for improved health and global poverty alleviation. Vegetables can alleviate poverty by creating new jobs and new sources of income for farmers and landless laborers, improve health by providing essential micronutrients lacking in diets, enhance learning and working capacities of adults and children through improved diets and health, and improve the sustainability of food production practices by diversifying cropping systems. The Center’s research and development work focuses on breeding improved vegetable lines, developing and promoting safe production practices, reducing postharvest losses, and improving the nutritional value of vegetables (https://avrdc.org). The centre’s mission is Research and Development to realize the potential of vegetables for healthier lives and more resilient livelihoods

1. Introduction

India has a rich tradition of plant-based knowledge on healthcare. It is reported that traditional healers use 2500 plant species and 100 species of plants serve as regular sources of medicine (Pei, 2001). Traditional medical knowledge of medicinal plants and their use by indigenous cultures are not only useful for conservation of cultural traditions and biodiversity but also for community healthcare and drug development in the present and future. Medicinal plants have curative properties due to the presence of various complex chemical substances of different composition which are formed as secondary plant metabolites in various parts of the plants such as roots, shrubs, leaves, flowers etc. (Gurib-Fakim, 2006).

A large number of plants are equally used by tribals and folklore traditions in India for treatment of cuts, wounds and burns (Biswas and Mukherjee, 2003). A wound is a type of injury in which skin is torn, cut or punctured, that disturbance in the normal skin anatomy and function. Wound healing consists of orderly progression of series of events that establish the integrity of damaged tissue and thereby the affected parts repair itself after injury. The wound healing herbs encourage blood clotting and induce the healing of wounds (Sudhakar et al., 2003; Nagori and Solanki, 2011; Binu Thomas et al., 2012).

Yam bean (Pachyrhizus erosus) is a leguminous tuber crop of immense production potential. The crop has high rate of dry matter production / day / unit area and is known for its high degree of photosynthetic efficiency. Besides contributing significantly as a source of food to  weaker sections, the crop has immense industrial value for extraction of starch and production of animal feed. Yam bean is well suited to small and marginal holdings and has the capacity to withstand adverse biotic and abiotic stresses. It comes up well in comparatively marginal lands and does not require intensive care. It has  great potential in developing and underdeveloped countries where most of the farmers are small and marginal . This crop is very important in the context of food and nutrition security and assumes great significance due to ever-increasing human population. Still the importance of this crop is underestimated and unlike most staples, the crop fails to attract attention of  agricultural researchers throughout the tropical and subtropical countries of the world. The crop is still largely under-exploited and is subjected to little selection pressure. A large degree of variability exists for several agronomic characteristics in the existing germplasm. With a little attention from the scientists ,this crop could usefully be exploited by genetic improvement and development of crop ideotypes which would meet a wide range of needs in developing countries.

Yam bean(Pachyrrhizus erosus), a leguminous crop, native of North America is cultivated for its edible tubers. Though six species of Pachyrrhizus are grown for tuberous roots, P. erosus, P. tuberosus and P. aphipa are important.

While P. erosus(L.) Urban(2n = 22) has pods of 7.5-13 cm long, P. tuberosus has longer pods of 13-30 cm. P. aphipa is a non climbing plant with fusiform tubers and this species is mainly cultivated in Bolivia.  Synonyms for P. erosus are P. angulatus, P. bulbosus and Dolichus erosus.  P. erosus is the species commercially cultivated in India.

Wild forms of yam bean are seen in Mexico and northern parts of Central America, where its cultivation is reported during pre-Coloumbus period.  Yam bean is believed to have spread from Mexico to Philippines, Amboina before 17th century.  Now, yam bean is cultivated in China, Thailand, Singapore, India and Hawaii.

In India, it is grown in Bihar, West Bengal and Orissa.  In Hindi, it is called as “Miskri kand” and in Bihar as “Kesaru”.