eChapters

23.1 Introduction

Cultural methods have been in practice for pest management in traditional systems of agriculture since time immemorial. The worldwide awareness of safe environment provided the impetus to foster non-chemical pest management strategies. Of these strategies, cultural control constitutes the most farmer-oriented approach, where the weak points in the biology and behaviour of insects are exploited and pressure is exerted on the population by manipulating the environment.  In addition to the cultural practices, the other widely used approach is the use of physical control methods which hold promise and provide an attractive alternative to current practices, particularly when integrated into a general control scheme incorporating cultural methods, plant breeding, biological or behavioural methods and pesticides. In physical control methods, the physical environment of the pest is modified in such a way that the insects no longer pose a threat to the agricultural crop.

22.1  Introduction

Plant pests have been part of man’s environment for a long time. Traditional agriculture, which included diverse crops and indigenous crop management practices, provided little opportunity for pests to build up and spread rapidly (Smith and Allen, 1954). Crop production is constantly threatened by increasing difficulties in controlling insect pests, which are a major impediment to improved livelihoods of poor farmers. However, in the quest to increase food production for the growing population, use of pesticides became a norm in crop management. Pesticides became an integral part of the process owing to losses from weeds, diseases and pests reducing the harvestable produce. Use of pesticides along with high yielding varieties, irrigation and improved seed did result in increased productivity. But the rampant use of these chemicals, under the adage, ‘if little is good, a lot more will be better’ has played havoc with human and other life forms.

21.1 Introduction

Plants and insects share a wonderful relationship. Both are dependent on each other at different levels and chemicals emitted by plants connect them to a large extent.  “Plants” contribute to a major share of occupancy on earth and makes several organisms such as insects & microbes and also humans to depend on them for their survival. This dependency leading to several interesting interactions between plants & insects which are often utilized by humans for their own benefit. Plants maintain incredible communication with their associated organisms. Since plants are rich banks of chemicals and constantly emit them in to its immediate environment which contributes in communication between insects and plants. Insects are the major organisms that have a long relation with the plants and there are several incredible ways how plants can interact with insect species.

Chemical ecology is the study of ecological interactions between organisms mediated by chemical produced by those organisms. In short it is considered as the ecological functions of the chemicals. An insect, in various stages of its life history, performs various activities like host plant location, host plant selection,  feeding and oviposition, mating, escape from its natural enemies etc. and the chemicals play a crucial role than visual and audio signals. Chemical ecology encompasses the studies of these chemicals based interactions.

19.1. Introduction

A wave of research on insect pheromones has been initiated in early 1960’s in response to public concern and alarm about chemical pesticides to develop an elegant and ecologically safe technology for the control of insect pests. Pheromones, a class of semiochemicals are considered as ‘Biochemical Pesticides’, belong to the subdivision of Biorational pesticides which include “Microbials” (Viruses, Bacteria, Pathogens etc.) and “Biochemicals” (insect plant growth regulators, semiochemicals etc.). The term biorational (biological + rational) pesticides can be defined as the use of specific and selective chemicals, often with a unique modes of action, that are compatible with natural enemies and the environment, with minimal effect on non-target organisms. Biorational control is based on a diversity of chemical, biological and physical approaches for controlling insect pests which results in minimum risk to man and the environment (Horowitz  et al., 2009).

Plantation crops are high-value commercial crops of greater economic importance which play a pivotal role in the world economy. These include coconut, arecanut, tea, coffee, rubber, cocoa, oil palm, cashew. In this chapter only Cashew and Rubber are dealt with since the other plantation crops have been dealt in the earlier chapters.

17.1 Introduction

Cotton is a major fibre crop of global importance and has high commercial value. It is grown commercially in the temperate and tropical regions of more than 100 countries. Specific areas of production include countries such as China, USA, India, Pakistan, Uzbekistan, Turkey, Australia, Greece, Brazil, Egypt etc., where climatic conditions suit the natural growth requirements of cotton. These include periods of hot and dry weather and adequate moisture obtained through irrigation. Cotton crop is considered as one of the most important cash crops that influenced the industrial and agricultural economy of the different cotton growing countries of world. Thus, cotton is an immensely important crop for the sustainable economy of these countries and livelihood of the farming community. Cotton crop is considered as one of the most important cash crops that influenced the industrial and agricultural economy of the different cotton growing countries of world. Cotton cultivation and textile industry provide livelihood to million persons, therefore any failure of cotton crop significantly influence the economic growth of cotton belt and textile sector.

16.1 Introduction
According to Howard (2001) the major world crop palms are coconut palm (Cocos nucifera L), African oil palm (Elaeis guineensis Jacq.) and date palms (Phoenix dactylifera L). Many other palm species provide products for international commerce and also grown as ornamentals. Some palm species are of local or regional importance and have great potential for expanded development and distribution. In general, commercial production of palms regularly starts on or near natural habitats with little agricultural development.

15.1 Introduction

In recent years, the role of plant secondary metabolites as protective constituents in the human diet has been a growing area of research. Unlike the traditional vitamins, they are not essential for short-term wellbeing, but there is increasing evidence that modest long-term intakes can have favourable impacts on the human health. Teas, coffee and cocoa represent plantation cash crops grown in many of the warmer, less developed regions of the world. They serve as stimulant beverages and their demand is ever increasing day by daily. However, production of these beverages is under the severe threat due to attack from various pests and diseases which cause considerable damage.

14.1 Introduction

Sugarcane, basically a tropical crop in nature, requires a suitable high temperature, a lot of sunshine and rainfall ranging from 1250-2500 mm for its growth and yield. Relatively speaking, it is an intensive user of water as compared to rice and other crops. The total water requirement to mature the crop is about 64-80 acre inches.  Although globally but Brazil and Mexicos in Americas, India, Pakistan, Thailand and China in Asias, Australia and Africa, the Caribbean and to a smaller degree in southern Europe and the Middle East are major sugarcane growing areas in the World (Khan and Jamil, 1983). Historically famous for sugar, this crop has now attained a significant nadir for biofuel production (Mino, 2010).

Sugarcane, a perennial grass, is exposed to all sorts of biotic and abiotic adversaries. The variation in weather parameters like sunlight, temperature, rainfall, humidity and solar radiation affect the different phases of growth like germination, tillering, cane formation and cane stalk elongation, as well as the maturity and ripening phases of plant (Malik, 2009).

13.1 Introduction

Citrus is one of the important fruit crops in India with the production of 111.47 lakh tons from 10.78 lakh hectares with the productivity of 10.34 tons/ha at national level as compared to 25-30 tons/ha in advanced citrus producing countries (NHB, 2013). The productivity and quality of citrus is severely affected by several factors; insect pests being one of them. More than 250 insect pests were reported to attack citrus in India. A total of  22 insect species  in Punjab (Atwal, 1976) ; 50  insect species  in  Karnataka;  42 insect species  in  North-Eastern Hilly region (Pathak and Rao, 1999);  20 insect species in West Bengal and  about a dozen  insect species  in central India have been reported on different citrus cultivars. Further, the pest occurrence and distribution in India indicated that about 21 species are common throughout the citrus growing areas and remaining species may occur in some areas either occasionally or rarely. Of the reported insect pests, Asian citrus psyllid (Diaphorina citri Kuwayama), citrus blackfly (Aleurocanthus woglumi Ashby), whitefly (Aleurolobus marlatti (Quaintance) and Dialeurodes sp.), leaf-miner (Phyllocnistis citrella Stainton), lemon butterfly (Papilio demoleus Linn.), leaf folder (Psorosticha zizyphi Stainton), aphids (Aphis spp. and Toxoptera spp.), thrips (Scirtothrips spp.), mealy bugs (Planococcus citri Risso), scales (Coccus hesperidus Linn), fruit sucking moth (Eudocima spp.), fruitfly (Bactrocera sp.), citrus trunk borer (Anoplophora versteegi Ritsema), bark eating caterpillar, lndarbela spp.

Introduction

Banana (Musa sp; family: Musaceae) is the most popular commercial soft fruit crop grown in equatorial and subtropical regions of the world and also serves as a staple food since the dawn of recorded history in many countries (FAO, 2012). It has bounties of significance to the human beings and is one of the 4th most important food in the world after rice, wheat, and maize. Musa species grow in a wide range of environments ranging from the edible bananas and plantains of the tropics to cold hardy fiber and ornamental plants. They thrive well in an average annual temperature of 20^°C and well distributed rainfall of 200 cm per year (Simmonds, 1959; Wardlaw, 1961). Banana is a large, perennial, monocotyledonous herb 2-9 m in height that arises from large, subterranean rhizomes called ‘corms’. Musa fruits are variable in size, shape, and color. They are generally elongate cylindrical, straight to strongly curved, 7-40 cm long, and 2-8 cm in diameter. The fruit apex is an important attributes in variety identification.

11.1 Introduction

Tropical Root and Tuber Crops serve as primary or secondary staple to meet the calorie needs of one fifth of world’s population. These crops have myriad and complex roles to play in the food security and reduction of hunger and elimination of poverty. The starch content, pharmaceutical and nutraceutical value endow these crops with an extra ordinary range of potential and uses. Root and tuber crops are also greater sources of industrial raw materials for biodiesel and starch derived materials.

10.1 Introduction

Grain legumes such as chickpea, pigeonpea, cowpea, field pea , lentil, ,  and Phaseolus beans are the principal source of dietary protein among vegetarians, and are an integral part of daily diet in several forms worldwide. They are an important component of cropping systems to maintain soil fertility because of their ability to fix atmospheric nitrogen, extract water and nutrients from the deeper layers of the soil as compared to cereals, and add organic matter into the soil through leaf drop. However, grain legumes are mainly grown under rainfed conditions and the productivity levels are quite low mainly because of severe losses due to insect pests and diseases.  Average grain yield of pulses (0.86 t/ha) is only about one-fourth the average yields of cereals (3.54 t/ha).  Production and productivity of grain legumes is constrained by several biotic and abiotic factors, and suffer an average of 31.9 to 69.6% loss in crop productivity due to insects, diseases, drought, weeds,  and soil fertility. Pod borers (Helicoverpa and Maruca), Fusarium wilts, viral diseases, Ascochyta blight and Botrytis gray mold (Chen et al., 2011).

9.1 Introduction

Cereal crops are of global importance and the lifeline of the human civilization. The four most important cereals grown for human food in the tropics are rice, maize, sorghum and pearl millet. There are other minor cereals of tropical origin which are of local importance in the tropics. These include finger millet (Eleusine coracana), a staple food in parts of East and Central Africa; barnyard millet (Echinochloa frumentacea), cultivated in India and Southeast Asia; foxtail millet (Setaria italica), grown in parts of India; and teff (Eragrostis tef), which is confined to the Ethiopian highlands. The winter cereals wheat and barley are also grown to a limited extent in the tropics, largely at high altitudes: for example, wheat in Kenya and barley in Ethiopia. Wheat and barley are important crops in the Indian subcontinent, and are grown there in the cool season at low altitudes, but the bulk of the crop area lies outside the tropics.

8.1 Introduction

Vegetables are cultivated over an area of about 19 million ha globally, with an annual production of 268 million tonnes; Asia and Africa account for more than 90% of the hectarage and production (FAO, 2011). Vegetable crops contribute to human and environmental health. Most vegetables can supply plant proteins, vitamins (especially vitamins A and C), folic acid, minerals such as iron and calcium, and dietary fiber to the human diet (Fowler, 2011). Vegetable legumes also fix atmospheric nitrogen in the soil, thus improving soil fertility. Their haulms can be used as high quality livestock fodder. Most vegetables are high-value, repeat-cycle crops that can help lift small-scale farmers out of poverty in developing tropical countries (Genova et al., 2010). However, vegetable production is often constrained by several severe biotic- and abiotic factors that reduce yields and profits.

7.1 Introduction

Sustainable agricultural systems must be adopted to increase the food production keeping in view of increase in human population. In tropical countries, insect pests are major challenges to increase food production by causing significant damage in the crop fields and stored grains and their products. Interventions by implementing timely integrated pest management strategies are necessary to reduce the yield losses. Efforts to control insect pests have predominantly relied on the use of broad-spectrum insecticides.  However, indiscriminate and irrational applications of insecticides have created the problems such as insecticide resistance, resurgence, secondary pest outbreak and the presence of residues in food and environment (Ansari et al., 2013). Globally, to reduce the pesticide dependence, various technologies have been developed using different approaches to monitor and maage insect pests which are discussed in this chapter.

6.1 Introduction

The sensitivities of plants and of crop yield to a changing climate, is a major challenge for the agricultural research community to relate these findings to the broader societal concern with food security. This chapter reviews the direct effects of climate on both crop growth and yield and on plant pests and pathogens and the interactions that may occur between crops, pests, and pathogens under changed climate. The better understanding of the roles of pests and pathogens in crop production systems that might   make to enhanced food security is discussed. Evidence for the measured climate change on crops and their associated pests and pathogens is starting to be documented. Globally atmospheric CO₂ has increased, and in northern latitudes mean temperature at many locations has increased by about 1.0–1.4 ^°C with accompanying changes in pest and pathogen incidence and to farming practices. Many pests and pathogens exhibit considerable capacity for generating, recombining, and selecting fit combinations of variants in key pathogenicity, fitness, and aggressiveness traits that there is little doubt that any new opportunities resulting from climate change will be exploited by them.

5.1 Introduction

Rainfed agriculture accounts for about 60-95% of farmed land in major areas of the world covering Saharan Africa, Latin America, North Africa and East Asia and South Asia. Agriculture in about 60 percent of 142 m ha of net cultivated area in India is rainfed without access to any source of irrigation. Rainfed agriculture is mostly practiced in arid, semi-arid and sub-humid regions where the rainfall is low in quantity, erratic in distribution and is also characterized by high inter-year variability. Together with poor and degraded soils, this limits the length of growing season as well as the choice of crops that can be grown sustainably. Coarse cereals, pulses, oilseeds and cotton dominate the cropping pattern in the regions where rainfed agriculture is concentrated. More importantly, these rainfed regions provide a livelihood to a majority of the rural poor, and as a result they are often described as concentrations of mass poverty and hotspots for civic strife. The productivity of crops grown in rainfed areas is considerably lower than its potential and much lower than that of irrigated crops. Enhancing the productivity of rainfed crops is therefore important from the viewpoints of growth, equity and sustainability.

4.1 Introduction

Insecticides, biocontrol agents and resistant varieties are the three important pest management tactics in vogue across the globe. Though several biocontrol agents have been recorded on major pests of economically important crops, mass multiplication techniques for most of them are yet to be perfected, and in several instances, the inundative releases of natural enemies are costlier than chemical insecticides. Moreover, unlike perennial crop ecosystems, the annual crop ecosystems like rice, cotton, sugarcane, pulses, etc. are frequently disturbed and hence, inoculative releases of biocontrol agents are often impractical. Above all, in spite of sustained effort from dedicated plant breeders across the globe, the resistant varieties with outstanding yield potential are very limited in numbers. Genetic engineering of crop plants though paved the way for introducing insecticidal genes more precisely and efficiently, the poorly understood ecological and sociological implications of genetically engineered crops in their target environment resist their strong footing in the pest management programmes in most of the crops especially of food crops. In this backdrop, insecticidal interference is inevitable to manage the insect pests, and they are the only weapon whenever the pest population crosses the economic threshold level.