1 Introduction

Rice Brown Planthopper, Nilaparvata lugens (Stal) (BPH) is the most economically important insect pest causing damage to rice crop. BPH is a small insect measuring about 4-6 mm in length and 3-4 mm in width in adult stage. Immediately after becoming adults, males and females mate. After mating, microscopic eggs are inserted by females into the leaf sheath with their ovipositor in batches of 30-80 per day. Egg period varies from 5-8 days and small whitish nymphs of about 1mm emerge. These nymphs as well as adults of BPH suck plant sap usually from phloem to derive nutrition and occasionally from xylem to satisfy the excess water deficit. Nymphs moult 5 times, each time increasing in size and finally becoming adults. Total nymphal period varies from 15-22 days depending upon temperature. Adult life span may vary from 7-15 days again depending on temperature and food availability. The population growth depends mainly on temperature and nutritional status of the plants on which they are feeding which results in wilting and finally death of rice plants (Krishnaiah, 2014a, b, c)

Field settling of BPH begins in newly transplanted crop, in about 15 days after planting either by short range travel or long range migration depending on source area of the insect. At the time of initial settling, population is very low ranging from 1-5 insects per 100 hills or to a maximum of 30 insects per 100 hills. At this stage long winged macropterous adults are randomly distributed in the field. They lay eggs on the same plants they settle or shift slightly to nearby plants after laying some eggs on original plant. Usually the nymphs that emerge are not uniformly distributed in the field or even in a small area of the field. Later, they move to nearby plants and become mainly short winged brachypterous adults capable of laying about 400 eggs per female. By the end of second generation populations reach damaging levels if unchecked. During the third generation damage starts appearing in the field in circular patches and if unchecked may spread to whole field causing total “hopper-burn” (Chaudhary et al., 2014; Krishnaiah, 2015).

2 General Pattern of BPH Occurrence in South Asian, South-East Asian and East Asian Countries

Critical analysis of BPH populations based on Insecticide susceptibility, Wing-form Response and Virulence for feeding on resistant varieties led to their demarcation to three distinct biotypes as East Asian, South-East Asian, and South Asian. BPH occurring in the region ranging from Northern Vietnam, China, and Korea to Japan belongs to the East Asian population. BPH present in The Philippines, Thailand, Myanmar, Laos, Cambodia, Malaysia and Indonesia belong to South-East Asian biotype. BPH present in Indian Subcontinent, including India, Pakistan, Bangladesh and Sri Lanka can be designated as South Asian Biotype (Sogawa, 1992). Each of these biotypes has its own migratory routes and patterns (Krishnaiah, 2015). Ever since BPH assumed a major pest status in early nineteen seventies in all these countries, use of insecticides remained as a major method of bringing down the BPH populations from damaging levels to those which appear to be safe temporarily. There are several reasons for this. Lack of suitable resistant varieties which can really contain the BPH populations and no effective natural enemies which can be depended upon either by inundative or inoculative releases or cultural methods which can drastically bring down BPH populations within a stipulated time prior to causing damage are the major factors.

3 Insecticide Application being the Major Method of BPH Management is Complicating the Problem

If we critically study the history of insecticide application against BPH in different rice growing nations, Japan is dominant in this sphere and used all the insecticides starting from DDT, HCH, organophosphates, carbamates, phenyl pyrazoles, neonicotinoids, buprofezin, and even the latest insecticide pymetrozine also. As an inevitable consequence there is high level of insecticide resistance development in BPH in almost all the countries. Further, migration of different biotypes adds another dimension to this problem. So all this points to a need to have an effective program to educate farmers in all these countries to enable to contain BPH the most important menace and yield limiting factor for rice today.

4 “BPH- a new problem in the old world” can be the Most Appropriate Theme in Educating Rice Farmers

The major differences between the agriculture of the old world or the oriental region comprising the Asia and the middle-east filled with traditions and the new world relating to U.S. and Canada having revolutionary and industrialized agriculture are well known to experts on the subject. In all the countries of Asia, agriculture is the basis for human settlements and agriculture is the initial and starting point of very human culture which means all other developments in humans in terms of clothing, housing, recreation, religion, health and sanitation, yoga and exercises etc. In the new world, humans could occupy the land only after development of sufficient civilization, ability to modify the environment and capability to manaevoure the nature to suit to their advantage and purpose. Then only complete colonization and further advancement in civilization was possible.

Since agriculture was the base for humans in the oriental world, major populations in villages of small, medium and bigger size had agriculture as their main way of living and people with skills to support the agriculturists as subsidiary occupations. All of them depended on agriculture as their base for living and life for thousands of years. So there are many festivals in relation to specific crops in the region and rice being is the major staple food crop occupied the major junk of the cultivated land while vegetables and fruit crops having subsidiary positions in the cultivation in the entire oriental region. Hence the land holdings were bound to be small and only fertile and useful lands with full irrigation were used for rice and those with partial irrigation for other crops (Hussain, 2004; Barker and Molle, 2004; Meenakanit et al., 1997).

In the new world there was hardly any civilization or agricultural activity before 15th century. Since all the lands were occupied by forests those could be suitably denuded and converted to agricultural fields. Hence a large-scale establishment of huge holdings was possible. With the already available technological skills mechanization and commercial agriculture enabled the farmers to manage huge farm establishments with minimum man power. Even the agricultural research, development of high yielding varieties, utilization of hybrid vigour in crops and animals resulted in viewing agriculture also as an industry. Hence like any other industry only small proportion of the total population started doing agriculture. Contrary, agriculture in the oriental region remained as a livelihood involving intensive manual labour and rice cultivation until recently travelled in the same path.

If we see the history, almost all oriental countries probably excluding Japan, were under colonial rule until the middle of twentieth century and towards the end of the second world-war. Large scale industrialization is known only towards the last quarter of twentieth century and beginning of the present century in almost all South Asian, South-East Asian and East Asian countries. Contrary to this, the new world proceeded with parallel advancements in industry along with agriculture and gained control over the world economy.

In the entire oriental region, the area under rice cultivation has undergone rapid expansion after construction of multipurpose dams on major rivers and exploiting the river waters to a maximum extent possible. Simultaneously the revolution in development of high yielding varieties and hybrids in rice have also taken a practical shape. Large scale epidemics of BPH in more and more intensive manner have become a common phenomenon also after 1970s. Further, the basic psychology of the farmers in the oriental region has moved from viewing agriculture and rice cultivation as a means of livelihood to as a commercial occupation to get income like any other commercial activity around them. This psychological shift is the major factor leading to adoption of hybrids in rice, moving away from organic agriculture to applying more fertilizers, attempting to apply more of insecticides and fungicides and also attempting to resort to weed management with chemicals due to inevitable burden on labour costs for manual weeding with changed government policies of very high wages in all other employment opportunities. All these again have a boosting effect on BPH attack and damage to rice crop (Krishnaiah, 2015).Thus any attempt to find a long-lasting scientific solution to BPH problem must keep all these historical aspects in view and must adjust ourselves to the new situation. Simply copying the methods of new world agriculture to BPH problem cannot be sustainable and long lasting.

We need to do a lot of basic research on understanding the ecological requirements of the insect under field conditions and simultaneously develop methods to create unfavourable ecology around the insect microenvironment but at the same time without adverse effect on yield levels. This could probably be a part of farmer education about BPH management in the entire oriental region apart from normal management practices like resistant varieties, cultural methods like adoption of alley-ways and optimum nitrogen application etc. in combination with suitable insecticides.

5 Linguistic Diversity in Asian Countries, the Major Hurdle in Farmer Education about BPH

The literacy level of an average rice farmer in Asia is very low. Hence it is obvious that the farmers’ education about BPH or rice cultivation practices is bound to be in the mother tongue of the farmer. Among the Asian countries China and Japan are more fortunate in this respect. In spite of being the most populous country in the world, every farmer in China can be educated about BPH in just one language. The same is the case with Japan also. In Vietnam, Vietnamese is the national and official language of the country as well as first or second language for the many ethnic minorities. Lao language is the official language of Laos although it has six dialects.

When we consider Indonesia, the problem is entirely different and highly complicated. There are 726 languages spoken across the Indonesian archipelago in 2009, the largest multilingual population in the world only after Papua New Guinea. Among these, 45 languages are spoken by different groups present in different parts of the country each by a population ranging from 0.3 million to 84.0 million while the official language Indonesian or Bahasa Indonesia a variant of Malay is spoken by 210.0 million. In many cases it is difficult to classify each one of them as a language or simply a dialect. In these languages different words are used for a single object and same word means different objects in different languages or dialects.

The picture in Malaysia is no different. In Malaysia there are 137 living languages, 41 of which are found in Peninsula region. The national, or official, language is Malay or Bahasa Malaysia which is the mother tongue of the majority Malay ethnic group and is a standardised form of the Malay language. The main ethnic groups within Malaysia comprise the Malays, Chinese and Indians, with many other ethnic groups represented in smaller numbers, each with its own languages. A common man in the west may wonder to hear that there can be riots for languages as each language is identified as symbol for a race.

The official language of Thailand is Thai. It is the principal language of education and government and is spoken throughout the country. The standard is based on the dialect of Bangkok, and it is written in the Thai alphabet. Apart from this, there are 73 living languages used in Thailand. There are approximately a hundred languages spoken in Myanmar (also known as Burma). Burmese, spoken by two thirds of the population, is the official language.

In Philippines, Filipino is declared as the national language of the country in 1987 Constitution. Filipino and English are the official languages. The indigenous script of Philippines (Baybayin) is no longer used.  Instead, Filipino languages are today written in the Latin script because of the Spanish and American colonial experience. In addition, there are some 120 to 175 languages in the Philippines, depending on the method of classification. Although Sri Lanka accords official status to Sinhalese and Tamil there are several other languages spoken in the island nation including those of Arab, Portugal, the Netherlands, Britain and neighbouring India, the Maldives and Malaysia (Woodard, 2004; Woodard, 2008; Lewis et al.,2010).

Under these circumstances one can imagine how difficult it is to send a particular message regarding BPH management to individual farmers precisely and emphatically.

In India there are 22 official languages each is confined to a small geographic area but spoken by huge population ranging from 50 million to 500 million. Apart from Hindi which is the national language along with English the other languages are also very ancient each having its own script and voluminous words related to social and cultural aspects of civilization. But at the same time the correct words related to science and technology are very scarce. The most important reason for this can be understood if we briefly analyse the history.

We all know that most of the modern science and technology had their real initiation from 15th century onwards and with Europe as the original region. Starting from that period till the middle of twentieth century when India as well as most of the Asian countries could get independence, these countries did not have scientific exposure for varied reasons. During this period, the industrial revolution has spread to U.S. and Japan from Europe. We all know that most of scientific literature even today is prevalent in English. So all the original terms of the scientific and technological importance are present in English and are mostly derived from Latin the mother of all European languages. Lack of suitable technical terms in Indian languages as well as in other Asian languages to indicate a particular scientific aspect or even an organism is now becoming the greatest hurdle in educating the farmers about BPH and so also other insect pests of rice and other crops.

The following simple illustration can make this point very clear. Rice Brown Planthopper in Telugu the language spoken in Andhra Pradesh and Telangana states is called “doma”. The term “doma” is also the same word that indicates “the mosquito” which bites humans and acts as a vector of many human diseases like malaria, dengue etc. When we communicate with the farmers as “doma” he understands by common sense that both BPH and mosquito are almost the same. Hence many a times when mosquitoes are present in rice field which is a normal feature either alone or along with BPH, farmer thinks that mosquito is also attacking rice and is the same as that of BPH. Even in other Indian languages also almost the similar situation exits. Poor education among farming community in India and other Asian countries is an important problem which is the root cause of all this but it is adding dangerous dimensions to BPH control.

Compared to a situation in U.S. or Canada where farmers are well educated and where any scientist speaks to his farmer colleagues as “Rice Brown Planthopper” or other insect like “European Corn Borer” or “Colorado Potato Beetle”, it is taken just as that and the scope for misunderstanding and misinterpretation is negligible or almost nil. It is in this context that we have to understand the difficulties in educating rice farmer in Asia about the problem of BPH and also disseminating the technology for its proper management.

6 Small Holdings, Unorganized Farming and Tenant Farming are Other Hurdles

For a movement let us compare the rice farmer of Asia to an average farmer in U.S. Average size of farms in U.S. at present is 1,100 acres and has increased from less than 600 acres in the early 1980s (MacDonald et al., 2013). Many larger farms now dominate crop production in the United States, while the average holding of a farmer in most of the Asian countries is less than 2 acres. The position is still worse in some countries like Sri Lanka and India. Thus it is obvious that the total number of farmers is bound to very high. So communicating with individual farmer up to sufficient extent to educate him at every point of rice cultivation and more importantly about every aspect of BPH is just impossible. Therefore, mass communication is a must and needs to be devised and streamlined for every language. “Digital India” the program presently devised by Indian government can incorporate farmer education program on BPH. It may take time but still it could be effective. Similar programs in other Asian countries can certainly help to educate rice farmers about BPH and can eventually help to manage the insect effectively and thereby to increase and stabilize rice productivity.

It may not be an exaggeration if one says that “the most inefficient people in villages not having knowledge or capability to do any other activity which can fetch them money” are engaged in agriculture in general and rice cultivation in particular in most of the Asian countries. This means that scientists have to communicate with the people endowed with low skills and low ability to understand and comprehend and adopt BPH management practices. Further, the normal extension machinery is working probably at lowest ebb or is almost defunct from disseminating information and providing service required for individual rice farmer to forewarn, assess and suggest suitable control measures for BPH. This entire means there is no scope for organised effort to educate Asian rice farmer about BPH management very similar to other activities concerned with rice cultivation or that of other crops. Hence, an average rice farmer is left to his own fate. When BPH attacks rice crop the farmer cannot diagnose until the external symptoms of damage visible from the field bund like “hopper- burn” can be seen here and there in the rice field. As scientists we can easily comprehend that that is too late a stage where control measures need to be initiated.

In many rice growing countries including India, government intends to help rice farmers in many ways. That can be in the form subsidy for purchasing the chemicals required for BPH management, fertilizers required as a part of rice crop cultivation, machinery involved in general cultivation as well as pesticide application etc. This is normally done based on the extent of land held by each of the rice farmers. The basis for recognizing the ownership of the land is through the records held by government and available with the farmers given in the form books or certificates indicating the extent of the land and other details.

The most important point here is in more than 50 to 60 % of the cases the land owner is not the actual cultivator. The owner mostly inhabiting in a nearby or distant towns and cities leases his land for cultivation to some person living in the village where the land is present. So many a times the benefits intended by government for cultivators for BPH management or other activities in rice cultivation can be routed through the owner of the land. This automatically means that the tenant becomes a captive in the hands of the land owner and many a times becomes victim without deriving any benefit from the government.

7 Communicating with Rice Farmers about BPH and its Management- Practical Difficulties and Possible Methods to Overcome

First of let us see what is communication? The term “communication” is derived from Latin word “communis” meaning “common image”. The main point here is whenever we think of something let it be an article, a person, a place, a situation, even coming straight to the point even damage of an insect in rice field or even more specifically speaking the damage by BPH, a scientist has got an understanding and detailed knowledge about that. But when a farmer whose level of education is far below that of a scientist he also has got an image about all those things but not very similar to that of a scientist. When a farmer sees BPH damage in the field and starts describing the same most farmers’ description can be different or at times very much different from what the scientist has got about the same in mind. Similarly when a scientist starts describing BPH damage to a farmer who has seen the same, then farmer often may not get the correct point under discussion. “The most efficient communication is the process in which a person having a picture in his mind is able to create the same picture in the mind of the other person”. This is easily possible when the back ground knowledge of the two people is almost similar. But the process becomes more and more difficult as the knowledge gap between the two persons communicating with each other is high to very high as it is the situation in case of a scientist and an average farmer in Asia whose understanding about many aspects including BPH is very poor. This is the most important practical problem while devising the strategies for BPH management. So we have to think how to overcome this problem with least wastage of time and money.

It is known that there are many methods to extend the scientific knowledge to a farmer which is more elaborately dealt at undergraduate level as a separate subject called “extension”. Now let us see the most common points in the whole of that subject of agricultural extension and how far we can utilize as many possible methods for creating a better understanding among the farmers about BPH finally leading towards better management of this important yield limiting factor in rice production in all Asian countries.

1. Printing pamphlets and small booklets in local language and distributing to the farmers used to be the method for a very long time, which is also utilized to a limited extent at present.

2. Making small video type pictures on the damage and process of spreading of damage under field conditions, BPH biology including the pattern of migration etc. can certainly create an understanding about BPH problem among the farming community. Undoubtedly everything should be in local language and at a level that can be perceived by the farmers.

But the most important practical limitation of both the above methods is that the farmer needs a correct and on the spot advice by a scientist and usually do not find time and feasibility for both the above methods. His poor educational status also adds another dimension to this crucial situation.

3. By utilizing the modern information technology, attempts are being made to take the photos at the field level by the farmer with his mobile phone and transfer the same to the scientists or extension worker who can suggest immediately and appropriate management strategies or more practically speaking appropriate insecticide and other relevant details.

Most important limitation in this process is the picture taken by a farmer whose understanding about BPH is poor to very poor, then the picture cannot really give a correct understanding to the scientist concerned. This method  although is being experimented at different levels i.e. by private agencies to promote the sale of their products, government agencies to help farmers as their routing duty, still it is bogged up with many practical difficulties and is often creating more problems of misunderstanding of the situation than solving BPH problem. The reason is while taking a photo if damage by other insect pests or disease symptoms or phytotoxic symptoms already existing due to faulty application of a chemical also appears, then it leads to completely erroneous picture in the mind of the scientist and thereby farmer is immediately put to heavy loss.

4. Another most practical method which involves lower cost and helps to diagnose correct field damage is asking the farmer to get into the field along with his mobile phone and at the other end scientist can ask a series of questions which can be extended normally for 5-10 minutes or more if need be. Then the scientist can get almost a definite idea about the actual field situation as a whole. This includes whether it is BPH damage or not if it is BPH damage at what stage the pest population is present, what is the extent of spread in the entire field, are there any other insect pests and or diseases also along with BPH. Several other things those are essential for the scientist to correctly assess the whole of the situation will also be revealed. Then the scientist can correctly guide concerned farmer to use the most appropriate control strategies including the insecticides, their dose, method of application and frequency of application etc. This is based not only on the personal experience of the authors but also on the practical field strategy of many other scientists, and many extension personnel with long experience.

8 Major Technical Aspects which need Emphasis in Farmer Education about BPH

8.1 Importance of cultural methods in lowering BPH multiplication

Optimum plant population, leaving 30 cm alley-ways after 3-4 meters of planted area, optimum NPK fertilizer application and avoiding excessive nitrogenous fertilizers, optimum water depth in a rice field are the key for lowering BPH populations with least adverse effect on yield levels.

8.2 Proper knowledge regarding BPH resistant and tolerant varieties

Although BPH has the capability to overcome varietal resistance after some time; those could serve useful purpose if properly used. For instance, MTU 1010, variety released from Maruteru Research Station in Andhra Pradesh India, maintained lower BPH populations under farmers’ conditions for 3-4 years, but slowly turned to become susceptible. Other varieties having some degree of BPH resistance are not preferred by farmers due to other factors like longer duration as in the case of MTU 1061, or due to low market preference for the grain quality of MTU 1001. Another point is even when the resistant varieties are in the field farmers resort to similar number of insecticide sprays as in susceptible varieties. Apart from these field observations, scientific efforts to quantify tolerance levels and basis for the mechanism are also lacking.

8.3 Using insecticides with different modes of action

Indiscriminate use of same insecticides at higher than recommended doses consecutively for several seasons resulted in hastening the insecticide resistance development in almost all rice growing countries. Due to poor or no understanding about mode of action of each insecticide or a group of insecticides, many farmers do not believe in rotation of chemicals having different modes of action on BPH. Hence proper emphasis on using insecticides with different modes of action in each of the geographic regions of south Asian, south-east Asian and east Asian countries can be the most useful and practical strategy to slow down resistance development in BPH (Heong et al., 2013).

8.4 Completely avoiding BPH resurgence causing insecticides in rice ecosystem

Another major factor contributing to BPH menace is extensive use of resurgence causing chemicals like chlorpyriphos, profenophos, Lamda Cyhalothrin or other synthetic pyrethroids or their combinations in early crop stages (vegetative phase) to manage leaf feeders and stem borers in rice.

8.5 Imparting proper knowledge about brand names of insecticides

In India and also in many other Asian countries, governments have the policy of licencing small companies with their brand names for each of the popular insecticides. This is mainly aimed to increase the competition among the companies and to cut down the price of the insecticide product in market which automatically leaves many brand names for each product. This inevitable situation creates problem in educating farmers about proper insecticides for BPH. Even then, this has to be overcome with proper planning in telling the farmers about all brand names for each product.

8.6 Methods for monitoring for BPH under field conditions

Educating farmers about favorable weather for BPH upsurge along with methods for proper monitoring by entering into the field and observing during peak periods can bring down the sudden upsurge of BPH problem and can facilitate timely control actions.

8.7 Regular monitoring for insecticide resistance and modifications in recommendations to farmers

Insufficient understanding of insecticide resistance in actual field situations is the major bottle neck in suggesting proper insecticides to rice farmers. Japan and China are far advanced in this area of research and extension. All other countries can follow their example. However, due consideration can be given about the actual migration pattern of three biotypes of BPH prevalent in south Asian, south-east Asian and east Asian countries (Krishnaiah, 2015). 

9 Summary and Conclusions

1. Rice Brown Planthopper, Nilaparvata lugens (Stal) (BPH) is a small insect measuring about 4-6 mm in length and 3-4 mm in width in adult stage and causes serious damage to rice crop by draining out plant sap, many a times resulting in total “hopper-burn”.

2. Three distinct biotypes of BPH designated as East Asian, South-east Asian, and South Asian are prevalent in respective regions, each with its own long range migratory routes.

3. Over reliance on insecticide use as the only practical management tactic led to high level of insecticide resistance development in the insect to all major groups of chemicals.

4. Thus a need for proper education of the farmers is essential at this juncture. For that “BPH- a new problem in the old world” can be the most appropriate theme in all the regions of Asia.

5. The literacy level of an average rice farmer in Asia is very low. Hence farmers’ education about BPH is bound to be in the mother tongue of the farmer. However, Linguistic diversity in Asian countries is becoming a major hurdle for precise and timely communication with the farmers in all the regions.

6. The infra-structural existence of small holdings together with unorganized and tenant farming conditions are also other hurdles.

7. Among different methods of communicating with rice farmers about BPH and its management, direct on the spot assessment under field conditions by rice farmer and simultaneous communication to the concerned scientist with the help of mobile phones appear to be the most effective practical method.

8. Major technical aspects which need emphasis in farmer education about BPH appear to be Importance of cultural methods in lowering BPH multiplication, Proper knowledge regarding BPH resistant and tolerant varieties, Rotating insecticides with different modes of action, proper knowledge about brand names of insecticides.

9. Educating farmers about favorable weather for BPH upsurge along with methods for proper monitoring of field populations of the insect along with regular monitoring for insecticide resistance and modifications in recommendations to farmers also appear to be very important.

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