CHAPTER 7Pest management practices of rice farmers in the rainfed lowland

environment of the Lao PDRH.R. Rapusas, J.M. Schiller, and V. Sengsoulivong

AbstractA survey of rice farmers was conducted in 11 provinces in the northern, central, and southern regions of Laos. A total of 463 respondents selected randomly from the sites were interviewed in February, March, and October 1994. Most of the respondents were 30-45 years old and were owner-operators (90.3%). Farm sizes ranged from 0.25 to 7 ha. Thirty-eight percent had <1–1 ha, 43% had >1-2 ha, and a few had >5 ha of land cultivated with rice. Farmers grew the traditional photoperiod-sensitive and glutinous varieties, growing 3–4 varieties in one season. The cropping pattern was usually rice-fallow (75.6%), although 23% had rice-rice and 1% had rice-others (maize, vegetables, watermelon). Stem borers, grasshoppers, rice bugs, gall midge, and other lepidopteran larvae and worms were reported to be the most common pests observed in fields. About 75% of the respondents indicated that they did nothing to control these pests, whereas 22.7% said they applied pesticides. Most of those who used pesticides applied them only once, mostly in the seedbed and within the first 40 days after transplanting. Most of the pesticides used belong to WHO most toxic categories. Yields of farmers who did not apply pesticides were higher than for those who treated their crops against insects, rats, and crabs. Seventy-two percent of the respondents perceived that leaf-feeding insects cause a yield loss and 43.5% believed that these insects should be controlled early. Some respondents were aware of the presence of natural enemies in their fields, such as spiders, dragonflies, beetles, and wasps, but were uncertain about their roles.

Introduction

Laos is located almost entirely in the Mekong River watershed, with a total land area of about 237,000 km2. Lowland alluvial plains and terraces in the central and southern areas constitute 20%, hills backing the lowlands, 50%, and mountains of 1,000- 3,000 m above sea level, 30%, to the north and along the eastern border with Vietnam. The country has a population of about 4.6 million.

As the most important sector of the economy of the Lao PDR, agriculture accounted for about 56% of the total value added in 1993 (UNDP 1994) and involved about 80% of the population. Rice is the most important crop, with about 83% of the 649,000 ha under cultivation devoted to rice. The main non-rice crops are maize (27,000 ha), vegetables (15,000 ha), and tuber crops (14,000 ha); the rest are cotton, soybean, sesame, peanut, tobacco, and sugarcane, which collectively account for about 100,000 ha. Coffee and tea are grown on about 22,000 ha. Approximately 97% of the total cultivated area depends on rainfall.

Total annual rice production ranges from 1.5 to 1.6 million t. But the dependence on rainfall can result in annual fluctuations. In 1993, serious flooding reduced production to 1.46 million t, whereas in 1995 it fell to about 1.25 million t as a result of serious drought in much of the rainfed lowland environment (LAO-IRRI Project Report 1996, Lao PDR 1996). Most of the rice produced is consumed domestically, with less than 5% believed to be traded.

The wet-season rice crop is produced on about 98% of the rice area and accounts for 97% of production. Sixty-two percent of the rainfed lowland contributes 76% of production, whereas 36% of the rainfed uplands accounts for 22% of production. In 1994, irrigated rice was grown on an estimated 11,000 ha and in 1995 on 13,300 ha. The highest production from lowland rice

comes from the central region (247,829 t) and southern region (123,325 t). The northern region produces upland rice. Approximately 86% of the rainfed lowland rice area is in the central and southern agricultural regions, mainly in the provinces adjacent to the Mekong River. The major rice-producing plains are the Vientiane Plain (Vientiane Province and Vientiane Municipality), Borikhamxay, Sebang-Faay (Khammouane and Savannakhet), Sebang- Hiang (Savannakhet Province), Sedone (Saravane Province), and Champassak. The topography of this area mainly consists of a system of ancient low terraces with an elevation of about 200 m. The remaining rainfed lowlands mostly occupy rather narrow river valleys in the more northern provinces. Some production areas of between 500 and 2,000 ha are also found in the north.

Rainfall in most provinces along the Mekong River valley ranges from about 1,500 to 2,200 mm on average per year, with about 75% being received from May to October. In other northern provinces (Sayabouly and Luang Prabang), it drops to about 1,300 mm. August and September are considered the wettest months of the year, when heavy rains can result in localized flooding. Soils of much of the rice-producing area adjacent to the Mekong River are derived mainly from old alluvial deposits and sandstone materials in the provinces of Saravane and Savannakhet.

In the rainfed lowland environment, a single wet-season rice crop is the predominant agricultural activity. Farmers commonly plant traditional glutinous photoperiod-sensitive varieties, with each farmer growing 34 varieties of varying maturity periods. Early maturing varieties are normally planted in the upper terraces, where water supply is less certain, whereas later maturing varieties are grown in the lower areas. Early maturing cultivars constitute 20% of the varieties planted, whereas medium varieties make up 50% and late varieties 30%. Until about 1993, the rate of adoption of improved varieties was low and based mainly on the use of the Thai glutinous varieties RD6, RD8, and RDl0 and non-glutinous variety Khaw Dok Mali 105 or KDML 105. In 1993, however, the recommended Lao varieties Niaw Thadokham 1 (TDK1), Niaw Thadokham 2 (TDK2), and Phone Ngam 1 were released and subsequently adopted by farmers, particularly in central and southern Laos.

The usual cropping calendar is for seedbed rice to be sown in early to mid-June and transplanted in early to mid-July. Timing of these operations, however, is much dependent on rainfall distribution. Because the rice production cycle is at a very low level of mechanization, more than 95% of the area is cultivated using traditional buffalo- drawn plows. Planting, weeding, and harvesting are all done manually. Mobile threshers have become evident since 1993, but they still account for less than 10% of the harvested area; the remainder is threshed manually.

The level of technology adoption in the country is usually low. Apart from family labor, farm inputs in the system are minimal. Organic fertilizer in the form of farm yard manure is usually applied to seedbed rice. The government’s aim of raising total production to between 2.0 and 2.2 million t by the year 2000 is largely based on achieving a significant production improvement in the rainfed lowland environment through improved cultural practices, nutrient inputs, and integrated pest management.

Pesticide use

Lao farmers do not have a history of pesticide use. This reflects a combination of active government discouragement of their use, a lack of access to them in much of the country, and the limited purchasing power of small farmers. The limited use of pesticides has been largely confined to areas of irrigated rice in provinces adjacent to the Mekong River. But more recently, pesticide use has increased in the areas of vegetable cultivation near the main population

centers. Most pesticides used are insecticides and rodenticides. In the late 1980s and early 1990s, some pesticides were brought into the country in the form of development aid. In 1993, the Department of Agriculture and Extension approved the import of approximately 63 t of various pesticides. The relatively open borders with Thailand, Vietnam, and China encourage the entry of pesticides, even those without government approval. Procedures for pesticide registration and regulation have not been established yet.

Farmers’ perception of insect pests as a production constraint

A survey of farmer perceptions of the main production constraints in the rainfed lowland was conducted in 1993 (Khotsimuang et al 1995). Farmer respondents (191) from nine districts in seven provinces were asked to rank 11 potential production constraints, which included insect pests, rodents, crabs and snails, drought, weeds, diseases, soil fertility, labor, varieties, credit, and flooding. Insect pests were rated within the top three constraints for seven of the eight districts (Table 1), whereas damage caused by crabs or snails was rated as second in importance in two districts.

Survey of farmer pest management practices

Farmers’ perceptions of pests, techniques available, and resources often influence the adoption of improved pest management practices. An assessment and understanding of farmers’ current practices, perceptions, and constraints is important for improving their pest management decision making (Lim and Heong 1984, Mumford and Norton 1984, Norton and Heong 1988). Similarly, a better understanding of the biological and ecological processes and socioeconomic factors that influence their decision making is often necessary. Understanding farmers’ perceptions may have research implications for improving pest management practices and decision-making processes. Between February and March and in October 1994, a survey of farmers’ knowledge, attitudes, perceptions, and current pest management practices was undertaken in the rainfed lowland rice environment in 18 districts distributed over 11 provinces of Lao PDR. Although some of the areas surveyed are irrigated during the dry season, they are usually considered rainfed during the wet season because of the inability to control water during this part of the year. The provinces included in the survey represented all three regions of the

country (Fig. 1). In the north were the provinces of Luang Namtha, Oudumxay, Luang Prabang, and Sayabouly; in the central region were Vientiane, Xieng Khouang, Borikhamxay, Savannakhet, and Vientiane Municipality. The southern region was represented by the provinces of Saravane and Champassak.

Method

A total of 463 farmers were interviewed; individual respondents were selected at random within each district (Table 2). The survey sites were identified by Lao researchers and technicians who were collaborators of the LAO-IRRI Project and these were mostly the places where they worked with farmers. From each district, two or three villages were selected for the survey. Respondents were selected by taking one farmer for every five households unless the farmer was not available during the time of the survey, in which case we chose the next farmer. We conducted the interviews using a structured questionnaire translated into the Lao language, and obtained information related to cropping activities during the 1993 wet season. We coded, summarized, and tabulated the gathered data in frequency tables.

Socio-demographic profile

Farm size and tenure status. The total planted area of respondents was about 756 ha, producing 1,482 t of rice. Farm sizes ranged from 0.25 to 7 ha. The smallest landholdings were in Oudumxay and Xieng Khouang (av 0.89 and 0.86 ha, respectively); the largest were in Savannakhet (mean 2.32 ha) and Vientiane Municipality (mean 1.87 ha). Some 38% of the respondents had less than 1 ha, and approximately 43% had between 1.1 and 2 ha. Only four respondents had more than 5 ha.

Some 90.3% of the respondents were owner-operators, mostly from the provinces of Luang Namtha, Oudumxay, Xieng Khouang, Borikhamxay, Saravane, and Xaybouli District of Savannakhet Province.

Age classes. Respondents’ ages ranged from 20 to 75 years, with farming experience from 1 to 60 years. Most (61%) were between ages 30 and 45.

Production practices

Cropping pattern. Some 75% of the respondents planted a single wet-season rice crop. Some farmers (23%) followed a rice-rice cropping pattern. Fewer than 1% reported that they planted non-rice crops such as maize, watermelon, cucumber, and vegetables after their wet-season rice.

Rice varieties. Farmers grew a wide range of varieties, most of which were traditional glutinous photoperiod-sensitive varieties. Most households cultivated 3–4 different varieties with varying maturity periods, to fit consumption needs and help distribute the labor requirement. Seed supplies for most farmers (90%) came from their own harvests or, occasionally, through seed exchange with other farm households in the area. Those with access to research stations (10%) sometimes obtained some seed from these stations. The most common methods of cleaning seeds before planting were winnowing and flotation.

Fertilizer use. Of 135 respondents from the northern region, only 13.3% applied inorganic fertilizer during the 1993 wet season. In contrast, 32% and 33% of the respondents from the central and southern regions, respectively, reported the use of fertilizer. Respondents using fertilizer were high in Vientiane Province (81%), Savannakhet (80%), Saythany District of Vientiane Municipality (67%), Saravane (66%), and Champassak (64%). None of the respondents from the provinces of Luang Namtha and Xieng Khouang reported using fertilizer.

Pest management knowledge, practices, and perceptions

In the 1993 wet season, the five most commonly mentioned pests that attacked rice plants were stem borers, orthopterans, rice bugs, gall midge, and leaf folders. The importance of these pests varied among the sites (Table 3). In Luang Namtha, grasshoppers and locusts, leaf folders, and caterpillars or worms were the three commonly mentioned pests, whereas in Oudumxay they were grasshoppers, caterpillars, and gall midge. Luang Prabang and Sayabouly respondents reported stem borers as the most common pest, followed by gall midge, grasshoppers, and rice bugs. In Vientiane Municipality, the two sites apparently had different pest problems. In Nasaythong, rice bugs, stem borers, and grasshoppers were ranked as the three most important pests, whereas in Saythany these were grasshoppers, stem borers, and thrips. Crabs were ranked as fourth at both sites. In Vientiane Province, stem borers and rice bugs were reported most. Stem borers and gall midge were reported in Borikhamxay and Xaybouly of Savannakhet, whereas in Champone thrips and crabs were mentioned most. In Champassak, gall midge, hoppers, and thrips were mentioned most.

Pest control practices

Pest control methods. Although respondents reported observing several pests in their fields, 74.5% did nothing to control these pests. Some 22.7% used pesticides to control them. A few others (2.8%) practiced handpicking, water management, baiting, and indigenous methods such as using leaves of some trees (Gliricidia sepium and Azadirachta indica, etc.) to control pests.

Pesticide use patterns. Of the 105 respondents who applied pesticides during the 1993 wet season, 75.2% of them made only one application and 20% made two applications. A few farmers (3.8%) applied pesticides as many as three times. One farmer from Savannakhet said he applied chemicals 10 times to control crabs. Seventy-four percent of those who used pesticides applied them during the first 40 days after transplanting (DT). The other applications were either made in seedbeds or after 40 DT.

Target pests. Pesticide applications in seedbeds were mainly for the control of grasshoppers (Table 4). Some 54% of the applications during the first 40 DT were aimed at controlling stem borers, crabs, caterpillars or worms, and hoppers. But 27% of the farmers reported that they sprayed their plants as a prophylactic measure. Rice bugs, stem borers, and rats were the targets of applications made after 40 DT.

Common pesticides used. Respondents indicated that methyl parathion was the most commonly used insecticide. Others mentioned carbaryl, diazinon, carbofuran, monocrotophos, metamidophos, endosulfan, BHC, and DDT. For rat control, farmers used zinc phosphide. These pesticides belong to categories I and II. Table 5 shows the pesticides used by respondents from the different provinces.

Precautionary measures in using pesticides. When farmers were asked what precautionary measures they practiced when using pesticides, the most commonly mentioned precaution was not to spray at all (27%). Some 12% were aware that wearing protective clothing (e.g., long trousers, long sleeves) and covering the mouth and nose (10%) while spraying were important. Ten percent were also aware that eating or smoking should be avoided while spraying. Other precautionary measures mentioned were not entering sprayed fields (5%), taking a bath or washing after spraying (8%), and using IPM, reading labels carefully, asking for advice, keeping chemicals away from children and animals, not throwing leftover solutions in water canals or rivers, not eating fish or vegetables from sprayed fields, and several others (14%).

Source of plant protection advice. For plant protection advice, the agricultural officers of the respective provinces were the major source of information (53.5%). Farmers also obtained information from other farmers, either their neighbors or from other places (15%). Pesticide dealers (1%), relatives (2%), radio (2.5%), television (1%), newspapers (1%), and some personnel from NGOs and banks were also mentioned. Some respondents (27.5%) claimed that they depended on their own knowledge and experience.

Farmers’ perceptions

Perceptions on effectiveness of pesticides. When respondents were asked whether or not pesticides could increase their yield, 68% believed that these pesticides would. Few (8%) said that pesticides would not increase yield, whereas others (23.9%) had no opinion.

Toxicity of pesticides. The majority of the respondents (72%) believed that pesticides would kill humans, fish, and animals. Respondents who had not used insecticides, such as those from Xieng Khouang, had no idea about the effect of pesticides on humans, fish, and animals.

Perceptions of leaf-feeding insects and other arthropods. Almost three-fourths of the respondents (72.5%) perceived that leaf-feeding insects would cause a yield loss. About 16% thought that they would not cause a yield loss. About 43.5% of the respondents perceived that leaf-feeding insects should be controlled early. Some 15% believed that leaf-feeding insects need not be controlled, whereas 42% had no opinion. Exactly two-thirds (66%) of the farmers also thought that leaf-feeding insects feeding on plants in the early stage of growth can cause severe damage to the crop, whereas 18% believed otherwise. Some 16% had no opinion. Fewer than one-half of the respondents indicated that all arthropods in the field would not cause damage to the rice plant. It is interesting to note that around 34% admitted that they did not know the effect of arthropods on the rice plant, whereas 22% said that they cause damage. Table 6 shows responses from the different provinces.

Knowledge of natural enemies

Despite their perception that not all arthropods in their field would damage the rice plant, many farmers were not aware of the presence of these arthropods in their fields. According to 44% of the respondents, spiders, damselfly, dragonfly, praying mantis, ground beetles, frogs, and wasps would not eat on the rice plants. Other orthopterans (crickets such as Conocephalus) and lady beetles were also mentioned (Table 7).

Yield comparisons of respondents who applied and did not apply insecticides

When average yields per hectare of respondents who applied and did not apply pesticides were compared, the majority of those who did not apply pesticides reported higher yields, although the differences were not significant (Table 8).

Knowledge on diseases

The respondents did not consider diseases to be a major constraint to rice production, although some farmers reported observing blast, sheath blight, and false smut in their fields.

Discussion

Rice production in Lao PDR has largely not been commercialized and is focused on meeting home consumption needs. The level of adoption of improved production technology is low, which reflects a combination of factors, including a lack of reliable technical advice appropriate to conditions in the country. New, improved higher yielding varieties are becoming available, and area-specific soil nutrient management practices are being formulated. The national extension service is poorly developed and the staff often lack the necessary technical expertise

to adequately advise farmers. In addition, even with access to technical advice and appropriate inputs, smallholders’ limited purchasing power can prevent them from adopting improved production practices.

But some changes are apparent with the development of a national research program with support from IRRI and the Swiss Agency for Development and Cooperation. For pest management, the survey showed that farmers are aware of the presence of pests in their fields. More awareness and higher levels of technology adoption, such as application of fertilizer and insecticide, had been noted near the main population centers such as Vientiane. This reflects the concentration of extension and project type assistance in these areas more than in others. The majority of those who did not apply pesticides obtained higher yields, although the differences were not significant. The insignificant differences seem to indicate that applying pesticides for rice is not necessary. Two possible reasons for the low use of pesticides are the lack of resources to buy the chemicals and the absence of crop losses from pests, except isolated reports of severe crab and gall midge damage. If farmers had more access to resources, pesticide use could increase. If this happened, the existing natural ecological balance in the rice environment might be affected markedly, which could lead to pest outbreaks.

At this stage, we need to improve farmers’ pest management decision making. Furthermore, the Pesticides Act to control the import, manufacture, and repacking of pesticides, as well as their sale in the country, must be enforced and implemented. Otherwise, pesticides that have been restricted or banned in other countries will continue to find their way into local markets. Most respondents were aware of the presence of other pests that do not feed on rice in their fields such as spiders, dragonflies, crickets, and beetles, but were not aware of the roles of these arthropods in the field. Educating farmers on the concept of natural enemies in their fields should be a part of any training program on pest management. Extension personnel should likewise be well versed in the concepts of pest management to be able to provide farmers with the appropriate information and technology. Doing so could lead to improvements in farmers’ well-being and in the status of the farming community in the country.

References

Khotsimuang S, Schiller JM, Moody K. 1995. Weeds as a production constraint in the rainfed lowland environment of the Lao PDR. In: Proceedings of the 15th Asian-Pacific Weed Science Society Conference, 24-28 July 1995, Tsukuba, Japan, p. 444-454.

Lao PDR. 1996. Basic statistics about the socio-economic development in the Lao PDR. State Statistical Center, Ministry of Economic Planning and Finance, Vientiane, Lao PDR. Lao-IRRI Project Report. 1996. Vientiane, Laos.

Lathvilayvong P, Schiller JM, Phommasack T, Kupkanchanakul T. 1995. Nutrient management in the rainfed lowland rice environment of Laos. In: Proceedings of the International Rice Research Conference, 13-17 February 1995, Manila, Philippines, p. 267-278.

Lim GS, Heong KL. 1984. The role of insecticides in rice integrated pest management. In: Judicious and efficient use of insecticides on rice. Manila (Philippines): International Rice Research Institute. p. 19-39.

Mumford JD, Norton GA. 1984. Economics of decision making in pest management. Annual Review of Entomology 29: 157- 174.

Norton GA, Heong KL. 1988. An approach to improving pest management in rice in Malaysia. Crop Protection 7:84-90.

UNDP (United Nations Development Programme). 1994. Development cooperation: Lao People’s Democratic Republic. 1993 report.

Notes

Author’s addresses: H.R. Rapusas, Entomology and Plant Pathology Division, InternationalRice Research Institute, Los Baños, Laguna, Philippines: J.M. Schiller, Lao-IRRI Project,Vientiane, Lao PDR; V. Sengsoulivong, National Agricultural Research Center, Naphok,Vientiane, Lao PDR.

Citation: Rapusas HR, JM Schiller, V Sengsoulivong. 1997. Pest management practices of rice farmers in the rainfed lowland environment of the Lao PDR. p. 99-114. In: Heong KL, Escalada MM (editors). 1997. Pest management of rice farmers in Asia. Manila, Philippines: International Rice Research Institute, 245 p.