How to manage pests and diseases

Farmers lose an estimated average of 37% of their rice crop to pests and diseases every year. In addition to good crop management, timely and accurate diagnosis can significantly reduce losses. If you are facing a problem in your crop and need help with diagnosis, seek advice from a professional or use the Rice Doctor.

If you have a problem in your field and you're not sure what it is, go to the Rice Doctor

Crop problems can be caused by other living organisms, like rats and fungus, or by non-living factors, such as wind, water, temperature, radiation, and soil acidity.

The best control for pests and disease problems is prevention. To limit pest and disease damage:

 Practice good cleaning of equipment and field between seasons

Diseases can be spread between fields or between seasons if you do not take proper precautions. After harvest, be sure to clean the harvesting equipment to prevent the spread of infected plants.
Some diseases can live on the stubble between seasons and infect a healthy planted crop. In general, plowing after harvest removes stubble that serves as remaining food and shelter for pests, especially insects. In cases where your field was infested, you should remove all stubble from the previous season (see disease section for more details).
Clean the bunds and patch all rat holes on bunds and around your field. If there are nearby fallow fields or forested areas, you may want to have a community rat control effort or put up trap barriers to keep rats from damaging your crop (see rat section for more details).
Ratooning (allowing your crop to sprout and continue growing after harvest) is not recommended because diseases and insect hosts can be sustained from season to season. It is best to clean the field of any crop and leave it fallow for a few weeks to a few months before planting again.

 Use clean seeds and resistant varieties

Certified seed is recommended but if you can't get certified seed, use clean seed that does not have any discolored seeds, weed seeds or other rice varieties mixed in.

Read: Choosing quality seed

Many varieties have been developed with resistance to different diseases. You should check with your local extension agent or a nearby seed dealer to find out which resistant varieties they carry.
Use short-duration and resistant cultivars to decrease insect pest populations. In short-duration cultivars, insects cannot compete as many generations, so populations may not reach damaging levels. Resistant varieties experience less feeding damage on their leaves and stems, which means less entry points for bacteria and fungal diseases.
IRRI has a major responsibility to develop rice varieties for the benefit of rice farmers and consumers.

 Plant at the same time as your neighbors

Planting at the same time (or within a 2 week window) as the neighboring fields can help to minimize insect, disease, bird, and rat pressure on individual fields. 

 Do not over apply fertilizer

High nitrogen can increase susceptibility to certain pests and diseases that is why specific fertilizer recommendations is very important.

 Encourage natural pest enemies

Overuse of pesticide is common among farmers and can actually lead to pest outbreaks. Natural insect enemies of the rice pests are also killed when pesticides are applied and this can lead to an outbreak of other rice insect pests. Other ways to encourage natural pest enemies are to allow plants on the bunds and between fields to flower (yellow and white flowers attract natural enemies).

 Do not apply pesticide within 40 days of planting

Generally, a rice crop can recover from early damage without affecting yield. The diseases section show the information on specific diseases that require early management. 

 Properly store grain

Store grain at moisture content below 13-14%, preferably in an airtight container. Clean the grain before storing so it is free of dust, chaff, and excessive broken grains. The storage area should be clean and have a dampproof floor and waterproof walls and roofs. Ideally, the storage area should be sealed to keep out rats and birds and to allow for fumigation if necessary. Stack bags on a pallett with at least 50cm of space on every side of the stack. 
Do not store grain for more than 6 months. Do not store new grain next to old grain that is infested with insects. Store grain as paddy or rough rice because it is less prone to insect attack than milled rice. Parboiled rice is also less susceptible to damage than raw rice.

Read: Storage

Rats

In Asia, rats cause an average of 5−10% loss in rice yield every year. Rats breed at an alarming rate when food is abundant. One female rat can produce 35 rats in a season. Rat management is critical before the breeding cycle, otherwise, the population can explode and yields will be greatly reduced.   

Read more

Insects

There are over 100 species of insect pests to rice around the world but only about 20 species can cause economic damage. The recommended control of insect pests is to develop and follow an Integrated Pest Management plan.

Read more

Diseases

Disease damage to rice can greatly reduce yield. They are mainly caused by bacteria, viruses, or fungi. Planting a resistant variety is the simplest and, often, the most cost effective management for diseases. 

Read more

Golden Apple Snail

The golden apple snail was introduced into Asia during the 1980s from South America as a potential food for people. Unfortunately, the golden apple snail has become a major pest of rice having spread to the Philippines, Cambodia, Thailand, and Vietnam.

Read more

Birds

Birds are considered to be a pest of rice but little is known about exactly how much damage is caused by birds. Only a few species of birds are grain eaters and others eat insects, worms, or snails. 

Read more

Nematodes

Root-knot nematode larvae infect plant roots, causing root knot galls. Galls drain the plant's photosynthate and nutrients. Severe infections in young plants may cause complete yield loss while infection of mature plants results in reduced yields.

Read more

Agriculture in Nepal

From Wikipedia, the free encyclopedia

This article is outdated. Please update this article to reflect recent events or newly available information. (November 2010)

Terraced farming on the foothills of the Himalayas is a common sight in many of the villages in Nepal

Nepali women planting rice

Cultivation in the Kathmandu Valley

In Nepal, the economy is dominated by agriculture. In the late 1980s, it was the livelihood for more than 90 percent of the population, although only approximately 20 percent of the total land area was cultivable, it accounted for, on average, about 60 percent of the GDP and approximately 75 percent of exports.^[1] Since the formulation of the Fifth Five-Year Plan (1975–80), agriculture has been the highest priority because economic growth was dependent on both increasing the productivity of existing crops and diversifying the agricultural base for use as industrial inputs.^[1]
According to the World Bank, agriculture is the main source of food, income, and employment for the majority.^[2]
In trying to increase agricultural production and diversify the agricultural base, the government focused on irrigation, the use of fertilizers and insecticides, the introduction of new implements and new seeds of high-yield varieties, and the provision of credit. The lack of distribution of these inputs, as well as problems in obtaining supplies, however, inhibited progress.^[1] Although land reclamation and settlement were occurring in the Tarai Region, environmental degradation and ecological imbalance resulting from deforestation also prevented progress.
Although new agricultural technologies helped increase food production, there still was room for further growth. Past experience indicated bottlenecks, however, in using modern technology to achieve a healthy growth. The conflicting goals of producing cash crops both for food and for industrial inputs also were problematic.
The production of crops fluctuated widely as a result of these factors as well as weather conditions. Although agricultural production grew at an average annual rate of 2.4 percent from 1974 to 1989, it did not keep pace with population growth, which increased at an average annual rate of 2.6 percent over the same period.^[1] Further, the annual average growth rate of food grain production was only 1.2 percent during the same period.^[1]
There were some successes. Fertile lands in the Tarai Region and hardworking peasants in the Hill Region provided greater supplies of food staples (mostly rice and corn), increasing the daily caloric intake of the population locally to over 2,000 calories per capita in 1988 from about 1,900 per capita in 1965.^[1] Moreover, areas with access to irrigation facilities increased from approximately 6,200 hectares in 1956 to nearly 583,000 hectares by 1990.^[1]

Crops

Rice is the most important cereal crop. In 1966 total rice production amounted to a little more than 1 million tons; by 1989 more than 3 million tons were produced.^[1] Fluctuation in rice production was very common because of changes in rainfall; overall, however, rice production had increased following the introduction of new cultivation techniques as well as increases in cultivated land. By 1988 approximately 3.9 million hectares of land were under paddy cultivation.^[1] Many people in Nepal devote their lives to cultivating rice to survive. In 1966 approximately 500,000 tons of corn, the second major food crop, were produced. By 1989 corn production had increased to over 1 million tons.^[1]

A Nepalese coffee grower

Other food crops included wheat, millet, barley, and coffee, but their contribution to the agricultural sector was small.^[1] Increased production of cash crops, used as input to new industries, dominated in the early 1970s. Sugarcane and tobacco also showed considerable increases in production from the 1970s to the l980s. Potatoes and oilseed production had shown moderate growth since 1980. Medicinal herbs were grown in the north on the slopes of the Himalayas, but increases in production were limited by continued environmental degradation. According to government statistics, production of milk, meat, and fruit had improved but as of the late 1980s still had not reached a point where nutritionally balanced food was available to most people. Additionally, the increases in meat and milk production had not met the desired level of output as of 1989. Nepal has more than 50% of people engaged in agriculture. Food grains contributed 76 percent of total crop production in 1988-89. In 1989-90 despite poor weather conditions and a lack of agricultural inputs, particularly fertilizer, there was a production increase of 5 percent. In fact, severe weather fluctuations often affected production levels.^[1] Some of the gains in production through the 1980s were due to increased productivity of the work force (about 7 percent over fifteen years); other gains were due to increased land use and favorable weather conditions. According to Statistical Information on Nepalese Agriculture (2008/2009) only 65.6% of people depends on agriculture and 21% of land is cultivated whereas 6.99% of land is uncultivated.
Agriculture mechanization in Nepal is led by Shrestha Agri Inputs, Satungal-9, Kathmandu.It supplies various farm machinery such as harvesters, threshers, corn sellers, and many more