Rice pests are no longer winning: the Khmer Smile is back

Hy Broey, rice farmer in Cambodia

Hy Broey, rice farmer in Cambodia © CABI

Contributed by Heng Chunn Hy and Ho Chea, General Department of Agriculture, Phnom Penh, Cambodia

Hy Broey, a farmer from Choeung Tik Khor village in Prey Veng Province, Cambodia, came with her problem to the plant clinic. She had many problems in rice planting and production, especially during the tillering stage. By attending plant clinics in her village she has learned how to solve her agricultural problems.

Mr Tep Say, the plant doctor, had identified the problem and told her that it was caused by stem borer. He showed her the affected part: dead hearts or dead tillers that can be easily pulled from the base during the vegetative stages. Also, during the reproductive stage, the plants were showing whiteheads: emerging panicles were whitish and unfilled or empty. He showed her tiny holes on the stems and tillers. He told her that she should synchronize planting, and use a recommended resistant variety. During the harvesting she should cut rice near the stem base in order to remove and kill all larvae and pupae. She should also try to conserve predators and try to catch the adult stem borer moths. If she removes all the affected plants, and only if the insect still persists, she can spray a named insecticide in order to kill the insect.

Later the plant doctor also visited the farmer’s field and gave her IPM recommendations. He told her and her husband not only to rely on chemical control but also include cultural practice to improve crop yields, and to protect the environment, thus allowing the natural enemies like dragonflies to breed and help control the adult stem borer moth.

The plant doctor had a follow-up visit to the farmer to see the implementation of his advice. After attending the plant clinic, Hy Borey and her husband changed their habit of only relying on chemical sprays and practised with IPM technique as provided by the plant doctor. They got good results and harvested a good crop. At the harvesting time the farmer was very happy since she got a better yield. Before visiting the plant clinic she got only 2.5 ton/ha but this year after visiting the plant clinic the yield had increased to 3.7 ton/ha. Before visiting plant clinics, she sprayed pesticide 3 times per season for management of pests but after visiting the plant clinic she learnt to apply the IPM method to control insects and diseases, and no more spraying of chemicals was required in this season. She was very happy and thanked CABI’s Plantwise plant clinic program for the support to help farmers in Prey Veng, and other provinces as well.

Tiny wasp that is having a big impact on pests in the Mekong

Rice productivity is seriously affected by the damage pests cause © IRRI

Rice productivity is seriously affected by pests such as the rice stem borer © IRRI

Rice is the most important crop in the Greater Mekong sub-region of Southwestern China, Laos and Myanmar, providing food, work and income for a diverse range of people living all along the Mekong river. However, the yield of this crop in the Mekong region is still missing the mark in terms of potential, partly as a result of the millions of tons of rice that are lost to pests, including insects, diseases and weeds. Unfortunately, in trying to resolve this, the excess use of pesticides in previous years has caused problems of its own with increasing pesticide resistance and damage to farmer health and the environment.  Read more of this post

Ecological Engineering Approach for Rice Pest Management-Need to Popularise its Advantages

           Example of Ecological engineering in Vietnam (Photo credit: Dr HV Chien)

The rice ecosystems are inhabited by more than 100 species of insects. Twenty of them can cause potential economic losses. With the change in the climatic factors and modern cultural practices adopted for production a drastic change has been caused in the pest scenario in the recent past. Besides stem borer, gall midge, brown plant hopper and green leafhopper which were the major problems in past, several other relatively minor pests such as leaf folder, armyworms, cut worms etc. have gained importance. In a study conducted by the International Rice Research Institute (IRRI), it was found that, on average, farmers lose 37% of their rice yield to pests and diseases, and that these losses can range between 24% and 41% depending on the production situation (http://irri.org). All the pests are generally kept under check by their natural enemies (parasitoids and predators) by feeding on them. The food web of their relationships prevents the explosion of their populations and keeps them under economic thresholds mimimising the pesticide use.

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Factsheet of the month: November – Brown planthopper of rice


Last week, Nature published an article on the story of rice, from a wild grass to the stable crop we know today. Rice is one of the most important crops in the world as it forms the basis of the diet of a large portion of the human population. Due to the high importance of this crop, there is a vast amount of research that goes into ensuring the world’s rice production is as efficient and sustainable as possible.

Like all crops, rice is affected by a range of pests including insects, pathogens, weeds, nematodes and birds. One of the most damaging pests for rice in Asia is the Brown Planthopper (BPH). This pest not only feeds on rice plants, but also transmits grassy stunt virus and ragged stunt virus which cause stunting and reduce productivity. There are chemicals that will control this insect pest but it is important to note that this isn’t always the best method of control, due to the effect on natural enemies that feed on BPH. There are a range of non-chemical options that are effective at preventing and controlling BPH including the use of resistant varieties and avoiding excessive urea application to the field.

To find out more about BPH and its management, read this month’s Plantwise Factsheet for Farmers which was written by staff from Shushilan, an agroecology and rights-based NGO situated in South West Bangladesh. Please note this factsheet is also available in Bengali.

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Backstopping visit to Bangkok, Thailand

As the last part of our data management trip, Claire and I headed to Bangkok for the 11th and 12th of September. We joined a group of plant doctors and farmers at the plant clinic/rally in Nong Kung village, Suppaya district, Chainat province. We saw a demonstration on biocontrol, looked through pamphlets and information available to farmers about crop problems, and discussed the rice harvest which was currently taking place. In the backstopping training at the Rice Department, the participants shared their concerns and plans for future data management in Thailand.


Participants of the data management backstopping in Bangkok. ©CABI


Farmers attending the clinic to listen to advice about crop protection. ©CABI


Emily, Claire, Fook Wing, and Siva observing how plant clinics operate in Chainat province. ©CABI


Discussing data management in Thailand. ©CABI


Looking forward to a delicious meal in Nong Kung village! ©CABI


Farmers learning about biocontrol products using fungal spores grown on a culture of cooked rice. ©CABI


A farmer and plant doctor discussing issues with food crops. ©CABI


Preserved samples and specimens for comparison purposes when diagnosing crop problems. ©CABI


View from the plant clinic into part of the village – it was a beautiful, sunny day. ©CABI

A plant doctor’s fight against rice blast in Tamil Nadu, India

Story by Malvika Chaudhary, CABI in India

Photo: Saurav Paul

DSC_4249Vargur is a small village in the Tamil Nadu state of India where paddy is grown on a large scale. The plant clinics in this region are very popular with farmers. For plant doctor Sarangpani it was a usual day, anticipating the regular crowd of paddy farmers in his plant clinic. He enjoyed this interaction with them, especially after improving his pest diagnostic and advisory skills through training provided by Plantwise and research non-profit M S Swaminathan Research Foundation (MSSRF).  His rich experience as a farmer in the past had now translated into service for his community through these regular plant clinics.

Though ‘samba,’ or long grain rice season was usually quiet, this time Balchander and many farmers like him had a different story. The farmers had been seeing white spots on the young leaves of their paddy plant, which began to turn to grey-green in couple of days, bringing them increasing worry. It was time for plant doctors like Sarangpani to take immediate action to try and help Balchander and his neighboring paddy farmers.

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Update: New Pest & Disease Records (11 Jun 14)

Fusarium oxysporum f. sp. cubense tropical race 4, associated with Panama wilt, has been identified outside Southeast Asia © Scot Nelson (CC BY-SA)

Fusarium oxysporum f. sp. cubense TR4, has been identified outside Southeast Asia © Scot Nelson (CC BY-SA)

We’ve selected a few of the latest new geographic, host and species records for plant pests and diseases from CAB Abstracts. Records this fortnight include Phytophthora cinnamomi in the rhizosphere of agricultural crops in southern Bahia (Brazil),  the first report of Fusarium oxysporum f. sp. cubense tropical race 4 associated with Panama disease of banana outside Southeast Asia and the first report of ‘Candidatus Liberibacter asiaticus’ associated with Huanglongbing on Persian lime in Martinique and Guadeloupe.

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