Rice fields with sesame grown on the bunds have higher natural enemies in Jinhua, China

Posted on February 25, 2010 by moni

by
Zhongxian Lu, Zhejiang Academy of Agricultural Sciences (ZAAS), Hangzhou
Guihua Chen, Director, Plant Protection Station, Jinhua, Zhejiang
Xiaoming Yao, Researcher, Plant Protection Station, Jinhua, Zhejiang

Rice field with sesame on bunds (left). Inset – Sesame flower visited by a bee.

Ecological engineering involves restoring floral biodiversity to provide resources for natural enemies.  We established sesame plants along the bunds of a rice field of about 0.5 hectares and monitored the natural enemies.  A neighboring farmer’s field without the sesame was used as a comparison. Sesame was selected because of the flowers last a long period, are aromatic and are frequently visited by hymenopteran species. In addition the sesame seeds may be harvested for use in making candies, sesame oil and seasoning for cooking.

Sesame seeds are harvested and made into a variety of cookies.

Using yellow pan traps we found that hymenopteran parasitoids were significantly more abundant in the field surrounded by sesame.  Similarly predators were also higher (figure below).

Yellow pan trap catches of predators and parasitoids in eco engineering and farmer’s fields.

The yellow sticky board traps  also showed significant differences in parasitoids caught in the two rice fields.  The farmer’s field was sprayed once with the insecticide, buprofezin mixed with fungicides at about 50 days after transplanting.  Even though buprofezin is known to be specific to planthoppers, it had significant effects on the parasitoids caught in the traps established in the farmer’s field.

Sticky board catches of parasitoids in eco engineering and farmer’s fields that was sprayed at 50 DAT

These are preliminary results from the Jinhua eco engineering site.  Detailed analyses of the predator and parasitoid biodiversity using qualitative and quantitative methods are being carried to further determine the effects of sesame grown along bunds.

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Farmers’ day for ecological engineering to restore biodiversity in Cai Be, Vietnam

Posted on February 12, 2010 by moni

by
Ho Van Chien
Director, Southern Regional Plant Protection Center
Long Dinh, Tien Giang, Vietnam

Bunds heavily populated with nectar producing flowers that provide resource for natural enemies.

One hundred and twenty farmers and plant protection officials attended a field day organized by the Plant Protection Department to demonstrate the ecological engineering techniques being used in Cai Be. Among the officials were Dr Nguyen Huu Huan, Vice Director general of Plan Protection Department, Mr Nguyen Van Nha, cice chairman of the Tien Giang Peoples’ Committee and 22 agricultural officials from 22 provinces. The crop of the 30 hectares of rice in the ecological engineering site was at the flowering stage and no insecticide application had been used.

Farmers participating in the field day

Pests were at its minimum and virus disease infections were very low.  One ecological engineering technique farmers in the site practiced was the “escape strategy” where farmers use light trap catches to determine their sowing dates to synchronize planting after the peak BPH migrations to avoid virus infections. Another technique farmers used was establishing bunds with flowering plants to serve as resource for natural enemies. Yellow pan trap and sticky board traps showed that there was marked difference in natural enemies in the ecological engineering site compared with the control. The area’s vulnerability to hopperburn had been reduced from such practices. The data collection is being continued for further analysis.

Yellow pan traps used to monitor natural enemies and pollinators

The main benefits of farmers participating in the ecological engineering demo were savings from unnecessary insecticide use, low pest infestations and good yields.

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Thai government to provide B2bn to compensate farmers hit by BPH

Posted on February 10, 2010 by moni

by
K.L. Heong
Insect Ecologist
International Rice Research Institute
Los Baños, Philippines

On 9 February Bangkok Post reported that about B2bn is allocated to compensate farmers hit by the losses caused by BPH. The report is below and also available in http://www.bangkokpost.com/business/economics/32588/state-to-pledge-b2bn-for-brown-planthopper-relief

This is about US$ 60.4 million based on today’s conversion rate of 1USD=33.1 baht.  In the last 6 months, the government has already spent on launching control campaigns (~ US$1.5 million) and providing free pesticides (~US$16 million).

Actual production loss due to BPH is hard to estimate as data is not available, but based on the recent revision of the 2010 season rice output from 8.3m to 7m tons, the loss in exports might be about 1.3 m tons paddy or 0.65 m tons rice.  Using a conservative price of rice of about US$ 500/ton, this loss may be more than US$ 325 million. So the BPH outbreaks that started in July 2009 and continued to spread might have caused a total loss of US$ 400 million will be my guess.  This does not include indirect costs, like environmental pollution from the increased insecticide inputs and farmers’ health, as there are reports of increased pesticide poisoning in the rural areas. In addition, the social cost as many farmers are in debt because pesticides had been bought on credit and with the loss in production, many are unable to repay loans taken out. BPH outbreaks are preventable as they arise because unsustainable practices that lead to ecosystem breakdowns. Restoring the ecosystem services in rice environments should be the main focus to achieve sustainable pest management and avoid incurring such huge losses. Check:

http://beta.irri.org/news/index.php/press-releases/restore-ecology-to-prevent-rice-pest-outbreaks-in-thailand.html#top

Business » Economics

State to pledge B2bn for brown planthopper relief

  • Published: 9/02/2010 at 12:00 AM
  • Newspaper section: Business

// Two billion baht has been allocated to compensate farmers hit by losses from an infestation of insects known as planthoppers in the North and Northeast.

The compensation budget and other measures to combat the infestation are scheduled to be tabled for cabinet approval at today’s meeting, said Prime Minister Abhisit Vejjajiva.

But the premier suggested the best solution to combat the insect infestation is to stop growing rice temporarily.

Insect infestation and reduced water supplies in key rice regions has recently prompted the Office of Agricultural Economics to cut its second-crop harvest forecast by nearly 16%.

Thailand may now only produce about 7 million tonnes of paddy from its second crop, rather than 8.3 million forecast earlier, according to the Office of Agricultural Economics.

The overall 2009-10 crop would then total 29 million tonnes of paddy – down from the previous forecast of 31 million and also less than last year’s crop of 31.4 million tonnes – which could add upward pressure on prices.

An infestation of brown planthoppers across about 1.1 million rai destroyed some crops and cut yields, according to the latest Rice Department report.

About 780,000 rai of crops were lost completely and the rest were 30% damaged, said deputy director-general Chairit Damrongkiat. That means a loss of 355,000 tonnes, based on an average yield of 400 kilogrammes per rai.

The hoppers spread from the North to the central provinces, the so-called rice bowl of Thailand.

The Food and Agriculture Organisation said in its latest forecast that world rice imports in 2010 could rise to 30.5 million tonnes, up from 30.3 million in 2009.

Import demand is mostly seen as rising in Asian countries, several of which would need to compensate for poor 2009 harvests.

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Toxicity of a carbamate, BPMC to BPH in three provinces of Thailand

Posted on February 8, 2010 by moni

by
Wantana Sriratanasak and Sukanya Tepandung, Rice Department, Thailand
Patrick Garcia and Lilia Fabellar, International Rice Research Institute, Los Baños, Philippines

Brown planthoppers. Photo credit: Jirapong Jairin, Rice Department

BPMC or fenobucarb, a carbamate insecticide, has been used for rice planthopper control in Asia for the last 30 years. It is still in use nowadays so its toxicity to BPH was evaluated. The brown planthopper (BPH) populations were collected from the provinces of Chainat, Ang Thong and Nakhon Ratchasima and reared in the laboratory. After 3 generations, the toxicity of BPMC to BPH was evaluated using the standardized procedure (http://ricehopper.files.wordpress.com/2009/07/monitoring-draft-protocol.pdf) and compared with BPH populations in the Philippines and China (Table 1). The data were analyzed using PoloPlus program and the relative potency ratios computed.

Table1. LD50 values in nanograms (ng )* and related statistics

Locations LD50(ng/g) Fiducial limit(95%) Slope (+se) Heteroge-neity Relative Potency Ratios
Chai Nat 634.11 369.97 – 935.84 1.653 (0.161) 1.62 1.0
Ang Thong 1418.51 1099.24 – 1744.20 2.061 (0.230) 0.55 2.2
Nakhon  Ratchasima 1904.74 1545.34 – 2271.65 2.488 (0.291) 0.15 3.0
San Pablo 847.16 627.46 – 1058.06 2.244 (0.295) 0.76
Jinhua 44791.92 24248.54 -61856.09 2.460 (0.338) 2.13

* 1 nanogram =  1.0 x 10 -4 microgram = 1.0×10 -6 milligrams

The analysis showed that the LD50s of the three BPH populations were significantly different (chi-square 79; p<0.05). The Nakhon Ratchasima and Ang Thong populations had similar slopes (chi- square 3.06 p<0.05) while the slope for Chai Nat population was significantly lower. The LD50s for Ang Thong and Nakhon Ratchasima were 2.2 and 3.0 times higher, respectively, than that of Chai Nat indicating that the populations in Ang Thong and Nakhon Ratchasima were more tolerant or resistant to BPMC, however, the populations with different slopes may not be comparable. The Ang Thong and Nakhon Ratchasima were more comparable with the latter population more tolerant or resistant by 1.35 times.

Topical application technique used to determine LD50

The LD50s obtained were also compared with BPH populations from San Pablo, Philippines and that from Jin Hua, China with those from Nakhon Ratchasima and Ang Thong in the same batch analysis. The LD50s were significantly different but the slopes were not and thus the populations might be comparable. We used the lowest LD50 of  San Pablo as the base and found that the Jin Hua population was 52.87 times more resistant and the populations in Ang Thong and Nakhon Ratchasima were 1.67 and 2.25 more resistant, respectively (Figure 1).

Figure1. Probit lines for BPH populations in Thailand, Philippines and China

The result indicated that in 2009 BPH populations in Thailand were about 2 times more tolerant or resistant to BPMC than those in the Philippines.  The BPH population in China was the most resistant, about 53 times and 25 times higher than population in the Philippines and Thailand, respectively. The level of insecticide resistance clearly reflects the intensity of insecticide use, with China using BPMC far more intensively than Thailand and Philippines and Thailand more intensively than in the Philippines. Thai farmers use abamectin and cypermethrin frequently, research is needed to determine if they can stimulate resistance development in carbamates or other insecticides.

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Estimating the reliability of an ecological engineering attitude scale for rice farmers

Posted on January 31, 2010 by moni

by
M. M. Escalada, University Professor, Visayas State University, Leyte, Philippines
Manit Luecha, Director, Chainat Rice Seed Center, Chainat, Thailand
Le Van Thiet, Deputy Director, Southern Regional Plant Protection Center, Long Dinh, Vietnam
Zhu Zeng Rong, Associate Professor, Zhejiang University, Hangzhou, China

Billboard of ecological engineering experiment, Cai Be, Tien Giang, Vietnam

In farmer surveys, scales are often used to measure respondent perceptions, beliefs, and attitudes. Results are then used to make inferences and judgments on intervention points that need to be addressed in subsequent upscaling initiatives. When a scale is used, it is a standard procedure in the social sciences to determine its reliability. A popular measure of reliability is Cronbach’s alpha which determines the internal consistency or average correlation of items in a survey instrument to gauge its reliability. Internal consistency estimates how consistently the respondents have responded to the items within the scale. The closer the Cronbach’s alpha is to 1, the higher is the internal consistency (Gliem & Gliem, 2003). In social science, the widely accepted alpha is 0.70 or higher for a set of items to be considered a scale.

Group discussion in Cai Be on ecological engineering experiment

We calculated the Cronbach’s alpha of the belief and attitude scale on non-rice habitats used in a baseline survey instrument. As items were worded either positively or negatively, reverse scoring was done to negatively worded statements. The items within the scale were drawn from focus group discussions (FGDs) with rice farmers in China, Thailand and Vietnam. We used a Likert-type scale, as follows:  Definitely not true, in most cases not true, may be true, in most cases true and always true. The attitude scale on ecological engineering included these items:

Uses of non-rice habitat

  1. Non-rice habitats are sources of pests and diseases.
  2. Non-rice habitats are home to natural enemies.
  3. All plants in the non rice habitats are of no use to me.
  4. Bunds have some beneficial flowers that attract natural enemies.
  5. Increase in wild flowers on bunds can reduce need for insecticide sprays.
  6. Increase in beneficial flowers on rice bunds can help the bees.
  7. Bees are important for pollinating fruit trees.
  8. Increasing the beneficial flowers on rice bunds will make our fields beautiful.
  9. Increasing beneficial flowers on rice bunds can bring better health to farmers and their families.
  10. The natural enemies that the beneficial flowers bring can help prevent planthopper outbreaks.
  11. Increasing the beneficial flowers on rice bunds can reduce the rat population.
  12. If farmers increase the beneficial flowers on rice bunds all year round, the population of beneficial insects will increase.
  13. Maintaining more beneficial insects will lower BPH population.
  14. Replacing plants growing on the bunds with cash crops will give farmers more income.

Maintaining non-rice habitat

  1. Increasing beneficial flowers on the bunds is a waste of time.
  2. Increasing beneficial flowers on bunds is easy to do.
  3. It is difficult to increase beneficial flowers on bunds because nearby paddy fields use herbicide.
  4. We cannot increase the beneficial flowers on bunds because we burn our rice straw.
  5. Increasing beneficial flowers on bunds is additional burden to farmers
  6. It is difficult to increase beneficial flowers on bunds because farmers will step on them.
  7. Farmers should not apply herbicide on the bunds.
  8. Our bunds are narrow so there is no place for beneficial flowers.
  9. Bunds in rice fields should not have any plants on them.
  10. I am willing to try increasing beneficial flowers in the bunds to learn more about what they can do.

Cronbach’s alpha from survey data

Using the Statistical Package for the Social Sciences (SPSS), the reliability of the attitude scale was computed. Table 1 shows that an acceptable Cronbach’s alpha of higher than 0.70 was generated by our baseline survey attitude scale on ecological engineering. The alpha suggests that the items in the attitude scale are related enough to combine into an attitude scale or index. For each data set, only 16 to 22 out of 25 items were used in the analysis. Some items were excluded to increase the reliability coefficient.

Table 1. Cronbach’s alpha obtained from attitude scale data in target countries.

Country Cronbach’s alpha Number of items
China (Jinhua and Lingui) 0.713 16
Thailand 0.717 22
Vietnam 0.745 22

References:

Gliem, Joseph A. & Gliem, Rosemary R. 2003. Calculating, interpreting, and reporting Cronbach’s alpha realiability coefficiens for Likert-type scales. paper presented at the Midwest Research-to-Practice Conference in Adult, Continuing, and Community Education, The Ohio State University, Columbus, OH, Oct. 8-10, 2003.

Santos, R.A. 1999. Cronbach’s alpha: A tool for assessing the reliability of scales. Journal of Extension. Vol. 37, No. 1.

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Thailand cuts second crop rice output forecasts by 16% because of BPH and water shortage

Posted on January 28, 2010 by moni

by
K.L. Heong
Insect Ecologist
International Rice Research Institute
Los Baños, Philippines

The Bangkok Post reported on 26 January 2010 that Thailand has cut the second crop output  forecast by nearly 16% from 8.3 million tons to 7 million tons.  The main reasons cited by officials were water shortage and heavy infestations by planthoppers in key rice areas. http://www.bangkokpost.com/business/economics/31763/second-crop-output-forecast-cut-by-16. Most of the water shortage problems are in the North Eastern region where farmers are unable to start planting.  This has drawn concerns from H.M the Queen of Thailand (http://teakdoor.com/thailand-the-royal-family/26767-thailand-queen-voices-concern-about-rice.html ). The BPH and virus infestations are in the irrigated areas of Central Thailand.

The total rice output for the 2009/10 is now expected to be 29 million tons paddy if the BPH and water problems do not persist. This expected output is about 2.4 million tons (or 7.6%) lower than 31.4 million tons obtained in the 2008/2009 crop. This might add pressure on world rice prices.

The BPH infestations started in July 2009 and spread to 14 provinces in Thailand’s rice bowl (http://ricehoppers.net/2009/08/10/hopperburn-in-thailand%e2%80%99s-rice-bowl/). Despite  the control campaigns and millions of baht spent in attempts to control the problem with pesticides in the last 6 months, problems from BPH and virus infestations seem to have gone worse (http://ricehoppers.net/2009/12/23/thai-ministry-of-agriculture-seeking-cabinet-approval-for-funds-to-control-bph-outbreaks/ ).  Farmers have been using pesticides that have high resurgence properties, like abamectin, cypermethrin and chlorpyrifos, especially in the early crop stages that have increased the vulnerability of their farms to hopperburn. (http://ricehoppers.net/2010/01/17/farmers%e2%80%99-insecticide-selections-might-have-made-their-farms-vulnerable-to-hopperburn-in-chainat-thailand/ ).

Hopperburn in rice fields in Chainat Photo credit: Manit Luecha (Chainat Rice Seed Center)

BPH and virus infestations in many areas in Central Thailand are still heavy. To add further miseries to farmers, many of them are in debt unable to repay bank loans because of the crop losses they suffered and the huge pesticide expenditures they had incurred. In Phichit province, about 30% of the rice fields were destroyed (http://ricehoppers.net/2010/01/26/planthoppers-destroyed-30-of-province%e2%80%99s-rice-production-in-thailand/ ).

For more information, click here …

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Planthoppers destroyed 30% of province’s rice production in Thailand

Posted on January 26, 2010 by moni

by
Orapin Wattanesk, Acting Director, Research Bureau, Rice Department, Thailand
Manit Luecha, Director, Chainat Seed Center, Rice Department, Thailand

Typical scene of fields with hopperburn in Phichit Province

The brown planthopper (BPH) has infested several provinces in Central Thailand in the in season of 2009/2010 and Phichit province was badly affected. Agricultural authorities reported that about 490,000 rai  (78,400 ha) have been destroyed which is about 30% of the province’s 1.6 million rai (256,000 ha) of rice production.  More than 28,000 farm households in the province have been badly affectedby the pest outbreaks.  Farmers here had typically planted short duration (about 75 days) varieties and had routinely applied abamectin and cypermethrin insecticides to “protect” their crops. These insecticides have properties that can induce secondary development and resurgence in BPH populations (http://ricehoppers.net/2010/01/17/farmers%e2%80%99-insecticide-selections-might-have-made-their-farms-vulnerable-to-hopperburn-in-chainat-thailand/ ). The provincial government released about 15 million baht (US$ 455,000) to combat the pest and most of this is to purchase pesticides, provide training in correct use of pesticides and knowledge on planthoppers. Two D Day campaigns (http://ricehoppers.net/2010/01/02/thailand-launches-another-campaign-series-to-curb-planthopper-crisis/), in Tambon and Muang districts were launched.

Many of the fields, infected with two virus diseases, the rice ragged stunt (RRSV) and the rice grassy stunt (RGSV) transmitted by the BPH (http://ricehoppers.net/2010/01/10/ragged-stunt-and-grassy-stunt-virus-infections-in-the-provinces-of-northern-provinces-of-central-thailand/ ), have been abandoned.  These can be potential sources of further virus spread to provinces where farmers are beginning to plant.

Close-up picture of BPH in rice canopy

More details are found in

http://www.thailandoutlook.tv/tan/ViewData.aspx?DataID=1023180

http://www.bangkokpost.com/news/local/28893/insects-devastate-rice-crops

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Farmers’ insecticide selections might have made their farms vulnerable to hopperburn in Chainat, Thailand

Posted on January 17, 2010 by moni

by
Manit Luecha, Director Chainat Seed Center
Rice Department, Thailand

A large variety of insecticides are sold for rice pest control. Farmers rely on salesmen’s recommendations when selecting what pesticide to use.

Insecticides are known to cause secondary developments and resurgences in brown planthopper (BPH) populations. They disrupt the food web structures, disorganize predator-prey relationships and favor rapid population developments of invading BPH resulting in hopperburn (Heong and Schoenly, 1998). Broad spectrum insecticides that have strong effects on natural enemies tend to make rice fields more vulnerable to hopperburn. We surveyed 341 farmers’ insecticide use in Chainat in August 2009 just prior to the massive BPH outbreaks in Central Thailand.

Farmers were growing rice varieties Phatum Thani 1 (61%), Suphan Buri 3 (14%), Chainat 1 (12%) , Suphan Buri 1 (8%), Suphan Buri 60 (3%) and 3 other varieties.  On average they sprayed insecticides 3. 1 times with some as many as 12 times and some none at all. We looked at the types of insecticides that farmers used at the various crop stages (Table 1).  The insecticides Abamectin (37%), Cypermethrin (12%), Chlorpyrifos (13%) were used in all crop stages although they were only recommended for treating leaf folders. These three insecticide accounted for 62% of all farmers using insecticides. In focus group discussions, we found that farmers’ insecticide selections had been based on recommendations from the pesticide salesmen.  Pesticides are called “ya” which mean medicine and they are good for all insects.

Farmers often spray their crops at very early stages using mist blowers. Such practices are detrimental to aquatic and biological control fauna.

Table 1. Percent of farmers using each insecticide at different crops stages

Crop stages (days after sowing)
Insecticide

0-15

16-40

41-60

61-70

> 70

Abamectin

39.1

31.0

40.0

39.1

37.5
Cypermethrin

26.0

3.3

 20.0 2.2

6.3
Chlorpyrifos

15.6

8.7

 13.3 10.9

15.0
Dinotefuran

4.2

14.6

 6.7 10.9

0
Fenobucarb

0.8

0.3

 6.7 2.2

0
Cartap hydrochloride

4.0

5.1

 0 8.7

0
Imidacloprid

0.6

3.0

 0 4.3

5.0
Fipronil

0.2

3.6

 0 0

0
Buprofezin

0.8

3.8

 0 2.2

0
Dimethoate

0.2

8.0

 0 8.7

25.0
Carbofuran

2.5

2.0

 0 2.2

5.0

The three most popular insecticides that Chainat farmers had used had poor ecological properties (Table 2). They have high toxicities to fish and aquatic fauna as well as bees.  Toxicities to key natural enemies were not available but their high toxicities to bees would mean that they are likely to be toxic to hymenopterans, including parasitoids.  Spiders tend to be susceptible to similar ecological properties and were probably badly affected as well.

Large areas in Chainat province were damaged by hopperburn

Table 2.  Ecological effects – Toxicities of selected insecticides on some non target organisms

Toxicity to Abamectin Cypermethrin Chlorpyrifos
Birds Non Non Moderate
Bees High Highly High
Fish High Very High Very high
Aquatic fauna Extremely high Very high High

Source: http://extoxnet.orst.edu/pips/

The three insecticides are known to have detrimental effects on biological control elements and cause resurgences. Their frequent usage in Chainat have probably disrupted the biological control services and increased the vulnerability of rice fields to hopperburn.

Reference

Heong, K.L. and Schoenly, K.G.  1998.  Impact of insecticides on herbivore-natural enemy communities in tropical rice ecosystems.  Pp 381-403  ( P. T. Haskell and P. McEwen  Eds.)  Ecotoxicology:  Pesticides and Beneficial Organisms. Chapman and Hall, London.

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Ragged stunt and grassy stunt virus infections in the northern provinces of Central Thailand

Posted on January 10, 2010 by moni

by
Witchuda  Rattanakarn and Pamorn Pattawung
Bureau of Rice Research and Development, Rice Department, Bangkhen, Thailand, and
Phitsanulok Rice Research Center, Rice Department

A field completely destroyed by hopperburn; many fields were in such condition

On December 24, 2009, we traveled to 11 sites in three provinces, Khampaengphet, Pichit and Pitsanulok, interviewed farmers and made field assessments of damages caused by brown planthopper (BPH) and the two viruses it transmits, the rice ragged stunt virus (RRSV) and the rice grassy stunt virus (RGSV).  All the 11 sites had hopperburn symptoms and virus infections varied from 5% to 70%. The farmers were using improved traditional varieties, Suphan Buri  4 and Patum Thani 1 and have been using broad spectrum insecticides, abamectin and dinofefuran. These insecticides have poor effects on BPH but have strong effects on the aquatic animals, bees and natural enemies. But farmers use it anyway because they were advised by the local pesticide salesmen. Below are details of our observations:

Phitsanulok Province

Numerous plants have mixed virus infections (A). Typical symptoms of infection by RRSV (B)

In Ban Meunjan, Meoung district, farmer, Pin Yodpetch grew traditional varieties, Po Ngern and Po Thong.  Signs of hopperburn appeared in the heading stage. He had tried to control the BPH using abamectin with no effects. In addition his crop had about 10% virus infection.

In Ban Meunjan Meoung district, farmer Prateung Pumpuong, grew Khao Phatum  and sprayed his crop using with dinotefuran to control BPH but it did not work. His crop suffered hopperburn and about 5% infections by the viruses. In addition his field also had heavy blast infections.

Crops were also infected with blast

In Bang Ragam district, the traditional rice varieties, Po Ngern and Po Thong, had severe hopperburn destroying 8 -10 ha. The farmers had harvested and the stubbles showed virus infection symptoms.

In another location in Bang Ragam district, rice was close to harvesting and about 5% of the crops had virus infection symptoms.

In Bang Kratum district, farmers grew Suphan Buri 4, and at the tillering stage, they sprayed abamectin. About 5% of the crop was infected with the viruses.

Stunted plants caused by mixed infections by RRSV and RGRS (A). Empty container of abamectin insecticide that farmers used (B)

In Ban Tong Maharach, Sai-ngarm district, the crop was in the heading and flowering stages. Nymphs and adult BPH populations were in low densities and 5% of the crop was infected with the viruses.

The rice crop in Bann Nerngroi, Sai-ngarm district, was in the tillering stages. BPH was low but about 70-80% of the crop was infected.

In Sai-ngarm district,the rice was in the heading stage and large densities of BPH nymphs were found in the crop. Hopperburn has occurred in neighboring fields and the crops were severely infected with viruses.

Patches on hopperburn (A) and field with typical virus infections (B)

Pichit Province

Rice was in the booting stages in Vachirabaramee district, virus symptoms were found in about 10 % of the crop.

In Sam Ngam district, farmers were growing a local variety called poung thong. The crops was in the booting and flowering stages. Low densities of BPH were found in the crops and about 10% had virus infection symptoms.

Farmers in Bang Ruong Chang, Mueong district, grew Suphan Buri 4 and there was abundance of plants with virus infection symptoms.

Typical symptoms of RRSV infection in Suphan Buri 4

Filed under: Planthoppers, Virus disease management | Tagged: , | 1 Comment »

Consortium initiated to research on new virus disease, Southern Rice Black Streak Dwarf

Posted on January 8, 2010 by moni

by
K.L. Heong and I.R. Choi
International Rice Research Institute
Los Baños, Philippines

The Steering Committee of the Consortium and participants from the Hainan Plant Protection Station

The Southern Rice Black Streak Dwarf Virus (SRBSDV) was first discovered in Guangdong province about 9 years ago. Zhou et al (http://ricehopper.files.wordpress.com/2009/01/zhou-et-al-2008-southern-rice-black-streakeddwarf-virus.pdf) and  Zhang et al (http://ricehopper.files.wordpress.com/2009/01/zhang-et-al-2008-a-black-streaked-dwarfdisease-on-rice-in-china-is-caused.pdf) published the descriptions of this new virus transmitted by the white back planthopper (WBPH). The virus has also been found infecting maize, sorghum and grasses. Lately large areas of rice and maize in the southern provinces of China and the northern provinces of Vietnam were found destroyed by the virus (http://ricehoppers.net/2009/11/03/new-virus-carried-by-wbph-becoming-wide-spread-in-hybrid-rice/.

Stunted maize (A) and rice (B) plants infected with the virus

In December 2009, Dr Bui Ba Bong, the vice minister of agriculture and rural development of Vietnam announced the formation of the China-IRRI-Vietnam consortium to initiate research on this new problem (http://ricehoppers.net/2009/12/08/consortium-set-up-to-address-new-virus-problem/) The Steering Committee of the Consortium held its inaugural meeting in Sanya, Hainan in January 6 -7, 2010 and visited the site, Lou Di Yang, where the virus had been discovered. Numerous rice ratoons and maize plants were found infected by the virus in the area.

Dr J. Y Xia, the DG of NATESC (in white) examining diseased maize plants with Professor Zhou (in grey)

The Consortium elected Dr K. L. Heong as the chair and Dr I.R. Choi as the secretary and developed a China-IRRI-Vietnam collaboration research plan.  The members from China are Dr Jing Yuan Xia, Director General of the National Agro-Tech Extension & Service Center (NATESC) (deputized by Dr Puyun Yang), Professor Jiaan Cheng (Zhejiang University) and Professor Jian Peng Chen (President of the Zhejiang Academy of Agricultural Sciences), and from Vietnam, Dr Nguyen Van Tuat, Vice President of the Vietnam Academy of Agricultural Sciences, Dr Ngo Vinh Vien, Director of the Plant Protection Research Institute and Dr Hoang Trung, vice Director General of Plant Protection Department (deputized by Mr Nguyen Tuan Loc).

In his opening address to the Committee, Dr Xia said that the immediate task of the Consortium is to do research to find out as much as possible about this new virus, develop a collaborative monitoring scheme to understand its spread and develop strategy options. He added that this problem is a top priority in NATESC and he will brief the Chinese Agricultural Ministry about the problem and seek more support for the Consortium.  China and Vietnam have developed a memorandum of agreement between the two ministries of agriculture in 2009 to support collaborative activities in pest monitoring.

There will be some funds available immediately to support the Consortium’s planned activities this year.  Two sites in Northern Vietnam were identified as the collaborative monitoring stations, Quang Nam and Nam Dinh, and they will each be equipped with an automated light trap, computers and support items by NATESC and provided with training on diagnostic methods. Five monitoring stations in China, one each in Hainan, Yunnan and Guangdong and two in Guangxi will be used in this collaboration.  In addition collaborative research in virus surveys, virus identification, developing field diagnostic kits, vector-virus relationships, plant-virus relationships, epidemiology and evaluation of control strategies will be carried out between scientists in Plant Protection Research Institute, Zhejiang Academy of Agricultural Sciences, South China Agricultural University and IRRI.

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