Solution to control brown backed rice plant hopper and twisted leaf dwarf disease

Measures to prevent brown backed rice plant hoppers and stunted twisted leaves have a different point. Using rice varieties with high BPH resistance is still the most effective method of preventing hoppers.

The area of ​​rice infected with brown planthopper and yellow dwarf (VL) and twisted leaf dwarf disease (LXL) are increasing rapidly. At the beginning of the summer-autumn season, there were 456 ha of infection, by the end of the season, it increased by 78 times, on October 3 increased to 60 thousand ha (131 times). And 72 thousand hectares are statistics to report to the October 18, 2006 meeting of the anti-hoppers meeting of the agricultural sector in Ho Chi Minh City. This is also a source of pests and diseases and diseases in the early winter-spring crop 2006 - 2007.

Due to the efforts of farmers and agricultural officials in the South, as there are nearly 20 provinces and cities, there is a Steering Committee for the prevention of aphids, thus limiting the scope of harm and not affecting the national food security. , because we have " food safety valves " at 20% of rice production for export. However, there has been a significant impact on family food security in many localities. As in Tien Giang, this outbreak of VL and LXL occurred in an area of ​​about 18 thousand hectares, the province damaged about 50,000 tons of rice, worth about VND100 billion, affecting 24 thousand households with about 120,000 people.

(Photo: Nhandan) Two major outbreaks of BPH in the Southern region were in 1978 and 1991, causing major damage due to the rice plant hopper infestation. Viral diseases and LXL are present, but are not clear. This time the disease is very serious. The rate of infected rice area compared to the pest infestation area increased very quickly. According to a PPD statistic in the last briefing: In the South, the ratio of infected areas and LXL compared to the pest infestation area in the summer-autumn crop in 2006 was 13.7%; in the next winter-autumn crop, 42%, up to 95% in the season! And the rate of infected pests on the total number of hoppers was initially estimated at 50-60%.

General characteristics of this disease and this time and the last time, including in the North, the epidemic of green leaf hoppers and yellow disease in the mid-60s of the last century was: the disease cannot be spread from rice to rice plants. heal, if there is no pest, there is a disease transmission. As in the previous study, just one infected hopper could transfer to even the rice bush, then the flock to suck the plastic from the disease will spread to healthy rice, sometimes reaching thousands of children / dust. This hopper can follow the wind to many remote places.

As such, only the psyllid will block viral disease and spread LXL. Moreover, except for hoppers, the pests are prevented even when the hoppers do not carry the disease. However, the " tracking " of the hoppers is quite complicated; need both spirit and skill; both farmers' self-reliance and technical support and funding. So far, the budget support of the local budget has actually paid 0.8 billion for the summer-autumn crop in 2006; 2.1 billion for the next winter crop, and 2.5 billion for the crop.

The prevention measures of psyllids also have a different point . Using rice varieties with high BPH resistance is still the most effective method of preventing hoppers. Localities have found many varieties produced on a large area with acceptable psyllid resistance, such as OM576, OMCS2000, IR64, VD 95-20, AS996 . There is an unstable resistance / infection, because When infected, when not, like Jasmin, this breed has resistance to VL and LXL . Using aphid-resistant variety is the best. When it is necessary to choose between aphid-resistant variety and a confirmed psyllid, this should be used for resistance against aphids. There have been many new rice lines / cultivars with good resistance, but also have to be challenged on a large area.

When current BPH and viral load and LXL are present, it is not appropriate to wait 40 days before sowing for pests. In Dong Thap province and many places after rice sowing for 20-25 days, brown backed rice plant hopper and disease and LXL have been reported. It is important to eliminate pests immediately, in rice fields or on bushes, at any stage of rice growth and development. The effect of minus hoppers with the highest chemical is the time of aphids, which will decrease rapidly when adults grow.

We have seen biological preparations except for white fungi and green fungi that have good effect, can be able to subtract psyllids after the aphid stage, if the fungus is in contact with the aphids, root into the psyllid and cause death. . Compared to bassa and other chemicals, the effect is slower than five to seven days, but more durable. However, it is difficult to distinguish which products do not contain enough fungi, or do not have a mushroom, of course. There is a need to apply this biological control method, although farmers apply it more difficult to use chemical drugs, but are "environmentally friendly" measures .

There is no good farming method, such as the " three rose three " movement, which does not promote the potential of the variety, which has the potential to resist psyllids. It is necessary to focus on implementing drastically technical measures that both limit development hoppers, increase productivity, increase quality and lower production costs. Sowing rice in rows by machines is a technical measure that satisfies the above requirements, the area of ​​application of this technique has reached 20-25% of the rice area. Normally, the number of hoppers / 1m ² in the rice field is 0 - 2, in the orchards, there are a few of them. The benefits of seed sowing have been summed up in a transparent way, compared to traditional practices: one ha saves more than one quintal of rice seed, one bag of urea, reduces 2-4 times of insecticide, significantly reduces the area Rat breaking.

The Southern Plant Protection Department has experimented on a wide area of ​​flat fields using lasers technology, putting the surface of the paddy field in white as a mirror. Consistent results of IRRI's research in Cambodia, increasing productivity by about 10%, increasing the effectiveness of other techniques; As the density of rice is uniform, reduce the amount of irrigation water, apply fertilizer evenly, and harvest more easily.

Entering with the movement of preventing and fighting against brown plant hopper and disease and LXL, the Mekong Delta Rice Institute considered the most preferred research and development activity for the whole hospital. Applying the experience of cooperation with QT Rice Institute (IRRI), with JIRCAS (Japan), with the Indian team working at the institute from 1982 to 1989, to seriously test the BPH resistance in the room. , in the field, with the sources of hoppers collected in the localities. The varieties being used in production on a large area require testing of localities such as OM 5765, OMCS 2000, IR 50404, ST ., promising lines / varieties of any author who wants to match The research will be researched and urgently. The Institute is willing to cooperate with localities and research facilities of relevant agencies.

Prof. Dr. NGUYEN VAN LUU