Agricultural Technology Center: some pesticides fail due to the increase of resistance to diseases and insect pests

At the beginning of 2017, the National Agricultural Technology Center organized 60 pesticide resistance monitoring sites in 20 provinces (autonomous regions and municipalities) to monitor the drug resistance of 11 major diseases and pests, including vegetables, rice, wheat, cotton and so on. the results showed that the resistance of some diseases and pests to common control agents in the field increased significantly. Which drugs don't work for diseases and insect pests? How can drugs be used to delay drug resistance? Let's take a look at the scientific medication strategies given by experts.

1. Vegetables

1. Beet armyworm, Spodoptera exigua, suspended or reduced use of chlorobenzamide in East and South China.

Shanghai Fengxian, Chongming and Guangdong Baiyun beet armyworm populations were highly resistant to bisamides chlorobenzamide (112-805 times), and moderately resistant to indenyl and insect growth regulators methoxyhydrazide. it is sensitive to macrolides to spinosad. Huangpi population in Hubei Province was sensitive to other three insecticides except that it was moderately resistant to chloramphenicol. The population of beet armyworm produced more than moderate resistance to chlorobenzamide and methoxyfenozide, and the resistance ratio was more than 15 times.

Countermeasures and suggestions:

In the vegetable producing areas of East and South China, it is suggested that the medication strategy should be adjusted in time, the use of chlorobenzamide to control beet armyworm should be suspended or reduced, and the use of methoxyfenozide, indenyl and spinosad should be strictly controlled. in addition, attention should be paid to the alternate use of agents with different action mechanisms, and it is suggested that organosilicon and Jiamejin should be added to enhance the efficacy.

2. Bemisia Tabaci resistance is light in the north and heavy in the south, pay attention to alternate use of drugs.

Bemisia Tabaci populations in Beijing, Tianjin, Shanxi, Shandong and other northern vegetable producing areas are sensitive to neo-nicotinic thiazide, macrolide avermectin and other insecticides, and are moderately resistant to bisamides, insect growth regulators, pyrethroids and quaternary ketoacid spiroethyl esters. Compared with the northern vegetable producing areas, the Bemisia Tabaci population in Hubei, Hunan, Hainan and other vegetable producing areas had a higher level of drug resistance, sensitive to avermectin and low resistance to thiazine. The resistance to propyl ether and spirochete ethyl ester was in the middle to high level, and the resistance to bromocyanamide was at a high level.

Countermeasures and suggestions:

In view of the characteristics of Bemisia Tabaci resistance in the north, light in the north and heavy in the south, vegetable producing areas such as Hubei, Hunan and Hainan should reduce the use of a single pesticide to control Bemisia Tabaci, and pay attention to the alternating use of pesticides among different mechanisms.

3. The resistance of Plutella xylostella to chlorobenzamide, fipronil, indenyl, avermectin and cypermethrin.

The results showed that compared with the northern vegetable producing areas, the resistance of pests in southern vegetable producing areas such as Hunan, Guangdong, Hainan and Yunnan increased rapidly, showing the characteristics of heavy resistance in the south and light in the north. Plutella xylostella population has a high level of resistance to avermectin and beta-cypermethrin, and the resistance to chlorbenzamide, fipronil and indenyl is medium to high level.

Countermeasures and suggestions:

Experts suggest that pesticides with different action mechanisms should be used alternately, and the rapid increase in drug resistance of vegetable pests is largely due to excessive drug use, random increase in frequency and concentration of use. For this reason, it is suggested that the drug use strategy should be adjusted in time, and the pesticides with different action mechanisms should be used alternately, especially in Hunan, Guangdong, Yunnan, Hainan and other areas, where each type of pesticide should be used no more than once per season. to slow down the development of drug resistance. In view of the fact that the Plutella xylostella population in most areas of China has a high level of resistance to avermectin and cypermethrin, it is suggested that it should be suspended and other agents with different action mechanisms such as ethyl spinosad, butyl ether urea and azadirachtin can be used alternately. It is suggested that organosilicon and Jiamei should be added to reduce drug resistance and enhance efficacy.

4. There is basically no ideal chemical control for black-headed maggots.

This kind of maggot has caused nearly no harvest of garlic and leek in many places. Large factories and small factories have used a lot of special effects, and the feedback results are that there is no ideal control effect. And although some organophosphorus pesticides have been banned in many areas, farmers still use them secretly, despite this, the control effect is not very satisfactory. Chlorpyrifos, phoxim, a variety of single agent mixture, the use of one mu of land is calculated according to kg, it is still not very ideal, that is, the use of phoxim is still part of the effect, but to be completely dead, it is also very difficult.

At present, various formulations have been tried, and the most popular ones are furosemide, thiamethamide, avermectin, chlorpyrifos, phoxim, cypermethrin, cis-cypermethrin, etc., as well as imidacloprid, acetamiprid and thiazine.

5. Root-knot nematodes are very harmful to many vegetable crops, field crops and fruit trees. Because of its invisibility to the naked eye, some literatures call it nematode disease, which is classified as disease, and here it is still called pest. At present, avermectin is the most widely used in nematode control, EC, water emulsion, granule, spreading, ditch application, hole application, flushing application, because of its more economical and affordable reasons, the use is very large. Because of this, after years of use, the resistance is also very obvious, another reason is that avermectin is difficult to move in the soil, resulting in its control effect against nematodes is getting worse and worse.

Thiazophosphonium is a popular product that is gradually replacing avermectin. In addition to the initial granules, major manufacturers are gradually developing liquid spray forms such as water emulsion, emulsion and soluble agents for single and mixed agents. At present, resistance has been reported in a small number of areas, but it has not been widely used because the cost has just been reduced, and the resistance does not show a too serious trend.

Flumidamide is currently not a response to resistant products, I think it should be the cost is too high, not many farmers are willing to use it repeatedly, after all, it is too expensive.

6. Whitefly is one of the main vectors of virus disease transmission, it can harm a variety of vegetables and even field broad-leaved crops, in many cases, if the whitefly prevention is not in place, the spread of virus disease is almost inevitable.

At present, as far as a single dose is concerned, there seems to be no particularly good products, such as acetamiprid, imidacloprid, imidacloprid, thiazide, deltamethrin, bifenthrin and so on, and the mixture of imidacloprid and imidacloprid is very popular for a period of time. The effect response is very good, but the resistance is not small at present.

On the market, there are many special effects products for the control of whitefly, most of them add invisible ingredients, and most of the effects are not good for two years, and nothing can really last forever.

There is a small way to use thiazide water dispersible granules, a little at the root of each vegetable, which is basically enough to control stinging mouthparts pests such as whitefly, thrips and aphids throughout the growth period.

7. When it comes to the resistance of jumping beetles, basically everyone who is an insecticide knows that the resistance is very high. Such as dichlorvos, trichlorfon, phoxim, chlorpyrifos, thiazide, deltamethrin and so on, all have certain control effects, but they are not really easy to use. At present, in terms of single dose, it seems that the effect of malathion and fipronil is relatively good, the rest are all kinds of compounding, and the formula can not be enumerated one by one.

II. Rice

1. Brown planthopper has a high level of resistance to imidacloprid, thiazine and buprofezin.

At present, all populations of brown planthopper in the monitored area have a high level of resistance to the first generation nicotine drug imidacloprid (resistance ratio is more than 1200 times) and to the second generation nicotine drug thiazide (resistance multiple 200,500 times). However, it is sensitive to enpypyram and low to medium resistance to the third generation nicotine drug furosemide. There was a high level of resistance to buprofezin, a kind of insect growth regulator, and the resistance ratio of brown planthopper to buprofezin was significantly higher than that in 2015. especially, the resistance ratio of brown planthopper in Jiangsu, Jiangxi and Hubei is more than 1000 times.

Moderate resistance to organophosphorus pesticide chlorpyrifos. According to the plant protection stations of Zhejiang, Jiangxi and Hunan provinces, the field control effect of pyramidone on brown planthopper has been declining due to its use for many years. During the monitoring, it was found that there was little difference in the mortality of brown planthopper between high and low concentrations, and the resistance ratio could not be calculated, indicating that the current level of resistance to aphid was rising, which should be paid close attention to by local agricultural departments.

Countermeasures and suggestions:

Brown planthopper has varying degrees of resistance to all kinds of insecticides, so during the control of brown planthopper, insecticides with different action mechanisms and no cross-resistance should be used alternately and alternately between the emigration area and the immigration area, and between the previous and next generations in the same area, so as to avoid continuous and single use of pesticides. In view of the fact that the brown planthopper has reached a high level of resistance to imidacloprid, thiazide and buprofezin, it is suggested that imidacloprid, thiazide and buprofezin should be suspended to control brown planthopper; strictly limit the use of imidacloprid and chlorpyrifos to control brown planthopper, and rice should be used once per season; alternately use new insecticides such as imidacloprid, furosemide and trifluorophenazine to delay the development of resistance to brown planthopper.

2. The resistance level of white-backed planthopper increased obviously.

At present, the population of white-backed planthopper in the monitored area is at a medium to high level of resistance to buprofezin and chlorpyrifos, and sensitive to new nicotine imidacloprid and thiazine. Compared with 2015, the resistance level of white-backed planthopper to all kinds of pesticides increased obviously.

Countermeasures and suggestions:

In view of the fact that white-backed planthopper and brown planthopper usually mix, and brown planthopper has developed a high level of resistance to buprofezin, it is suggested that the use of buprofezin should be suspended to control white-backed planthopper in order to delay the development of resistance. At the same time, because the toxicity of new nicotine to white-backed planthopper is still very high, it can be considered to use imidacloprid, thiazide or fipronil alternately with imidacloprid when the field rice planthopper population is mainly white-backed planthopper.

3. The use of chlorpyrifos should be restricted in the future.

In the middle and lower reaches of the Yangtze River (Jiangsu, Anhui, Zhejiang and other provinces), the gray planthopper population is sensitive to thiazide, pyrimidine and aphids, and is moderately resistant to chlorpyrifos, compared with the monitoring results in 2015. the resistance ratio of most gray planthopper populations to chlorpyrifos decreased.

Countermeasures and suggestions:

In the future, the use of chlorpyrifos should be limited and alternately used with thiazide, enpyrimidine or aphids to delay the further development of its resistance.

4. The resistance of Chilo suppressalis to bisamides increased obviously.

The population of Chilo suppressalis in the eastern coastal areas of Zhejiang, the areas around Poyang Lake in Jiangxi and the southern areas of Hunan have a high level of resistance to chlorobenzamide, which is in the middle level, which is higher than that in 2015. The results of field trials in Jiangxi showed that the insecticidal effect of chlorobenzamide on Chilo suppressalis was only 30% and 70% 14 days after treatment.

At present, the population of Chilo suppressalis in the monitored area is in the middle level of resistance to avermectin, which is a macrolide agent. Compared with 2015, the resistance ratio of most populations of Chilo suppressalis has been significantly increased, especially in Zhejiang and Hunan. The population of Chilo suppressalis in Zhejiang, Jiangxi and Hunan was at low to medium level of resistance to chlorpyrifos and triazophos, while those in Jiangsu, Anhui and Hubei were sensitive to chlorpyrifos and triazophos.

Countermeasures and suggestions:

The population of Chilo suppressalis has obvious regional resistance to insecticides, among which most populations in Zhejiang, Jiangxi and Hunan have generally produced low to medium level resistance to organophosphorus insecticides. the resistance to bisamides and macrolides is increasing obviously. in the future, we should continue to limit the use of bisamides and macrolides to prevent Chilo suppressalis from being exposed to the same mechanism for multiple generations. At the same time, the overuse of avermectin should be controlled to reduce the killing effect on natural enemies.

3. Wheat

1. The control effect of carbendazim used in Jiangsu and other places is poor.

The results of resistance monitoring showed that the resistance of Fusarium graminearum to carbendazim mainly occurred in Jiangsu Province and its surrounding provinces, and the degree of resistance reached the dangerous level that could be detected by conventional method. The effect of using carbendazim to control scab in some areas of Jiangsu Province has been very poor.

Countermeasures and suggestions:

It is suggested that different mechanism agents such as cyanenoxim and tebuconazole should be used alternately in carbendazim-resistant areas to delay the development of resistance.

2. Wheat aphids need to be rotated to delay the development of resistance.

At present, the population of APHIS gossypii in the monitored area is sensitive to imidacloprid, acetamiprid, fipronil, organophosphorus omethoate, carbamate aldicarb, pyrethroid cypermethrin and so on. The sensitivity of Rhopalosiphum gossypii to insecticides in different locations was greater than that of wheat aphids. Low to moderate resistance to imidacloprid was detected in populations of Dongtai in Jiangsu and Zhumadian in Henan. It was detected that Zhumadian population in Henan was moderately resistant to cypermethrin and was sensitive to cypermethrin, acetamiprid, aphid and omethoate.

Countermeasures and suggestions:

It is suggested that different mechanism agents such as new nicotine and aldicarb should be used alternately in wheat aphid resistance areas to delay the development of wheat aphid resistance.

IV. Cotton

1. Pyrethroids should be banned in North China cotton area of Helicoverpa armigera.

It was detected that the populations of Wangjiang in Anhui, Jingzhou and Zaoyang in Hubei were at a low level of resistance to cyhalothrin, and other populations were at a medium to high level of resistance to cyhalothrin. Especially, the populations of Qiu County in Hebei, Anyang in Henan, Binzhou and Xiajin in Shandong produced high resistance to cyhalothrin (resistance ratio 129-166 times). The population of Helicoverpa armigera in North China and Yangtze River valley was in the middle level of resistance to phoxim and methylaminoavermectin benzoate, while the population in Xinjiang was at a low level. Compared with the monitoring results in 2015, the resistance ratio to phoxim increased. The resistance ratio of Helicoverpa armigera population to methylaminoavermectin benzoate in North China was higher than that in 2015.

Countermeasures and suggestions:

In the areas where Helicoverpa armigera has a high level of resistance to pyrethroids, especially in North China, the use of pyrethroids should be prohibited to control Helicoverpa armigera in order to delay the continuous increase of resistance. In the cotton areas of North China and the Yangtze River Basin, the use of organophosphorus and macrolides should be limited (the growing period of cotton is no more than 2 times), and other agents with different action mechanisms such as spinosad and chlorobenzamide can be used alternately.

2. All populations of APHIS gossypii showed high resistance to deltamethrin and imidacloprid.

At present, all populations of cotton aphid in the monitored area are at a high level of resistance to pyrethroid deltamethrin and neo-nicotinic imidacloprid, and in some areas the resistance ratio is more than tens of thousands of times (to deltamethrin > 4545). The resistance ratio to imidacloprid was 188-316402 times, carbamate was in the middle to high level, and omethoate was in the middle level. The resistance of cotton aphid to insecticides developed rapidly, and it developed resistance to almost all the pesticides used at present, especially to pyrethroids, carbamates and new nicotine, and there was still an increasing trend.

Countermeasures and suggestions:

Cotton aphid has become one of the pests with serious drug resistance and difficult to control. It is suggested that deltamethrin, carbofuran and imidacloprid should be suspended in agricultural production, and other pesticides with different action mechanisms should be selected for control. At the same time, comprehensive resistance management measures were adopted to achieve a better control effect.