During the growth of rice, various pests and diseases will be encountered, which seriously affects the healthy growth of rice and reduces rice yield. Therefore, the use of chemical methods such as rice special insecticide products to prevent pests and diseases has become the first choice for farmers. This article introduces the common products and applications of rice special effects insecticides for your reference.
Rice special effects pesticides commonly used products
1. Low-to-low toxic organophosphorus insecticides
After the high-toxic organophosphorus pesticides were eliminated or banned, some low-toxic organophosphorus pesticides were still used in the rice market, which was not only well received by users, but also occupied a certain market share.
1.1, chlorpyrifos
Chlorpyrifos is a moderately toxic organophosphate insecticide. It has been used as a substitute for highly toxic pesticides to control rice-field pests due to its contact, stomach and fumigation effects. It has good properties for the leaf roller, the stem borer and the stem borer. Insecticide and seedling protection effect (86% to 97%). Li Ying and other studies have shown that the half-life of chlorpyrifos in paddy soil is 6.7 ~ 1.7 d, still a fast dissolving agent. Compared with fipronil, chlorpyrifos has a slightly less control effect on the leaf roller and aphid, but it has better effect on the planthopper, and both quick-acting and long-lasting effects can be considered. Chlorpyrifos is generally safer to use on rice fields, but it is more toxic to aquatic organisms and bees. It has become the most widely used organophosphate insecticide for controlling the "three insects" of rice. The annual domestic consumption is about 18,000 tons.
1.2, triazophos
Triazophos is a moderately toxic organophosphate insecticide with a wide spectrum of insecticides and good control effect. It is a variety of high-toxic pesticides that have been widely promoted in China in the early 1990s. It is mainly used to control pests such as stem borer. It has a good effect, and the field control effect on Chilo suppressalis is 90%. At present, triazophos has been used for more than ten years, and some areas have become significantly resistant to stem borer. In addition, it has been reported that the use of triazophos can stimulate the growth of the planthoppers and cause problems such as the occurrence of planthoppers. Therefore, when using triazophos in paddy fields, strict control of the number of uses and the amount of use is a problem that needs to be taken seriously.
1.3, acephate
Acephate is a low-toxic organophosphorus insecticide with strong systemic effects, as well as contact, stomach toxicity and certain fumigating effects, and is safe for poultry and aquatic organisms such as fish and shrimp. However, the effect is generally poor when used alone (only 68% to 80%), and it is better to use it with other agents. For example, the use of 20% oxazoline acetoacetate 1 500 mL / hm2 to control stem borer is more than 92%, 30% higher than acephate single agent, and better than triazophos single agent. The combination of acephate and fipronil not only reduces the amount of use, but also significantly prolongs the duration of the control of rice leaf roller or stem borer. This indicates that acephate is suitable for compounding or mixing with other insecticides, which can improve its application effect and value.
2. Pyrethroid insecticides
The toxicity of pyrethroid insecticides is low toxicity or poisoning. Although it has the characteristics of high efficiency, broad spectrum, high insecticidal efficiency and low residue, it has long been banned from use in paddy fields due to its high toxicity to aquatic organisms and the possible cause of rice planthoppers.
In recent years, research on the effects of pyrethroid pesticides on paddy fields has progressed. For example, the toxicity of deltamethrin to seven environmental organisms has been determined, indicating that it is less toxic to birds, bees and mites, and moderately toxic to fish. (This is rare in pyrethroid pesticides) and is highly toxic to mites, algae and silkworms. However, due to the low dosage of deltamethrin, it degrades rapidly in the environment, and in fact it is much less harmful to aquatic organisms when used in the field.
Different dosage forms of lambda-cyhalothrin were used to control rice-field pests. The effects of different 2.5% beta-cyhalothrin formulations on rice stem borer and rice leaf roller were compared, which provided a basis for evaluating its application in rice fields. The results showed that 2.5% of the cyhalothrins SC, EW and ME were superior to WP and Ecru, and the leaf leaf control and pest control of rice leaf roller were more than 80%. The usual dosage of 20% triazophos EC and 50% methamidophos EC and 2.5% lambda-cyhalothrin wP, EC dosage form. 2.5% cyhalothrin SC, EW, ME three water-based dosage forms have more than 90% control effect on stem borer, and the pest control effect is over 85%, which is close to the conventional dose of 20% triazophos EC. , better than 2.5% beta-cyhalothrin WP and EC dosage form, significantly more than 50% methamidophos EC conventional dosage.
Despite this, some scholars believe that pyrethroid pesticides are highly toxic to aquatic animal natural enemies and silkworms, and are widely used for the environmental risks of rice. They should not be included in the application of rice. However, in recent years, there have been reports that fenthrin and flumethrin are generally low in toxicity to mammals and fish and can be safely used in rice fields.
3. Carbamate insecticides
Carbamate insecticides are mainly used to control planthopper pests. For example, the use of insecticides such as Isoprocarb, Accumulation, Zhongdingwei and Misuwei is characterized by good quick-acting effect on the planthopper and strong knockdown force. The shortcoming is that the effect period is short, generally 3 to 4 days. Some have better selectivity and have much lower killing effect on natural enemies than organic phosphorus. However, due to long-term use, pests have developed resistance, and with the popularization and application of imidacloprid and buprofezin, the amount of carbamate insecticides has been decreasing. However, in recent years, due to the long-term continuous use of imidacloprid, the pests have been severely resistant to imidacloprid, which has led to the re-application of a small number of carbamate insecticides, such as 20% isoproteril, on rice fields. And achieved significant results, the control effect against whitebacked planthopper reached more than 90% within 14d, comparable to buprofezin, and its quick-acting effect is superior to buprofezin.
4, silkworm toxin insecticide
The silkworm toxin insecticide is mainly used for controlling various pests such as rice leaf roller, big cockroach, stem borer, and stem borer. The main varieties are insecticide and insecticide. They have the advantages of broad spectrum of insecticides, low toxicity, low residue and low price, but they have a short duration. Due to long-term continuous use, many pests have produced high resistance, especially in stem borer. The field efficacy has been greatly reduced. It is obvious that some areas use insecticides and insecticides to control stem borer. The effect has dropped to 40% to 70%. Another problem worthy of attention is that the silkworm toxin insecticide is highly toxic to silkworms. In the past, the use of insecticidal and insecticidal doubles in the sericulture area has caused repeated occurrences of silkworm poisoning. Therefore, it is not suitable for use in sericulture areas. Class of medicine.
5, biological insecticides
Biological insecticides are characterized by high efficiency, low toxicity, good compatibility with the environment and strong safety. With the love and demand of organic foods and pollution-free agricultural products, people are increasingly favored by people. The main insecticides used in rice are avermectin, doxorubicin and carbaryl salts.
Avermectin original drug to people, livestock, bees and silkworm highly toxic, but the preparation is of low toxicity. It has the characteristics of high efficiency, low toxicity, no pollution, long-lasting effect, less resistance to drug resistance, and no cross-resistance with other pesticides. It has been used on rice in southern provinces and has achieved good results.
Rice insecticide application
1. Use different rice insecticides for different targets.
As mentioned above, compared with fipronil, chlorpyrifos has a slightly less control effect on the leaf roller and aphid, but it has a better effect on the planthopper, and both quick-acting and long-lasting effects can be considered. For the control of planthopper pests.
Acephate is suitable for mixing with other insecticides (such as fipronil 1), which not only reduces the dosage, but also significantly prolongs the duration of the control of rice leaf roller or stem borer, thereby improving its application effect. And value.
Indoor virulence was measured on brown planthopper using 13 agents. The results showed that different kinds of agents showed different activities against brown planthopper, and for the control of brown planthopper, high-efficiency, low-toxic and safe agents such as nitenpyram, buprofezin and pymetrozine were preferred.
For drugs that produce drug resistance and reduced drug efficacy, new drugs can be used instead, such as chlorantraniliprole, flubendiamide, indoxacarb, flumethrin, and nitenpyram, which can achieve better results. .
2, choose safe and environmentally friendly dosage form products
Pesticide products for controlling rice pests should use safe and environmentally friendly dosage forms. In particular, the suspending agent and the water emulsion in the water-based dosage form are not only safe, low in toxicity, good in efficacy, environmentally friendly, but also low in processing cost. The performance of all aspects of water-dispersible granules (safe, low toxicity, efficacy, environmental protection) is very good, the only drawback is that the price is relatively high.
3, rice pesticides wet and spread
The critical surface tension of plants is an important parameter in pesticide applications. When the surface tension of a pesticide is less than the critical surface tension of a certain plant, it means that it can be wetted and spread on the surface of the plant. Rice has a small critical surface tension value (36.7 mN/m), which is a difficult-to-wet plant. After spraying many agents, it is easy to roll off the leaves in the form of water droplets. At present, pesticide formulations (including rice insecticides) have generally not been considered to increase the ability to infiltrate the foliage and the ability to retain liquid, which may result in reduced efficacy.
In order to ensure that the pesticides used in rice have a value below the critical surface tension, the usual solutions are:
1) A dosage form product that is processed below the critical surface tension of rice leaves. For example, Fan Peng et al. developed a 0.5% calcium salt microemulsion that can be wetted and spread on rice leaves. The results showed that the surface tension of 0.5% KM salt microemulsion solution with the concentration of 2.0～100.0mg/L was lower than that of rice leaf, while the surface tension of 1.0% KM salt emulsion liquid of the same concentration was greater than that of rice leaf. The critical surface tension; at the same concentration, the former has significantly more retention in the rice leaf surface than the latter.
2) Add effective auxiliaries to reduce surface tension. For example, Chen Mingyan added 3% silicone auxiliaries to 2% avermectin EC at a dosage of 45 g/hm2, and the control effects at 1, 3, and 7 days after the drug were 78.54%, 90.35%, and 97.19%, respectively; The control effect of the control agent 2% avermectin EC was only 68.80%, 72.72%, 85.69%. This shows that adding 2% avermectin EC with 3% silicone auxiliaries can significantly improve the control effect of effective agents.
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