Sensitivity of Laodelphax striatellus to several pesticides
2018-08-10 02:01:40
Laodelphax striatellus is one of the important rice pests in Asia. The Laodelphax striatellus was the earliest among the three rice planthoppers, mainly the rice seedlings of the early, middle-season and the Honda tillering stage. In addition to adult and nymph sucking, it also spreads viral diseases such as rice black streaked dwarf disease and stripe leaf blight, and its loss caused by poisoning is huge.
Since there is no ideal anti-disease and anti-virus agent in production, it has become the main means to recover food losses by treating insects. For a long time, the control of Laodelphax striatellus in Asia has mainly focused on the use of chemical pesticides, but long-term drug selection pressure has led to the emergence of resistance to various insecticides. At present, there is a lack of ideal chemicals for controlling the planthoppers in the domestic production, and even the use of high-efficiency imidacloprid for the brown planthopper is not satisfactory. To this end, this study used the indoor bioassay method for the four kinds of agents of the planthopper [10% imidacloprid WP (trade name: Dagongchen, Nanjing Red Sun Group); 25% buprofezin WP (trade name: è™±Ling, produced by Jiangsu Changzhou Pesticide Factory); 20% acetamiprid SP (trade name: Mobilan, produced by Japan Soda Co., Ltd.); 5% fipronil SC (trade name: Regent, Rhone Planck Agrochemical production). The sensitivity of the method was determined in order to clarify the most suitable agent for the control of Laodelphax striatellus, and provide an important basis for the prevention and control of this important poisonous pest.
The virulence of the planthoppers to imidacloprid, buprofezin, acetamiprid and fipronil was determined by rice stem impregnation method and spotting method. The results showed that fipronil was the most toxic in the four agents. Among them, the results of the rice stem impregnation method showed that the virulence index of fipronil (LC50=0.0655 mg per liter) (active ingredient, the same below), buprofezin and imidacloprid to the 3rd instar nymphs of the Laodelphax striatellus were acetamiprid 314 3142.0, 388.8 and 4.5 times. When tested by the drop method, fipronil (LD50 = 0.00008 μg per liter) and imidacloprid were 925.0 and 2.9 times, respectively, of acetamiprid. Because fipronil is a positive temperature effect insecticide, the effect is better when the temperature is higher. It is recommended that chemical pesticides must be used in a targeted manner in production.
In the period of the migratory larvae, the use of 5% fipronil SC or 10% imidacloprid WP with strong knockdown effect is better at the peak of nymphs. When the density of the insect population is small, it is conceivable to use a conventional agent or a 25% buprofezin WP which has a slow effect but a good effect. Proper rotation of the drug helps to slow the development of resistance and thus extend the actual life of the new drug.
Since there is no ideal anti-disease and anti-virus agent in production, it has become the main means to recover food losses by treating insects. For a long time, the control of Laodelphax striatellus in Asia has mainly focused on the use of chemical pesticides, but long-term drug selection pressure has led to the emergence of resistance to various insecticides. At present, there is a lack of ideal chemicals for controlling the planthoppers in the domestic production, and even the use of high-efficiency imidacloprid for the brown planthopper is not satisfactory. To this end, this study used the indoor bioassay method for the four kinds of agents of the planthopper [10% imidacloprid WP (trade name: Dagongchen, Nanjing Red Sun Group); 25% buprofezin WP (trade name: è™±Ling, produced by Jiangsu Changzhou Pesticide Factory); 20% acetamiprid SP (trade name: Mobilan, produced by Japan Soda Co., Ltd.); 5% fipronil SC (trade name: Regent, Rhone Planck Agrochemical production). The sensitivity of the method was determined in order to clarify the most suitable agent for the control of Laodelphax striatellus, and provide an important basis for the prevention and control of this important poisonous pest.
The virulence of the planthoppers to imidacloprid, buprofezin, acetamiprid and fipronil was determined by rice stem impregnation method and spotting method. The results showed that fipronil was the most toxic in the four agents. Among them, the results of the rice stem impregnation method showed that the virulence index of fipronil (LC50=0.0655 mg per liter) (active ingredient, the same below), buprofezin and imidacloprid to the 3rd instar nymphs of the Laodelphax striatellus were acetamiprid 314 3142.0, 388.8 and 4.5 times. When tested by the drop method, fipronil (LD50 = 0.00008 μg per liter) and imidacloprid were 925.0 and 2.9 times, respectively, of acetamiprid. Because fipronil is a positive temperature effect insecticide, the effect is better when the temperature is higher. It is recommended that chemical pesticides must be used in a targeted manner in production.
In the period of the migratory larvae, the use of 5% fipronil SC or 10% imidacloprid WP with strong knockdown effect is better at the peak of nymphs. When the density of the insect population is small, it is conceivable to use a conventional agent or a 25% buprofezin WP which has a slow effect but a good effect. Proper rotation of the drug helps to slow the development of resistance and thus extend the actual life of the new drug.
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