How to control the tea green leafhopper? Efficacy trial of 10% imidaclothiz wettable powder
Efficacy trial of 10% imidaclothiz wettable powder against the tea green leafhopper
Abstract: Field trials showed that 10% imidaclothiz wettable powder has good control efficacy against the tea green leafhopper, and the control efficacy of the 3000-4000x dilution still reached above 80% at 14 d after treatment.
Keywords: imidaclothiz; tea green leafhopper; control efficacy
10% imidaclothiz wettable powder is a nitromethylene systemic insecticide. The mechanism of action of imidaclothiz is to selectively inhibit the nicotinic acetylcholine esterase receptor in the insect nervous system, binding with extremely high competitiveness, thereby disrupting normal conduction in the central nervous system. From 2001 to 2002, we conducted field efficacy trials in Yixing City, Jiangsu Province, and the results showed that 10% imidaclothiz wettable powder has good control efficacy against the tea green leafhopper. The trial results are reported as follows:
1 Materials and methods
1.1 Test agents
10% imidaclothiz wettable powder (active ingredient: imidaclothiz, Nantong Jiangshan Agrochemical & Chemicals Co., Ltd.); 10% imidacloprid wettable powder (Nanjing First Pesticide Factory).
1.2 Target pest: tea green leafhopper
1.3 Trial treatment design and methods. The trial included 10% imidaclothiz wettable powder at 3000x, 4000x and 5000x dilutions, 10% imidacloprid wettable powder at 4000x dilution, and a clear water control, for a total of 5 treatments. The plot area was 33.3 sq m, arranged in a randomized block design, with 4 replicates, with spacing between treatments and a protective row around the perimeter. The trial field was located at the tea plantation of Shanggan Village, Zhangzhu, Yixing City, Jiangsu Province; the tea trees were 21 years old, the soil was clay loam, the organic matter content was medium, and the pH value was 6.5. The application date in 2001 was July 5, and the application date in 2002 was June 26. The water volume was about 50 kg/667 sq m, applied as a uniform spray.
1.4 Survey contents and methods
Surveys were conducted before treatment and at 1, 3 and 7 d after treatment. The basin-tapping method was used: 4 points were checked in each plot, with 1 basin (0.5 sq m) per point, and the number of insects falling into the basin was recorded. The population decline rate was calculated by comparison with the pre-treatment base number, and then compared with the population decline rate in the control plot to calculate the control efficacy.
2 Results and analysis
2.1 Control efficacy. In the 2001 trial, the control efficacy at 1 d after treatment was 96.13%, 90.65% and 88.30% for the 10% imidaclothiz wettable powder 3000x, 4000x and 5000x dilution treatments, respectively, with no significant difference among treatments; the control efficacy at 3 d after treatment was 96.12%, 91.85% and 87.50% for the 10% imidaclothiz wettable powder 3000x, 4000x and 5000x dilution treatments, respectively, with no significant difference among treatments; the control efficacy at 7 d after treatment was 93.92% and 82.83% for the 10% imidaclothiz wettable powder 3000x and 4000x dilution treatments, respectively, with no significant difference among treatments, while the 5000x dilution treatment was 75.92%, with a significant difference. In the 2002 trial, the control efficacy at 1 d after treatment was 93.83%, 93.41% and 89.69% for the 10% imidaclothiz wettable powder 3000x, 4000x and 5000x dilution treatments, respectively, with no significant difference among treatments; the control efficacy at 3 d after treatment was 96.72% and 92.65% for the 10% imidaclothiz wettable powder 3000x and 4000x dilution treatments, respectively, and the control efficacy of the 5000x dilution was 89.30%, which was significantly different compared with the 3000x dilution; the control efficacy at 7 d after treatment was 83.90%, 78.89% and 76.86% for the 10% imidaclothiz wettable powder 3000x, 4000x and 5000x dilution treatments, respectively, with no significant difference among treatments.
2.2 Safety to tea plants. After systematic observation following treatment, no symptoms of phytotoxicity were seen on the tea plants in any of the treated plots, and during the growth period and in growth vigor they were the same as the tea plants in the control plot, indicating that the trial doses of 10% imidaclothiz wettable powder are safe for tea plants.
3 Summary and discussion
The trial results showed that 10% imidaclothiz wettable powder has good control efficacy against the tea green leafhopper, with both rapid action and persistence against the tea green leafhopper. The 3000-4000x dilution (equivalent to an effective dose of 25-33 mg/kg) has very good control efficacy against the tea green leafhopper and is safe for tea plants.