Study On Biological Control Of Heliothis Assulta Guenee In Southern Of Hunan

As the main pests of tobacco, Heliothis assulta Guenee often cause significant losses. This paper makes the Heliothis assulta Guenee as research object, and the Heliothis assulta Guenee occurrence rules and biological control were studied in the southern of Hunan. The main research results are as follows:1?The Heliothis assulta Guenee in southern of Hunan happened in early April,2013. Generation is about 4. The Heliothis assulta Guenee mainly damage the upper leaves. And tobacco stem present damage in mid to late may.2?Treatment of 4 biological agents were better than the control at the safety, the effect of moth prevention and the improvement of yield and quality.0.3% matrine aqueous solution 750 times and 2.5% lambda cyhalothrin EC 1500 times liquid were better than others. The average field control effect was 88.1% and 89.3% respectively and output value increased by 6.2% and 3.4% compared with the control.3?The sex pheromone trap can monitor Heliothis assulta Guenee population dynamics, 2 sets/mu is the best cast-density of field moth resistant. The average daily number of insect population was 2.5, and the percentage of victims strains decreased to 23.5%.4?150000/hm2 was the best Trichogramma release density. The two stage parasitic rate was 75% and 50%, respectively, and the number of worm holes in the two stage respectively decreased by 75% and 72.6%.5?The density of predatory natural enemies in the ecological control area was greater than that of the traditional control area, and increased steadily in the investigation time period. In the ecological control area, the rate of leaf damage and the rate of the tobacco plant were the lowest, which were 7.12% and 26%, respectively. Compared with the blank control area, it respectively decreased by 77.4% and 40%.