Preliminary Study On Occurrence And Prevention Of Blight In Flax

Blight is the main diseases of flax production, there is different occurrence level in Heilongjiang province. Generally, the disease incidence is20%-30%, even up to50%. The development of blight is faster and more serious year by year, the positivity of famers and economic benefit of factories is influenced severely.This paper mainly studies biological characteristics of blight pathogen, occurrence regularity of blight, screening sensitive reagent of pathogen, field experiment of sensitive reagent, we study out technical measures for integrated control of blight in flax combined with agronomic measures of flax production. This work was conducted with pot and field plot experiment combined with improving fertilization and water conditions, using pathogen separation and cultivation in laboratory, screening sensitive reagent of pathogen. The results showed that:Mycelial growth and conidia germination of blight pathogen in flax could carry out during10-35℃, the suitable range was20～30℃; the lethal temperature of pathogen was75℃keeping lOmin; illumination had no significant effect on mycelial growth but gone against the production of spore; blight pathogen could grow during pH2.0～9.0. The condition of pathogen was better during pH3.5-5.5, the lower pH was, the smaller diameter of colony and the less density of colony was when pH was less than3.5, which showed that mycelial growth was inhibited severely with increasing acidity. The higher pH was, the smaller diameter of colony was when pH was more than5.5, which showed that mycelial growth was inhibited severely with increasing alkalinity.Different from the flax sowing density, application of different fertilizers and continuous cropping conditions, analyze the occurrence of flax blight. Explicit that the more serious blight owe to the greater planting density; Luxuriant nitrogen on flax will increased the infection rate of anthrax, while applied reasonably with nitrogen, phosphorus and potassium, it will help reduce the incidence of blight linen; The more soil moisture, the greater occurrence of the serious flax blight; flax blight will increased on continuous cropping, the longer cropping period due to the more serious disease.Based on laboratory test, the better effect reagents for blight in flax, Inezin, Mancozeb, Carbendazim, Armure and Fenaminosulf were selected to carry out field efficacy trials. The results showed that:the most effective reagent was Inezin. When the seed dressing is0.3%of seed weight, prophylactic effect could up to85.0%, straw yield increased13.4%, seed yield increased29.2%and long fibre yield increased2.1%; the Mancozeb as the second most effectives reagent could make the prophylactic effect raise to83.3%.