连续施药及室内药剂驯化对番茄灰葡萄孢对咯菌腈敏感性的影响

Effect of continuous application and taming in vitro on sensitivity of Botrytis cinerea in tomato to fludioxonil

为了解连续施药对番茄灰葡萄孢对咯菌腈敏感性的影响,在温室条件下,从灰霉病发生初期开始,按推荐剂量(有效成分67.5 g/hm2)定期向番茄苗喷施咯菌腈,通过菌丝生长速率法检测灰葡萄孢对咯菌腈的敏感性。结果表明,在番茄1个生长季节中连续施药7次后,病菌对咯菌腈仍表现敏感,其EC50值在0.004 7～0.046 2μg/mL之间。在含咯菌腈的PDA培养基上对30个灰葡萄孢敏感菌株进行药剂驯化7代后,共产生2个抗药性突变体(Rg-12和Rdz-28),其中Rg-12对咯菌腈的EC50值是其亲本菌株g-12的46倍,Rdz-28的EC50值大于500μg/mL,2个抗性突变体在菌丝生长速率、产孢量和产菌核能力方面均显著低于其亲本菌株。推测灰葡萄孢可能不易对咯菌腈产生抗性,咯菌腈可作为防治番茄灰霉病的理想候选药剂。

To clarify the effect of continuous spraying of fludioxonil on sensitivity of Botrytis cinerea in tomato to fludioxonil,a fungicide spraying programming was conducted in selected tomato greenhouse where fludioxonil was sprayed at the recommended rate（active ingredients 67.5 g/hm2,a.i.） for 7 times regularly since the initial occurrence of gray mould,the sensitivity of B.cinerea to fludioxonil was detected through mycelial growth rate test.The results showed that the B.cinerea was still sensitive to fludioxonil after 7 continuous sprays,with EC50 values ranging from 0.004 7 to 0.046 2 μg/mL.Two mutant strains（Rg-12 and Rdz-28） resistant to fludioxonil were selected from thirty sensitive strains of B.cinerea which were subcultured for 7 generations on the PDA medium that contained with fludioxonil.The EC50 value of Rg-12 to fludioxonil was 46 times of its parent strain g-12 and the EC50 value of Rdz-28 to fludionxonil was more than 500 μg/mL.The mycelial growth rate,sporulation and sclerotia of the two mutants decreased obviously,comparing with their parent strains.All the results showed that the level resistance of B.cinerea to fludioxonil is low,then fludioxonil could be used to control B.cinerea as an ideal fungicide.