Bailey D J, Kleczkowski A, Gilligan C A
Epidemiology and Modelling Group, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
Present address: INRA-Bordeaux, UMR Santé Végétale, BP 81, 33883 Villenave d'Ornon, France.
New Phytol. 2004 Feb;161(2):569-575. doi: 10.1111/j.1469-8137.2004.00973.x.
• A combination of experimentation and modelling is used to examine the role of epidemiological dynamics on the production and infectivity of inoculum and the efficiency of biocontrol by Trichoderma viride during consecutive epidemics of damping-off disease caused by the pathogen Rhizoctonia solani in crops of radish. • Changes in the net infectivity of inoculum at the beginning of first and second crops caused a switch in epidemiological dynamics. Epidemics of first crops were dominated by secondary infection leading to amplification of inoculum so that epidemics of second crops were overwhelmingly determined by primary infection. • The biocontrol agent reduced primary infection and hence parasitic amplification of inoculum in both first and second crops but the efficiency of control dropped from 91.7% in first crops to 64.8% in second crops, with sudden outbreaks of disease in second crops which had previously been disease-free. • We conclude that parasitic amplification can cause a rapid build-up of disease and inoculum over consecutive crops, leading to loss in the efficiency of biocontrol. This form of inoculum production is supplemented by saprotrophic infestation which can result in sudden outbreaks of disease in protected crops where control of disease had previously been fully successful.
• 采用实验与建模相结合的方法，研究了在萝卜作物中由立枯丝核菌引起的猝倒病连续流行期间，流行病学动态对接种体产生、感染力以及绿色木霉生物防治效率的作用。
• 第一季和第二季作物开始时接种体净感染力的变化导致了流行病学动态的转变。第一季作物的流行以二次感染为主，导致接种体扩增，因此第二季作物的流行绝大多数由初次感染决定。
• 生物防治剂在第一季和第二季作物中均减少了初次感染，从而减少了接种体的寄生扩增，但防治效率从第一季作物的91.7%降至第二季作物的64.8%，第二季作物中先前无病的地方突然爆发了病害。
• 我们得出结论，寄生扩增可导致连续作物中病害和接种体迅速积累，导致生物防治效率下降。这种接种体产生形式还伴有腐生侵染，这可能导致在先前病害防治完全成功的保护作物中突然爆发病害。
