Paugh Kelley R, Gordon Thomas R
Department of Plant Pathology, University of California, Davis, CA 95616, U.S.A.
Plant Dis. 2021 Apr;105(4):912-918. doi: 10.1094/PDIS-07-20-1464-RE. Epub 2021 Mar 11.
f. sp. , the cause of Fusarium wilt of lettuce, can survive on crop residue in soil. Persistence of the pathogen over time will be influenced by the rate at which residue decomposes. We evaluated the effect of drying and fragmenting crop residue on the rate of decomposition and survival of f. sp. . In a controlled experiment that represented optimal drying conditions, fragmenting and oven drying infested lettuce taproots at 30°C significantly reduced the frequency of recovery of the pathogen, compared with untreated tissue. However, in a field experiment, drying infested crop residue on the soil surface prior to incorporation did not significantly reduce survival of f. sp. after 1 year. Regardless of treatment, there was not a significant decrease in soil inoculum density between 1 and 12 months after residue was incorporated. In a greenhouse experiment, fragmenting crop residue prior to incorporation in pathogen-free soil resulted in significantly higher inoculum densities of f. sp. after 1 year. The increase in inoculum levels was associated with a faster rate of residue decomposition, which may be beneficial in the long run but not where lettuce will be replanted within the next year.
生菜尖孢镰刀菌（F. sp.）是生菜枯萎病的病原菌，可在土壤中的作物残体上存活。病原菌随时间的持续存在将受残体分解速率的影响。我们评估了干燥和粉碎作物残体对生菜尖孢镰刀菌分解速率和存活的影响。在一个代表最佳干燥条件的对照实验中，与未处理的组织相比，将受侵染的生菜主根在30°C下粉碎并烘干，显著降低了病原菌的回收率。然而，在田间实验中，在将受侵染的作物残体翻耕入土之前先在土壤表面进行干燥处理，1年后并没有显著降低生菜尖孢镰刀菌的存活率。无论处理方式如何，在残体翻耕入土后的1至12个月之间，土壤接种密度均未显著降低。在温室实验中，将作物残体在翻耕入土到无菌土壤之前进行粉碎处理，1年后生菜尖孢镰刀菌的接种密度显著更高。接种水平的增加与残体更快的分解速率有关，从长远来看这可能是有益的，但对于次年要重新种植生菜的情况则并非如此。
