LI Xin-shen, SHAO Hua, CHEN Jian, WEI Lin-gen, HUANG Rui-rong, HUA Ju-ling
Bacterial wilt is one of the serious diseases of sesame and peanut. In order to explore a reasonable
crop rotation model for plant disease control, six crops were inoculated with a rifampicin-resistant strain(JXS02-L)
of Ralstonia solanacearum by the method of soil inoculation, including sesame, peanut, sweet potato, soybean, corn,
and shallot. Based on the dynamic changes of R. solanacearum in rhizosphere soils and roots of six crops, the occur⁃
rence of bacterial wilt on sesame and peanut were analyzed under different rotation patterns. Results showed that
the population of R. solanacearum were lower than its initial inoculum in rhizosphere soils of six crops at three
weeks after sowing, in particular, the population of the pathogen decreased mostly in rhizosphere soils of shallot and
only reached 0.64 ×102 CFU·g-1. The population of R.solanacearum in rhizosphere soils of sesame, peanut and sweet
potato had increased to the initial inoculation bacteria level (3.20 × 106 to 4.93 × 106 CFU·g-1) at 6 weeks after sow⁃
ing. From 6 to 12 weeks, the population of R.solanacearum continued to increase in rhizosphere soils of sesame, pea⁃
nut and sweet potato, and that in rhizosphere soils of soybean and corn continued to decrease. At 12 weeks after sow⁃
ing, the population of R. solanacearum in rhizosphere soils of soybean and corn were less than 10-4 compared with
that in rhizosphere soils of sesame, peanut and sweet potato. However, the pathogen was not detected in rhizosphere
soils of shallot from 6 weeks to 12 weeks. On the other hand, the population of R. solanacearum increased continu⁃
ously in the roots of sesame, peanut and sweet potato, while that in the roots of soybean and corn increased at first
and then decreased. At 12 weeks after sowing, the population of R. solanacearum in the roots of soybean and corn
were less than 10-5 compared with that in rhizosphere soils of sesame, peanut and sweet potato. Moreover, the patho⁃
gen was still not detected in the roots of shallot after sowing. The effects of different rotation patterns on the occur⁃
rence of bacterial wilt disease of sesame and peanut indicated that disease indexes of sesame bacterial wilt for sesa⁃
me-soybean-shallot-sesame rotations and sesame-soybean-corn-sesame rotations were significantly lower than
that for sesame-peanut-soybean-sesame rotations and sesame-peanut-sweet potato-sesame rotations, and its dis⁃
ease indexes decreased by 19.95% and 12.87% respectively. In addition, the diseased plant rate of peanut bacterial
wilt for peanut-soybean-corn-peanut rotations was significantly lower than that for peanut-sesame-sweet potatopeanut
rotations, and its diseased plant rate decreased by 11.63%. In summary, the results made great contribution
in understanding the ecological diversity of bacterial wilt, and further in preventing and controlling of bacterial wilt.
