عنوان مقاله [English]
Introduction. Sugar beet cyst nematode, Heterodera schachtii Schmidt is the major disease of sugar beet worldwide, causing considerable damages, and even death of the plants, in the infested fields. There are several suggested methods of controls, which may have its own difficulties to be taken into consideration. To avoid the use of nematicides, and reduced the risk of chemical hazards in the environment, any sorts of nonchemical management is incorrigible. However, any method of management must be safe, large scale application and economical. Thus, in this manuscript, polyethylene sheaths were used to solarize and or disinfection of the infested soils to H. schachtii. And, also, the incorporation of the farm yards manure was taken into consideration too. Therefore, the field experiments were carried out in infected sugar beet growing regions, where there was a heavy infestation to the sugar beet nematodes, Isfahan province, Iran, to determine the effects of soil solarization alone and or along with undecomposed farm yard manure on sugar beet cyst nematode, H. schachtii.
Material and Methods. Transparent Polyethylene sheaths of 2microns were used to solarize and or disinfection of the infested soils to H. schachtii. The fresh farm yards manure for 40 tons per hector for the incorporation was taken into consideration. The field experiments were carried out in infected sugar beet growing regions, where, there was a heavy infestation to the sugar beet nematodes, Jey and Ghahab of Isfahan, Isfahan province, Iran, for determination of the effects of soil solarization alone and or along with undecomposed farm yard manure on sugar beet cyst nematode, H. schachtii.
Treatments were consisted of soil solarization with transparent polyethylene sheets, fresh yard manure, integration of soil solarization with farm yard manure and untreated, control and or ckecks in a randomized block design in three replications each in an infested field conditions, in the hottest periods of the year, Jun - July. The experiments were repeated for the two years. Before, the covering of the soil, a very heavy irrigation was performed to wet the soil plots deeply, up to 60 cm. The considered factors were, the number of cyst and eggs and second larvae per gram of soils before and after the experiments. The related data on final population of cysts, number of eggs and second larvae per cyst and per gram of soil were subjected to statistical analysis. The reproduction factor and the percent reduction and or increasing population of sugar beet cyst nematode were taken into consideration in comparison to initial population of every treatment in the first and second years.
Results and Discussions. The result revealed that, among all the treatments, the combination of soil solarization along with fresh yard manure had great and significant effects on the total nematode population reduction in the first, second and in the mean of the both years. Then, followed by of both trials of soil solarization and fresh yard manure treatments alone, with no significant difference in between. Also, the least reproductive factors in first, second as well as both years were 0.04, 0.003 and 0.021, which were attributed to combination of soil solarization with fresh farm yard manure. Population levels of the nematodes showed a descending trend in this treatment. Furthermore, the second effective treatment on population density 95, 98 and 96.5 percent and reproductive reductions 0.05, 0.02 and 0.035 in the first, second and both trials was in this treatment respectively. Combined analysis of variance showed that, in both of the years, in the first and second years of study, no significant differences, with an average of 83.27 and 108.08 in both the field before the treatments application, had the highest number of population. Other treatments except for the control of these two factors did not show significant differences (P = 0.01), solarization and fresh farm yard manure in compare to checks.
Conclusions. It can be concluded from the results of these experiments that, the combination of fresh yard manure and soil solarization is having the greatest effects in reducing the sugar beet cyst nematode population in the sugar beet. Whereas, the manure and solarization alone were not statistically different from each other and both were together in one group, as compared to the combination of manure and solarization and of the control and or checks.