Study On Part Of The Biology And Ecology Of Root Lesion Nematode To Wheat

The disease daused by the Wheat Root Lesion Nematode is distributed throughout the world, it has caused severe yield losses in abroad and it has posed a serious threat to the wheat production. It has been reported that Root Lesion Nematode could harm the other crops in domestic and we have found the Root Lesion Nematode also harm the wheat in the experimental plots of Henan agricultural university. The Root-lesion nematode also have been found in wheat in many urban areas in Henan throngh investigation. By initially identifying we found out that this nematode is different from the species which has been reported to infect wheat, it is a new kind of parasitic nematodes in wheat. So it is significant to find out the biological and ecological characteristics of the root-lesion nematode on controlling the disease and ensure the security of wheat production. This article includes a systemic survey that the population densities changes of the root-lesion nematode in wheat root inside and outside in the field of Zhengzhou city along with seasonal. Artificial culture methods of the root-lesion nematode are also compared. In it the method of culturing the root-lesion nematode on wheat, corn and tomato in vitro in different culture media is firstly used and at the same time, carrot disk cultures are used to reproduct the root-lesion nematode; Besides, compare the effect of different culture temperature, time and inoculum numbers with carrot disk cultures method on the reproduction of the root-lesion nematode; determine the tolerance of Root-lesion nematode on different temperature, fast drying and UV irradiation and test the pathogenicity of root-lesion nematode to 10 species of economic crops to clear host range. The results are as follows:The field experiment results show that:the population of Root Lesion Nematode of wheat in Zhengzhou city appeared two peak values on December 15,2008 and May 1,2009.It illustrate that the incidence of this nematode can reach two Peaks in one growing season.The study on the artificial cultivation of the Root Lesion Nematode of wheat indicate that it is successful to cultivate nematodes on carrot disk cultures after disinfecting them with 0.2% streptomycin solutions for 5 hours; Relatively, the result of using 1% streptomycin solutions for 5 hours is not successful. The test on the growth of three kinds of plant root in vitro on different culture medium demonstrate that wheat grows best in 1/2MS and commonly in culture medium add hormone; the site of tomato in MS is better than that in 1/2 MS, but the site is worse in this two kinds of culture medium that add hormone; The best growth of corn is in 1/2MS and that add hormone and the growth in MS and that add hormone is common.Reproduction of the root-lesion nematode on carrot disk cultures at different temperature, time periods after inoculation, and initial inoculum numbers was studied. Over 7 weeks incubation at 15℃,20℃,25℃,and 30℃, its reproductive rate was 0.6,19.2,31.1.and 0.2, respectively; At 25℃and with an initial inoculum of 10 females per disk, the final nematode population increased with the time after inoculation, but its reproductive rate may decrease at the end of the culture because of lacking food; Increasing the number of inocula (5,10,15,20 nematode per disk) the final nematode population also increased, but in this test the nematode had the highest reproductive rate when the nematode initial population was 20.The relationship between nematode survival rate and the storage time at -5℃could be described by liner formula, the mortality was 100% when the nematode be kept at -5℃for 2.5h, while it would be 9% at 40℃for 2.5h; Result showed that more than 50% nematode died at the 75%,85%, and 97% of relative humidity for 10 min, the mortality was 100% at the 75% and 85% of relative humidity for 10 min. The experiment result showed that the root-lesion nematode could not resistant strong ultraviolet irradiation, the survival rate was 37% after treated by UV for 6 min.The test results on the pathogenicity of the root-lesion nematode showed that the nematode which were separated from the experimental plot of Henan agricultural university and were cultivated artificially had pathogenic capability to wheat.12 species of crops were tested for susceptibility to the root-lesion nematode. The results demonstrated that cucumber, pepper, cushaw and calabash are poor hosts of the nematode; mungbean, peanut and helianthus are intermediate, wheat, tomato and soybean are good hosts of the root-lesion nematode.