Identification Of Plant-parasitic Nematodes Of Some Economical Crops And The Fermentation Of Paecilomyces Lilacinus And Its Studies In Biocontrol Of Plant-parasitic Nematodes

Species composition of plant-parasitic nematodes in some economical crops were investigated during 2006-2008 in the city of xiamen and zhangzhou in Fujian province.Thirteen plant-parasitic nematodes had been found and 7 of them belonging to 5 genera,5 families,2 orders were observed and identified,including a new record species in China.These species are:Criconemella annulata(Cobb in Taylor,1936) Luc& Raski,1981Tylenchorhynchus thermophilus Golden,Baldwin&Mundo-Ocampo,1995Helicotylenchus microcephalus Sher,1966Helicotylenchus digonicus Perry,1959Helicotylenchus scoticus B.boag&M.shamim(1985)M.incognita(Kofoid & White,1919)Chitwood,1949Aphelenchus avenae Bastian,1865Among these,Criconemella annulata(Cobb in Taylor,1936)Luc&Raski,1981 is a new record species in China.We used cheap raw materials to ferment Paecilomyces lilacinus-9410,and obtained Paecilomyces lilacinus productswith high CFUs.The cfu and biomass (include medium) of Paecilomyces lilacinus were 3.1×10¹¹ CFU/ml,0.225g/ml in the seed can respectively.And the cfu and biomass(include medium) of Paecilomyces lilacinus were 3.1×10¹¹CFU/ml,0.225g/ml in the fermentor.Then we carried out the test that P.lilacinus colonized the roots of citrus.The result showed that P.lilacinus had a strong ability to colonize outside the rhizosphere of citrus effectively.A month later,the cfu of P.lilacinus outside the rhizosphere of citrus was 7800cfu/g in the group which applied liquid P.lilacinus.The cfu of P.lilacinus outside the rhizosphere of citrus was 7800cfu/g in the group which applied P.lilacinus powder.The cfu of P.lilacinus inside the rhizosphere of citrus was 27cfu/g in the group which applied liquid P.lilacinus.The cfus of P.lilacinus intside the rhizosphere of citrus was 12cfus/g in the group which applied P.lilacinus powder. Therefore PL could control the parasitic nematodes and it did not have impact on the other microorganisms.We applied the liquid P.lilacinus fermented by the fermentor,P.lilacinus powder and chemical nematocides to do the control experiments at citrus and guavas. The results showed that the chemical nematocides had better ability of controlling the parasitic nematodes than P.lilacinus at the initial stage.The density of guava nematodes showed a certain degree of seasonal dynamics.The number of nematodes was lowest in June,which was 20/5g roots in comparison group.And the number of nematodes reached the maxilnum in December.it was 1057/5g roots in comparison group,so the time of applied P.lilacinus could be September and December.From the test groups compared with comparison group in September,we can see that the density of the group applied 3kg PL/667m² decreased by 64.9%,the density of the group applied 2kg PL /667m² decreased by 12%,but the density of the group applied 3kg chemical nematocides/667m² increased by 38.2%.From the test groups compared with comparison group in September,we can see that the density of the group applied 3kg PL/667m² decreased by 63.8%,the density of the group applied 2kg PL/667m² decreased by 65.8%,the density of the group applied 3kg chemical nematocides/667m² decreased by 60.2%.With the passage of time,PL can continue proliferation in the suitable conditions.Therefore it can continue to play the later part of its role in biocontrol,and it maintained the density of parasitic nematodes at a certain range.The density of citrus nematodes also showed a certain degree of seasonal dynamics.The number of nematodes reached the maximum in June,and the density of nematodes in comparison group was 1013/5g roots.The time of applied P.lilacinus could be March and June.In March,the density of citrus nematodes decreased by 85.0 %,35.4%,27.9%among the group applied liquid PL,the group applied PL powder and the group applied chemical nematocides.The density of nematodes in the group applied liquid PL was 34/5g roots in September,and the density of nematodes in the comparison group was 35/5g roots.At the same time,the desity of nematodes in the group applied PL powder is 33.3%higher than comparison group,the desity of nematodes in the group applied chemical nematocides is 534.3%higher than comparison group.In December,the density of nematodes in the group applied liquid PL deceased by 56.1%,and the density of nematodes in the group applied PL powder deceased by 49.2%.However,the density of nematodes in the group applied two chemical nematocides inceased by 968.9%and 47.7%respectively.As can be seen from the whole process that PL controlled the parasitic nematodes,and effects of PL were better than chemical nematocides.It has a strong potential for generalizing.At the same time,the author made use of PL to do experiments on the podocarpus.The results showed that the height of podocarpus in the group which applied PL was higher than that in the comparion group by 26.87%after half a year. The circuit of podocarpus also grew obviously.The group which applied PL was higher than comparison group by 20.47%;One year later,the height and circuit of podocarpus were higher than the comparion group by 50.08%,92.57%.It vertified that PL could not only promote the growth of podocarpus obviously,but also could keep sustainable in the role of promoting the growth of podocarpus.