Fungi associated with the sugar beet cyst nematode Heterodera schachtii in Jerash-Jordan

Qadri, A.N.

Fungi associated with the sugar beet cyst nematode Heterodera schachtii in Jerash-Jordan

1989

Qadri, A.N.

Fungi associated with cyst of Heterodera schachtii have been investigated through direct microscopic examination and isolation. Thirteen fungal species were isolated from cysts and cyst contents. Among these Aspergillus fumigatus, Fusarium oxysporum, solani and Verticillium chlamidosporium were the most frequent. Acremonium sclerotignum, Aspergillus erythrocephalus, flavus and versicolor, Fusarium equiseti, solani (macroconidial isolate), Penicillium aurantiogresum, Preussia sp. and sterile mycelial fungus were also frequent. Group of fungi referred to as "miscellaneous" were isolated from cysts and cyst contents and included: Cladosporium sphaerospermum, Cylindrocarpon olidium, Fusarium culmorum, F. equiseti, F. flocciferum, Gliocladium roseum, Mortierella hyalina, M. polysephala, Pleospora sp., Trichoderma sp., Ulocladium consortiale. On agar-media: F. solani, V. chlamydosporium, Preussia sp., a sterile fungus, and Acremonium sclerotignum resulted in 71.7-82.3 % parasitism and disorder of H. schachtii eggs, whereas, on M. javanica only V. chlamydosporium and F. solani were able to reach similar level of egg parasitism. Of five fungal sp. added to soil A. sclerotignum, F. oxysporum, F. solani reduced tomato galling index caused by M. javanica by 62.5, 44 and 44%, whereas, Preussia sp. and V. chlamidosporium had little effect on root galling. The impact of soil fungi on H. schachtii and M. javanica in nature was evaluated through inhibition on these fungi. The effect of individual fungal sp. on nematodes was determined through addition of nematode to culture media and to soil in pots. Inhibition of fungi by fungicides-benomyl, hymexazol, or formalin, resulted in increase of H. schachtii cyst production by about 73 %. Similarly, soil pasteurization or fungicide treatments increased root galling index by about 120 % over the non-treated control

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