Pathogens And Biology Of Peanut Nematode Diseases

The parasitic nematodes of peanut and peanut nematode diseases were investigated in Fujian, Hebei and Shandong Province of China. Main results for this study were as follows.The six species of nematodes Pratylenchus brachyurus, P. coffeae, P. scribneri, Meloidogyne hapla, Mesocriconema ornata and Rotylenchulus reniformis were identified by the morphological characters and molecule sequencing analysis.Symptoms of peanut diseases and inoculation test showed that P. brachyurus and P. coffeae infected the pods and roots of peanut, limited the growth of peanut and reduced the number of pods. It really indicated that P. brachyurus and P. coffeae could cause the disease seriously. This paper was the first time record that the peanut diseases caused by P. brachyurus and P. coffeae in China. P. brachyurus were dominant populations of the community that infected peanut.Biology characteristics of P. brachyurus were tested and analyzed. This kind of nematode thrived in warm conditions, with growth and reproduction occuring at a suitable temperature from 25℃ to 30℃ and the optimal temperature was 30℃. The embryonic development of P. brachyurus was observed by light microscope. The results showed that it needed 8-9 days from egg to J2 hatching at 30℃. P. brachyurus survive and overwinter mainly as J3 or J4. P. brachyurus in peanut shells had strong resistance to cold and drought.The host ranges of P. brachyurus were tested through pot experiments by artificial inoculation. The black beans and peanut were suitable host crops for P. brachyurus. The tests also showed that tomato, cucumber and tobacco were low level hosts while sweet potato, white radish, pepper and banana were unsuitable hosts.Accoring to microscopic observation and histological staining examination, M. ornata infecting peanut was observed and discribed in China.