[Effect of various substrate nutrient on the spore germination and infective germ tube inducing of Pandora delphacis].

The influence of nutrients on spore germmination of P. delphacis was investigated using amino acids, fatty acids, carbohydrates, vitamins, minerals, and extracts of aphids or planthoppers. It was found that the formation of germ tubes from primary conidia was significantly stimulated by cysteine, asparagine, behenic acid (C22:0), trehalose, fructose, glycerol, maltose, ascorbic acid, thiamine(VB1), Folic acid, ZnSO4, FeSO4 and extracts of aphids and planthoppers. Of these many could suppress the formation of secondary conidia from primary conidia, e.g., cysteine, behenic acid (C22:0), myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), arachidic acid (C20:0), lignoceric acid (C24:0), ascorbic acid, thiamine (VB1), riboflavin (VB2), folic acid, nicotinic acid, ZnSO4, and FeSO4. However, the nutrients not conducive to the formation of germ tubes were stimulants to the formation of secondary conidia. These included tyrosine, alanine, glucose, galactose, sucrose, glycogen, inositol, pyridoxal (VB6), NaCl, and KCl. Moreover, nutrients including asparagine, trehalose, glycerol, maltose, fructose, thiamine (VB1), and folic acid stimulated the formation of both germ tubes and secondary conidia. The result above indicated that the substrate nutrients which can stimulate the formation of germ tubes were general in planthoppers and aphids, it means the formation of aggressive germ tubes was one of important factors of successful for infection to the hosts. Of which it confirmed that the host specificity for P. delphacis against N. lungus and M. persicae.