Sufficient pathogen, susceptible host and favourable environmental conditions, which are necessary to the outbreaking of the plant disease.

一定数量的病原生物、易感病的寄主以及有利的发病条件是任何病原生物引起的植物病害发生的必要条件。

Sometimes low voltage restraint outbreaking with high wave, slow waves and spikes appeared in 17 cases while wide low voltage restraint occurred in 10 cases, but false normal EEG appeared in 1 case.

发作期脑电图17例表现为高波幅慢波夹杂棘波爆发-低电压抑制，10例表现为全脑各导呈广泛性低电压抑制，1例表现为假性正常脑电图改变。