  We formulate general plant-herbivore interaction models with monotone plant
growth functions (rates). We study the impact of monotone plant growth
functions in general plant-herbivore models on their dynamics. Our study shows
that all monotone plant growth models generate a unique interior equilibrium
and they are uniform persistent under certain range of {parameters} values.
However, if the attacking rate of herbivore is too small or the quantity of
plant is not enough, then herbivore goes extinct. Moreover, these models lead
to noise sensitive bursting which can be identified as a dynamical mechanism
for almost periodic outbreaks of the herbivore infestation. Monotone and
non-monotone plant growth models are contrasted with respect to bistability and
crises of chaotic attractors.
