  Zebras were observed not only in the solar radio emission but also in radio
emissions of Jupiter and Crab Nebula pulsar. In their models, growth rates of
the electrostatic waves play an important role. Considering the plasma composed
from the thermal background plasma and hot and rare component with the
Dory-Guest-Harris distribution, we compute the growth rates $\gamma$ and
dispersion branches of the electrostatic waves in the $\omega - k_\perp$
domain. We show complexity of the electrostatic wave branches in the
upper-hybrid band. In order to compare the results, which we obtained using the
kinetic theory and Particle-in-cell (PIC) simulations, we define and compute
the integrated growth rate $\Gamma$, where the "characteristic width" of
dispersion branches was considered. We found a very good agreement between the
integrated growth rates and those from PIC simulations. For maximal and minimal
$\Gamma$ we showed locations of dispersion branches in the $\omega - k_\perp$
domain. We found that $\Gamma$ has a maximum when the dispersion branches not
only cross the region with high growth rates $\gamma$, but when the dispersion
branches in this region are sufficiently long and wide. We also mentioned the
effects of changes in the background plasma and hot component temperatures.
