Dear Massoud Latifian

I think speed of biological control application depend on your target (pests or pathogens), biological control agents and environment. Based on my practices in entomology laboratory and green house, commonly predators (such as Staphylinidae) more dispersal than parasitoids, because predators are generalism than parasitoids need specific host and more time to established. 

 regards,

Sri

Dear Massoud Latifian

This is very important, which is the best; predators, parasitoids or pathogens. The answer is not a simply because the control methods depends on many factors as the pest type we need to control, the habitat, the population fluctuation, the environmental factors and so many. So for each target or pest insect there is a useful method to control. Finally, Conservation of natural enemies and development is a good start for pest control.

Best Regards

aly younes

Dear Massoud Latifian,

If weather favors to entomopathogen then pathogen is best there are many records of epizootic of HaNPV, SlNPV, and entomopathogenic fungi. I had also seen epizootic of Beauveria bassiana infecting Chrysodexic (Green semilooper) in soybean crop at Dahod district of Gujarat, India. However, predators or parasitoids required more time even under full of favorable situations. So as per my personal experience, pathogens have the highest speed effect under fully favorable situations.

Regards,