Too much CPU usage from [php] <defunct>- 50.0% CPU

[oisy]

Hi all! Today I recived this problem - Too much CPU usage from [php] <defunct>- 50.0% CPU.
Did someone have the same and what can i do for it?

Thanks!

[CREATIVE Options]

It must has to do with 3rd party component / module / bot.

[oisy]

I didn't change mod's and bots since I have the site it is from a year and no problems till today.

[CREATIVE Options]

High pick of visitior's ?
Attempts of attack in your website?

[oisy]

Visitors are not so huge about 50/day.
About attacking I didnt notice any.

I will try to turn on Flood blocker and see if it works...