laurel (bay) bush attacked by white bugs

I've had a nice large bay bush on my terrace, about 4 feet tall, and it;s been there for probably 15 or 20 years. 

This year i noticed it wasn;t doing well and on closer examination i found these large (1/2 inch) stark white bugs that look almost like funny seashells (their backs are sort of ridged, and their heads seem hidden). 

I sprayed them with dish detergent and they died, and i pruned off all the places where their carcasses remained, figuring there may be eggs. 

Now i noticed that some of the branches they were on are hollow and it seems other white things are about to emerge from the hole.  Shyould i throw out the plant, not to contaminate my other plants (I have a lemon and an olive, and all kinds of other things)? 

What, if anything, can be done. 

I found on internet something about "cocciniglie" (koh- chee- nee-lyeh) which looks like these and says they make red dye from them (yes, for food).  yuck

(the article recommends insecticides)

Thanks, not just baked, but i really wonder where i could get ladybugs here.  Were your white bugs huge like mine (about half an inch)?

Quote:

Originally Posted by not just baked 

You are welcome.  Well, no, not half an inch, more like a quarter of an inch.  But I got my lady bugs at a local hardware, nursery store.  At the time I lived in Sacramento, Ca, and it is called Emigh Hardware. Most hardware stores, like Ace Hardware, carry them. Just ask, but usually they are n a fridge to keep them dormant. They look dead, but as soon as they get out of the fridge for a bit they start crawling around, it very cool. Or take the photo to a local nursery. Smaller nurseries usually are very helpful and sometimes carry ladybugs. I would try the photo thing first too. Just in case, like I said, I would hate for the other bugs to eat the lady bugs.

Ah, alas, this is italy and emigh hardware and ace hardware are nonexistent.  I discovered i can get them online, but these look five times the size of a ladybug.  I guess it wouldn't be bad to have extra ladybugs hanging around ... but maybe that's what the person who introduced rabbits to australia said...

The nurseries i've been to are pretty unhelpful - personnel seems not to even know what i want to know, and they have tons of insecticides, but i haven;t seen any ladybugs, though i suppose i could ask.  i think i can find them online, but from companies that sell to large producers, i wonder if they will sell me a small jar of the bugs. 

I bought some cape daisies (i believe that's what they;re called in the US) which i've always seen blooming happily all summer.  Mine bloom once or twice in the spring, and then they never bloom again.  I went back to TWO nurseries, several times, explaining that my terrace is exposed to sun from morning to night (very hot and dry).  First time they said they needed fertilizer.  Next time, after that didn't work, they said i must have put too MUCH fertilizer, then next time i shoulod take off all the dead flowers (I was already doing that).  Next time too much water.  Next time too little water.  I realized they had no clue, were just saying things off the top of their head.  I finally found what they;re called, and looked them up.  They don;t flower when it's hot!  For nursery personnel who don;t know the minimum information, or just blabber off the top of their heads, there is not much hope for me to get good info from them, especially if i don;t want to use pesticides (since i do want to use the bay in cooking!

They don't have Dawn detergent here - i wonder what it contains, because i've seen it recommended even on forums for stain removal! (red wine, mix dawn and peroxide).  But it seems that most detergents work to kill on contact - i think they emulsify the fat of the insect body.  One website said to put some alcohol in the places where they made holes.  I was pouring alcohol on it, and then decided to take the bull by the horns and just prune it down radically.  I cut off any branch that had been attacked and very carefully washed the newly budding ends.  Some of the branches turned out to be hollow!  Here's hoping it will work.  It was probably too big anyway- about 6 ft high.

not sure it would be anything called "mealy" since that usually is soft and cream colored.  These are bright white.  They;re  tiny at birth, when the armies of them run out of the holes to attack the plant, and then they sort of settle down on a spot, usually a joint between branches, and form a sort of seashell shape as they grow, white, and one on top of and overlapping with the other.  I don't have a camera  any more and even when i did, am not good at posting thihngs without help.  The detergent worked, it seemed, but then a couple of months later it was attacked again.  More detergent, but the plant looks like it's had it, i imagine it's riddled with holes that harbor eggs waiting to burst out in the spring.  maybe i should cut it down to the root and see what happens. 

Yeah, ed, those are probably the other kinds of bugs i get, but never on the bay leaves.  They go easily with a spray of dish detergent solution.  These are hard and resistent and go inside the wood itself.