Have seen a report this weekend on the NAFEX discussion list of damage to pears from this compound... and this person was an experienced orchardist...I'm certain there was no incorrect mixing of his spray.

I'm taking the liberty of posting portions of the discussion, with the thought that the author would want other growers to be aware... At this point, it's circumstantial evidence...but better safe than sorry.

"Dear fellow pear growers,
I just wanted to warn other readers on this group about Azera insecticide from MGK. It is an OMRI-approved insecticide that's basically a mixture of azadirachtin (the main active ingredient in neem oil) & pyrethrins. I sprayed a mixture of Azera and Serenade at the recommended rates on my orchard on Sunday and by Tuesday, several cultivars of pear with European heritage (P. communis) were completely black. The damage is not fireblight. The symptoms are quite different and it is hitting certain blight-resistant cultivars while blight-susceptible cultivars right next to them are unaffected. I will compile a complete list this weekend, but I wanted to send a note quickly so that others can avoid the damage that I experienced.
I think the trees will survive, but I'll get no fruit from them.
I've been orcharding in the Southeastern U.S. since 1979 and have never seen anything like it. I've sprayed this same orchard with neem oil and pyrethrins (separately) and neem oil & Serenade together for several years in the past with no ill effects. Other species were not affected at all. I have one tree with 6 cultivars grafted in it. One pure communis cultivar has all of its leaves killed and another communis X pyrifolia cultivar has slight damage while the other 4, including one pure pyrifolia ('Koyama') are completely fine."

Grower posted an updated list - out of 30 pear varieties he sprayed, 7 experienced total (100%) leaf death. The other 22 were unaffected.

This well could be the start of fireblight. Pears are very subject to this...especially in damp springtime weather. Monitor it and google pear fireblight. Pruning out affected branches is the answer.

Doesn't look like fireblight.

My money's on the neem derivative product.

i always see some type of damage on my pears when i spray them. finally stopped spraying them after green growth is present. I have Orient, shineki, and Moonglow. All respond poorly to any of the traditional sprays (copper, captan, immunox, bonide fruit tree spray and others) once they have leafed out.

Outdoor,

Of all the materials you mentioned "copper, Captan, Immunox, bonide fruit tree spray", only copper could do damage when spraying after trees having leafed out. Captan and Immunox can spray before and after leafed out. Bonide usually is used after trees have leafed out.

Reading labels and following them is the best practice.

I'm not sure where you are in zone 8, but I never spray my pears
for anything, and I've never had any disease or insect problems.

Same here, rayrose. I had to go dumpster-diving to pull up that report of leaf damage...had already sent that thread to the trash bin, 'cause it didn't apply to me...