[Koha-devel] Apache error logs

[Paul A]

For the last couple of days, our production server has "gone bonkers" with 
tens of thousands of the following:

[Wed Jan 20 18:41:58 2016] opac-search.pl: Use of uninitialized value 
$code_wanted in string eq at /usr/share/perl5/MARC/Field.pm line 314.

Appears to involve control fields MARC < 10

I have noted that two new (to us) spiders are quite busy, and date-times 
appear to correspond -- webmeup-crawler.com and ahrefs.com -- but I don't 
want to libel them before digging deeper (probably end up firewalling 
them.) It *might* have something to do with ISBD view.

Has anyone got any thoughts?

Thanks and best regards -- Paul