i've suffered a similar attack earlier on, i believe some sort of leaf cutting insect may be responsible, the plant seemed to get over it though,it's still flowering now, although the plant seems a bit smaller than when planted, but what a pretty flower it is,be getting more of them

Thank you Kev. My plant also seems smaller than when I bought it last year. Maybe it will recover as there are still many buds ready to open.

It will be the dreaded Lily Beetle.
Buy some insecticide called Provado, asap, as this is the very best remedy, one application will last for months.
I grow dozens of Alstro's here and i've only seen 2 such beasties all year :-)))

Thank you Louise. I bought the product this afternoon and have sprayed it on the plant. Let's hope ..........

No need to hope, this is a very good product and very good value for money :-)

If you're getting the amount of rain we are i'd use a couple of applications as it's going to reduce its efficacy, always being washed off.

Lily beetles eat Alstroemerias, too? Ouch!

They love them.

mmm, i agree tug, ouch indeed,does that mean we're liable be looking uder the leaves for their horrible larvae? still keep findind a few beetles on my lillies even tho they done flowering???

Kev, they'll be quite evident so keep an eye out - these are just another member of the family that will attract the horrid little things, unfortunately.

thanks for the heads up louise,will be keeping eyes peeled, never encountered so many beasties in the garden as i have this year :O

Hi - would like to draw your attention to the possibility that Provado and other similar insecticides are contributing to the demise of the bee population 'Experts believe there are many possible causes of bee decline, including imidacloprid (main constituent of Provado), and a recent bee malady termed colony collapse disorder (CCD). In 2011, according to the United States Department of Agriculture, it seems clear that no single factor alone is responsible for the malady, however honey bees are thought to possibly be affected by such chemicals which are known to work their way through the plant up into the flowers and leave residues in the nectar and pollen which bees forage on."
Lily beetles and their eggs (slimy, yucky substance they leave usually on the stems) can be picked off and squashed!