The larger, spottier cousin of the beloved common ladybird is a force to be reckoned with, as country gardener Amy Willesee has discovered.

Ladybirds are meant to be lucky, prized as one of the good guys of the insect world, but there is a black sheep in the ladybird clan and it is an altogether different proposition.

The common ladybird's predatory inclinations keep it munching through pests like aphids, scale insects and powdery mildew, but its bigger, uglier cousin, the 28-spotted ladybird, is a dedicated vegetarian. And this year, my garden provided its summer smorgasbord.

This has come as a shock because, whether it's through the success of the organic system or just good luck, I haven't had much in the way of pest or disease problems these past few years. Early on, slugs struck a blow by routinely demolishing seedlings overnight, but the chooks sorted that out and, other than a small re-emergence this past very wet winter, they haven't been back. White cabbage moths have been a more constant foe, but I've dealt with that by only planting their favoured feast of brassicas in winter, when it's too cold for them to get any decent numbers up.

Then a couple of summers ago, I noticed pockmarks in my eggplant leaves and traced them to an oversized ladybird. There were only a few of them and the harvest was abundant, so I didn't worry.

The following year, their numbers grew but not enough to propel me out of my inertia. This year, however, the plague descended. Not just the eggplants, but potatoes, zucchinis, cucumbers, pumpkins and melons as well. Within a week, beds went from vibrant and lush to tattered and sad.

My plan of attack was to squash-and-conquer. I figured that squashing them onto the leaf and leaving the evidence behind might send a warning that this was enemy territory. I also fed their eggs and larvae from the underside of the leaf to the chooks.

It may have halted their march, but they had the numbers and I was a lone soldier. A quick internet search for alternative organic attacks recommended chilli or garlic spray, but the problem with spraying is that it could also wipe out the good ladybirds. Another tip recommended weeding out any blackberry nightshade in the vicinity, as it acts as a host to the critter.

The whole episode made me wonder whether my plants were less resistant to pests this year. Were they depleted of certain nutrients? Had they become heat stressed or too dry at some point? I have been very slack with seaweed tea, and I almost never water them. They manage to survive regardless, but maybe it wouldn't hurt to give them a lovely potassium-rich drink and an occasional deep watering for their troubles.

Maybe this plague was a wake-up call that my garden could do with a little more TLC.

Spotting the problem

The 28-spotted ladybird is significantly larger than other ladybirds, growing up to 1cm long, and is noticeably less delicate. After a few sightings, you won't need a magnifying glass to recognise them but if in doubt, skeletonised leaves in the vicinity are the smoking gun.

Looking for more outdoor inspiration? Check out our Outdoor section.