Strawberry Seed beetles cause damage by eating the seeds and also the fruit flesh of ripe and developing strawberries. They are more widespread in the UK than is generally realized, and should be one of the first eliminations in fruit damage investigation – especially if in dry – rather than damp conditions. The damage is mainly on the underside of the fruit.
Whilst it is commonly known as a ‘seed’ beetle, it does in fact gauge considerable chunks out of the ripe fruit. Sometimes the damage is wrongly identified as being caused by birds. This is on account that - on ripe strawberries in particular - it gauges out the flesh which is attached to the seeds. Very often, they damage the fruit from underneath – next to the soil, so are rarely noticed until too late.
The Strawberry Seed Beetles live on weeds and other vegetation surrounding the strawberry crop, and they move on and off the strawberry crop when then need to feed.
No known insecticide is available to home gardeners combat this pest of strawberries, so best to keep areas surrounding free of weeds and debris. This goes for the areas between rows. Cleanliness is an important factor to mitigate the damage done.
The main reason for lack of chemical control, is the fact that the strawberry seed beetle comes into action near to harvest time. The chemical that could possibly destroy this pest, are unsuitable for use on crops near to harvest.
Another ‘method’ we have hear of – from a commercial strawberry grower, is to sink jam jars or used yoghurt pots into the soil level with the surface to act as a trap. Once the beetles fall in, they cannot get back out.
Beetles are approx 1cm long and black. They have a typical beetle appearance, with shiny shell and feelers at front as can be seen in the image. Strawberry beetles are quick movers – as with most soil beetle. They lay their eggs in the ground in midsummer, and the Weed Fat Hen is a particularly good place for the hatching larvae feed on the roots of that plant – among others.
Unlike the Vine weevil – another beetle pest of strawberries, they do not leave tell-tale bites on the foliage. They are fruit eaters. Neither do the larvae do the same damage as the vine weevil beetle, for they lay their eggs away from the crop – in the soil among weeds.