Thornless Blackberry failure...again

it could be raspberry beetle according to my RHS book, below is the description:

Symptoms All cane fruits, inclucing raspberry, blackberry, loganberry and tayberry, are susceptable. The ripe fruits have dried up patches at the stalk end of the berries. When fully grown the larvae are up to 8mm long are creamy-white with pale brown markings on their upper surface. The grubs feed intiallt at the base of the berries but later feed on the inner core or plug. They are often seen crawling around the bowl after the fruits have been picked.
cause The larval stage of a small greyish brown beetle, Byturus tomentous. Eggs are laid on the flowers during early and mid-summer.
Control Timing control measures is important in order to control the newly-hatched grubs before extensive damage has occurred. On Raspberries, spray when the first pink fruits are seen; on logan berries and other hybrid berries, at 80% petal fall; and on blackberries, when the first flowers open. Spray with fenitrothion or derris at duck to minimise the risk to bees and other pollinating insects.

don't destroy the plants just treat them next year and hopefully you'll have a glut of berries.

Louise.

Thanks Louise. It is beetle...I always get them on the rasps, but didn't realise they did this much damage to the whole crop. I am still reluctant to spray, though I guess Derris at least is organic. I may still rip out the bushes, and plant something useful like a hammock

Could it be just the weather conditions? It's been a really wierd year (again) and cane fruits like it cool(ish) and damp. OK this year hasn't been hot, but the rainfall has been erratic to say the least.

I suspect the weather. We usually get a LOT of raspberry bettle.. and don't spray.. but very little this year ... maybe the rain?

I used to grow thronless blackberry but poor yields and security meant they were replaced by Himalayan Giant. 2-3 metres long , very vigorous, LOTS of BIG thorns and lots of blackberries...
(and the intruders who used to use our garden as a short cut to the fields don't like them:-)

I grow thornless evergreen blackberry too, They produce loads from 2 bushes but something( apart from the black birds )has been attacting them too. It is exactly like what 2 shed has describe, they dried out on the vine and the rest of the berry never fully ripe, there are always some red pach on the ripe black berry making them looks alike mix coloured ( black and red ). I was told some mites or so has been eating it and has to spray them during spring time. They suggested micro sulfat ( organic ) for preventions.

Cheers,
Momol