Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
 

News:

How to Post Pictures on the forums.


Author Topic: Raspberry beetle  (Read 8130 times)

0 Members and 1 Guest are viewing this topic.

Bernard

  • Experienced Member
  • ***
  • Location: West Riding of Yorkshire
  • Posts: 266
Raspberry beetle
« on: July 23, 2009, 22:28 »
I just did a search for threads about raspberry beetle and found the information a bit sparse.

Did I understand correctly that derris dust is no longer available? I have nearly run out of the tub I bought about 3/4 years ago and it has given some protection.

Do I correctly understand that some people have no problem with the pest? Or do they just not notice it? I thought it was ubiquitous, especially if there are wild blackberries in the area as there are here( for which reason I don't eat other peoples' blackberry pies).

Can anyone recommend an effective control?


bonfire

  • Full Member
  • **
  • Location: Lewes, East Sussex
  • Posts: 86
Re: Raspberry beetle
« Reply #1 on: July 23, 2009, 22:49 »
Yes I have had some raspberry beetle this year for the first time.

I don't like the idea of spraying when the flowers are open - how can this not harm pollinating insects? Nor do I understand the advice to spray when the flowers have set - because my raspberries are setting over several weeks so I am bound to spray open flowers - they don't come on and go off like light bulbs.

I will try digging around the row as some advise but would value any tried advice from an experienced grower.

Allotment Jon

  • Full Member
  • **
  • Location: Solihull
  • Posts: 97
Re: Raspberry beetle
« Reply #2 on: July 24, 2009, 09:04 »
I,ve done raspberry plants for the first time in a raised bed. Every time I go to water them I see hundreds of little things running around. I did post the question some months ago but no reply. I presumed they are harmless but one of my plants has recently lost all it's follage so perhaps not.

Will look foward to future replies.

strangerachael

  • Senior Member
  • ****
  • Location: Rugby
  • Posts: 769
    • Weedybeanz
Re: Raspberry beetle
« Reply #3 on: July 24, 2009, 09:44 »
I also have them - they seem to have got worse each year.  We haven't eaten a single one this year as they are so badly affected. At the moment I have them in the garden and intend to dig them all out at the end of the year. I was going to get new ones and grow them at the allotment, but looking at my neighbour's plants, it appears she has them too, so now I'm having second thoughts. Unless I sprayed them regularly I think they would be unavoidable.
So why do people say raspberries are so easy to grow?
Rachael

Salmo

  • Hero Member
  • *****
  • Location: Peterborough
  • Posts: 3744
Re: Raspberry beetle
« Reply #4 on: July 24, 2009, 11:13 »
RHS guidelines as follows
Rotenone* (Bio Liquid Derris Plus* or Vitax Derris Dust*) can be used to control raspberry beetle. Spray or dust raspberries when the first pink fruits are seen, with a second application two weeks later. Treat hybrid berries at 80% petal fall and blackberries when the first flowers open. Apply rotenone* in the evening when bees are not active on the flowers.

* Rotenone/derris-based insecticides are being withdrawn from sale. Gardeners who have this pesticide may continue using it until 10 October 2009. Any unused products after that date should be disposed of safely by handing them to the staff at a local authority manned waste disposal facility.

You can still use Derris although I would be wary of anything that the EU has banned because it affects the nervous system and has connections with Parkinsons disease.

A synthetic pyrethroid, Bifenthrin, which is the ingredient in Bug Clear and others, is the alternative. As with Derris it is applied when the first pink fruits are seen. It is purely contact with no residual effect. Bug Clear bottle says you can eat crops next day.

As the grubs drop back into the soil and pupate there until they hatch next May it would seem logical to either stop the grubs getting back to the soil or kill then in the soil. Although the original infection may have come from local blackberries I would guess that most of yours now come from your own plants.

Non-chemical advice is to hoe around the base of the plants in the Spring to expose the pupae to the elements and birds. I would suggest extreme hygiene such as picking all fruit off and not dropping infected fruit on to the ground.

I have not tried this, or know of anyone who has, but I wonder if you put something like weed fabric round the base it would prevent grubs that drop from reaching the soil, either because they cannot physically get there, or because they die due to exposure. What do others think?

Only the very early fruits of Autumn respberries are affected so they might be an alternative.
« Last Edit: July 24, 2009, 11:17 by Salmo »

tode

  • Hero Member
  • *****
  • Location: NW France
  • Posts: 2525
Re: Raspberry beetle
« Reply #5 on: July 24, 2009, 11:27 »
What are raspberry beetles? Ive been growing R'berries about 15 years, and have only found a few small green caterpillar-looking things making holes. Were in the country, so quite a lot of wild B'berries around us.

drdave

  • New Member
  • *
  • Location: South Hants
  • Posts: 45
Re: Raspberry beetle
« Reply #6 on: July 24, 2009, 15:02 »
I had gooseberry sawfly caterpillars on mine, but they have not caused significant damage, unlike the gooseberries...

agapanthus

  • Hero Member
  • *****
  • Location: In a slum in Norfolk :(
  • Posts: 3334
Re: Raspberry beetle
« Reply #7 on: July 24, 2009, 19:38 »
Are you sure they are'nt shield bugs? I used to have hundreds on my rasps every year......but they did'nt do any damage :nowink:

tode

  • Hero Member
  • *****
  • Location: NW France
  • Posts: 2525
Re: Raspberry beetle
« Reply #8 on: July 24, 2009, 19:49 »
Shield bugs may not do any damage, but they certainly give the raspberries a disgusting taste if you sqish one  :tongue2: :tongue2: :tongue2: :tongue2: :tongue2: :tongue2: :tongue2:

agapanthus

  • Hero Member
  • *****
  • Location: In a slum in Norfolk :(
  • Posts: 3334
Re: Raspberry beetle
« Reply #9 on: July 24, 2009, 22:25 »
Shield bugs may not do any damage, but they certainly give the raspberries a disgusting taste if you sqish one  :tongue2: :tongue2: :tongue2: :tongue2: :tongue2: :tongue2: :tongue2:


That'll larn ya!!!!! :D ;)

bonfire

  • Full Member
  • **
  • Location: Lewes, East Sussex
  • Posts: 86
Re: Raspberry beetle
« Reply #10 on: July 25, 2009, 00:26 »
The damage is on the fruit and is caused by small grubs which emerge when the fruit is fully ripe but slightly distort the fruits on one side before this.
So no - they are not in the slightest bit like shield bugs - you see hardly any adult beetles at all and they are very small. - And of course if you haven't got them and don't know what they are you really needn't worry about them.

Yes the RHS advice is on line with what I have seen elsewhere but leaves me less than reassured for pollinating insects. When the first pink fruit appears there are still other canes in flower. You would be bound to spray the flowers leaving the contact poison on them. I tend to think of how I would behave if I had a beehive of my own on the plot. I am not sure that the RHS advice really meets this standard.

I will try digging and perhaps later clearing the soil and replacing it as much as possible.

Bernard

  • Experienced Member
  • ***
  • Location: West Riding of Yorkshire
  • Posts: 266
Re: Raspberry beetle
« Reply #11 on: July 25, 2009, 15:51 »

A synthetic pyrethroid, Bifenthrin, which is the ingredient in Bug Clear and others, is the alternative. As with Derris it is applied when the first pink fruits are seen. It is purely contact with no residual effect. Bug Clear bottle says you can eat crops next day....

.. infection may have come from local blackberries I would guess that most of yours now come from your own plants.

Non-chemical advice is to hoe around the base of the plants in the Spring to expose the pupae to the elements and birds.

Useful info, Salmo, though I have some 'buts' -

I must look for Bifenthrin. But as someone else said, no matter when you spray there are flowers/fruit at different stages. However, I have always tried to apply derris to unopened flowers only, this being the advice I received. Most significantly, I do not know at what stage the fruit is attacked.

I suppose my infection came from blackberries but there is an aspect which indicates that treating the ground will be no use: I planted these canes late one year on a plot which had never had raspberries or blackberries (which are in a distinct area of ground 10 yards distant) and next year, the first crop was infected. So exactly how does infection occur? Where does the adult beetle lay its eggs and how far do they travel to do so?

For those who have not seen the problem, it is a small grub/maggot which is usually squirming in the core of the berry. I went right off them years ago when on holiday in the Norfolk Broads. I picked a bag full of blackberries, left them for one day and found a mass of maggots in the bottom of the bag. Anyone who picks raspberries or blackberries and cooks or eats them immediately without looking may well be eating plenty of grubs without knowing. That is why I don't eat other peoples' blackberry pies.

Salmo

  • Hero Member
  • *****
  • Location: Peterborough
  • Posts: 3744
Re: Raspberry beetle
« Reply #12 on: July 25, 2009, 18:28 »
Quote RHS
The 4mm long adult beetles are brown and they lay eggs on the flowers in May to mid-July. The young larvae feed at the stalk end of the developing fruit, but later move inside to feed on the central plug.

They fly so 10 yards is no distance.

Bernard

  • Experienced Member
  • ***
  • Location: West Riding of Yorkshire
  • Posts: 266
Re: Raspberry beetle
« Reply #13 on: July 25, 2009, 22:06 »

They fly so 10 yards is no distance.

That's what I suspected. So no treatment of my patch of ground will be any use.

Now, I have had a brilliant idea. I doubt if the flying beetles can be stopped by a simple net, but how about a net impregnated with insect repellant? Doesn't even have to be toxic. It will stop the bees also of course, so are raspberries self-fertile or do they need the bees?

Salmo

  • Hero Member
  • *****
  • Location: Peterborough
  • Posts: 3744
Re: Raspberry beetle
« Reply #14 on: July 25, 2009, 23:51 »
I did see some work that was being done hanging white/pink petal coloured sticky boards to trap beetles when they were attracted to the petal colours.

 


Share via twitter

xx
Raspberry beetle

Started by plopleuk

1 Replies
499 Views
Last post April 19, 2011, 10:38
by viettaclark
xx
Raspberry Beetle

Started by LivvyW

3 Replies
836 Views
Last post November 06, 2008, 21:02
by Aunt Sally
xx
raspberry beetle in blackberries

Started by Annen

3 Replies
551 Views
Last post September 17, 2012, 12:36
by Annen
xx
Treatment for Raspberry beetle/botrytis

Started by Nobbie

2 Replies
672 Views
Last post May 11, 2009, 17:02
by mumofstig