Raspberry beetle

Raspberry beetle causes damage in its grub stage, which feeds at the stalk end of the fruits. It is mainly a problem on summer-fruiting raspberries. Early fruits on autumn raspberries may be damaged, but those ripening after late August are less likely to be affected.

• Damaged ripe berries have greyish-brown dried up patches at the stalk end
• A brownish-white grub, up to 8mm (about1/4in)  long, may be found inside the fruits

Non- chemical control

A host plant odour (karimone) water trap is available from Agralan. This will trap both male and female beetles which may help reduce infestation levels.  

Chemical control

• Ideally best control will be achieved by spraying raspberries when the first pink fruits are seen, with a second application two weeks later, however plants should not be sprayed when in flower due to the danger to pollinating insects
• Pyrethrum (considered organic e.g. Bug Clear Gun for Fruit & Veg, Ecofective Bug Killer (also contains fatty acids)) may give some control of raspberry beetle. A minimum one day interval is required between spraying and picking the fruit
• A better level of control may be achieved with the synthetic pyrethroid insecticides deltamethrin (e.g. Sprayday Greenfly Killer), which has a seven-day harvest interval on most cane fruits or lambda-cyhalothrin (e.g. Westland Resolva Bug Killer) which has a 28 day harvest interval on raspberry. For both these pesticides check and follow the manufacturer’s instructions for these food plants
• Inclusion of a pesticide product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener
  

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Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)

• The 4mm (about 1/8in) long adult beetles are pale 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
• In late summer, the fully-fed larvae move into the soil where they overwinter as pupae

Chemical labels explained
Chemicals: using a sprayer 
Chemicals: using safely and effectively
Pigeons
Protect your garden
Raspberry
Raspberry and blackberry aphids
Raspberry cane blight
Raspberry spur blight
Red berry mite