Rose Chafer Control

We have a rose chafer infestation in raspberries, gooseberries, hollyhocks and even our Richter's basil! I would be very grateful for any suggestions of what might help.

To get rid of the chafers you can try several remedies. To stop their feeding on plants spray the affected plants with neem oil (one teaspoon of neem oil plus one quarter to one half teaspoon of dishwash detergent per liter of water) and repeat after every rain or overhead watering. This will make the chafers lose their appetite and starve to death.
To stop them from reproducing spray as much of your soil as possible but especially around the affected plants with scanmask, the cysts of a predatory nematode (Richters catalogue number T2600). Keep the soil moist to get quick hatching and they will attack the pupal stage of the chafers.
Pyrethrum soap spray will kill the pests you manage to hit with the spray and should help to keep the numbers down, until you can get the scanmask to work. (Richters catalogue number T2212)