Biological control: Banded fruit weevil (Phlyctinus callosus) culture methods

The development of a rearing technique for the production of large numbers of banded fruit weevil (BFW) is necessary before different biological control measures of BFW can be investigated.

Adult BFW were collected from corrugated carton strips secured around apple trees. Adults were kept on Coprosma plants in Perspex cages according to the method of Ferreira (2010) at room temperature in the laboratory at 23°C. Eggs were collected from moistened cotton wool disks placed with adults twice a week. All eggs were removed from disks under a microscope and placed on a moist filter paper disk inside a petri dish. Eggs were kept in a cool room under 5 °C until enough eggs were collected and then placed in the laboratory at room temperatures for emergence. After emergence larvae were placed onto carrots (Ferreira 2010) planted in course river sand. Final instar larvae or pupae were removed from the sand and kept in peat moss (Horne & Stackpoole 1989) until adults emerged.

Rearing larvae from emergence on carrots placed on peat moss was examined with different treatments. Dipping carrots into Sporekill to postpone fungal growth on carrots was tested to see whether or not there was an effect on the survival of BFW larvae. Survival of different numbers of larvae per container was also investigated. Results varied as eggs were exposed to temperatures higher than the expected 5°C the cool room was supposed to be when they were collected causing different ages in the larvae used.

Final instar larvae and pupae reared with the method where larvae fed on carrots placed on peat moss were supplied for preliminary testing of biological control with entomopathogenic nematodes (EPN’s).