Croesia zimmermani (Lepidoptera: Tortricidae)

Alien (biocontrol agent)

Larva- I have no larval picture. The larva is a brown leaf-roller.

Adult

This was introduced to Kaua`i for control of alien Rubus in 1965 from Jalapa, Mexico, and established quickly. At the time of introduction it was undescribed and attributed to a different genus. When Zimmerman was writing his Microlepidoptera volume of Insects of Hawaii, he asked J.F. Gates Clark to describe the species, which he did in Zimmerman's honor (Zimmerman, 1978: Insects of Hawaii, vol. 9: Microlepidoptera).

Host plants recorded from the Alaka`i Swamp:

• Rubus argutus* (Rosaceae) Blackberry; Alien

This is one of two biocontrol agents on Rubus argutus that I collected (in addition a sawfly, much less common, was also introduced for this purpose). I did not have any of the native Hawaiian Rubus hawaiensis on my plots, although it does occur in the vicinity of Koke`e State Park. I don't know if anyone has determined whether the biocontrol agents introduced against alien Rubus attack R. hawaiensis as well.

Development time in the laboratory at 20°C:

• Larva: 1 month
• Pupa: 2 weeks

Larval parasitoids recorded from the Alaka`i Swamp:

A biocontrol agent is probably most effective and desirable when not attacked by any parasites or predators, and is a specialist. At least the no-parasites condition apparently holds true in the case of C. zimmermani and the other Rubus biocontrol agent, Schreckensteinia festaliella.