Sustainable Slug Control for Vegetable Growers and Gardeners on Rota, Commonwealth of the Northern Mariana Islands

SUMMARY
Alien non-marine slugs and snails pose significant concern in the Pacific Islands, both for the damage they inflict on island crops and as constraints on the potential export of island crops to Hawaii and the U.S. mainland. Populations of slugs have exploded in recent years on Rota Island in the Commonwealth of the Northern Mariana Islands. But producers have little knowledge about them.

This project sought to pinpoint a biological control technique growers could use to deal with the slugs. However, some of the techniques planned for the project could not be implemented because USDA/APHIS stipulated quarantine restrictions on the potential biological control for slugs. As a result, the project coordinator redesigned the project to allow for the use of a standard moluscicide recommended by USDA/APHIS. Use of this commercial product reduced vegetable losses to slugs by 70-90%. The information was extended to others through two workshops.

OBJECTIVES
Establish a sustainable methodology for the use of a commercially available biological control agent called Nemaslug, (not yet registered in the United States). However, because of restriction on the product, it was not used, and the objective became on to employ a combination of physical, mechanical and chemical methods to control the slugs.

SPECIFIC RESULTS
As a result of this project, the principal slug pest on Rota was identified to the species level as Veronicella cubensis. An integrated control strategy was developed to assist producers in CNMI in adopting economically and environmentally sound pest management system.

Through farm records, the project coordinator verified that losses on his farm have been reduced by 70-90% since adopting this integrated pest management approach. Additionally, local agricultural suppliers and vendors are bringing in more appropriate and effective moluscicides so producers will have access to them.

BENEFITS OR IMPACTS ON AGRICULTURE AND PRODUCER ADOPTION
Although slugs remain a major agricultural pest on Rota, farmers are now better equipped to address the problem through the extension efforts (workshops and farmer field days) developed and executed through this project. Agricultural suppliers are now retailing the appropriate bait materials as a result of the lessons learned from this project.

REACTIONS FROM PRODUCERS
The farming community has already expressed appreciation for the efforts and results from this project, and commendations have been extended during advisory council meetings, at various workshops and through newspaper articles.

FUTURE RECOMMENDATIONS OR NEW HYPOTHESES
Given the present level of infestations observed on Rota, farmers cannot afford not to adopt the practices used in this project. The local Department of Lands and Natural Resources supports the efforts and recommendations evolving from this project and has sought further financial assistance through USDA/APHIS.

DISSEMINATION OF FINDINGS
Two major workshops on the “Biology of Slugs and Snails and Control Methods” were conducted as a result of this project. Fifty-four people attended these workshops, and a high level of interest was developed. In addition, extension materials are being developed in collaboration with the CNMI Division of Fish and Wildlife.