Comparative Study of Cuban Slugs (Veronicella cubensis) Suppression Using Grazing Ducks, Neem (Azadirachia indica) Extract and Chemical Baits in the CNMI

Final Report for FW08-305

Project Type: Farmer/Rancher
Funds awarded in 2008: $23,673.00
Projected End Date: 12/31/2010
Region: Western
State: Northern Mariana Islands
Principal Investigator:
Alejandro Badilles
Northern Marianas College
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Project Information


The Cuban slug (Veronicella cubensis) has recently risen in prominence as an agricultural, ornamental and nuisance pest on the island of Rota, CNMI. This study examines and demonstrates the most effective suppressing practice for Cuban slug during testing of three available management practices in field demonstrations. Results showed that three practices at weekly observations: Ducks Feeding on Cuban Slug, Neem (Azadirachta indica) Extract and Slug Pellets (Deadline M-Ps) suppressed the population of Cuban slug. Observations indicated that these practices should be effective at controlling Cuban slug.


The agricultural industry on Rota, an island within the Commonwealth of the Northern Mariana Islands, is vulnerable to slugs and snails. Slugs are causing severe crop losses and a false image of the safety of vegetables grown. The high cost of current control measures, such as baiting, is prohibitive, so this Professional + Producer project explored three cost-effective and sustainable control methods for slugs in vegetable crops.

The first producer used grazing ducks to eat the Cuban Slugs. The ducks also cleared weeds and fertilized the ground. The second producer planted rows of Neem trees to use as windbreaks and for their pesticide properties. These trees are also known for their germicidal and medicinal purposes. The third producer set up modified baiting traps on his farm that are safe and cost effective.

This project has developed sustainable practices for Rota’s agriculture industry. Increased harvest yields led to decreased imports. Risks from harmful pesticides are reduced.

Project Objectives:

This project aimed to explore and demonstrate the cost effective, environmentally-friendly and sustainable practices for slug and pest control in vegetable production. Millions of Cuban slugs had infested Rota, and the hardest hit area was Sabana area where the pests feasted on vegetable crops even before they could bloom. The slugs could wipe out an entire seedlings plot overnight. This discouraged the farmers so badly that no one wanted to till the land and plant vegetables anymore.


Click linked name(s) to expand/collapse or show everyone's info
  • Edel Depalog
  • Joaquin Manglona
  • Nurul Islam Paeda


Materials and methods:

Using Slug Pellets (Deadline M-Ps):

We tested Deadline M-Ps' ability to withstand breakdown of pellets due to weather, safeness and sustainability of baiting Cuban slug. The demonstration plot was conducted at Nurul Islam Paeda in Sabana area. This area has an abundant population of Cuban slugs due to its topography and farming activity.

Modified slug baiting traps, using pallets, were placed five feet apart in the perimeter of the demonstration plots. It was covered with tin and treated with Deadline MP-s. Replenishment was done as needed.

Plots were planted with head cabbage and tomatoes and treated weekly with Deadline M-Ps. Weekly monitoring by treating the plots with Deadline M-Ps was done, dead individuals were counted, recorded, removed from the experimental arena and discarded immediately in all practices.

Each practice had four treatment plots with an area of three feet by forty feet and three feet apart covered with a plastic weed blocker.

Using Ducks Feeding On Cuban Slugs:

Lead producer Mr. Jack Manglona was responsible for operating the 38 duckling’s parent stock (brooding, growing to laying stage). He was feeding the ducks and trained them to feed on Cuban slugs. Three feet wide duck confinement using chicken wire was placed in the perimeter of the vegetable beds to prevent slug damage.

Using Neem Extract:

Edel Depalog's and Brian Richard’s farm in Santa Cruz, Rota was chosen as a source of Neem as an organic pesticide against Cuban slugs. Neem was planted in one row in the perimeter ten feet apart, designed for windbreak and soil erosion control. A three feet wide perimeter was sprayed with a dilution of one liter of Neem leaf extract to nine liters of water plus 100ml of soap. It was stirred well and sprayed evenly to repel the slugs from intrusion into the vegetable beds.

Research results and discussion:

Mortality to Cuban slug was high in the first week of treatment. There were few or no slugs detected in the following weeks after treatment. Results of the three practices in field trials indicate that any of these practice should be effective at controlling Cuban slugs.

Participation Summary

Research Outcomes

No research outcomes

Education and Outreach

Participation Summary:

Education and outreach methods and analyses:

A video production on DVD was completed and published. Publications such as brochures and flyers were completed and out for general public use. Power point presentations were given at two major conferences and various mini-workshops at different schools and agricultural fair exhibit grounds in the CNMI. A newsletter entitled “Cuban slugs meet their match in Rota ducks” was published in the Marianas Variety News & Views Green Tips column, dated June 22, 2010.

Education and Outreach Outcomes

Recommendations for education and outreach:

Potential Contributions

The use of slug pellets is expensive. In contrast, ducks can also control the pests and provide or contribute to another form of livelihood source to farmers. The ducks turned out to be an economically viable means in controlling the Cuban slugs. The farmers on Rota have started to realize this. Many of them now have surrounded their vegetable plots with ducks. The risk of lungworm disease contamination to humans will be prevented when ducks consume Cuban slugs as carriers as host specific to mammalians. Ducks that feed on Cuban slugs become healthier, and the females hatch a surprisingly bigger number of eggs.

Future Recommendations

The use of ducks, Neem extracts and slug pellets were found to be significantly effective in suppressing the population of the Cuban slugs. The use of ducks is highly recommended as predators and a form of sustainable livelihood due to its economic viability and by keeping the environment safe and healthy.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.