Caribbean Slug Control Measures

The FAO (The Food and Agriculture Organization of the United Nations) Sub-Regional Office, Barbados sponsors a list to allow the exchange of information to promote sustainable agriculture and the control of various pests of agronomic crops in the Caribbean.  FAO-Carib-Agri resource list recently described several methods for end-users/growers to control slugs that may prove useful in other locations.  The following list is a compilation of some of the list suggestions.  This list is for informational purposes and doesn't infer a recommendation by the University of Florida and conversely, lack of mention doesn't imply other effective measures don't exist.   Local, State and or Federal laws govern the use of pesticides so check with your municipality to verify an item is a registered insecticide/molluscicide prior to use.  The listserv may be subscribed to at:  carib-agri-l@mailserv.fao.org

Leidyula floridana (Leidy).
CREDITS: Florida Department of Agriculture and Consumer Services- Division of Plant Industry

 

This slug is native to the Caribbean (Cuba to Jamaica) and southern Florida. (Stange, 2006).
Caribbean Slug Control Measures:                              

• Ground up sea or egg shells were reported to be effective against slugs especially in seedling nurseries. In Barbados 'cuss cuss' or its cousin 'silver' grass, is used to reduce the slug population when used as mulch in the fields. Though the fresh grass has razor sharp edges, fresh mulch needs to be added as the previous amendments break down into the soil. 
• 1 ounce of metaldehyde to three (3) pounds of animal feed mixed together with the addition of a small quantity of water works extremely well. Metaldehyde is the active ingredient in most slug preparations and usually makes up less than 2% of the various formulations that can be purchased over the counter for the destruction of slugs.  Metaldehyde at concentrations up to 100% can usually be found in most hardware stores.  It is beneficial to cover the bait using small sections of PVC pipe or small hollowed out sections of bamboo into which the mixture can be inserted, this way it does not wash away.  The chemical is potentially harmful to pets so be careful with its use.
• One FAO-Carib-Agri member reports the use of organically certified Sluggo® or other iron phosphate pellets for slug control and finds it works well if used with consistent applications, especially since slugs first start appearing in numbers after the dry season. 
• A USDA-ARS study reported in the journal Nature (27 June 2002) that caffeine is deadly to slugs. (Entire article)  FAO-Carib-Agri members question whether coffee beans produced in the Caribbean can be used against slugs since caffeine is categorized as GRAS or 'Generally Recognized as Safe' by the U.S. Food and Drug Administration (FDA).  Since local West Indian coffee processors decaffeinate their beans, there is the potential that the extracted caffeine can be utilized for making/marketing a local anti-slug remedy.
• Ammonia kills slugs almost instantaneously.  Research on establishing the optimal concentration to eradicate pest but not promote phytotoxicity would be very useful.  Caution should be exercised as household ammonia can be toxic to plants.
• Slugs can also be controlled with a 10% solution of copper sulphate - approximately 2 ounces per gallon of water. However this will be phytotoxic to plants so apply the spray to the walls, paths, pots and the soil. Do not apply to leaves.
• For an organic control method - saucers of beer will attract the slugs and they will drown happy! One FAO-Carib-Agri listserv member reports that slugs prefer Heineken® over other brands and it must be put down fresh every evening.  Combining this technique with manual removal of slugs can offer very good pest control. The use of a pair of clippers and a flashlight late at night to locate and remove feeding slugs will help to reduce the infestation.
• A natural slug control was reported from Trinidad.  "A small brown snake that eats slugs can often be found inhabiting compost heaps". The FAO-Carib-Agri listserv reporter cautions that there is "such a dislike for snakes in the Caribbean, the idea of encouraging them to destroy a predator would be seen as ridiculous". To view the slug-eating snake use this link:  https://naturalhistoryphotography.net/trinidad-snail-eating-snake-dipsas-trinitatis/

FAO-Carib-Agri listserv members have expressed concerns about increased intensity of slug and ant problems from the build-up of organic matter.  Slugs can be adequately controlled with organically-certifiable preparations, but an answer for the hordes of biting and running ants encouraged by organic matter on the ground surface is a pressing need.  "The ants destroy or make unmarketable a significant portion of produce and certainly make work on the farm less pleasant."  Anyone have any solutions?  Biological, chemical and cultural control method suggestions can be directed to carib-agri-l@mailserv.fao.org.

References:

• Stange, L., Deisler J.E., 2006 Florida Department of Agriculture and Consumer Services, Division of Plant Industry.  Originally published as DPI Entomology Circulars: 197 and 261.
  
• Robert G. Hollingsworth1, John W. Armstrong1 and Earl Campbell2,3 2002   Pest Control: Caffeine as a repellent for slugs and snails. Nature 417, 915-916
  
• US Pacific Basin Agricultural Research Center, USDA-Agricultural Research Service, PO Box 4459, Hilo, Hawaii 96720, USA
  
• USDA-APHIS-WS-National Wildlife Research Center, Box 10880, Hilo, Hawaii 96721, USA
  Present address: US Fish and Wildlife Service, Box 50088, Honolulu, Hawaii 96850, USA

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