A Sustainable Pest Management Strategy for Sweetpotato Weevil in Cuba: A Success Story
Sweetpotato is one of the most important staple foods in Cuba, covering around 60,000 ha each year. The potential to increase sweetpotato production is limited by damage from the sweetpotato weevil. The weevil is present in all provinces of Cuba, causing up to 45% damage in the absence of control measures.
The Asian sweetpotato weevil, Cylas formicarius (Fabricius), is the single most important sweetpotato pest in the Caribbean. Farmers in Cuba used to spray their fields 10 - 12 times a season. With such an intensive spray schedule, weevil damage rarely exceeded 10%. With the elimination of subsidized pesticides, Cuban farmers faced losses of 40 to 50% of total production.
CIP initial work on sweetpotato weevil management concentrated on the use of sex pheromone traps. They proved very effective, and farmers showed great interest. CIP, in collaboration with INIVIT, developed an IPM strategy based on several management components. The most effective component is the use of pheromone traps to lure and eliminate male weevils.
The naturally occurring insect-killing fungus, Beauveria bassiana, proved very effective against the weevils, including larvae, pupae and adults. A cottage level industry for producing the fungus has been established in Cuba. The technology is low-cost, effective and has been adopted by many farmers. Use of the fungus is particularly attractive because it relieves farmers of the high cost of chemical pesticides.
The use of ants against weevils is another component of the IPM strategy adopted for the sweetpotato weevil, in Cuba. Two species of predatory ants, Pheidole megacephala and Tetramorium guineense, are common inhabitants of banana plantations. Our collaborators at INIVIT have devised a simple system using rolled banana leaves as “temporary nests" to transport the ants from their natural reservoir to sweetpotato fields, where they prey upon weevils and other insects. Setting up colonies in the field 30 days after planting with 60-110 nests/ha can keep weevil infestations at low levels (3-5%).