The Andean potato weevil is a severe pest of potatoes in the high Andean mountains of South America. The pest complex contains mainly the genus Premnotrypes (Curculionidae). The most common species are P. suturicallus Kushel in central Peru; P. latithorax (Pierce) in Bolivia and southern Peru; and P. vorax (Hustache) in northern Peru, Ecuador, Colombia, and Venezuela.  Rhigopsidius tucumanus Heller and Phyrdenus muriceus Germar also contribute damage and are mainly found in Bolivia.  Growers near commercial centers often use pesticides, but can nevertheless experience up to 30% tuber damage.  In the high Andes, subsistence farmers can suffer 50% or greater tuber damage, since they generally cannot afford insecticides.

It is common for farmers to use a modest trapping method to impact beetle populations.  Early in the season potato leaves are placed on the ground around the perimeter of the field.  These leaves attract scores of immigrating and emigrating weevils,  which are then sprayed with insecticide or collected and disposed.  This method relies initially on an attraction to potato kairomones, but we hypothesize that the attraction is enhanced as weevils begin to feed.  In these experiments we tested this hypothesis with a laboratory bioassay and field-collected weevils.

Small potato seedlings, seedlings protected with screening, or live beetles were placed in 500 mL Erlenmeyer flasks.  The flasks were buried in cardboard boxes with moist sand flush to the mouth.  Weevils were released in the boxes and their location recorded 24 hours later.  Free seedlings attracted significantly more beetles than seedlings protected with screening, suggesting that an aspect of recruited-weevil feeding influenced the attraction.  Further experiments that determined the exact mode of attraction will be presented.  Our goal is to develop a cost-effective and environmentally sound mass-trapping system.