Are Sweetpotato Weevils (Coleoptera: Brentidae) Differentially Attracted to Certain Colors?

The sweetpotato weevil Cylas formicarius (F.) (Coleoptera: Brentidae) is one of the most serious insects causing damage to sweetpotatoes in the world. Small populations of these insects can cause severe damage to tubers of the crop. Without proper and effective control, weevil populations are likely to cause a huge or complete loss of sweetpotato production in sweetpotato growing areas. Consequently, there is an urgent need for development of an eco-friendly control method for this weevil. Although some control methods are effective, toxic pesticides applications are detrimental and damaging to our environment. Although pheromone traps are currently being used, no effective control of this weevil was achieved. Therefore, studies were carried out as part of the development of a trapping system for C. formicarius. Previous color-choice field tests have confirmed that C. formicarius preferred red traps over gray, green, brown, blue, white, yellow, or black; light red was more attractive than other shades of red. The current study aimed to know whether C. formicarius behavior changes in indoor conditions. Among the eight colored traps tested in the laboratory, green-colored traps were more effective in attracting C. formicarius than all other colors. It attracted nearly double the number of weevils than standard traps presently being used by growers. Based on these results, it is recommended to use green-colored traps to mass trap weevils (by attracting and killing) from sweetpotatoes grown under indoor (storage) conditions.