Pest Of The Month: Giant Sweet Potato Bug
October 1, 2007 
Identification
The Florida Department of Agriculture Department of Plant Industry inspector found a large colony of giant sweet potato bugs (Spartocera batatas) in June 1995 on an Asian cultivar of sweet potatoes (Ipomoea batatas) in Homestead. The plants were badly damaged by the insects. This find represented the first report of S. batatas in the continental US. Subsequent surveys have found the insects sporadically and recently a large colony was found on ornamental sweet potato in Naples.
The giant sweet potato bug is found on several of the Caribbean islands. It is considered a minor pest on sweet potatoes in Puerto Rico. Records from Cuba indicate apparent range of expansion across the island. It is not known when or how the insect was introduced into Florida, but its limited distribution suggests that the introduction was recent at that time.
Adults are a very large obvious bug with a nasty odor. They are entirely dark brown and range from ¾ to 1 inch in length. Lateral angles of the pronotum are rounded and without teeth, and the lateral margins of the pronotum are not expanded. Newborn nymphs are red. They soon lose their bright color and become very dark brown except for the head. Eggs are shaped like tiny fat sausages, and their color varies from gold to brown with age.
The most important host of S. batatas appears to be sweet potato, after which it was named. Other hosts listed in the literature include members of the Solanaceae (tomato, eggplant, potato, and Solanum nigrum, as well as avocado citrus). Observations in Florida indicate that the giant sweet potato bug adults sometimes disperse in high numbers. Thus, transient adults could be collected on a wide variety of plants.
Commercial Pest?
The pest potential of S. batatas in Florida is currently unknown. It is unlikely that it will prove to be a serious pest. In Puerto Rico, S. batatas is abundant, but is not considered to be a major pest, even on sweet potato. Although S. batatas is reported on citrus, there are no reports of damage.
Spartocera batatas has been found in Florida on Asian cultivars of sweet potato grown for their tender shoot tips rather than for tubers as well as ornamental varieties and in home garden situations. The damage to plants is often severe, indicating that some sweet potato varieties may be susceptible to serious injury. In some cases nearby commercial fields of sweet potatoes were not infested suggesting that damage may depend on plant variety. It remains to be seen whether S. batatas will become a pest in commercial fields.
Based on experience controlling squash bugs on pumpkin and winter squash, control may prove to be very difficult. Adequate control may depend on timing of pesticide application, so that young nymphs are exposed to the insecticide. Efficacy data on specific materials are not currently available.
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