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Sugarcane Rootstock Weevil. Photo by Juliana Cardona-Duque, University of Puerto Rico.
Scientific Names
Anacentrinus deplanatus
Biology
Sugarcane rootstock weevils are most commonly found infesting sorghum during dry years. The adults overwinter in plant residues. They are commonly found in areas with johnsongrass and will move into sorghum in the spring. When females reach a sorghum plant she pierces deep into the sorghum with her long mouth. She then lays eggs in that small hole and conceals it. Adults can feed on sorghum, but the larvae cause the greatest amount of damage inside the stalk. The larvae hatch and develop inside of the stalk protected from outside forces. They burrow down into the stalk towards the roots. This damage can sometimes allow pathogen entry into the roots.
Positive Identification
Adults are about 1/8″ long. They are dark brown or black beetles. Weevils in general are distinguished by their elongated mouth parts that almost look like a long thin nose coming off their head pointing down. The larvae are legless white grubs that are about 1/5″ long.
Other Important Hosts
Johnson Grass
Scouting Tips
Larvae can be found often feeding at the nodes of the sorghum or near the outside surface of the plant. A plant affected by these insects can often cause a drought stressed appearance and lodging of sorghum plants.
Although we tried to include the most significant pests related to sorghum our tool cannot help you identify every insect found on sorghum. This tool is built to inform you of the most common and significant pests of sorghum in Texas. If the insect you are dealing with does not match the description above then talk to your extension agent or visit this page to look at all the different important potential pest associated with each part and growth stage of sorghum. For management information of a specific pest talk to your local extension office.
Image Details:
Juliana Cardona-Duque, University of Puerto Rico, Bugwood.org
licensed under a Creative Commons Attribution-Noncommercial 3.0 License.