Apinocis deplanatus

Adults distinguished from other stalk-boring weevils by small size, dark coloration, and association with sorghum and johnsongrass. Larval damage characterized by tunneling at or below soil level in stalk nodes, often accompanied by lodging and drought-stressed appearance of plants. Distinguished from lesser cornstalk borer by lack of silken tunnels and from Diatraea stalk borers by smaller larval size and different tunnel location (near outer stalk surfaces rather than central pith).

Agricultural fields, particularly sorghum and sugarcane plantings. Associated with weedy margins and fields containing johnsongrass. Overwinters beneath plant residues on the ground surface. Infestations more common in dry years and sandy soils.

Southern United States, particularly Texas. Distribution closely tied to sorghum and sugarcane production areas and presence of johnsongrass.

Adults emerge from overwintering sites in early spring. Infestations in sorghum occur after wild grass hosts (johnsongrass) are colonized. Multiple generations possible with generation time approximately 40 days. Activity peaks during dry periods.

Adults feed on young sorghum plants, creating pinpoint holes in leaves. Larvae feed internally on sorghum and sugarcane stalk tissues, tunneling just above or below the soil surface.

• Sorghum bicolor - primary cultivated hostEconomic damage occurs in grain sorghum
• Saccharum officinarum - hostCommon name references sugarcane as host
• Sorghum halepense - wild hostJohnsongrass serves as early-season host before sorghum flowering

Female uses mouthparts to create small puncture at plant base, deposits single egg per puncture. Average fecundity approximately 16 eggs per female. Eggs hatch in 6 days. Larval development occurs within stalk tunnels, with fully grown larvae reaching 5 mm. Generation completed in approximately 40 days. Overwintering stage is adult beneath plant residues.

Adults migrate from overwintering sites to wild grasses in early spring, then disperse to cultivated sorghum later in season. Adults are weak fliers or crawlers. Larvae tunnel in stalks near nodes and outer surfaces, often at or below soil line. When disturbed, larvae may remain in tunnels.

Primary consumer of grasses in family Poaceae. Larval tunneling creates entry points for stalk rot pathogens, indirectly facilitating disease. Population dynamics influenced by presence of johnsongrass, which serves as reservoir host.

Sporadic pest of grain sorghum and sugarcane. Damage includes reduced yield from lodging, stalk breakage, and secondary disease. Economic thresholds not established; control rarely justified. Cultural practices including elimination of johnsongrass and residue management recommended over insecticide application.

• Lesser cornstalk borer (Elasmopalpus lignosellus)Both are stalk-boring larvae of similar size, but E. lignosellus constructs silken tunnels covered with soil particles and has distinct reddish-brown transverse bands on light bluish-green body.
• Sugarcane borer (Diatraea saccharalis)Both infest sugarcane and sorghum stalks, but D. saccharalis larvae are larger (25 mm), creamy white with conspicuous round brown or black spots on body segments, and tunnel in central pith rather than near outer stalk surfaces.
• Southwestern corn borer (Diatraea grandiosella)Similar stalk-boring habit in sorghum, but larvae tunnel in central pith, are larger, and have distinct spotting pattern. Overwinters as larva in stalk rather than as adult on ground.

• pest
• agricultural
• Coleoptera
• Curculionidae
• sorghum pest
• sugarcane pest
• stalk borer
• sporadic pest

• BugGuide
• iNaturalist taxon
• Stalk-boring insect pests - AgriLife Extension Entomology
• Insects that feed on developing grain in the head - AgriLife Extension Entomology