ASIAN GREY WEEVIL (AGW): Myllocerus undatus Marshall
Order – Coleoptera: Family – Curculionidae

DISTRIBUTION: AGW is an Old World weevil native to Sri Lanka, but may be distributed over a wider area within Asia. Introduced populations in the United States are known only from Florida.

DESCRIPTION: Eggs (fig. 5) are small (0.7-1.0 mm), ovoid, and cream colored, gradually changing to darker beige when close to hatching. Larvae (fig. 4) when mature are 6.5-8.5 mm long, grub-like (C-shaped), creamy white with brown heads, and legless. Pupae are creamy white and resemble adults, and are found in earthen cells (pupal chambers) in the soil presumably near the host plant. Adults (fig. 1 & 2) are 7.0-8.5 mm long and whitish-grey with an irregular pattern of dark spots dorsally. The snout is short and quadrate and slightly expanded towards the apex. There is often a yellowish-orange patch below and behind each eye. The antennae are clubbed and elbowed. All the femora are armed with one to three spines on the lower surface near the distal end (fig. 3).

HOSTS: Extremely polyphagous. At least 68 different hosts have been recorded, including: palms, citrus, crepe myrtle, ficus, hibiscus, lantana, cotton, and oaks.

DAMAGE: Adult feeding is usually evidenced by an irregular pattern of notches cut along leaf margins and along veins (fig. 6). AGW larvae may cause extensive damage to their host plants by feeding on the roots.

INSPECTION TIPS: Look for the characteristically notched leaves caused by adult feeding (fig. 6). Examine the roots of the host plant and associated soil for larvae and pupae. Many specifics regarding egg deposition are currently unknown. Eggs are laid in the soil, presumably near the adult’s host plant, and may be discovered if inspected closely (fig. 5). In Florida, AGW tends to be more common in landscape settings and less common in crop production fields. The reason for this is currently unknown, but may be related to pesticide use.

LIFE CYCLE: Very little is known about the biology of AGW; however, they are expected to complete multiple generations in Arizona if they become established here. Laboratory reared populations in Florida completed a life cycle in 50.6 days at 27o C (80.6o F.). Under these conditions the egg stage lasted 6.7 days, the larval stage 35.8 days, and the pupa stage 8.1 days.

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