In some regions of the U.S., cattle grubs are making a comeback. Cattle grubs are the larval form of heel flies that resemble honeybees in size and shape but are colored like a bumblebee. Heel flies pester cattle, hovering and darting around their legs. Two species parasitize cattle: Hypoderma bovis and H. lineatum.
Control of adult heel flies is nearly impossible as they live only a week or less. Control is aimed at destroying first-stage larvae within the cattle, before they travel to the animals’ backs. This also ensures there will be no flies next season.
Source: Angus Beef Bulletin Extra, October 11, 2023. Link. Treatment in northern regions should be given before December. Treatments in warm southern states should be administered no later than mid-October.