Field Tests with Systemic Insecticides For the Control of Cattle Grubs1

Abstract

Three systemic insecticides were compared during 1957-58 in Mississippi in an effort to establish the relative effectiveness of these materials for the control of the common cattle grub, Hypoderma lineatum (DeVill.). Dow ET-57 (Trolene), administered as a bolus, and Bayer 21/199 (Co-Ral), administered as a spray, when applied in the late summer or early autumn to test groups of Hereford cattle were equally effective in giving significantly better control of grubs than Am. Cyanamid 12880 (Dimethoate). The groups treated with dimethoate, administered as a bolus and as an intramuscular injection, were observed to have significantly fewer grubs than the groups which received no treatment. No significant weight gain due to grub treatments could be shown. The failure to show weight gains may have been due to the fairly low grub population encountered during the period of these tests. The average numbers of grubs per untreated animal on four test herds were 13.1, 16.1,11.0 and 11.9. One herd of brood cows at Poplarville, Mississippi, was treated with phenothiazine for authelmintic action at the same time the grub control materials were administered. Although no weight response attributed to the action of the systemic materials was shown in this herd, a significant weight gain due to the action of phenothiazine was demonstrated.