Abamectin Formulations Research Articles

Efficacy of abamectin against ivermectin-resistant strain of Trichostrongylus colubriformis in sheep

The efficacy of two formulations of abamectin, i.e. oral and injectable was determined against ivermectin-resistant strain of T. colubriformis in sheep. Twenty-four lambs were infected with 10,000 third stage larvae of ivermectin-resistant strain of T. colubriformis . Twenty-four days post-infection, the lambs were divided randomly into four groups of six animals each according to egg counts. The first group was left untreated and kept as a control. The second group was treated with ivermectin (oral) at 0.2 mg kg −1 body weight. The third group was treated with oral formulation of abamectin at 0.2 mg kg −1 body weight. The fourth group was treated with injectable formulation of abamectin at 0.2 mg kg −1 body weight. Fecal egg count and controlled slaughter tests were employed to determine the efficacy of abamectin (oral and injection) against ivermectin-resistant strain of T. colubriformis in sheep. Reduction in arithmetic mean fecal egg counts achieved by ivermectin (oral), abamectin (oral) and abamectin (injection) was 66, 98 and 76%, respectively 10 days after treatment. Ivermectin (oral), abamectin (oral) and abamectin (injection) reduced arithmetic mean worm burden by 63, 97 and 74%, respectively. The findings demonstrated that abamectin oral formulation was more effective than abamectin injection against ivermectin-resistant strain of T. colubriformis in sheep.

Use of Soil and Trunk Injection of Systemic Insecticides to Control Lace Bug on Hawthorn

Several systemic insecticides are labeled for control of sucking insect pests of trees, and numerous application methods are available for arborists. A field trial was conducted to test 2 formulations of imidacloprid (Pointer 4% and Merit 75 WP systemic insecticides), a formulation of abamectin (Greyhound 1.9%, Bl), and 2 different delivery systems. The delivery systems evaluated were the Kioritz soil injector and ArborSystem's Wedgletip tree injection system. The target pest in this field trial was hawthorn lace bug (Corythucha cydoniae) on hawthorn (Crataegus viridis) trees. The Kioritz is a handheld soil injector made for injecting fertilizer and systemic pesticides into the root zone of trees and shrubs with relatively small amounts of water. The Wedgle tip is an injection system that uses a blunt-edged tip inserted through a small hole through the bark, just to the edge of the sapwood. Wounding to the tree with the Wedgle tip is minimal. This study indicates that systemic insecticides applied through soil injection and trunk injection have potential for controlling sucking insects that feed on ornamental trees.

Performance of abamectin bait formulations against German cockroaches (Dictyoptera: Blattellidae).

Commercial and experimental formulations of abamectin-based baits were evaluated in laboratory and field studies against the German cockroach, Blattella germanica (L.). In continuous exposure tests with adult males, toxicity and presumably bait consumption varied with the design of the bioassay. LT50s ranged from approximately 0.9 to > 41 d for an aerosol gel formulation for males deprived of water for 72 h before the test and for undeprived males tested with alternative food and water, respectively. Dry formulations had lower LT50s than water containing formulations for nondeprived males. There was no difference in bait toxicity between males deprived of food or water, but in arena tests, moist formulations were preferred by mixed-stage populations of cockroaches. Powder formulations were more repellent (approximately 14.9%) than moist formulations (approximately 6.4%) in Ebeling choice boxes assays, but all abamectin formulations had positive performance indices. A powder formulation reduced cockroach trap catch in infested apartments more rapidly when applied to 50, rather than 12 sites, even when the same amount of bait was applied per apartment. When applied at approximately 50 sites as a series of thin smears, an aerosol formulation provided nearly an 80% reduction in trap catch. Other abamectin formulations provided substantial, but smaller reductions in trap catch. Abamectin-based baits can reduce German cockroach populations when properly applied.