Violeta T Pardío Sedas

Resistance to amitraz and flumethrin in Varroa destructor populations from Veracruz, Mexico

SUMMARY Dose response curves were determined for amitraz and flumethrin for Varroa destructor collected near Veracruz city, Mexico. Both pesticides were sprayed at known concentrations on female mites using a Burgerjons tower. Probit analysis was performed to calculate mean lethal concentrations (LC50). We estimated the LC50 for amitraz to be 0.526 mg/litre; this estimate is 2.3-times higher than the LC50 baseline established nine years earlier in Mexico. The LC50 for flumethrin was estimated as 0.286 mg/litre, 327-times higher than the LC50 baseline, suggesting the development of resistance.

Two commercial formulations of natural compounds for Varroa destructor (Acari: Varroidae) control on Africanized bees under tropical climatic conditions

It is not uncommon for natural pesticide products to perform inconsistently under different test conditions. Because patented treatments based on natural products have not been tested for the control of Varroa destructor on Africanized hybrid bees under tropical climates in field conditions, an experiment comparing the efficacy of two such natural products was performed. Apilife Var® is a product based on thymol, menthol, eucalyptus and camphor, mixed in a matrix of vermiculite. Hive Clean® contains oxalic acid, sucrose, citric acid, formic acid and propolis. Eighteen Jumbo type hives with Africanized hybrid bees of Apis mellifera from the central region of Veracruz, Mexico, were used. A hive was considered as an experimental unit. Hive Clean® and Apilife Var® treatments consisted of 6 hives each, and the control consisted of 3 hives at an apiary at Tejería, Veracruz, Mexico. The experiment took place from October to December 2013, with an average temperature of 28° C. A Mann-Whitney Rank Sum test was used to separate the corrected percentage of fallen varroa. Apilife Var® was significantly more effective (p = 0.002) with a median number of fallen varroa of 95.8% (mean = 95.5%). The results show that Apilife Var® is a product with a considerable acaricide action on varroa infestations, with an even emission of volatiles under a tropical subhumid climate, with no harm to the bee population on the hive. On the other hand, Hive Clean® showed a median percentage of fallen varroa of 19.7% (mean = 16.7%), indicating lower efficacy levels than those reported by European laboratories under temperate climates and with European bees (A. mellifera carnica). Thus, this product may need to be reformulated and re-tested under tropical climate conditions with Africanized bees.