Flies are not just a nuisance just in our lives but also our livestock. Flies act a vector transmitting parasites and diseases to our livestock and poultry. Stable flies bite and blood feed on cattle, causing physical and mental trauma to the livestock. University of Nebraska recorded a daily weight loss of 0.44lbs to both pastured and confined cattle, when exposed to stable flies. Fly controlling methods must be implemented in order to protect U.S. live stock and protect against farming losses. Current prevention includes insecticides, grow regulators, vaccinces, sanitation, etc. These methods however are not full-proof. Currently scientist at University of florida are studing the effects of entomopathogenic fungi on various fly life stages.
Previous work determined that entomopathogenic fungi take approximately 4-6 days to kill an adult fly. Current work published in Journal of Insect Science, Ericka T. Machtinger, E.N.I weeks, and C.J. Garden studied the effect of two entomopathogenic fungi strains on houseflies and stable flies fecundity. They were specifically testing effect on fly egg-laying and pupae development. A total of 4 commercial formulations and 2 strains were tested. Beauveria bassiana found in BontaniGard ES, Mycotrol O, balEnce and Metarhizium brunneum found in Met52 EC.
In order to test fly egg-laying, oviposition balls were treated with each formulation combined with horticultural oil. A control was also used with a mixture of horticultural oil and sterile water. For the houseflies there was a decrease in the number of eggs laid on the etomopathogenic fungi treated balls. Of the balls treated with formulations containing B. bassiana, there was no difference in the amount of eggs laid. While the egg amount on M. brunneum (Met52 EC) treated balls were half as compared to the control. Stable flies’ egg production resulted differently. Balls infected with B. bassiana products showed varying effects. Egg amounts on balls infected with balEnce and BontaniGard ES were equal to the control. While fewer eggs were laid on Mycotrol O and Met52 EC. Concluding the Mycotrol O formulation contains an ingredient, other than B. bassiana, that drives away the stable flies. The Met52 EC formulation containing M. brunneum, proved to be most effective in decreasing egg-laying in both species of flies.
IMMATURE SURVIVAL EXPERIMENT
Fungal formulations were administered onto cloths in low, medium and high doses to determine larval survival. Results for the pupae development in a low dose treatments showed no difference compared to the control. Similarly medium dose B. bassiana treated cloths had no effect on either species larval growth. However larval exposed to Met52 EC or M. brunneum had significantly low pupae formation. Finally high doses of either fungal strain had impacts on fly larvae. As compared to the control, only half of B. bassiana exposed larvae developed. Once again M. brunneum (Met52 EC) treatment produced significantly fewer pupae than all other treatments at any doses, resulting in less than a 16% recovery (of pupae).
The use of M. brunneum to reduce fecundity in flies was more effective than formulations containing B. bassiana. However both strains demonstrated their potential use for in an integrated pest management program. Understanding fungal interactions with insect immune system and development can lead to far more insect applications, resulting in reducation of insecticides/pesticide use.