Introduction:

Bactericera cockerelli is an insect pest that damages Solanaceous crops, mainly potato (Solanum tuberosum L) and tomato (Solanum lycopersicum Mill). The B. cockerelli management has been the chemical control, however, attempts have been made to implement other control strategies with less toxic insecticides for the environment, human health, and non-white insects. This implementation consists of including biological control organisms such as predators, parasitoids, insecticides of natural and botanical origin, entomopathogenic fungi and chemical insecticides with less impact on beneficial fauna. In order to deepen these interactions, the present work determined the median lethal concentration (LC50) of insecticides on B. cockerelli populations and its parasitoid Tamarixia triozae. With these data, the selectivity percentage (SP) of different insecticides with the parasitoid T. triozae was calculated.

Method:

Bioassays were performed using the immersion method evaluating six different insecticides; Profenofos and Cypermethrin of chemical origin; Azadirachtin and AEC (Essential oils of citrus with cinnamon and soap of vegetable oils) of botanical origin; strains of Beauveria bassiana and Metarhizium anisopliae from biological origin. With the data obtained, selectivity was determined using the Selectivity Ratio (PS), dividing the LC50 of the product over the natural enemy by the LC50 of the product over the pest insect, where values equal to or greater than one indicates selectivity.

Results:

The insecticide products evaluated showed mortality in B. cockerelli and its parasitoid T. triozae. The lowest selectivity ratio was for Cypermethrin (PS = 0.01) and only M. anisopliae showed selectivity with T. triozae when obtaining a value of PS = 3.58. The other insecticides showed PS values less than one, so they were considered non-selective for parasitoids.

Conclusion:

The lowest proportion of selectivity was for Cypermethrin (PS = 0.01) and only M. anisopliae showed selectivity with T. triozae when obtaining a value of PS = 3.58. The other insecticides showed PS values lower than one, so they were considered non-selective.

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