Evaluation of Phloxin B as a photoinsecticide on immature stages of the Hornfly Haematobia irritans

FILIBERTI, A.; RABOSSI, A.; ARGARAÑA, C.; QUESADA ALLUÉ, LUIS A.

AUSTRALIAN JOURNAL OF ENTOMOLOGY

Wiley-Blackwell

Año: 2009 p. 73 - 78

1326-6756

The use of photoactive substances for controlling adult or immature stages of insect pests is an attractive alternative to chemical insecticides. Phloxine B is an environmentally friendly xanthene derivative that is safe for mammals but toxic for dipterans. In this study we tested the effect of phloxine B as a phototoxic larvicide against immature stages of the blood-sucking horn fly, Haematobia irritans (L.).          The mortality rate of phloxine B was very low in the dark during the larval stage (100 hours) unless a 0.5 mM dye concentration was used. However, a high mortality rate was attained when larvae III were transferred to containers exposed to 5000 lux during the last two hours before pupariation. This was concentration-dependent up to 0.1 mM phloxine B. After a two-hour larval exposure to light the phloxine B LC50 was 0.043 mM. These results indicate that H. irritans larvae are very sensitive to this dye, which in turn seems a promising component for larvicide formulations to control horn flies. Key words: photosensitising agents, xanthene, larvicide.