ABSTRACT
Clitoria fairchildiana Howard (Leguminosae, Papilionidae) used in urban arborization and roads, is stripped by caterpillars of Urbanusa cawoios (Lepidoptera: Hesperiidae) in occasional sudden appearances. This study tested the pathogenicity of Bacillus thuringiensis to var. Kurstaki, in splash dust formulation, in dosages of 0, 250, 750 and 1,500 g/ha. The product was sprayed on the leaves of "sombrero tree" and it was offered to the caterpillars. Ten caterpillars of third stage and 10 caterpillars of fifth stage were used per dosage in 4 repetitions, kept in ambient temperature. Morphological and behavioral alterations of the insects were observed and recorded, and every 12 hours mortality was also registered. Signs of susceptibility were noticed 10 hours after the ingestion of the contaminated food. There was observed loss of appetite, abandonment of food, reduction of movements until stoppage, flaccidity and loss of larval agility. The coloration of the epidermis changed and the consistency of the excrements turned watery (diarrhea). The first deaths were observed 12 hours after the ingestion of the food. The dosages of 250 and 750 g/ha were effective for the caterpillars of fifth and third stages, respectively, not differing in results from the highest dosage used (1,500 g/ha). B. thuringiensis was efficient in the control of caterpillars of U. acawoios.
KEY WORDS:
Biological control;
Clitoria fairchildiana
; insecta; caterpillar-of-sombrero-tree.