Efficacia di Beauveria bassiana nel contenimento della dorifora della patata

The Colorado beetle is the potato target insect: the occurrence of insect populations resistant to synthetic molecules and the interest towards nonchemical control measures promote the research on eco-compatible management of crops. From this point of view, near Turin, in 2002, trials have been carried out using, against Leptinotarsa decemlineata (Say), the bioinsecticide Naturalis®, a concentrated suspension containing spores of the fungus Beauveria bassiana (Balsamo) Vuillemin recently put on the Italian market; the strain tested does not produce toxins. So far, the use of this insecticide has been licenced for use on a series of different crops, still not including potato. It was tested in comparison with the insect growth regulator teflubenzuron. In the field, a randomized pattern with four repetitions per treatment has been created. Dosages and application intervals have been selected in accordance with instructions given by producers with regard to crop type. Field surveys have been carried out every 10 days in the period 5th of June / 5th of July. Presence of eggs, larvae and adults, defoliation rate and surveys on yield were evaluated using statistical elaboration. Results showed a good efficacy of B. bassiana, especially against eggs and larvae, and confirmed previous data concerning teflubenzuron prolonged efficacy.