Treshold of Leptinotarsa decemlineata in Italy
In central Italy, experiments were carried out to measure the economic threshold of Leptinotarsa decemlineata (EPPO A2 pest) in potatoes. The studies indicated that one egg-mass per plant could lead to a density of 24 4th instar larvae with a subsequent yield reduction of 50%. The authors suggest that a treshold of 25 egg-masses on 50 plants ha-1 sampled in the 3rd or 4th week of May would be sufficient to have a rational margin of recovery.
Pucci, C.; Dominici, M.; Forcina, A. (1991) Population dynamic and economic treshold of Leptinotarsa decemlineata (Say) (Col., Chrysomelidae) in Central Italy.
Journal of Applied Entomology 111, 311-317.