Observations on the over~·intering and \\'inter mortality of the San Jose scale in fruit orchards in Emilia Romagna (Northern Italy)

Abstract

To establish the developmental stage of overwintering San Jose Scale.
Quadraspidiotus perniciosus {Comstock) (Homoptera: Diaspididae) specimens in
Northern Italy, a monitoring progran1me \Vas canied out in Emilia-Romagna
during winter 1998-99, mainly on stone fruit. According to the data collected,
most of the specimens ~pend the greatest part of the winter in the first ~tag e. Only
in 1narch specimens begin lo develop quite quickly to\vards the second and then
the adult stage. The natural winter mortality recorded is significant but ~o i~ the
fact that important differences exist bct,,.,,een years. The importance of these data
for timing insecticide treat1nent also 1.vith IGRs and for choosing the most
satisfactOl)" and suitable \Vinter control strategy of the pest. is discussed.