Using degree-day accumulations and host phenology for predicting larval emergence patterns of the olive psyllid, Euphyllura phillyreae

Abstract

The olive psyllid, Euphyllura phillyreae Foerster is one of the most destructive pests on buds and Xowers of olive tree (Olea europaea L.) in May when the olive growers cannot apply any insecticides against the pest. Temperature-dependent development of the psyllid was studied at constant temperatures ranged 16-26°C. A degree-day (DD) model was developed to predict the larval emergence using the weekly cumulative larval counts and daily mean temperatures. Linear regression analysis estimated a lower developmental threshold of 4.1 and 4.3°C and a thermal constant of 164.17 and 466.13 DD for development of egg and larva, respectively. The cumulative larval counts of E. phillyreae approximated by probit transformation were plotted against time, expressed as the sum of DD above 4.3°C, the starting date when the olive tree phenology was the period of Xower cluster initiation. A linear model was used to describe the relationship of DDs and probit values of larval emergence patterns of E. phillyreae and predicted that 10, 50 and 95% emergence of the larvae required 235.81, 360.22 and 519.93 DD, respectively, with errors of 1-3 days compared to observed values. Based on bioWx depends the development of olive tree phenology; the DD model can be used as a forecasting method for proper timing of insecticide applications against E. phillyreae larvae in olive groves.

Population Dynamics of Cacopsylla melanoneura (Hemiptera: Psyllidae) in Northeast Italy and Its Role in the Apple Proliferation Epidemiology in Apple Orchards

“…Similar studies were built in the past to forecast the occurrence of a particular life stage of a pest with the aim to improve its control (Beránková and Kocourek 1994, Kapatos and Stratopoulou 1999, Kumral et al 2008, Morgan and Solomon 1993, Schaub et al 2005, but never to predict the adult immigration in the orchards.…”

“…For this reason a phenology model will be a useful support for vector management decisions. Many forecasting models have been produced for other psyllid species, using means of driving variables, mainly temperature, and based on developmental thresholds (DT) and degree-days (DD) (Beránková and Kocourek 1994, Kapatos and Stratopoulou 1999, Kumral et al 2008, Morgan and Solomon 1993, Schaub et al 2005. These models refer to some phases of the life cycle and predict when a developmental stage (generally the most damaging stage) will appear.…”

Temperature Dependence of the Extrinsic Incubation Period of Orbiviruses in Culicoides Biting Midges

“…Current EU legislation already permits the movement of unvaccinated animals during periods of minimal Culicoides activity, as measured using light trap networks (see [50] for a review). The earliest date on which it is possible for transmission from vectors to hosts to resume could be estimated from temperature-EIP relationships such as the ones described in the present study using thermal time accumulation models [51] similar to those used already to forecast crop growth [52] and the development of insect pests [53] , provided the temperature of the environment in which the vectors rest after feeding is known. Such an approach has already been suggested for West Nile virus in the United States [54] .…”

Life history and demography ofPsyllaephagus zdeneki(Hymenoptera: Encyrtidae), a potential candidate for biological control of olive psylla,Euphyllura pakistanica(Hemiptera: Psyllidae)

“…In comparison, pre-imaginal development was reported as 30.2 days for females and 20.2 days for males for P. pistaciae (Mehrnejad and Copland 2006b), as 28.5 days (at 21.58C) for P. yaseeni females (Patil et al 1993), and as 22.6 days (at 208C) for P. bliteus (Daane et al 2005). The pre-imaginal development time for P. zdeneki was lower than those reported for some olive psyllid species; for example, E. olivina was reported as having an incubation period of 10 to 15 days and pre-imaginal development of 24 to 35 days under optimum conditions (Tzanakakis 2003;Kumral, Kovanci and Akbudak 2008). There is no published information, which we are aware of, for the development times of E. pakistanica.…”