A forecasting model to predict the kiwifruit bacterial canker infections was developed in New Zealand. In 2012 such forecasting model was intended to be validated in the kiwifruit growing areas of Emilia-Romagna Region. Model, using hourly temperature and leaf wetness data, calculates the bacteria multiplication rates (M). M values were three days accumulated (actual + two preceding days) to provide a daily Risk Index R whenever a rain event (> 1mm) occur during the growing season. Validation was carried over 2012-2014, exposing micro-propagated potted kiwi plantlets under untreated infected plants from march untill november. Every week, after being exposed, 18 Plantlets (9 Hayward and 9 Tomuri) were removed and placed in climate chamber with 24 hours wetness duration. Afterwards, part of them were placed in greenhouse at 15-18°C temperature to check for symptom occurrence, and the remaining analyzed by both pathogen isolation on selective growing media and PCR on isolated bacterial colony. Analysis were carried out as soon as kiwi plantlets were remove from the field (T0) and after 7 days (T7). In 2012 an 2013, the experiment was carried out in two kiwi orchard of the cv Hayward (1 located in the plain and 1 in the hillside), while in 2014 the experiment was carried out on 2 A.deliciosa and 1 A.chinensis orchards. Over the years 2012-2014, symptoms on plantlets were always observed from march to the first week of june. In the same period of time disease symptoms occurred in the unprayed kiwifruit plot, confirming what observed in potted trap plants. However diagnostic analysis showed that bacteria can be detected in potted trap plants throughout the year (particularly in 2013 and 2014), except some sporadic week during summer even without a rain event. Validation experiment using trap plants permitted to effectively validate the forecasting model during springtime (from march to june) showing a robust correspondence between the infection index R and the symptom occurrence. In fact, all the disease symptoms occurred in coincidence of R infection Index higher than 15, value that can be taken as action threshold. At the same time, molecular analysis as well showed a clear relationship between the infection index R and the bacterial inoculum contaminating the trap plants during the growing season.
Validation of New Zeland Psa forecating model in Emilia Romagna Region (Italy) / Antoniacci, Loredana; Bugiani, Riccardo; Rossi, Rossana; Calzolari, Alessandra; Alessandrini, Ambra; Gozzi, Rossella; Spinelli, Francesco; Donati, Irene; Buriani, Giampaolo; Mauri, Sofia. - STAMPA. - (2015), pp. 40-40. (Intervento presentato al convegno 2nd International Symposium on Psa tenutosi a Bologna nel 10-13 june 2015).
Validation of New Zeland Psa forecating model in Emilia Romagna Region (Italy)
ALESSANDRINI, AMBRA;SPINELLI, FRANCESCO;DONATI, IRENE;BURIANI, GIAMPAOLO;MAURI, SOFIA
2015
Abstract
A forecasting model to predict the kiwifruit bacterial canker infections was developed in New Zealand. In 2012 such forecasting model was intended to be validated in the kiwifruit growing areas of Emilia-Romagna Region. Model, using hourly temperature and leaf wetness data, calculates the bacteria multiplication rates (M). M values were three days accumulated (actual + two preceding days) to provide a daily Risk Index R whenever a rain event (> 1mm) occur during the growing season. Validation was carried over 2012-2014, exposing micro-propagated potted kiwi plantlets under untreated infected plants from march untill november. Every week, after being exposed, 18 Plantlets (9 Hayward and 9 Tomuri) were removed and placed in climate chamber with 24 hours wetness duration. Afterwards, part of them were placed in greenhouse at 15-18°C temperature to check for symptom occurrence, and the remaining analyzed by both pathogen isolation on selective growing media and PCR on isolated bacterial colony. Analysis were carried out as soon as kiwi plantlets were remove from the field (T0) and after 7 days (T7). In 2012 an 2013, the experiment was carried out in two kiwi orchard of the cv Hayward (1 located in the plain and 1 in the hillside), while in 2014 the experiment was carried out on 2 A.deliciosa and 1 A.chinensis orchards. Over the years 2012-2014, symptoms on plantlets were always observed from march to the first week of june. In the same period of time disease symptoms occurred in the unprayed kiwifruit plot, confirming what observed in potted trap plants. However diagnostic analysis showed that bacteria can be detected in potted trap plants throughout the year (particularly in 2013 and 2014), except some sporadic week during summer even without a rain event. Validation experiment using trap plants permitted to effectively validate the forecasting model during springtime (from march to june) showing a robust correspondence between the infection index R and the symptom occurrence. In fact, all the disease symptoms occurred in coincidence of R infection Index higher than 15, value that can be taken as action threshold. At the same time, molecular analysis as well showed a clear relationship between the infection index R and the bacterial inoculum contaminating the trap plants during the growing season.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
