New Zealand Plant Protection 66 (2013): 303-307
Ascospores of Venturia inaequalis constitute the principal source of primary inoculum for epidemics of apple black spot (scab). Mathematical models that describe ascospore release have been developed in USA, New Zealand and Italy. These models are based upon degree-day accumulation. In this work, the seasonal pattern of released ascospores of V. inaequalis in Vacaria, Brazil, was evaluated. During four apple growth seasons (2009 to 2012) the natural release of ascospores from five orchards was recorded. The cumulative percentage of ascospore release was predicted using three different degree-day models. The released ascospore data showed the best fit to the model developed in Italy, with a start date of 22 August rather than the phenological stage of apple bud break. It is concluded that in regions with warm winter temperatures, models that use bud break to initiate ascospore maturation will tend to underestimate availability of ascospores at the beginning of the apple growth season.
Keywords: Venturia inaequalis, epidemiology, apple scab, Malus domestica.
|Validation of an ascospore release prediction model for apple black spot (Venturia inaequalis)|
R.M. Beresford (1999)
Proceedings of the NZ Plant Protection Conference 52: 148-152
|Evaluation of an ascospore monitoring method for Venturia inaequalis to improve apple black spot fungicide management|
D.W.L. Manktelow and R.M. Beresford (1995)
Proceedings of the NZ Plant Protection Conference 48: 78-82
|Methods for disease assessment in apples, including growth stages, leaf emergence, black spot and powdery mildew|
R.M. Beresford and D.W.L. Manktelow (1995)
Proceedings of the NZ Plant Protection Conference 48: 89-94
Copyright © 2013 New Zealand Plant Protection Society (Inc.).