Ascospore Maturity Model Previous Year's Data!

The Ascospore Maturity Model is a tool that predicts the maturity of ascospores of the apple scab pathogen at a given time. Since infection is caused by ascospores liberated by rain events, the model can be used with weather data to predict the possible onset and end of primary apple scab infection.

Click on the name of the location below to obtain an estimate of spore maturity for a given region.

Guidelines for using the model and interpreting the results

1. Compare the predicted % ascospore maturity with rain events for your location.

2. Infection events are likely to occur when high percentages of ascospores are mature and rain events occur

3. When 95% of ascospores are mature, essentially all ascospores will be released after a daytime rain event exceeding 1/10th of an inch (0.25 cm) with a temperature over 50F (10C).

Note of Caution: Ascospores are tiny, produced in astronomical numbers, and only one successful spore is needed to infect and begin the epidemic.

Brief Model Description and History:

In short, the model uses degree-days (base = 32F), accumulated from an early apple bud phase (green tip), to estimate the cumulative maturity of ascospores . The model was initially developed at the University of New Hampshire and was refined in subsequent studies conducted in New York and Norway over a period of more than 25 years. The model provides an estimate of ascospore maturity that is suitably accurate for many decisions that are made with respect to controlling apple scab. Click here for guidance on how to interpret the model estimates and general information on epidemiology and control of scab.