Weather for 2016 continues to be unpredictable. And although bad weather can damage crops, it does little to stop the pathogens that plague pome fruit. The past few weeks of cool weather has slowed things down, but not scab—at least, not completely. All plants, insects, and pathogens develop in response to temperature–The warmer the weather, the more quickly they develop; Conversely, the cooler the temperature, the slower they develop.
When controlling scab, it is important to realize that ascospores don’t all ‘shoot’ at once. Instead, as the fruiting bodies (called pseudothecia) develop on the leaf litter, they gradually mature and release ascospores over the course of several weeks. The rate of ascospore maturation follows a bell curve—they increase, reach a peak, and then decrease. Evolution has had a very long time to get this right. As a result, ascospore release is perfectly timed to coincide with a large amount of highly susceptible tissue. Think about it: If you shoot all your spores too early you’ll probably miss and you’ll die. If you shoot all your spores too late, something else has already eaten your food, and you’ll still die!
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Development in Phenological Stages
