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UC IPM Home > Homes, Gardens, Landscapes, and Turf > Fruits and Nuts > Diseases
How to Manage Pests
Pests in Gardens and Landscapes
Seasonal development and life
cycle—Pear scab
 The
pathogen overwinters primarily in infected leaves on the
ground. In spring, primary spores are carried by air currents
or splashing water from the infected leaves to flowers, leaves,
or fruit, where they germinate and cause infections. Overwintering
twig lesions may also be an important source of inoculum
in spring. New spores, or secondary spores, are produced
on the infected leaf or fruit surface 8 to 17 days later,
allowing further spread of the disease in the tree until
conditions become too hot and dry. Infection occurs most
rapidly between 55° and 75° F and leaves or fruit must remain
wet continuously for a minimum of 9 hours for infection to
occur. If spring weather is dry from the green tip stage
of bloom through fruit set, scab will usually not be a problem.
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