A: After looking at the leaf under the scope it was evident that your tree has Entomosporium leaf spot, which is a common problem in all members of the rose family including Bradford pear. Spots may enlarge and merge to form larger blackened areas.Tiny black specks, which form spores, can often be observed in the center of each leaf spot. Severe infections often result in early and heavy leaf drop. Heavy leaf drop severely reduces its landscape value and can cause plant death.
While fungicides may be helpful, the disease is not curable; and cultural management practices will probably be more effective. Space plants to improve the air movement around the plants and promote rapid drying of leaf surfaces. If plants are overgrown, consider removing every other shrub to allow for better air circulation. Avoid overhead irrigation as this spreads the spores from leaf to leaf. Trees and shrubs should be irrigated at the root area only. Remove fallen diseased leaves; do not use them as compost or bedding mulch. Establish trees and shrubs do not require the same irrigation and fertilization as lawns. Excessive nitrogen and water promote weak stem growth which will intensify the problem. Severely defoliated plants may need to be pruned to reduce the source of spores and improve air circulation. As a last result, you may need to remove severely diseased plants and replace them with another plant species that is not susceptible to leaf spot.

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