Questionleaves of photinia are spotted and dropping. Indian hawthorne on other side of yard doing the same thing. Any ideas?
AnswerSince both the photinia and hawthorne are in the Rose family, it is most likely that your plants have leaf spot.
Leaf spot, caused by the fungus Entomosporium maculatum, is a widespread and destructive disease of red tip (Photinia fraseri), India hawthorn (Rhaphiolepis indica), some pear cultivars (Pyrus sp.) and several other members of the rose family. This disease is most damaging to plants in the landscape and nurseries during periods of cool, wet weather and when active growth is occurring.
Symptoms include tiny, circular, bright red spots on both the upper and lower surfaces of young expanding leaves are the first symptoms of Entomosporium leaf spot. Numerous small spots may coalesce into large maroon blotches on heavily diseased leaves. Leaf spots on mature leaves have ash brown to light gray centers with a distinctive deep red to maroon border. Tiny black specks, spore producing bodies of the fungus, can often be observed in the center of each leaf spot. Spots similar to those on the leaves can develop on leaf petioles and tender stem growth during prolonged periods of cool, wet weather.
Low levels of leaf spot usually cause little more than cosmetic damage but maintain a source of spores for future infections. Severe infections, however, often result in early and heavy leaf drop. Heavy leaf drop severely reduces the landscape value of red tip and can cause plant death. Some cultivars of India hawthorn are as severely affected as red tip.
Disease Cycle
Spots on the leaves and young shoots are important in the survival of the Entomosporium leaf spot fungus. Fallen, diseases leaves are less important sources of the fungus. Masses of spores are released during periods of wet weather from the fungal spore producing structures in the center of the spots from late winter through much of the year except during the hot periods of summer. These spores are spread to healthy foliage by a combination of splashing water and wind. New leaf spot symptoms appear within 10-14 days after a wet infection period.
Control
If possible, remove fallen diseased leaves. Do not water or fertilize plants any more than necessary to avoid promoting excess new growth. Also, reduce pruning during the summer which promotes continual new growth. Severely defoliated plants may need to be pruned heavily to have a small, easier to spray plant, to reduce the source of spores and improve air movement. It may be necessary to remove severely diseased plants that have also been damaged by cold injury and replace them with another plant species that is not susceptible to leaf spot.
Several fungicides may also be help in the management of leaf spot in the landscape. Since different governments have regulations about fungicide usage, I am not sure of which may be available to you.
In the USA, there are retail fungicides by the tradenames of
Banner
Daconil
Chlorothalonil
Fore
Bayeleton
Funginex EC
You may seek help at your local garden center for fungicides in your area that may be effective in controlling this disease caused by this fungal species (_Entomosporium maculatum_). The disease is often refered to as "Entomosporium Leaf Spot."