Our Indian hawthorn bushes seem to have a disease. They were thriving a few weeks ago, and now they are practically bare. The leaves have spots and are turning red and dropping off. What would you recommend as a course of treatment? — Kelly Conlon Gripshover
This is Entomosporium leaf spot, a common disease on Indian hawthorn (Raphiolepis indica) and red tip photinia (Photinia fraseri). Initial symptoms are the appearance of circular, reddish to reddish-purple spots on the new foliage that quickly develop light-gray to dark-gray centers. Part of or the entire leaf may then turn red. Defoliation of severely diseased leaves often follows. The disease needs wet foliage to infect the leaves, and this rainy spring has provided ideal conditions.
Young, expanding leaves are most susceptible to infection, and the disease develops most rapidly during the cool, wet weather of spring and fall.
Management of Entomosporium leaf spot relies on the combined use of cultural practices, resistant varieties and the timely applications of fungicides.
Because disease development requires that the foliage be wet, avoid wetting the foliage when you irrigate, plant in sunny spots where the foliage will dry fast and avoid locations with limited airflow.
Practice good sanitation by raking up the leaves on the ground and discarding them. This will help to lower the amount of inoculum available for dispersal.
Choose resistant varieties when establishing a new planting, but also remember resistance does not imply immunity. Varieties of Indian hawthorn that have some resistance to leaf spot include Eleanor Tabor (light pink), Sonata Spring (white), Snow White or Snow (white) and Clara (white). There are no resistant photinia varieties.
Several fungicides can be helpful in the management of Entomosporium leaf spot, including products with chlorothalonil, myclobutanil, propiconazole or tebuconazole as the active ingredient. Begin fungicide applications as soon as new growth is evident during spring and make repeated applications every 10 to 14 days until hot weather sets in.
Additional applications may be necessary during fall if weather conditions are suitable for disease development.
Last October, I had my in-ground swimming pool demolished and filled in with sand and the broken-up concrete from around the pool. Ryegrass seeds were spread around so that the ryegrass would prevent the sand from washing away. Most of the rye grass looks like it is dying, and I want to lay St. Augustine grass over the area. But I wondered if I should first remove the remaining ryegrass or if the sod can be laid over it. Thank you for always having the answers to our many questions! — Sharon Gunn
It is best to lay sod so that the underside of the sod is in direct contact with the soil. This facilitates root growth into the soil and establishment of the sod. Rake off the ryegrass before laying the sod. Every bit of the ryegrass does not have to be gone — but try to remove most of it. The raked off ryegrass would make a great addition to your compost pile.
I have a pot of blooming tulips. Will they bloom again next year if I save them after they finish blooming? — William Graves
When tulips are forced in pots, they are discarded after blooming. Due to our Deep South climate, even tulips growing in the ground will not reliably bloom again next year and are pulled up and discarded after they finish blooming.
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Dan Gill is a retired consumer horticulture specialist with the LSU AgCenter. He hosts the “Garden Show” on WWL-AM Saturdays at 9 a.m. Email gardening questions to email@example.com.