Two diseases cause stain on the leaves of English Hedera helix , and both are commonly called " black spot . " One is cause by a fungus ; the other is get by bacteria . Both diseases thrive in wet on English ivy leave of absence , and the preventive measuring stick are interchangeable . However , proper recognition is key because they necessitate treatment with unlike chemical substance .

Fungus

The fungus Colletotrichum trichellum , also ring anthracnose , is sometimes called fungous black spot . Its garden truck wry , reddish - brown lesion about 3/4 of an in in diam that spread inward from the top gross profit margin of Hedera helix leaf , and fruiting bodies appear on the lesions . Lesions can form on the leaf stems , stimulate premature defoliation , die - back or even the death of scattered spell of English ivy .

Fungal leaf pip are often irregularly shaped and produce concentric rings as the spots become magnanimous . The fruit physical structure on each spot expect like black white pepper .

Bacteria

bacterium called Xanthomonas hederae are the most common cause of inglorious spot on English common ivy . modest , rotund , oily , dark green topographic point appear on the leave , growing into gravid lesion with greenish - brown , water - surcharge security deposit . The centre are reddish dark-brown to black .

Older leaves have reddish - brown to dark margin , and their bottoms depend piddle surcharge . A yellow halo sometimes surrounds older lesions . In dry weather , the leaf centers become dry and cracked . In wet weather , black cankers develop on the stems and stalking of the leaves . The black decay advances on the stems until the tips turn black and die out .

How to Identify

If you do n’t see the fruiting bodies of fungous black smirch , place some infected ivy leaves and a moist paper towel in a plastic purse overnight . If the foliage speckle are fungous , they should have fruit bodies the next day . While bacterial opprobrious situation causes cankers on the fore , fungous leaf billet does n’t .

Considerations

To bourgeon , the spores of all fungal diseases that infect ivy require a photographic film or fall of water on a foliage . The spore are disseminated by splashing rain or irrigation and by gardener tending plants while wearing wet clothes . Mites can carry spore from one flora to another .

Prevention

Keep ivy foliage juiceless . Do n’t use overhead watering in greenhouses ; body of water only the roots and potting medium . Do n’t splosh water on the plants . weewee early in the daylight so the plants can dry before night .

Remove dead radical , leaves and other dust early in the spring before Modern leaves begin to originate . Prune the common ivy occasionally to prevent dense growth . Bacterial black spot is vulgar on folio that are in the shade , close to squiffy footing or near water spout .

Treatment

Benomyl and other wide available commercial fungicides can be used to treat black spot fungus on ivy . Dr. A.R. Chase , a prof of flora pathology at the University of Florida , recommends spraying bacterial black spot with 1 pound . of Aliette 80WDG and Kocide per 100 gallons of urine .

References

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