The English ivy in your home garden is under the threat of invasion by fungi that cause powdery mildew. Due to particular cultural preferences, expect powdery mildew during warmer temperatures. Become familiar with what to look for on your ivy as well as how to respond should an infection occur for the continued protection and health of your home landscape.
Vigorous, healthy English ivy has a much greater likelihood of avoiding or fighting off powdery mildew than neglected plants with diminished health. Grow English ivy in areas that offer plentiful shade like locations facing east or north, according to the Clemson University Extension. Providing shade becomes easier when growing English ivy in hanging containers that you may position away from excessive sunlight. English ivy thrives in moist soil high in nutrients and organic content.
Powdery mildew on English ivy is caused by a variety of fungal pathogens that spread sporadically in air, germinating in ideal conditions once they land on susceptible host plants. Spreading begins when temperatures exceed 60 degrees Fahrenheit, primarily during the spring, according to the Clemson University Extension. For successful germination, spores prefer high humidity but do not need standing water, an uncommon trait among fungi that generally thrive in waterlogged soils and wet surfaces. Cool days and balmy nights usually see the development of powdery mildew on English ivy.
Powdery mildew fungi grow on English ivy plant surfaces, most prevalently on the densely packed leaves closest to the ground, according to the Purdue University Cooperative Extension Service. Sometimes, but not in every case, a mildew that resembles a white-hued powder becomes apparent. As the disease progresses, fungi partially insert themselves in plant tissue, parasitically removing nutrients. This extraction of tissue fluids leads to stunted plant growth, malformation and discoloration of leaves and overall diminished vigor, according to the Clemson University Extension.
Since the shaded conditions English ivy prefers promote fungal development, keeping your plants thinned out is essential; create better air circulation by pruning dense areas of ivy, according to the Purdue University Cooperative Extension Service. Avoid overhead irrigation, particularly at night, to lower moisture content. Remove and destroy affected plant parts to prevent disease spread. Always sanitize pruning tools between each snip and from use on one plant to the next to inhibit transfer of pathogens.
For chemical control of severe powdery mildew problems on English ivy, apply a fungicide as soon as symptoms are apparent. Apply a fungicide with the active ingredient myclobutanil, triadimefon or chlorothalonil for a longer-lasting control than other options, according to the Clemson University Extension. For a gentler control with lower toxicity toward plants and humans, use botanically based oils like neem oil or horticultural oil. For assistance and advice particular to your region, contact a licensed professional or your local county extension agent.