What are the control methods for English ivy leaf spot?

[Symptoms] Large water-soaked brown to dark brown patches form on the leaf margins, often spreading rapidly to 1/3 to 1/2 of the leaf or the entire leaf, and a gray mold layer develops when humidity is high. In some years the outbreak is severe.

[Occurrence pattern] It mainly overwinters as sclerotia in diseased plant debris. In spring the sclerotia germinate and produce conidia for primary infection. It easily becomes epidemic during continuous rain, frequent fog or high humidity, causing large-scale flower drop or plant rot. When the soil temperature is too low or the plants have poor ventilation, this fungus becomes quite rampant and causes severe damage.

[Control methods] (1) Rain-shelter cultivation is recommended. (2) When the greenhouse or open field enters the disease season or at the first onset of disease, spray 40% pyrimethanil suspension concentrate at 1200 times dilution, or 50% Miemeiling wettable powder at 900 times dilution, 50% Sumilex wettable powder at 1500 times dilution, 50% iprodione wettable powder at 1000 times dilution, or 65% thiophanate-methyl and diethofencarb wettable powder at 1000 times dilution. Apply once every 10 days, for 2 to 3 consecutive treatments.

English ivy leaf spot

Symptoms and pathological changes: In the early stage of the disease, very small round dark spots appear on the leaf surface, with an oil-soaked-looking halo. They then enlarge and turn black. Some become angular, and sometimes there is brown sediment around the lesions, with canker spots occasionally also appearing on the petioles. Infected leaves generally do not drop off.

The disease overwinters in diseased tissues. Under warm and humid conditions, the pathogen oozes out of the diseased tissues and is spread by wind and rain or insects, causing primary infection and secondary infection. It is more likely to occur where ventilation is poor and light penetration is insufficient.

Control methods: 1. Select disease-free mother plants for propagation. Thoroughly remove diseased leaves to reduce the source of infection. 2. Strengthen management and enhance plant disease resistance: reasonable close planting, scientific fertilization, and effective measures to keep plants growing robustly and enhance disease resistance. 3. Chemical control: In the early stage of the disease, spray streptomycin sulfate at 3000 times dilution, or 12% lü emulsion concentrate at 600 times dilution, or 20% Longkejun suspension concentrate at 500 times dilution. When the rate of diseased leaves reaches 10%-15%, the chemicals can be 50% carbendazim wettable powder at 1500 times dilution; or 50% thiophanate-methyl wettable powder at 2000 times dilution; or 80% zineb wettable powder at 400 times dilution; the control effect is even better.

1: Anthracnose

Symptom expression: When severely affected, the leaves turn grayish white; it mainly occurs during continuous autumn rain.

Control methods: Place English ivy in a well-ventilated and well-lit location, and do not water directly onto the leaves. If English ivy is found to be infected with anthracnose, spray 50% carbendazim wettable powder at 500 times dilution, once every 7 days, for 3-4 consecutive sprays to control it.

2: Leaf spot

Symptom expression: Leaves wither, yellow and drop, mostly caused by poor ventilation and a stuffy, hot and humid environment.

Control methods: In the early stage of the disease, remove diseased leaves and burn them in a concentrated manner. At the same time, spray 1% Bordeaux mixture, once every 7 days, for 4-5 consecutive sprays.

3: Scale insects

Symptom expression: English ivy grows poorly and can also be contaminated by sooty mold, causing leaves to turn yellow and drop early.

Control methods: Scrape them off by hand. When the affected area is large, 40% omethoate emulsion concentrate at 800 times dilution can also be sprayed.

Summary: English ivy can also suffer from some pests and diseases during care. When growing it, just pay appropriate attention to timely prevention and deal with problems promptly when they are found.