In the landscape industry, plant diseases and pests are a common occurrence. An experienced commercial contractor should be prepared with the expertise and knowledge needed to combat these diseases and pests, to ensure a property’s landscape thrives throughout the year. Here are some of the plant diseases and pests we commonly see and how you can prevent and treat them.

1. Sooty Mold

Sooty mold is caused by insects excreting honeydew onto plant leaves and other surfaces, such as outdoor furniture, and can be identified by its dark, soot-like appearance. It’s especially common in warm climates and during drought. Although sooty mold doesn’t directly infect plants, it can inhibit the plant’s sunlight exposure which can inhibit plant growth. To control sooty mold growth, your commercial contractor should utilize an effective pest management program to reduce insect populations.

2. Fusarium Wilt

Fusarium wilt is one of the most devastating and costly plant diseases, most often affecting Canary Island palms here in Southern California. When infected with Fusarium, a type of fungus, a canary palm’s leaves turn yellow and then brown, and it can die within a few months depending on the surrounding climate. It’s important to dispose of these palms properly, so as not to increase risk of spreading Fusarium to other palms, and avoid planting another palm in the same location since the soil most likely contains remnants of the fungus.

3. Fire Blight

Fire blight is a disease that commonly affects Ornamental Pear trees as well as Camphors, which can cause the branches can cause the fruit or tree leaves to turn black when infected. To control fire blight, your commercial contractor should monitor the fruit trees regularly (if tree maintenance is included in your contract) to identify and remove infected areas, use treatments that control the disease, and the proper maintenance techniques needed.

4. Aphids

Aphids, plant-damaging pests, are a common issue for landscape professionals in Southern California. If untreated, they can destroy entire affected plants and surrounding plants, and lead to sooty mold growth. Implementing proper pest management techniques and constant monitoring are essential to prevent and/or control current aphid infestations.

5. Thrips

Thrips are plant-feeding insects which cause discoloration of plant leaves. While thrips may not threaten the life of a plant, the damage is often unsightly. If your commercial contractor encounters thrips within your landscape and significant damage is caused, it may be a good time to consider landscape renovations that are more sustainable. If damage is not that substantial, there are integrated pest management programs that can be effective in controlling thrips.

6. Oleander Leaf Scorch

Oleander Leaf Scorch is a disease that causes Oleander shrubs to decline and die within 3 to 5 years of being infected. It’s a common plant disease in Southern California, and one that landscapers are encountering more frequently in recent years. Symptoms of Oleander Leaf Scorch develop year round but are more noticeable in late Spring and early Summer when weather is warm, and include yellowing and wilting of leaves. As the disease progresses, other branches will be affected, and the plant will eventually die.