A Detailed Guide to Identifying Symptoms and Control Methods of Goji Berry Powdery Mildew

Goji berry powdery mildew, also known as goji berry leaf spot, mainly damages leaves and fruits. When leaves are infected, circular to nearly circular lesions initially appear, 2 to 4 mm in size, with brown edges and grayish-white centers. Black-gray mold-like growth often appears on the underside of the leaves. Infected fruits also develop similar symptoms. Let's take a look at the control methods for goji berry powdery mildew below!

Symptoms

Goji berry powdery mildew mainly damages leaves. The leaf surface becomes covered with white mold patches (early stage) and powdery patches (later stage). The white mold patches and powdery patches are both the symptoms and the signs of this disease (fungal conidiophores and conidia). In severe cases, the goji berry plant appears entirely white on the outside, which is quite striking. Photosynthesis of the diseased plant is blocked, ultimately causing the leaves to gradually turn yellow and fall off easily.

Causal Pathogen

The pathogen of goji berry powdery mildew is Oidium sp. in the Deuteromycota. In cold regions, the fungus overwinters in the soil as the sexual fruiting body, cleistothecium, along with diseased debris. In warm regions, the fungus mainly uses the asexual conidia for primary and secondary infection, completing the annual disease cycle without a distinct overwintering period. Warm and humid weather or planting site conditions favor disease development, but the fungal spores have drought-tolerant characteristics and can still germinate and infect normally under high-temperature and dry weather conditions.

Conditions for Disease Development

The pathogen of goji berry powdery mildew overwinters as mycelium or conidia on dead branches and fallen leaves of goji berry or in the soil with diseased fruits. The following year, conidia spread via wind and rain to cause primary infection and secondary infection, expanding the damage. Disease is prone to occur in years with high temperature and abundant rain, high soil moisture, humid air, soil nutrient deficiency, and weakened plants.

Control Methods

1. Select improved goji berry varieties, such as Ningqi No. 1. After leaf fall in autumn, promptly clean the goji berry orchard, remove diseased leaves and fruits, and bury them deeply in a centralized manner or burn them to reduce the source of inoculum.

2. Strengthen cultivation management. It is recommended to apply compost fermented with Japanese enzyme bacteria, increase the application of phosphorus and potassium fertilizers, and enhance disease resistance.

3. Starting in June, spray 70% mancozeb wettable powder at 500 times dilution, or 75% chlorothalonil wettable powder at 600 times dilution, 64% oxadixyl wettable powder at 500 times dilution, or 30% Lvdebao suspension concentrate at 400 times dilution, once every 10 days or so, for 2 to 3 consecutive treatments. Stop applying chemicals 7 days before harvest.

Symptoms and Control Methods of Goji Berry Powdery Mildew

What are the symptoms of goji berry powdery mildew? What is the pathogen of goji berry powdery mildew? What are the conditions for the development of goji berry powdery mildew? What are the control methods for goji berry powdery mildew? Today, the editor will share relevant knowledge about goji berry powdery mildew with you.

Symptoms of Goji Berry Powdery Mildew

Also known as goji berry leaf spot. It mainly damages leaves and fruits. When leaves are infected, circular to nearly circular lesions initially appear, 2-4 mm in size, with brown edges and grayish-white centers. Black-gray mold-like growth often appears on the underside of the leaves. Infected fruits also develop similar symptoms.

Pathogen of Goji Berry Powdery Mildew

Cercospora lycii Ell. et Halst., called goji berry tail spore, belongs to the Deuteromycota fungi. The fruiting bodies grow on the underside of leaves; the stroma is small and brown; conidiophores are brown, clustered in groups of 3-7, narrower and lighter in color at the tip, unbranched, straight or with 0-4 knee-like nodes, nearly truncate at the tip, with obvious spore scars, mostly septate, 48-156 x 4-5.5 (μm); conidia are colorless and transparent, whip-shaped, straight or slightly curved, nearly truncate at the base, pointed or relatively pointed at the tip, with many septa, not obvious, 66-136 x 2-4 (μm).

Transmission Routes and Conditions for Disease Development of Goji Berry Powdery Mildew

The pathogen overwinters as mycelium or conidia on dead branches and fallen leaves of goji berry or in the soil with diseased fruits. The following year, conidia spread via wind and rain to cause primary infection and secondary infection, expanding the damage. Disease is prone to occur in years with high temperature and abundant rain, high soil moisture, humid air, soil nutrient deficiency, and weakened plants.

Control Methods for Goji Berry Powdery Mildew

(1) Select improved goji berry varieties. Such as Ningqi No. 1. After leaf fall in autumn, promptly clean the goji berry orchard, remove diseased leaves and fruits, and bury them deeply in a centralized manner or burn them to reduce the source of inoculum.

(2) Strengthen cultivation management. It is recommended to apply compost fermented with Japanese enzyme bacteria, increase the application of phosphorus and potassium fertilizers, and enhance disease resistance.

(3) Starting in June, spray 70% mancozeb wettable powder at 500 times dilution, or 75% chlorothalonil wettable powder at 600 times dilution, 64% oxadixyl wettable powder at 500 times dilution, or 30% Lvdebao suspension concentrate at 400 times dilution, once every 10 days or so, for 2-3 consecutive treatments. Stop applying chemicals 7 days before harvest.

How to Control Goji Berry Powdery Mildew Damage

How to control goji berry powdery mildew? Have you mastered all the control methods for goji berry powdery mildew? Next, the editor will introduce in detail the control methods for goji berry powdery mildew to help everyone grow goji berries better.

Control methods for goji berry powdery mildew:

1. Reasonable dense planting. During the growth period of goji berry, the field needs to maintain good ventilation and light transmission to reduce the chance of powdery mildew occurrence. For overly dense branches and overlapping branches, they can be appropriately thinned, and spray New High Lipid Film to isolate pathogen infection, improve the plant's ability to resist natural disasters and the intensity of photosynthesis, and protect the healthy growth of goji berry.

2. Strengthen field management. Promptly remove diseased residues and fallen leaves from the field, and carry them out of the field in a centralized manner for deep burial or burning, to reduce the sources of powdery mildew infection in the field.

3. Timely spray chemicals for control. At the early stage of powdery mildew damage, spray targeted pesticides together with Hushu Dajiangjun, once every 7-10 days or so, for 2-3 consecutive sprays, to consolidate the control effect, enhance the resistance and immune positive energy of goji berry, and protect its healthy growth with high yield and quality.