Question

Plant disease caused by fungi.
- fungal like organisms

Answer 1

Fungal diseases in plants are caused by various types of fungi and related organisms, which can lead to significant agricultural losses. Below are some common plant diseases caused by fungi and fungal-like organisms:

### Common Fungal Diseases in Plants

1. **Powdery Mildew**
- **Caused by:** Various genera, primarily *Erysiphe* and *Podosphaera*.
- **Symptoms:** White, powdery fungal growth on leaves, stems, and buds.

2. **Rusts**
- **Caused by:** Fungal pathogens from the order *Pucciniales* (e.g., *Puccinia* species).
- **Symptoms:** Orange, brown, or black pustules (uredinia) on leaves, often leading to leaf drop.

3. **Leaf Spot**
- **Caused by:** Various fungi, including *Cercospora*, *Alternaria*, and *Septoria*.
- **Symptoms:** Distinct spots on leaves, which may expand and cause leaf necrosis.

4. **Blight**
- **Caused by:** Fungi like *Phytophthora*, *Botrytis*, and *Colletotrichum*.
- **Symptoms:** Rapid wilting and death of plant tissues, often affecting flowers and stems.

5. **Root Rot**
- **Caused by:** Fungi such as *Rhizoctonia*, *Fusarium*, and *Phytophthora*.
- **Symptoms:** Dark, mushy roots; stunted growth; and overall plant decline.

6. **Downy Mildew**
- **Caused by:** Oomycetes such as *Bremia* and *Peronospora*.
- **Symptoms:** Yellowish-green lesions on the upper leaf surface with a downy growth of the pathogen on the leaf underside.

### Fungal-like Organisms

Fungal-like organisms, primarily belonging to the group of oomycetes, can also cause plant diseases. While they are not true fungi, they share a similar appearance and ecological niche:

1. **Late Blight**
- **Caused by:** *Phytophthora infestans* (an oomycete).
- **Symptoms:** Dark lesions on leaves and stems, leading to sudden plant collapse (notably affected potato and tomato).

2. **Root Rot and Damping Off**
- **Caused by:** Oomycetes such as *Pythium* and *Phytophthora*.
- **Symptoms:** Seedlings can collapse and die; older plants may show root decay.

3. **Downy Mildew**
- (As mentioned above) caused by various *Peronospora* species.

These diseases often thrive under specific environmental conditions, such as high humidity, temperature fluctuations, and poor air circulation. Control methods include proper cultural practices, fungicide applications, and the use of resistant plant varieties.