8. Name some common plant diseases their causative microorganisms mode of transmission with the help of the figures.

Here are some common plant diseases along with their causative microorganisms and modes of transmission:

1. Powdery Mildew (caused by fungi in the order Erysiphales):
   • Causative Microorganism: Fungi belonging to the order Erysiphales, such as Blumeria graminis (wheat powdery mildew) and Podosphaera xanthii (cucurbit powdery mildew).
   • Mode of Transmission: Powdery mildew is typically spread through airborne spores produced by infected plants. These spores can be carried by wind currents and deposited on healthy plants, leading to new infections.

2. Late Blight (caused by the oomycete Phytophthora infestans):
   • Causative Microorganism: Oomycete pathogen Phytophthora infestans.
   • Mode of Transmission: Late blight is commonly spread through airborne spores, known as sporangia, which are produced on infected plant tissues, such as leaves and stems. Rain splash, wind, and human activity can contribute to the dispersal of these spores, leading to the spread of the disease.

3. Citrus Canker (caused by the bacterium Xanthomonas citri):
   • Causative Microorganism: Bacterium Xanthomonas citri.
   • Mode of Transmission: Citrus canker is primarily spread through the movement of contaminated plant material, such as infected leaves, fruits, or pruning tools. Rain, wind, and insects can also contribute to the spread of the bacteria between plants.

4. Tomato Yellow Leaf Curl Virus (caused by viruses in the genus Begomovirus):
   • Causative Microorganism: Viruses in the genus Begomovirus, such as Tomato yellow leaf curl virus (TYLCV).
   • Mode of Transmission: Tomato yellow leaf curl virus is primarily transmitted by whiteflies (Bemisia tabaci), which feed on infected plants and then transmit the virus to healthy plants when feeding on them.

These are just a few examples of common plant diseases and their causative microorganisms, along with their modes of transmission. Effective management and control strategies, such as crop rotation, sanitation, and the use of resistant plant varieties or fungicides, are essential for minimizing the impact of these diseases on agricultural crops.