Correct Option: B. Cocoa Detailed Explanation: Swollen shoot disease is a viral disease that primarily affects cocoa plants (Theobroma cacao). This disease is caused by the Cocoa swollen shoot virus (CSSV), which is transmitted by mealybugs and other sap-sucking insects. The disease is characterized by the swelling of the stems and petioles, leading to stunted growth, reduced yield, and ultimately, the death of the plant if not managed properly. Why Cocoa is Affected: 1. Host Specificity: The Cocoa swollen shoot virus specifically targets cocoa plants. It has evolved to infect this species, making cocoa the primary host for this disease. 2. Transmission: The virus is spread by insect vectors, particularly mealybugs, which are commonly found in cocoa plantations. When these insects feed on the sap of infected plants, they acquire the virus and can transmit it to healthy plants. 3. Symptoms: Infected cocoa plants exhibit symptoms such as swollen stems, leaf curling, and reduced pod production. These symptoms can severely impact the health of the plant and the economic viability of cocoa farming. Why the Other Options are Incorrect:

• A. Groundnut: Groundnut (Arachis hypogaea) is not known to be affected by swollen shoot disease. Instead, groundnuts are susceptible to other diseases such as leaf spot and root rot, but not the specific viral infection associated with swollen shoot disease.
• C. Corn: Corn (Zea mays) is primarily affected by diseases such as corn smut and various fungal infections. It does not experience swollen shoot disease, which is specific to certain plants like cocoa.
• D. Cotton: Cotton (Gossypium spp.) is affected by a range of diseases, including cotton wilt and bacterial blight, but it is not a host for swollen shoot disease. The viral pathogens that affect cotton are different from those that cause swollen shoot disease in cocoa.

Summary of Key Points:

• Swollen shoot disease is primarily associated with cocoa plants due to the Cocoa swollen shoot virus (CSSV).
• The disease is transmitted by mealybugs and is characterized by swelling of stems and stunted growth.
• Other options (groundnut, corn, cotton) are not affected by swollen shoot disease and are susceptible to different diseases.
• Understanding the specific diseases affecting different crops is crucial for effective agricultural management and disease control.

Revision Summary:

• Swollen shoot disease is common in cocoa plants (Theobroma cacao).
• Caused by the Cocoa swollen shoot virus (CSSV) and transmitted by mealybugs.
• Symptoms include stem swelling and reduced yield.
• Other crops listed (groundnut, corn, cotton) are not affected by this disease.