Tobacco worm on pepper plant

Disease name: Tobacco worm on pepper plant

The scientific name: Manduca sexta

Type of disease: insect

Disease family: Sphingidae

(Tobacco worm that infects pepper plants)

• The causes of disease:

The tobacco worm is found on all parts of the pepper plant, from the leaves to the stem, and may extend to the fruits. The tobacco worm is mixed with the green foliage due to its green color, as it cannot be distinguished quickly, so it is only seen during the day most of the time.

• Symptoms of the disease:

The larvae feed by consuming the leaves of pepper plants. The leaves become distorted and often strip the entire leaves to the midrib, causing them to fall. They also attack the stems and fruits, causing holes in them. They also secrete black droppings that cover the plant.

• Disease development cycle:

The life cycle of an adult tobacco worm is approximately 4 to 7 weeks. The tobacco worm feeds mainly on plant sap, which it digests easily and secretes a sugary juice. The sugary substances are an attractive source for black mold, which covers most of the plant leaf with black.

• Conditions suitable for the spread of the disease:

The tobacco worm needs a moderate temperature of about 25 degrees Celsius, and a relative humidity of approximately 60%, where its eggs will hatch.

• Losses resulting from the spread of the disease:

The tobacco worm causes major economic damage to pepper crops, as the larvae feed on immature green fruits and stems, leaving wounds that attract other pathogens. They also reduce the area for photosynthesis and are a vector for viruses.

• Control:

1. Use an organic pesticide that contains Bacillus thuringiensis, which is a bacterium that acts as an infectious poison for the tobacco worm and is considered safe for other plants and animals.
2. Remove infected plants and dispose of them away from the field in case of severe infestation.
3. The worms can be removed manually in the case of mild infestations.

• preventive measures:

1. Till the soil in spring or fall.
2. Continuously monitor the crop for early detection of infection.
3. Good fertilization of the plant helps in resisting the disease.
4. Installing a good irrigation and drainage system for the crop.

• Sources:
• https://extension.usu.edu/pests/research/tomato-tobacco-hornworms
• https://entnemdept.ufl.edu/creatures/field/tobacco_hornworm.htm