
Appearance
Tomato hornworms are closely related to the tobacco hornworm. This confusion arises because caterpillars of both species feed on the foliage of various plants from the family Solanaceae, so either species can be found on tobacco or tomato leaves, and the plant on which the caterpillar is found does not indicate its species.The larvae of these species can be distinguished by their lateral markings: Tomato hornworms have eight V-shaped white markings with no borders; tobacco hornworms have seven white diagonal lines with a black border.
Additionally, tobacco hornworms have red horns; tomato hornworms have dark blue or black horns. Furthermore, the caterpillars can be distinguished from the larval stage onwards by the color of the horns on their back ends: "M. quinquemaculata" caterpillars have black horns, while "M. sexta" caterpillars have red horns. The moths can be distinguished by the number of spots on their abdomens, with "M. quinquemaculata" having, as its name suggests, five.
Behavior
They are difficult to spot due to their green coloration. Tomato hornworms fluoresce differently from tomato leaves. Using an ultraviolet light source of 375 nm and viewed behind a blue-blocking filter, a tomato hornworm fluoresces in bright green while a tomato leaf appears deep red/amber. This sharp color contrast helps gardeners locate tomato hornworms at night. They can be reduced by planting marigold flowers around these plants.Reproduction
The tomato hornworm is a green caterpillar, with eight light-green v-shaped markings which extend from the dorsal line to its sides. At the rear end, the caterpillar has a black, bumpy horn, from which the name for the "hornworm" is derived. Nine spiracles appear on each side of the body and are used for respiration.
Food
Tomato hornworms are known to eat various plants from the family Solanaceae, commonly feeding on tomato, eggplant, pepper, tobacco, moonflowers and potato. Accordingly, they are often found on defoliated tomato plants, the caterpillar clinging to the underside of a branch near the trunk.References:
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