Step 1: Understanding the Concept:
Quarantine pest management is highly essential for the international export of fresh horticultural produce.
Treatments must eliminate target pests (such as fruit flies) residing inside the fruit without causing physical damage, heat injury, or chemical residues.
Step 2: Detailed Explanation:
Vapour Heat Treatment (VHT) is an environmentally friendly, non-chemical quarantine disinfestation technique widely used on tropical fruits like mangoes, papayas, and guavas.
The process involves exposing the fruits to saturated water vapor (high relative humidity, typically \(\ge 90\%\)) under carefully controlled temperatures (usually around \(43\text{--}48^{\circ}\text{C}\)) for a specified duration.
The high-humidity air transfers heat rapidly to the fruit tissues, raising the internal temperature of the fruit pulp to a lethal threshold.
This thermal energy is highly effective at killing both insect eggs (1) and larvae (2) of devastating quarantine pests like the Mediterranean fruit fly (Ceratitis capitata) and Oriental fruit fly (Bactrocera dorsalis).
Because both life stages are heat-sensitive, VHT effectively sterilizes the interior of the fruit, ensuring compliance with strict import regulations while maintaining the sensory and nutritive quality of the fresh fruit.
Step 3: Final Answer:
Therefore, VHT is used to kill both insect eggs and larvae (1 and 2 both).