Hot water immersion for surface disinfestation of Maconellicoccus hirsutus (Homoptera: Pseudococcidae)

Area of Science:

• Agricultural Entomology
• Pest Management
• Thermal Treatments

Background:

• The mealybug Maconellicoccus hirsutus (Green) is a significant agricultural pest.
• Understanding the thermal tolerance of different life stages is crucial for effective control strategies.

Purpose of the Study:

• To determine the susceptibility of Maconellicoccus hirsutus life stages (adults, nymphs, crawlers, eggs) to hot water immersion.
• To establish efficacious temperature-time treatments for controlling mealybug infestations.

Main Methods:

• Mealybugs at various life stages were subjected to hot water immersion at 47, 48, and 49 degrees C.
• Lethal time (LT) estimations for 99.9% mortality were calculated using logit-transformed data and a kinetic model.
• Treatment durations were assessed based on the survival of eggs within ovisacs.

Main Results:

• Eggs within ovisacs exhibited the highest tolerance to hot water, requiring longer treatment durations than other life stages.
• Predicted LT 99.9 values ranged from 11.1 to 47.0 minutes depending on temperature and model used.
• No egg emergence was observed after specific treatment durations at each temperature (52 min at 47°C, 24 min at 48°C, 14 min at 49°C).

Conclusions:

• Hot water immersion is an effective method for controlling Maconellicoccus hirsutus across all life stages.
• Specific temperature-time parameters, particularly for eggs in ovisacs, are essential for achieving complete eradication.