The influence of different treatments causing emigration of nitidulid beetles

Experiments were carried out to investigate the influence of different modified atmospheres, low pressures alone, methyl bromide (MB) alone, and MB in combination with CO₂ or low pressure, in causing nitidulid beetles to emigrate from infested dried fruit for which dates served as a model. All the treatments at 4 h and 16 h exposure and at 26°C, had a marked influence in causing insects to abandon the infested fruit. The most effective treatments at the two exposures were pressures of 50 mm Hg, and 1.4% O₂ in air, both of which caused over 87% of the initial insect populations to emigrate from the fruit. At 4 h exposure, 2.8% O₂ was less effective than 100 mm Hg or MB. At 16 h exposure, MB+CO₂ was third in effectiveness and 100 mm Hg was one of the least effective treatments.