CONTROLLED ATMOSPHERE TREATMENT OF TEXTILE PESTS IN ANTIQUE CURTAINS USING NITROGEN HYPOXIA - A CASE STUDY

Abstract:
A commercial controlled atmosphere treatment of wool/silk curtains infested with textile pests was carried out as part of a National Trust conservation project. The curtains, together with small cages containing 20 late instar larvae of the textile pests Tineola bisselliella (common clothes moth), Tinea pellionella (casebearing clothes moth) and Anthrenus verbasci (varied carpet beetle), were heat-sealed into a 'bubble' of gas-impermeable sheeting (polyethylene-aluminium laminate) and exposed to a low oxygen atmosphere. The atmosphere was produced and maintained by flushing with high purity nitrogen and introduction of sachets of oxygen absorber. The oxygen concentration in the bubble was 0.6% v/v one day into the treatment, falling to 0.13% after 7 days, 0.03% after 11 days and 0.01% after 21 days, remaining at 0.01% until the bubble was opened after 73 days. Within the bubble, RH was maintained at about 50-70%. Temperature in the bubble was about 11-19°C up to day 11, ranging thereafter from 4-20°C. Cages of insects were retrieved from the enclosure after 4, 7, 11,21 and 31 days. Five percent of the T. pellionella larvae and 50% of the A. verbasci larvae survived seven days hypoxia. Neither species survived 11 or more days hypoxia. Larvae of T. bisselliella required at least 11 days exposure to hypoxia to produce complete mortality. The practical implications of these findings are discussed.