Development of automated fumigation chamber for treatment of grapes with SO ₂ and CO ₂

The export of grapes from one country to another is dependent on the grape's quality that should pass the strict phytosanitary requirements of the importing country. There is a requirement of fumigation of grapes with CO 2 and SO 2 at specified concentrations for a certain period besides the other pack‐house protocols and export standards. This study was focused to develop and establish an electronically controlled model fumigation chamber for the treatment of grapes in the grapes‐producing region. The gas injection and evacuation systems are electronically operated, and the fumigant concentration can be varied according to the requirement. Heaters of 2 kW are fitted inside the chamber to maintain the treatment temperature above 16°C for grapes fumigation. The fumigation chamber was found leak‐proof during pressurized helium leak testing. The CO 2 and SO 2 gas concentrations can be maintained between 600 and 60,000 ± 100 ppmv and 10 and 10,000 ± 2 ppmv, respectively, for 1–90 min (1% is equivalent to 10,000 ppmv). The fumigation of grapes with 6% CO 2 for 30 min followed by fumigation with 1% SO 2 for 30 min ensured 100% mortality of the adult fruit fly ( Drosophilla melanogaster ). This chamber may also be used for the fumigation treatment of other fruits, vegetables, nuts, and so on, as per the time and concentration of gases required for the 100% mortality of target pest. Nevertheless, the protocol for such treatments should be developed for other fruits, and the effect of the gases on the quality of the products should be studied. Practical Applications The developed automated fumigation chamber for treatment of grapes with CO 2 and SO 2 is an effective measure for disinfesting the grapes from invasive pests like Drosophilla suzukii , spiders, and so on. This would help in overcoming phytosanitary measures put in place by many grapes importing countries like New Zealand, Australia, and so on. These countries offer huge market potential for export of Indian grapes, and if the trade barriers are overcome, it would lead to earning huge foreign exchange. Furthermore, the developed automated fumigation chamber can be used as an integral part of horticultural pack houses both for domestic as well as international trade as it would eliminate most of the adult field pests at preliminary stages before pack‐house operation.