Global: Potato Tuber Moth Can Destroy Up to 100% of Potatoes in Stores Without Cooling
Storage losses to the potato tuber moth reach 50–100% in warm countries. Cooling below 10°C, deep planting and clean tubers are the main defences; plant powders showed results in Egypt.
While Europe fills cooled stores, many potato growers in warm countries keep potatoes in simple sheds, heaps or pits without cooling. There, the potato tuber moth (Phthorimaea operculella) is often the main enemy. Its larvae tunnel into tubers and leave them unfit for sale.
A 2024 fact sheet from the University of Florida IFAS Extension lists reported storage losses: 50% in Yemen and Peru, 86% in Tunisia, Algeria and Turkey, 90% in Kenya and up to 100% in India and the Philippines. In Egypt, losses of up to 100% are reported in fields and in stores. A study in the Bulletin of the National Research Centre (2019) also reports losses of up to 100% in stores in Saudi Arabia and Egypt.
The moth breeds fast. According to UF/IFAS, a female lays 60 to 200 eggs over four days, eggs hatch in about five days, and larvae feed for up to two weeks. There can be two to eight generations a year, depending on climate. One generation can take only two weeks in summer.
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Cool storage and clean tubers
Temperature is the strongest tool. UF/IFAS says development stops below 50 °F (10 °C) and advises storage below 52 °F (about 11 °C). Where cooling is not possible, prevention starts in the field: plant tubers with more than 2 inches (about 5 cm) of soil cover, irrigate so that soil cracks do not reach tubers, and harvest promptly. Pheromone traps help monitoring. The fact sheet names a threshold of 15–20 moths per trap per night, with traps checked twice a week.
The Egyptian study tested powders of 12 plants at 25 g per kg of tubers. Coriander and Zygophyllum powders fully stopped moth emergence. Basil, geranium and chamomile cut emerging moths to 17–19, against 95 in untreated tubers. Coriander and Zygophyllum still worked at week 10, while most powders lost their effect by week 12. The powders did not harm sprouting.
Why it matters
In warm regions, the moth can turn a good harvest into a total loss within one storage season. Cooling is the best defence but is often too expensive for small farms. For them, clean fields, careful sorting before storage and low-cost treatments such as plant powders are the practical options.
Only undamaged, sorted tubers should go into storage, and stores should be checked often during the first weeks.
Prevention & control · Editorial note
Potato tuber moth (Phthorimaea operculella): what growers can do
- Prevention: plant deep, irrigate to avoid soil cracks, harvest promptly, store only sound tubers and cool stores below 10 °C where possible.
- Monitoring: pheromone traps checked twice a week in field and store.
- Chemical protection in the world: cypermethrin (IRAC 3A) — check the national register.
- Resistance management: use each IRAC group no more than once per season; combine with cool storage and sanitation.
This note is provided by the potatoes.news editorial team for information only. It is not a recommendation of any company and is not mandatory. Use only plant protection products authorised in your country and follow the label. Product names and registrations differ between countries; consult a local agronomist.
Photo: Potato tuber moth (Phthorimaea operculella) (illustrative). Ilia Ustyantsev from Russia / Wikimedia Commons, CC BY-SA 2.0
