# Sustainable Management of Potato Tuber Moths Using Eco-Friendly Dust Formulations During Storage in the Andean Highlands

## TL;DR

A study in the Andean highlands found that eco-friendly dusts like Bt-talc and agricultural lime effectively protect stored potatoes from moth damage, offering a sustainable alternative to chemical insecticides.

## Contribution

The study introduces Bt-talc and agricultural lime as low-cost, sustainable, and effective alternatives to synthetic insecticides for managing potato tuber moths in high-altitude storage.

## Key findings

- Bt-talc reduced potato damage to below 15% in Cochapampa and below 30% in Sulluscocha.
- Agricultural lime also performed well and is inexpensive and widely available.
- Bt-talc and lime significantly reduced both incidence and severity of moth damage compared to untreated controls.

## Abstract

Potatoes are a key food in the Andean highlands of South America. Stored tubers often suffer heavy losses from small moth larvae that tunnel into the potatoes and make them unsuitable for eating or planting. Farmers commonly rely on chemical insecticides, which can be costly and raise health and environmental concerns. We tested four practical, low-cost options that can be applied directly to seed potatoes during storage: a powder made with the natural bacterium Bacillus thuringiensis mixed with talc (Bt-talc), talc, agricultural lime, and wood ash. Over five months in two high-altitude communities in Cajamarca, Peru, we compared these options with an untreated control. The Bt-talc powder consistently provided the best protection, keeping the proportion of damaged potatoes below 15% in Cochapampa and below 30% in Sulluscocha, and markedly reducing both the incidence and the severity of internal injury caused by moth larvae. Agricultural lime also performed well and is inexpensive and widely available in rural areas. These results show that simple, eco-friendly materials can help Andean families protect their potatoes in storage, reduce dependence on synthetic insecticides, and safeguard food and seed for the next planting season.

Postharvest losses caused by potato tuber moths severely impact storage in the Andean highlands, where reliance on synthetic insecticides poses sustainability and safety concerns. This study evaluated eco-friendly alternatives for protecting stored seed tubers of the widely adopted cultivar INIA 302 Amarilis in Cajamarca, Peru. In two storage facilities, a completely randomized block design compared four treatments: Bacillus thuringiensis plus talc (Bt-talc), talc, agricultural lime, and wood ash against an untreated control. Powders were applied at 50 g per 10 kg of tubers, and incidence, severity of damage, and live larvae were assessed over 150 days. Bt–talc consistently achieved the lowest damage. Incidence in Cochapampa was 16.8% ± 6.2 with Bt-talc, compared with 58.1% ± 3.9 in the control; in Sulluscocha, incidence was 25.5% ± 4.8 and 64.2% ± 3.0 for Bt-talc and the control, respectively. A similar pattern was observed for moth-damage severity in both localities. Live larvae per unit were also markedly lower with 1.3 ± 0.3 (Cochapampa) and 1.6 ± 0.6 (Sulluscocha) under Bt–talc. A single dusting with Bt–talc, or alternatively agricultural lime, offers effective, accessible, and sustainable control of potato tuber moths in high-Andean storage.