In North Africa, the potato tubermoth Phthorimaea operculella (Zeller) is an important pest in traditional, non-refrigerated potato stores. A collaborative research programme of the Institut National de la Recherche Agronomique de Tunisie (INRAT) and the International Potato Center (CIP) investigates the relationships between, (a) the dynamics of the field populations, (b) the harvest date, (c) the economic damage in the field, and (d) the subsequent damage in stores under Tunisian conditions. Emphasis was given to the identification of cultural practices that allowed reduction of pesticide applications and to the replacement of the commonly used parathion with less toxic products.
Potato tubermoth control was achieved by applying a synthetic pyrethroid (permethrin) or Bacillus thuringiensis at the beginning of the storage period. The latter, however, seemed to be less effective on tubers with a high initial infestation (over 20%). The studies showed that tuber damage could be avoided by an early harvest and insecticide applications in the field were not indicated.
An integrated control approach including an early harvest date (to reduce initial tuber infestation), and the application of B. thuringiensis or a synthetic pyrethroid is being developed.