The potato tuber moth, Phthorimaea operculella (Zeller), is a serious pest of potato and other commercial crops belonging to the Solanaceae family. In recent years, it has become an emerging problem in potato-growing regions of the Nilgiri hills of southern India. It is responsible for the reduced quality and quantity of marketable potatoes. In this regard, the development of an eco-friendly control method for the management of the potato tuber moth is urgently required. Therefore, in the present study, the virulence of Steinernema cholashanense CPRSUS01 originally isolated from the potato rhizosphere was tested on fourth-instar larvae and pupae of P. operculella. Steinernema cholashanense caused the greatest mortality in the fourth-instar larval stage (100%) than the pupae (30%). In addition to this, penetration and reproduction of this nematode was also studied in fourth-instar larvae of P. operculella and this is the first report of penetration and reproduction of any entomopathogenic nematode species on potato tuber moth larvae. The reproduction capacity of S. cholashanense on P. operculella is higher (702 infective juveniles mg−1 body weight). Our results indicated that S. cholashanense has good potential as an alternative tool for the management of P. operculella. But before including S. cholashanense in the integrated pest management program of P. operculella, its efficacy should be tested under field conditions.

Many regions are increasingly threatened by agricultural pests but suffer from a lack of data that hampers the development of adequate population dynamics models that could contribute to pest management strategies. Here, we present a new model relating pest survival to temperature and compare its performance with two published models. We were particularly interested in their ability to simulate the deleterious effect of extreme temperatures even when adjusted to datasets that did not include extreme temperature conditions. We adjusted the models to survival data of three species of potato tuber moth (PTM), some major pests in the Tropical Andes. To evaluate model performance, we considered both goodness-of-fit and robustness. The latter consisted in evaluating their ability to predict the actual altitudinal limits of the species in the Ecuadorian Andes. We found that even though our model did not always provide the best fit to data, it predicted extreme temperature mortality and altitudinal limits accurately and better than the other two models. Our study shows that the ability to accurately represent the physiological limits of species is important to provide robust predictions of invasive pests' potential distribution, particularly in places where temperatures approach lethal extremes. The value of our model lies in its ability to simulate accurate thermal tolerance curves even with small datasets, which is useful in places where adequate pest management is urgent but data are scarce.

Various physical and chemical properties of host plants influence insect larval performance and subsequent adult fitness. Tomato plants are relatively new hosts to the potato tuber moth, Phthorimaea operculella (Zeller), with the fruit being its preferred feeding site. However, it is unclear how the biochemical and physical properties of tomato fruits relate to potato tuber moth performance. Significant amounts of α-tomatine were detected in maturing green and ripening fruits of cherry (cv. Ceres) and processing (cv. Serio) types of tomatoes whereas none was detected in a fresh market variety (cv. Marglobe), at comparable stages. α-Tomatine is negatively and significantly correlated with development rate (head capsule size) of larvae reared in the fruits of the cherry and processing type tomatoes. Generally, survival, growth and development were significantly superior for larvae reared in the ripening fruits of the fresh market cultivar. At this stage, the fruits of this cultivar are also the largest. Based on these results it is concluded that fruit α-tomatine content, as wellas fruit size and maturity, all affect performance of P. operculella larvae in the fruits of cultivated tomatoes.

The growing recognition of problems associated with chemical pesticide use has led to increased attention on integrated pest management (IPM). This paper describes how Tunisian potato farmers have learned to manage an important field and postharvest insect pest, the potato tuber moth, Phthorimaea operculella (Zeller), and how interdisciplinary research on integrated pest management has contributed to this process. During the 1980s, new pest control technology and better farmer awareness led to changes in how farmers manage the potato tuber moth in their fields and stores. Farmers reduced insecticide treatments in potato fields and made more use of agronomic practices to avoid crop losses from the insect pest. New government regulations and agricultural extension efforts have caused farmers to discontinue use of environmentally harmful chemicals such as DDT. Research is continuing on biological insecticides that are not toxic to mammals and some farmer adoption of these products has occurred.

The potential egg production and egg viability of the potato tuber moth, Phthorimaea operculella (Zell.) was significantly lowered when moths of either sex were exposed in 250 ml glass jars to vapours of orange peel oil emanating from 160 μ oil. Oviposition and egg hatching was totally inhibited when female moths of both sexes were exposed to 220 μl of the oil.

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.

Insect-free tubers of four potato varieties, namely Kenya Baraka, Anett, Kerrs Pink and Roslin Gucha were exposed to adult Phlhorimaea operculella for 14 days in uncontrolled conditions in storages. On examination of the tubers 16 days after exposure, the percentage of infested tubers was determined: Kenya Baraka—62.50, Anett—77.50, Kerrs Pink—85.00 and Roslin Gucha—86.25%. The larvae made the following mean tunnel lengths: 44.65, 95.33, 88.33 and 104.23 cm in Kenya Baraka, Anett, Kerrs Pink and Roslin Gucha varieties, respectively. Although there were no statistically significant differences in the number of tubers infested (per cent), there were significant differences in the mean length of tunnels made by the larvae in Kenya Baraka and the other three varieties at P < 0.05. The mean number of larvae which survived in 10 tubers were 6.75, 11.25, 15.75 and 18.00 for Kenya Baraka, Anett, Kerrs Pink and Roslin Gucha varieties, respectively. There were statistically significant differences between Kenya Baraka and Kerrs Pink; Kenya Baraka and Roslin Gucha; and Roslin Gucha and Anett varieties (P < 0.05). Thus Roslin Gucha was the least resistant of the four varieties tested, whereas Kenya Baraka emerged as the most resistant variety. The mechanism of resistance in this case was most probably antibiosis.