Seasonal pattern of infestation by the carob moth Ectomyelois ceratoniae in pomegranate cultivars Seyed Ali Hosseini a, b , Seyed Hossein Goldansaz b, * , Seyedeh Masoumeh Fotoukkiaii a , Steph B.J. Menken a , Astrid T. Groot a, c a Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090 GE, Amsterdam, The Netherlands b Department of Plant Protection, College of Agriculture and Natural Resources, University of Tehran, Karaj 77871-31587, Iran c Max Planck Institute for Chemical Ecology, Dept. Entomology, Hans Knoell Strasse 8, 07745 Jena, Germany article info Article history: Received 10 May 2017 Received in revised form 11 August 2017 Accepted 12 August 2017 Keywords: Fruit cracking Multiple cropping Punica granatum seasonal patterns Infestation Susceptibility of cultivars abstract Pomegranate (Punica granatum L.) orchards in the Middle East are typically composed of a mix of different cultivars in which variation in fruit infestation by carob moth Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae) has been observed. However, seasonal variation in infestation and adaptation of the carob moth to this cropping system have not been explored. We monitored the progress of fruit infestation in 10 pomegranate cultivars during the growing season of two consecutive years in pome- granate orchards of Iran. Overall, levels of infestation in fruits were strongly correlated with susceptibility to fruit cracking in pomegranate, so that cracked fruits and cracking-susceptible cultivars were infested the most. However, this pattern changed during the season. Infestation was first observed on cracking- susceptible cultivars. At this point almost all cracked fruits were infested. Towards the end of the season, infestation in uncracked fruits and cracking-resistant cultivars increased. Uncracked fruits seem better overwintering sites for carob moth as under simulated winter conditions, survival of insect larvae in uncracked fruits was >3 times higher than in cracked fruits. Taken together, our data reveal that cracked fruits of pomegranate are the better host during the growing season, while uncracked fruits better sustain carob moth population in winter. It seems therefore advisable not to grow cracking-susceptible and cracking-resistant cultivars together in the same area. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Phytophagous insects synchronize their life cycle with growth stages and phenology of the host plants to enhance fitness, opti- mize food intake, and minimize the impact of adverse environ- mental factors such as natural enemies and winter (Kooi et al., 1991; Zvereva, 2002; Schoonhoven et al., 2005; Visser and Both, 2005; da Silva et al., 2016). Synchronization can be achieved when both insects and plants respond to the same environmental conditions or when insects respond to signals that are specific to the phenology of their host plants (Tasin et al., 2005; Proffit et al., 2007). Variation in suitability and availability causes phytophagous insects to display distinct preferences for particular plant species, cultivars, and even plant growth stages during the season (Jallow et al., 2004; van Asch and Visser, 2007). Heteroecious, host- alternating aphids, for example, switch host plants during the season; they spend winter on tree or bush, but in summer they migrate to herbaceous plants, and at the end of season they return to the trees (Vilcinskas, 2016). Also, population sizes of the thrips Frankliniella occidentalis (Pergande) change over a season among chrysanthemum (Dendranthema grandiflora Tzvelev) cultivars, because resistance against this insect develops differently among the cultivars (de Kogel et al., 1997). The carob moth Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae) is a polyphagous destructive pest worldwide, attacking different fruits before harvest and, as a stored product pest, after harvest. The insect is recognized as the economically most impor- tant pest of pomegranate, Punica granatum L. (Lythraceae), in almost all pomegranate production areas of the Middle East, causing 30e80% yield loss (Kashkuli and Eghtedar, 1975; Shakeri, 2004; Sobhani et al., 2015). The pest larvae feed on internal parts of the fruit, resulting in contamination with saprophytic fungi, * Corresponding author. E-mail address: goldansz@ut.ac.ir (S.H. Goldansaz). Contents lists available at ScienceDirect Crop Protection journal homepage: www.elsevier.com/locate/cropro http://dx.doi.org/10.1016/j.cropro.2017.08.008 0261-2194/© 2017 Elsevier Ltd. All rights reserved. Crop Protection 102 (2017) 19e24