Development of Anastrepha grandis (Diptera: Tephritidae) under constant temperatures and field validation of a laboratory model for temperature requirements Anderson Bolzan a, * , Dori E. Nava b , Giovani Smaniotto a , Ricardo A. Valgas b , Fl  avio R.M. Garcia a a Departamento de Ecologia, Zoologia e Gen etica, Instituto de Biologia, Universidade Federal de Pelotas, Avenida Eliseu Maciel s/n, 96010-900, Cap~ ao do Le~ ao, Rio Grande do Sul, Brazil b Laborat orio de Entomologia, Embrapa Clima Temperado, Rodovia Br 392 km 78, 96010-970, Pelotas, Rio Grande do Sul, Brazil article info Article history: Received 16 December 2016 Received in revised form 31 May 2017 Accepted 1 June 2017 Keywords: Biology South American cucurbit fruit fly Thermal constant Thermal threshold abstract Anastrepha grandis (Macquart) is one of the main pests of cucurbits in the countries of Central and South America. Besides direct damage caused to fruits, A. grandis occurrence in producing regions can lead to export embargos. Despite its economic importance, little is known of the effects of temperature on its biology. This study investigated the development of A. grandis under different temperatures to estimate thermal requirements and then validated the model developed in the field. Development time was inversely proportional to temperature and greater fecundity and fertility were observed at 25  C. Greater egg and pupa viabilities as well as a greater number of insects per fruit were also observed at 25  C. The thermal threshold and the thermal constant for egg and pupal stages were 8.3  C for both stages and 132.3 degree-days (DD) for the egg stage and 347.0 DD for the pupal stage. For the egg-to-adult period the values were 5.2  C and 858.7 DD. Data collected in the field showed DD (937.9) and duration (79.7 d) values of the egg-to-adult period similar to those estimated in the laboratory. This information could support management of A. grandis, since the model for temperature requirements can be used to predict pest occurrence in crops and estimate the number of generations per year. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction The South American cucurbit fruit fly, Anastrepha grandis (Macquart) (Diptera: Tephritidae) is one of the main pests in plantations of native and exotic cucurbits in the countries of South and Central America (Norrbom, 2000). In Brazil, A. grandis occurs primarily in the South, Southeast and Midwest (Zucchi, 2000a). The main hosts of A. grandis are melon (Cucumis melo L.), zucchini (Cucurbita pepo L.), squash (Cucurbita moschata Duchesne), pumpkins (Cucurbita maxima Duchesne), watermelon (Citrullus spp.), cucumber (Cucumisa sativus L.) and chayote (Sechium edule (Jacq.) Swartz) (Costa Lima, 1926; Silva et al., 1968; Malavasi et al., 1980; Silva and Malavasi, 1993). However, among the hosts, the genus Cucurbita allows greater viability of A. grandis and shorter duration of immature stages, consequently, generating a greater number of insects than hosts from other genera (Bolzan et al., 2015). Anastrepha grandis can cause damage to fruit at different stages of development. After oviposition, when up to 30 eggs are laid per puncture, the larvae hatch and feed on the fruit pulp, building galleries. In addition, the puncture for oviposition allows microor- ganisms to enter the fruit, leading to fruit rot. The damage makes the fruit unfit for consumption, marketing and industrialization (Malavasi and Barros, 1988). In Brazil, A. grandis is one of seven species of genus Anastrepha of economic importance (Zucchi, 2000b). In addition to direct damage caused to fruits, A. grandis occurrence is directly linked to quaran- tine restrictions imposed by various importing countries (Paranhos, 2008; NAPPO, 2009). Because of the embargo on exportations of Brazilian cucurbits, the Ministry of Agriculture, Livestock and Supply (Minist erio da Agricultura, Pecu aria e Abastecimento (MAPA) in Brazil) along with Secretariats of Agriculture established Pest-Free Areas (PFA) and Risk Mitigation Systems (RMS) in different regions in Brazil undertook to monitor the areas * Corresponding author. E-mail address: ander_bolzan@hotmail.com (A. Bolzan). Contents lists available at ScienceDirect Crop Protection journal homepage: www.elsevier.com/locate/cropro http://dx.doi.org/10.1016/j.cropro.2017.06.001 0261-2194/© 2017 Elsevier Ltd. All rights reserved. Crop Protection 100 (2017) 38e44