1144 © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com. Biological and Microbial Control Effect of Cold Storage on Biological Traits of Psix saccharicola (Hymenoptera: Platygastridae), an Egg Parasitoid of Acrosternum arabicum (Hemiptera: Pentatomidae) Farzane Forouzan, 1 Mohammad Amin Jalali, 1,3 Mahdi Ziaaddini, 1 and Hamid Hashemi Rad 2 1 Department of Crop Protection, College of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan 7713936417, Iran, 2 Pistachio Research Center, Horticultural Sciences Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Rafsanjan 7714613657, Iran, and 3 Corresponding author, e-mail: ma.jalali@vru.ac.ir Subject Editor: Julio Bernal Received 11 August 2017; Editorial decision 15 March 2018 Abstract Psix saccharicola (Mani) (Hymenoptera: Platygastridae) is a solitary egg parasitoid of the pistachio green stink bug, Acrosternum arabicum (Wagner) (Hemiptera: Pentatomidae), which is one of the most important pests of pistachio in Iran. Augmentation of P. saccharicola feld populations using mass-reared individuals may provide an alternative to conventional pesticide use for pistachio green stink bug control. Cold storage is an important component of mass- rearing protocols for optimum timing of host egg parasitization and potentially extended storage of P. saccharicola pupae prior to adult emergence. The impact of cold storage on A. arabicum eggs for various time intervals at 4.0°C was investigated. Results indicated that host eggs stored at 4.0°C for up to 60 d could be exploited by P. sacchricola, whereas no offspring were produced when eggs were stored for 120 d. The emergence rates of the F 1 and F 2 generations declined with increased host egg storage time. Both sex ratio and survival rate of the F 2 generation decreased as the refrigeration time of host eggs increased. The impact of cold storage on P. saccharicola pupae was evaluated. Reared pupae of P. saccharicola were held for 1 wk at three temperatures and compared with a control (27 ± 1°C). Psix saccharicola pupae were tolerant to cold storage at 8 and 12°C. Cold storage adversely affected mean adult emergence at 4°C, which decreased following low temperature exposure. Furthermore, mean percentage survivorship was unaffected by storage at low temperatures in the F 1 generation, but was reduced at 4°C. The sex ratio of the F 1 generation became more male-biased when held at lower storage temperatures. The highest female proportion was observed at 12°C. Key words: Platygastridae, biological control, pentatomidae, mass-rearing, cold storage Pistachio is a major horticultural crop and agricultural export com- modity extensively cultivated in Iran’s tropics. The crop is often severely damaged by a variety of pests, especially green stink bugs (Hemiptera: Pentatomidae), whose direct feeding on the nuts results in smudging of premature nuts and signifcant nut drop and qual- ity issues (Mehrnejad et al. 2013). The pistachio green stink bug, Acrosternum arabicum (Wagner) (Hemiptera: Pentatomidae), is one of the most important hemipteran pests of pistachio because it attacks the nuts causing damage during the growing seasons (Mehrnejad et al. 2013). Given the exorbitant use of pesticides and growing concerns about their effects on human and animal health, egg parasitoids may be good candidates for biological pest control and a preferable alter- native to chemical management of A. arabicum (Mehrnejad 2001). Among the egg parasitoids of stink bugs, some members of the Platygastridae (e.g., genera of Trissolcus Ashmead, Psix Kozlov & Lê, and Telenomus Haliday) are known worldwide because of their importance as biocontrol agents of hemipteran pests (Cônsoli et al. 2010, Sithanantham et al. 2013). Psix saccharicola (Mani) (Hymenoptera: Platygastridae) is an effective parasitoid of A. arabi- cum eggs in Rafsanjan, the main pistachio-producing region of Iran. This species reaches high population densities and is active in pista- chio orchards over long periods of time (Mohammadpour et al. 2016). One problem in designing effcient biocontrol augmentation programs using egg parasitoids is that these natural enemies have a relatively short adult lifespan. Releases should be implemented only during critical periods of the year when pest outbreaks occur. Journal of Economic Entomology, 111(3), 2018, 1144–1150 doi: 10.1093/jee/toy087 Advance Access Publication Date: 5 April 2018 Research Article Downloaded from https://academic.oup.com/jee/article/111/3/1144/4961501 by guest on 26 May 2022