Abstract
The present investigation aimed to study the effect of four constant temperatures (17, 22, 27 and 32°C) on the developmental rates of different stages of cotton leafworm, Spodoptera littoralis. The incubation period, larval duration, pupal duration, pre-oviposition period and duration of generation were estimated. The time required for development was decreased as the temperature increased. The threshold temperatures were 11.8°C for egg, 7.56 °C for larvae, 12.27 °C for pupae, 12.58°C for the pre-oviposition period, and 10.5 °C for a generation. The average thermal requirements needed for completing the development were 40.1, 283.76, 149.5, 23.96 and 480.6 degree-days for egg, larvae, pupae, pre-oviposition period and generation; respectively.
Highlights
The Egyptian cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is a native pest to Africa (Shonouda and Osman, 2000; El-Khawas and Abd ElGawad, 2002), and distributed in many European countries (Pineda et al, 2007; Lanzoni et al, 2012; EPPO, 2019), Asia Minor and the Middle East countries (El-Aswad, 2007; ElSabrout, 2013; Azzouz et al, 2014)
The temperature plays an important role among environmental factors for determining the rate of development, survival and any other biological and ecological aspects
This work was pointed mainly on the following aspects: (1) - Relationship between temperature and rate of development, which give a quantitative expression for this relationship, using thermal accumulation. (2)- Study the biological aspects of S. littoralis as a prior to determine its requirements of heat units that used through forecasting system for establishing IPM program against S. littoralis. (3)- Determine the thermal units required to complete the development of different stages for one generation, which help in the design of development indexes are used for determining the required times for these stages under field fluctuating temperatures in the field
Summary
Threshold Temperatures and Thermal Requirements of Cotton Leafworm, Spodoptera littoralis Hb. Eslam A. 1- Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, Egypt. 2- Plant Protection Department, Faculty of Agriculture, Assiut University, Assiut, Egypt. 3- National authority for remote sensing and space science, cairo, Egypt 1- Plant Protection Research Institute, Agricultural Research Center, Dokki, Giza, Egypt. 2- Plant Protection Department, Faculty of Agriculture, Assiut University, Assiut, Egypt. 3- National authority for remote sensing and space science, cairo, Egypt
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More From: Egyptian Academic Journal of Biological Sciences. A, Entomology
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