~ 85 ~ Journal of Entomology and Zoology Studies 2017; 5(6): 85-90 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2017; 5(6): 85-90 © 2017 JEZS Received: 15-09-2017 Accepted: 16-10-2017 Mansoor-ul-Hasan Department of Entomology, University of Agriculture, Faisalabad, Pakistan Asad Aslam Department of Entomology, University of Agriculture, Faisalabad, Pakistan Muhammad Jafir Department of Entomology, University of Agriculture, Faisalabad, Pakistan Muhammad Wajid Javed Department of Entomology, University of Agriculture, Faisalabad, Pakistan Muhammad Shehzad Department of Entomology, University of Agriculture, Faisalabad, Pakistan Muhammad Zubair Chaudhary Department of Entomology, University of Agriculture, Faisalabad, Pakistan Muhammad Aftab Department of Entomology, University of Agriculture, Faisalabad, Pakistan Correspondence Muhammad Jafir Department of Entomology, University of Agriculture, Faisalabad, Pakistan Effect of temperature and relative humidity on development of Sitophilus oryzae L. (coleoptera: curculionidae) Mansoor-ul-Hasan, Asad Aslam, Muhammad Jafir, Muhammad Wajid Javed, Muhammad Shehzad, Muhammad Zubair Chaudhary and Muhammad Aftab Abstract Study was conducted to determine the different life stages of Sitophillus oryzea and the effect of various combinations of temperature (25, 30 and 35 °C) and R.H. (55, 60 and 65%) under lab conditions in university of agriculture Faisalabad in 2015-16. Three replications were used for each treatment. Ten pairs of adults were released to get eggs. Data regarding oviposition, fertility and adult emergence was recorded on daily basis. For this effort, first temperature (25 °C) was in practice on decontaminated rice which exposed slow development of S. oryzae while highest temperature (35 °C) presented very high developmental rate of all life stages of S. oryzae. So, result presented S. oryzae has great influence of temperature on its life span. It exhibited high appearance at high temperature in comparison with low temperature. Relative humidity has also excessive influence on the development of S. oryzae. At 65% R.H. the maximum mean value of adult appearance was significantly higher as compared to than that of 55%. It is stated that different relative humidity level such as 55, 60 and 65%, 65% level is most favorable for its development and 55% level is less favorable for its growth as compared to other levels. Keywords: climatic regimes, controlled atmosphere, lab conditions, management, rice weevil, stored pests 1. Introduction Rice is infested by many insect pests during storage but Sitophilus are most destructive and wide spread species in the world particularly in warm and tropical areas [1] but Sitophilus oryzae (L.) cause most critical infestation in many cereal crops as primary pest like in rice, wheat, maize and other split pea [2] . Rice weevil can damage the whole grain but can also survive on other commodities such as pasta and split pea [3,4] . The infestation caused by S. oryzae (L.) is mostly due to feeding of adults and grub on whole cereal grains [5] . S. oryzae showed more growth on polished rice grains than other varieties [6] . It causes quality and weight losses of cereal grains and produce grain dust [7] which attract the secondary pest attack including Tribollium castenium (H.), Oryzaephilus surinamensis (L.), Cryptolestus ferugenius (S.) and mites which are secondary insect pests which feed on broken grains and grain dust [8] . The activity of rice weevil allows to attack of pathogens by manipulating the internal temperature and relative humidity of infested grains [7,8] . S. oryzae (L.) have four life stages egg, larvae, pupae and adult. First three stages remain within the cereal grain while adult remain outside of grain and complete its further life cycle [9] . The adult of rice weevil is able to survive up to two years under unfavorable environmental conditions and may transfer to field crops due its flying capability [10] . Females can lay up to 300 eggs during its whole life cycle [11] . Maximum development takes place at 28 and 75% relative humidity and greater growth, time period as both factor increases [12] . Rice weevils can be controlled utilization of several grain protectants like malathion, methopereetc to save grains from infestation [13] but it develops resistant against many protectant chemical [5,13] . Now days, fumigation is used prominently to control rice weevil but resistant has been developed due to their residues and toxicity [5] . However, methyl bromide which is used as prominent fumigant since 1930s but now it is banned due to its residual its environmental toxicity under the Montreal Protocol in 2005 [14] . Several control measures are adopted to control insect pest on grain such as use of different botanicals like Pea, Neem, Eucalyptus, Datora and clove oil extracts [15,16] .