Journal of Phytopathology and Pest Management 2(1): 36-46, 2015 pISSN:2356-8577 eISSN: 2356-6507 Journal homepage: http://ppmj.net/ Effect of extreme low and high temperatures on the almond moth, Ephestia cautella (Walker) (Lepidoptera: Pyralidae) Y. A. Darwish1*, A. M. Ali1, R. A. Mohamed2, N. M. Khalil2 1 Plant Protection Department, Faculty of Agriculture, Assiut University, 71526 Assiut, Egypt 2 Plant Protection Research Institute Agricultural Research Center, Dokki, Giza, Egypt Abstract The different immature stages of the almond moth, Ephestia cautella (Walker) were exposed to low temperature of -5ºC for different exposure times. Exposure of eggs to 240 to 360 minutes is sufficient to achieve 100% mortality for this stage. Exposed early larval instar to -5ºC for 180 minutes is sufficient to achieve 100% mortality. Exposure of the late larval instars to 300 and/or 360 minutes is effective to achieve a complete mortality for the late larval instars of the pest. The calculated LT50 and LT95 were 113.73 and 208.64 minutes. Exposure of pupae to 300 minutes or more is effective to get a complete mortality for the pupal stage. High temperatures of 45º, 50º, 55º and 60ºC were tested against egg, late larval instars and pupal stages of E. cautella. Mortality tended to be increased with the increasing of temperature and exposure time. Exposure time for more than one hour at 45ºC, 15 minutes at 50ºC and 10 minutes at 55ºC were more effective and led to more than 95% mortality for the egg stage of E. cautella. Exposure of the late larval instars for more than 97.22, 72.17, 17.65 minutes at 45, 50 and 55ºC is sufficient to achieve more than 95% mortality for the late larval instars as indicated by LT values. Exposing the pupae to 25 minutes at high 95 temperatures of 50ºC and to 15 minutes at 55ºC is an effective to get complete mortality for the pupal stage. Thus exposure times for more than 90 minutes at high temperature of 45ºC; 33 minutes at 50ºC and/or 11.67 minutes at 55ºC were more effective to achieve more than 95% mortality of the pupal stage of E. cautella. Key words: almond moth, date palm, physical control, IPM program. Copyright © 2015 ∗ Corresponding author: Y. A. Darwish1, E-mail: [email protected] 36 Darwish et al., 2015 Introduction 1985; Sharma & Dwivedi, 1997; Faruki et al., 2005; Ayvaz & Tuncbilek, 2006; Ayvaz et al., 2007, 2008; Azizoglu et al., Among stored product pests, the almond 2010). moth, Ephestia cautella (Walker) (Lepidoptera: Pyralidae) is one of the The advantages of physical control (low major date palm pests in Egypt. The and high temperature) as a pest control infestations begin in date palm procedure includes the absence of plantations and continue in storehouse undesirable residues in the treated foods, through infested dates and can go no resistance development by pest through multiple generations (Howard et insects and a few significant changes in al., 2001).Besides date palm fruits, dried the physicochemical properties or the fig, raisin, rice and maize grains, cereal nutritive value of the treated products products, cocoa, chocolate, spices, nuts, (Lapidot et al., 1991; Ahmed, 2001; dried fruit, processed foods and peanut Zhao et al., 2007). are reported as hosts of almond moth (Singh & Moore, 1985; Shahhosseini & The present study aimed to study the Kamali, 1989; Hodges & Farrell, 2004; effect of extremely low and high Rees, 2007). Larvae cause a considerable temperatures on the mortality of the pest. damage by feeding and/or by However, results of this study will be contaminating stored food with dead useful for understanding the mechanism bodies and their own products, e.g. of population build-up of Ephestia excreta, wibbing and silk. cautella on date palm fruits. Moreover, these information will be necessary for Generally, control of stored product pests the development of an IPM program for is applied using insecticides such as date palm pests in Egypt. malathion, chlorpyrifos-methyl, phosphine, and methyl bromide (Arthur, 1996). Chemical insecticides have Materials and methods showed numerous environmental problems such as depletion of Rearing technique: The experimental atmospheric ozone (Fields & White, insects were collected from infested date 2002; Hansen & Jensen, 2002), fruits of traditional stores and date palm development of resistance in insects plantations in the New Valley (Sinha & Watters, 1985), mammalian governorate and transferred to laboratory toxicity, disruption of the food chain, at Plant Protection Department, Faculty proliferation of more harmful insects and of Agriculture, Assiut University during sensitive species (Regnault-Roger, 1997). June 2007. Larvae were collected and Recently many researchers have been kept in glass jars 2 Kg and provided with devoted for seeking alternatives against clean semi-dry date fruits (Saidy) as a insect pests in warehouses. source of food until pupation. Pupae Among the alternative control tactics, were individually introduced into glass physical control is one of the most vials (10x4 cm) and covered with muslin promising methods (Brower & Tilton, by means of rubber bands until the adult 37 Darwish et al., 2015 emergence. The newly emerged adults Effect of high temperatures: The effect of were transferred into ovi-position cages high temperature on the mortality of egg, measuring 30 x 30 x 35 cm at a rate of larval and pupal stages of the almond about 10 pairs males and females / cage. moth was determined. Temperatures The cages consisted of a wooden bottom were 45º, 50º, 55º and 60ºC and the and side, the other sides were made of a 2 exposure times to each temperature were mm wire mesh and the whole unit was 5, 10, 15, 20 and 25 minutes. For each covered with a wood plate. A cloth temperature, separate sets of individuals sleeve was fitted to the wooden side to were used for the different exposure enable handling the moth. The pest was intervals. About 80 eggs (<24 hrs old), reared under laboratory conditions for 100 late larval instar and 30 pupae were several generations before the study was exposed to each temperature. After undertaken to ensure complete exposure, individuals were removed adaptation. The present investigations from the oven and placed under were carried out to study the effect of laboratory conditions for subsequent low temperature and high temperature of assessment. Control mortality under 45º, 50º 55º and 60ºC on mortality of laboratory conditions was negligible egg, larval and pupal stages of the through the test and no corrections were almond moth, E. cautella. necessary for treatment comparisons. If all individuals were dead after initial Effect of low temperature (-5ºC): The time exposures as recorded at 60 C, no at which 50% (LT50) and 95% (LT95) of further tests were conducted. In case of the treated insects died, was determined eggs, mortality was evaluated using a by cooling groups of 80 eggs, early (1-2 binocular microscope (Paralux 4-10× days old), late larval instars( >25 days magnification power). Estimation of old) and pupae. Four replicates of 20 mortality on the egg, larval and pupal individuals of each stage for each stages were made as in the treatment were exposed to temperature of aforementioned treatment (low -5ºC for 30, 60, 120, 180, 240, 300 and temperature treatment). The values of 360 minutes. After exposure, individuals LT50, LT95 and slopes were calculated by were transferred to laboratory conditions a probit analysis using SPSS V. 10 of temperature ranged from 25 to 30 °C system (SPSS Inc., 1999). and 60 to 65% relative humidity. Eggs and pupae were left undisturbed at room Results temperature and laboratory conditions for 7 days and considered to be dead if no Effect of low temperature (-5ºC): Low hatch or emergence was noted by that temperature of -5ºC was tested against time. Early and late larval instars were egg, early and late larval instars and assumed to be dead if they did not pupal stage22 of E. cautella. Data in respond to a gentle prodding after 24 Tables (1 – 4) showed the percentages of hours recovery at laboratory temperature. mortality in relation to exposure time at - Our observations clearly indicated that 5ºC. The calculated values of LT50 and we can distinguish between them after LT95 are given in Table 5. about one day. 38 Darwish et al., 2015 Effect of low temperature (-5ºC) on egg for one hour or less did not lead to any stage: Table (1) revealed that the mortality and the larvae completed their exposure for 60, 90, 120, 180 and 240 development after this time of exposure. minutes was able to achieve 40.00, 60.00, The LT50 and LT95 values were 86.25, 92.50, and 100.00% mortality, calculated as 143.11 and 226.53 minutes respectively. Exposure time to 4 hrs was (slope = 8.19). Thus exposure time for sufficient to achieve complete mortality more than 226.53 minutes was sufficient for the egg stage. The LT50 and LT95 to kill 95% of late larval instars as values were calculated as 65.26 and indicated by the value of LT95 (Table 5). 156.99 minutes (slope = 4.09). It is clear that about 160 minutes at -5ºC were Effect of low temperature (-5ºC) on pupal sufficient to kill 95% of the egg stage stage: Table (4) revealed that exposure (Table 5). times of 90, 120, 180, 240 and 300 minutes were able to kill 14.00, 62.00, Effect of low temperature (-5ºC) on early 81.48, 92.59, and 100.00%, respectively. larval instars: Early larval instars were Exposure time for 5hrs or more was exposed to -5ºC for different times from sufficient to achieve 100% mortality for 30 to 360 minutes. Table (2) revealed the pupal stage.