Carbon Dioxide-Enriched Atmosphere to Control Oryzaephilus surinamensis L. On Stored Saqie Date Fruits.

<b>Background and Objective:</b> Control of the stored date insects by an eco-friendly method is essential to maintain the fruit for prolonged periods, especially that dates are eaten fresh. The search for a safe method, as an alternative to commonly used chemical pesticides, is needed. The objective is to investigate CO₂ enriched atmosphere on the Mortality Percentage (MP) of the Saw-toothed grain beetle, <i>O. surinamensis</i>, life stages with special emphasis on reducing damage to stored dates. <b>Materials and Methods:</b> The effect of high levels of CO₂ as an alternative control method against the Saw-toothed grain beetle, <i>Oryzaephilus surinamensis</i> L., at different life stages was studied on infested 'Saqie' dates. Four CO₂ pressures (25, 50, 75 and 90 kPa, balance is nitrogen) were tested for 6, 12, 18, 24, 48, 72 and 96 hrs intervals. The response of different life stages of <i>O. surinamensis</i> to the different treatments varied according to CO₂ level, developmental stage and exposure period. <b>Results:</b> Mortality (%) was higher during the larval stage, followed by adults, pupae and eggs, in descending order. The larvae and adult stages were more sensitive to CO₂ treatment than the pupal and egg. Exposure time was more effective on eggs, larval and adult MP than the CO₂ atmosphere level. Mortality% at 96 hrs exposure time was almost 100% with CO₂ atmospheres of 50, 75 and 90 kPa. Mathematical equations were developed to model the relationship between mortality% and CO₂ treatments using multiple regression analyses for each life stage. <b>Conclusion:</b> The results confirmed that CO₂ could be applied to final food products during packaging to control the residual occurrence of insect pests after storage and before the packaging process to prevent further infestation in the final packages.

Aphytis lepidosaphes (Hymenoptera: Aphelinidae) as an Effective Parasitoid for Controlling the Lepidosaphes tapleyi (Williams).

<b>Background and Objective:</b> The guava long scale insect <i>Lepidosaphes tapleyi</i> (Williams) (Hemiptera: Diaspididae) is considered one of the main destructive pests of guava around the world. Biological control represents a sustainable alternative for saving control of <i>L. tapleyi</i>. The main objective of the present work was to study the seasonal activity and evaluate the impacts of climatic factors on populations of the parasitoid, <i>Aphytis</i> <i>lepidosaphes</i>, during two successive years (2017/2018 and 2018/2019) in Esna district, Luxor Governorate, Egypt. <b>Materials and Methods:</b> Estimation of the relationship between the population density of <i>L. tapleyi</i> and <i>A. lepidosaphes</i> activity, by using different models of correlation and regression analyses. The estimate of the effects of climatic factors (daily mean max. temp., min. temp., mean of % relative humidity and mean of dew point) on seasonal activity of the parasitoid, <i>A. lepidosaphes</i>, during two successive years (2017/2018 and 2018/2019). <b>Results:</b> The results showed that the relationship between the population density of <i>L. tapleyi</i> and <i>A. lepidosaphes </i>activity was positive during both years. Furthermore, simple regression analysis indicated that the abundance of <i>A. lepidosaphes </i>was more highly correlated with the <i>L. tapleyi</i> population density in each whole year during the two successive years. The percentages of explained variance EV (%) indicated that all tested variables, i.e. daily mean maximum temperature, minimum temperature, relative humidity and dew point were responsible for 76.26 and 65.40% of the changes in parasitoid, respectively. Furthermore, the dew point was the most effective variable for the change in the parasitoid populations by 33.61 and 18.62%. <b>Conclusion:</b> The results showed that <i>A. lepidosaphes </i>had three peaks of seasonal abundance over the entire year. As well, the activity of <i>A. lepidosaphes</i> was more highly correlated with the <i>L. tapleyi </i>population size over the two successive years.