Population Density of some Insect Pests Infesting Fallen Soft Dates and their Associated Natural Enemies in Giza Governorate, Egypt

Abstract

This study aimed to determine the population density and survey the insect pests infesting fallen dates fruits of soft cultivars (Zagloul, Samani and Amhat) in Giza Governorate, Egypt and associated natural enemies, parasitoid and predatory species during two successive seasons 2016/2017 & 2017/2018. Ten insect pests belongs to three insect orders (Lepidoptera, Coleoptera, and Homoptera) were recorded. Lepidopterous insects were,Batrachedra amydraula Meyrick (Fam.: Cosmpterigidae), Arenipses sabella Hampson (Fam.: Pyralidae), Ephestia calidella Guenee (Fam. Pyralidae),Ephestia cautella Walker (Fam. Pyralidae), Ectomyelois ceratoniae Zeller (Fam.Pyralidae) and Stathmopoda auriferella (Walker) (Fam. Stathmopodidae). Coleopterous pests were Coccotrypes dactyliperda (Fabricius) Fam. Scolyitldae, Carpophilus spp. (Fam. Nitidulidae) and Oryzaephilus surinamensis Linnaeus (Fam. Silvanidae). The Homopterous insect was Parlatoria blanchardi Targioni (Fam. Diaspididae).one predatory species, Labidura riparia Pallas, (O.:Dermaptera: Fam.: Labiduridae )and one parasitoids species bracon hebetor (Say) (Hymenoptera: Braconidae ) were found. Results showed that there was no significant difference between the numbers of insects in the two years of study or between the three tested cultivars. While there were significant differences between the inspection dates and between the recorded insect's species numbers. In addition, the results showed that the highest average number of the insect species were Carpophilus spp. followed by E. calidella, P. blanchardi and E. cautella respectively. Mean daily temperature &RH had a low and negative effect on insect population density, while there were differences between the insect pests numbers in different date of inspection. In addition, there was a significant difference between the insect pests numbers, which belongs to order Homoptera and each of (Lepidoptera and Coleoptera).Regarding infestation, percentage, there were significant differences between the averages infestation percentage for the three tested cultivars as well as between the two years of study. Bracon hebetor (Say) was the only recorded parasitoid during the period of study. Percentages of parasitism had no significant difference between the two years of the study, while it had a significant difference between the three date palm cultivars.