الفهرس 
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Abstract
Accurate, quick and economic measurements of the quality of entomopathogenic nematodes (EPNs) were proposed and applied on two Egyptian nematode isolates, namely Steinernema carpocapsae (Weiser) BA2 and Heterorhabditis bacteriophora Poinar S1. Proposed measurements on infective juveniles (IJs) included assays of the image analysis, dry weight, heat tolerance and heat shock. For testing their validity, results of proposed measurements were compared with those of the viability assay, traditional laboratory bioassay and semi-field assay of the nematode efficiency using larvae of Agrotis ipsilon (Huf.) and/or Galleria mellonella (L.). Five levels of the nematode quality were induced by storing IJs at 28oC for different durations and the resulting nematodes were used for detailed comparisons. The nematodes were finally sprayed in a corn field for assessing their field performance against larvae of A. ipsilon and Spodoptera littoralis (Boisd.). Results on nematode species showed a strong positive correlation (r -gt; 0.9) between the image analysis, mean dry weight (MDW) and traditional bioassays of the nematode quality in laboratory and semi-field scales. Mean gray level (MGL) had a strong correlation with all other measurements of the quality of S. carpocapsae BA2 except with the heat tolerance (HT) and heat shock (HS). The correlation was positive with all measurements except with the storage period (SP). MDW had also a significant strong correlation with all other measurements of the quality of S. carpocapsae BA2 and H. bacteriophora S1 except with HT and HS. The heat assays (HT and HS) looked independent in their relation to other quality measurements of S. carpocapsae BA2 and H. bacteriophora S1. These two assays were also independent in relation to each other. S. carpocapsae BA2 caused 100% larval mortality for A. ipsilon and S. littoralis in the field, while H. bacteriophora S1 induced 83.81 and 33.57% mortality for the two species, respectively. For testing the potential of an EPN species, the image analysis is recommended as an accurate, quick and economic quality measurement instead of the traditional laboratory bioassay and semi-field assay.