This experiment was carried out at El-Riad region, Kafr El-Sheikh Governorate during two sugar beet successive seasons, 2013 and 2014. The aim of this study examined the efficiency of silica nanoparticles, bioinsecticides (Dipel 2X and Biofly), peppermint extract and insecticide (Match 50% EC) in controlling the cotton leafworm, Spodoptera littoralis (Boisd.) and their effects on some associated natural enemies in sugar beet. Results showed that the chemical insecticide (marshal) was the highest efficiency in controlling the cotton leafworm flowed by silica nanoparticles in high rate. Data showed also the extract of peppermint attractive the natural enemies to sugar beet filed and made moderate control the cotton leafworm.

The present study aimed to evaluate the toxicological as well as biochemical effects of the three photosensitizer compounds; rose bengal, eosin yellow lactone and methylene blue on the fourth larval instar of the cotton leaf worm, Spodoptera littoralis (Boisd.). Results of insecticidal activity against the fourth larval instar of S. littoralis revealed that rose bengal is the most toxic photosensitizer compound followed by eosin yellow lactone, then methylene blue. The corresponding LC 50 values were 37X10-5 M, 81X10-5 M and 136X10-5 M; respectively. Concerning, the photodynamic process of the thee photosensitizer compounds to control the 4 th instar larvae of S. littoralis , the LT 50 values of the lowest concentrations of rose bengal, eosin yellow lactone and methylene blue were >4hrs for each. On the other hand, the LT 50 values of the highest concentrations were 2.2, 3.25 and 2.50 hrs; respectively. This indicates that rose bengal was the most active compound. On the light of the median lethal effects of the three tested photosensitizer compounds on the total protein ,total lipids and total carbohydrates content in the tested fourth larval instar of the cotton leaf worm, the results proved that the three photosensitizer compounds decreased these biochemical contents except methylene blue slighty increased total protein content relative to control.