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Cypermethrin, esfenvalerate, chlorpyrifos and Bacillus thuringiensis, Kurs. were tested against the cotton leaf worm, Spodoptera littoralis (Boisd.) treated as 4 th instar larvae. In addition, LC 50 , s of tested compounds were applied on S. littoralis larvae to investigate the ultra structural changes in the integument, muscle, fat body and mid gut of alive and dead larvae. Meanwhile, the nerve cord sections were investigated for alive larvae only. All investigations were done by light and electronic microscopes.Cypermethrin was the most potent compounds against S. littoralis larvae, followed by esfenvalerate, chlorpyrifos and then B. thuringiensis that had the least toxicity on the cotton leaf worm compared to other tested compounds.Ultra structural investigations showed that cypermethrin caused thickening of outer cuticle fibrous layer in the integument of S. littoralis larvae. Also, hypodermis layer had swelling at the same treatment and necrosis in other treatments. In addition, all the treatments caused appearance of fissure and breaking down of muscles into small parts. While, all tested compounds except B. thuringiensis caused swelling in the integuments of dead larvae compared to control. On the other hand, B. thuringiensis caused drastically necrosis in the integument and hypodermis layers of dead larvae. All the compounds caused a noticeable destruction on the fat body cells as well as vacuolization and destruction the fat body membranous sheath. Many deleterious effects in the mid gut of S. littoralis as destruction of columnar or hyperphesia cells lining mid gut, losses of brush border with increase of goblet cells. Mid gut of died larvae had the highly destruction as affected by cypermethrin treatment. Meanwhile, other treatments caused shrinking in mid gut parts and necrosis in another parts. Neurosecretory cells of S. littoralis larval nerve cord had shrunk and dwarfed in cypermethrin, chlorpyrifos and B. thuringiensis, while; it had swelling in esfenvalerate treatment. Also, nucleus and nerve cells were disappeared partly in the most treatment compared to control.

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Two field experiments were conducted on potato (Solanum tuberosum L.) Spunta cv plants during the winter seasons of 2008/2009 and 2009/2010 at Kafre Meet Faris village near El-Mansoura, Dakahlia Governorate, Egypt, to study the effect of organic fertilizer rates (20, 30 and 40 m 3 /fed) and some inorganic fertilizers (NPK) levels (100%, 75% and 50% from recommended dose), either alone or in combination with foliar spray with some macronutrients sources (Hi-Fertil 1 and Ferty More) on the plant growth, yield, and yield components. The results showed that the plants fertilized with 40 m 3 /fed. farmyard manure (FYM) followed by 30 m 3 /fed. significantly increased plant stem length, number of leaves/plant, leaf area/plant and foliage dry weight/plant as well as average of tubers weight/plant and total yield. Increasing the supplied NPK level up to 100% from recommended level caused significant increases in the most vegetative growth parameters.Also, tubers weight/plant, marketable yield and total yield were increased significantly. Also, the results indicated that the plants sprayed with Hi-Fertil 1(19-19-19, NPK), had a significant effect in most vegetative growth parameters while, plants sprayed with Ferty More (5-3-43, NPK) resulted in significant increases in foliage dry weight/plant, tubers weight/plant, marketable yield and total yield. In general, the best results were obtained by using 40 m 3 FYM, 50% NPK level and foliar spray with Ferty More (5-3-43, NPK) followed by the interaction among 40 m 3 FYM, 50% NPK level and foliar spray with Hi-Fertil 1(19-19-19, NPK). These treatments achieved increases in tubers weight/plant total yield and marketable yield as well as decreasing unmarketable yield. Therefore, these treatments could be recommended for raising productivity, improving quality of potato and will also decrease the pollution of environment under the conditions of El-Dakahlia Governorate.

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