SUSCEPTIBILITY OF SOME COMMERCIAL CORN VARIETIES TO INFESTATION WITH CERTAIN CORN PESTS IN EGYPT

Five commerical corn varieties; D.C. 215, D. C. 204, Giza 2, hy‌brid 310 and Comp. 45 were tested for their suceptibility to infestation with spodoptera exigua (Hb.), Spodoptera littoralis (Boisd.), Rhoalosi‌phum maidis (Fitch) and Tetranychus arabicus Attiah. Investigation were caned out under natural infestation conditions ar different stages of plant growth. Results showed that variety D.C. 215 was the most susceptible to infestation by the seedling pest S.exigua, followed by variety D.C. 204 Giza 2 and hybrid 310. The variety Comp. 45 was the least susceptible to S. exigua. High infestation with R. maidis was recorded in the tasseling stage during the pollination period (70 days after sowing) . Variety Comp. 45 appeared to be the most susceptible followed by Giza 2, D.C. 215 , Hybrid 310 and D. C. 204. On all corn varieties, the highest abundance of S. littoralis Oc‌curred to days after sawing, and infestation was common with no signifi‌cant differences. The hybrid 215 was highly susceptible to T. arabicus while the other varieties (Giza2, Composit 45, Three-way cross 310, Double cross 204) were less susceptible.