To find out the level of susceptibility of certain sugarbeet varieties to Meloidogyne incognita. Also to determine the combined effect of Meloidogyne incognita on the growth and yield components of different varieties used. Four experiments were carried out; two of them were pots trails in greenhouse and the other two were field trails in west Nubariya region throughout seasons of 2009/2010 and 2010/2011. Considering the tested sugarbeet varieties for susceptibility to M. incognita, all the cultivars according to Canto-Saenz's host suitability, can be distinguished to three categories, as responded to M. incognita, the first seriously affected and involved Alexa, Gazella, Panther and Sofie as susceptible ones, the second included reasonably affected varieties (Farida, Pamela, Pleno, Top and Toro) as Tolerant ones and the third as severely affected with nematode represented by Helios variety as Hypersusceptible one. In field Conditions experiment, studied parameters were; germination percentage, leaf weight, beet root yield, number of beets per feddan, TSS%, pol%, sugar recovery% and sugar yield. Data of this part of study cleared that germination percentage, Leaf weight t fed-1, Number of roots and root yield t fed-1 with average values of 78.3%, 14.3, 31.0 and 27.0, respectively. This paper as well seeks to study the yield response of high yielding sugarbeet varieties to different levels of Nemacur (Fenamiphos) input (T: No nematicide or Control; T1: Rate applied once at planting; T2: 50% applied at planting + 50% at 45 day After Planting)  on root-knot nematodes under field conditions as percentage of avoidable loss. The maximum protection treatment rate applied once at planting (T1) was established to be most effective in reducing the damage caused by root-knot nematode   comparison with treatment of 50% applied at planting + 50% at 45 day After Planting (T2). it can be concluded that sugarbeet varieties that categorized previously as susceptible had the highest avoidable loss% due T1 and/or T2 for both roots and  sugar  yields, where sugarbeet varieties that categorized as tolerant had avoidable loss% less than susceptible ones, also, in roots yield  avoidable loss% was greater than in sugar yield. This suggesting that sugarbeet varieties that categorized as tolerant were the best genotype with highest beet root
yield, sugar recovery and ultimately gave maximum sugar yield under some nematode control measures.