Influence of Meloidogyne javanica on growth of sunflower

The relationship between initial population densities of Meloidogyne javanica and the growth of sunflower plannts was investigated in a glasshouse experiment. Clay pots containing 750 ml of steam sterilised sandy soil were inoculated with a range of population densities of eggs and juveniles. Tolerance limits of 3.03, 3.43 and 1 eggs and juveniles of M. javanica/ml soil were estimated for fresh and dry top plants weights, height and number of nodes and capitulum diameter, respectively. A minimum relative yield of 0.30 was calculated for fresh, dry top plant weight and diameter of capitulum, and 0.75 for height and number of nodes. Equilibrium density of the nematode was 862.41 eggs and juveniles/ml soil. Maximum reproduction rate was about 74-fold. Histological examination of infected roots indicated that vascular and cortical tissues surrounding the nematode were hypertrophic and hyperplastic, and multinucleate giant cellsformed around the nematode head.