The Influence of Meloidogyne incognita Density on Susceptible Tomato

The purpose of this study was to assess the effects of increasing initial population density (Pi) of Meloidogyne incognita on nematode reproduction and growth of susceptible tomato (Lycopersicom esculentum cv. Round-41) at 25 degrees C +/- 2 in growth chamber. 21-days-old tomato seedlings transplanted in13-cm dia. earthen pot was inoculated with Pi including 250, 500, 1000, 1500 eggs of M incognita. Nematode reproduction was assessed by determining the number of galls, eggs masses, eggs per root system, and reproduction rate values per root system at 60 days after inoculations. Egg-masses on Phloxine B- stained roots were quantified and root systems were rated for galling and egg mass presence on a 0 to 5 scale where 0 = no gall or egg masses, 1 = 1-2, 2 = 3-10, 3 = 11-30, 4 = 31-100, and 5 = >100 galls or egg masses per root system. Nematode reproduction was directly proportional to Pi. Reproduction rate (Pf/Pi, where Pf = final number of eggs / initial egg density) for Pi's of 250, 500, 1000 and 1500 eggs/plant was lowest when Pi = 250 (2.23) but similar when Pi = 500, 1000 or 1500. Shoot and root growth were inversely related to Pi. Strong liner relationship exited between root length, root galling index and foliage growth but very poor between root weight and foliage growth. High Pf = final eggs per root system than at all Pi suggests that Round-41 is a good host for M. incognita