Final Report to the Elvenia J. Slosson Endowment Fund Title: Root-knot nematode-destroying microorganisms for home garden and landscape use Investigators:

INTRODUCTION Plant-parasitic nematodes are inconspicuous pests because of their small size, hidden activities and often non-specific damage to their hosts. Root-knot nematodes (RKN), Meloidogyne sp., are perhaps the best known of these pests attacking well over 2000 different plant species including many vegetable crops and ornamentals grown in home gardens. In California, four species of RKN are of main concern, M. incognita, M. javanica, M. arenaria and M. hapla. RKN spend only a short part of their life in soil either as eggs or as second stage larvae. The latter then enter the roots and establish feeding sites in susceptible hosts. They undergo three more molts during which the roots become swollen and have a characteristic "knotty" appearance (galling). Each female can produce several hundreds of eggs that under favorable conditions continue to develop into the next generation. Normal functions of water and nutrient uptake as well as transport are severely limited by the root galling. Secondary root tissue infections by fungi and bacteria can accelerate the damage and ultimately may lead to root death. Limitation of the root function is typically expressed with symptoms of malnutrition, chlorosis and stunting. Consequently, vigor and production capacity of diseased crops are noticeably reduced.