RESPONSES OF MELOIDOGYNE-ARENARIA AND MELOIDOGYNE-INCOGNITA TO GREEN MANURES AND SUPPLEMENTAL UREA IN GLASSHOUSE CULTURE

The recent loss of many effective nematicides has led to renewed inter est in alternative methods of nematode management. Greenhouse experime nts were conducted to determine the effects of rapeseed and velvetbean green manures, and supplemental urea, on the root-knot nematodes Melo idogyne arenaria and M. incognita. Green manures were incorporated wit h M. arenaria infested soil using rates totaling 200, 300, and 400 mg N/kg soil. Squash plants grown in this soil were evaluated using a gal l index and plant dry weight. A second experiment tested ratios of rap eseed green manure to urea resulting in rates of 50, 100, and 150 mg N /kg soil on viability of M. incognita eggs and degree of palling on sq uash test plants. A third experiment examined combinations of velvetbe an preen manure and urea resulting in rates of 100, 200, and 300 mg N/ kg soil on viability of M. incognita eggs. When applied at rates of 20 0, 300, and 400 mg N/kg soil, rapeseed green manure was more effective than velvetbean green manure at reducing galling of squash roots caus ed by M. arenaria. Decreased viability of M. incognita eggs observed f rom treatments that received rates greater than or equal to 200 mg N/k g soil with higher percentages of N from urea.