New Chemical and Biological Agents for Controlling Root-Knot Nematode Meloidogyne arenaria on Cucumber under Greenhouse Conditions

Results of pre and post - planting application of different control agents showed their significant effect in reducing infection criteria of cucumber compared to uncontrolled plants. No infection was found after pre - planting application of Velum prime nematicide, where decreasing in all infection criteria was 100% to be the best pesticide and application method for controlling Meloidogyne arenaria on cucumber under greenhouse conditions with significant differences compared to other treatments, followed by application the same pesticide at post - planting application. The effect of pre - planting application of Abamectin biopesticide and Trichoderma bio - control agent was very close to each other in number of galls to be similar in root - knot index, but they differed significantly in nematode population density, whereas the lowest effective was found by post - application of goat manure, where the highest number of galls (365 galls/root system),nematode population density (1142.3 J2s/pot) and root - knot index (8/ root system) were recorded, but it didn’t differ significantly with the aqueous extract of tobacco leaves by the same application method. The highest increasing in cucumber growth criteria was reported after pre-planting application of Velum prime nematicide, except the dry weight of roots, where the highest value of root system length (41.7 cm), length (99.3 cm) and dry weight (15.5 g) of shoot system and chlorophyll content (37.2 SPAD) was recorded, with significant differences compared to the most control agents at both application methods The lowest improvement in growth criteria was found after post - application of the aqueous extract of tobacco leaves, as the values reached (23.5 cm, 51.3 cm and 10.1 g) for each of root system length, length and dry weight of shoot system respectively. The lowest increase in chlorophyll content (22.1 SPAD) by percentage (20.76 %) was reported by post - application of goat manure with no significant difference to its content (22.2 SPAD) after post - planting application of the aqueous extract of tobacco leaves by percentage (21.31 %).