Evaluation of Polymer- based Nematicidal Combinations against Root-knot infected sugar beet fields in West Nubaria district

The present study was conducted during two experienced growing seasons of 2016/ 17 and 2017/ 18 at West Nubaria Sector. The experiments were designed to evaluate certain management strategies for root-knot nematode, Meloidogyne incognita. The main studied factors were plowing depth and control treatment; there were three plowing depths and six treatments. Experimental design was a split plot randomized complete block design, split plot with plowing depth as main plot, strip-plot arrangement and treatments as subplot with four replicates. Single treatments and combinations of Abamectin, Nemastop, Mocap 10% G and potassium-based polymer yet were compared with untreated control. Analysis of variance for the combined data of the studied seasons significantly at P ≤ 0.05 cleared out the effect of various treatments. Management strategy efficacy %., denoted that 30 cm-plowing depth scored the best At level of control treatments, the lead was due to (Nemastop + Polymers) followed by Polymers followed with (Abamectin + Polymers). Interaction effects on efficacy % revealed that the best results obtained were with 30 cm- plowing depth × (Abamectin + Polymers) followed by the same depth with Polymers followed by 30 cm- plowing depth with (Nemastop + Polymers). All treatments achieved positive impacts on root-knot nematode and sugar beet yield parameters when interacted with each other under deficit irrigation (DI) to level of 75 % of Irrigation water requirements (IWR)
Plowing depth of 30 cm achieved the most promising results for number of plants after thinning, at harvest and losses percentages in number of plants/ fed. in sugar beet field. Also, plowing depth of  30 cm scored the highest values for root yield and extractable white sugar yield. 50 cm-plowing depth recorded the best value for purity percentage followed by depth 30 cm. Plowing depths of 30 cm and 50 cm showed the lowest values for sodium (Na) percentage and potassium (K) percentage. Plowing depth of 50 cm scored the highest value for extractable white sugar percentage (ZB %) , with significant difference between it and the two other plowing depths of 30 and 40 cm at P ≤ 0.05. The lowest number for root- knot nematodes number/g soil as affected by plowing depth was recorded at plowing depth of 30 and 50 cm. also, the lowest record for disease severity % recorded was for plowing depth of 30 and 50 cm. Drop rate % is another indicator for efficiency of management strategy. The most excellent drop rate % was achieved by plowing depth 30 cm,
consequently, the study recommends plowing depth of 30 cm and adequate nematicide seed treatments under deficit irrigation (DI) of 75 % water requirement is best combination to increase water use efficiency (WUE) as well as to improve the efficiency of modern integrated management strategies to control          M. incognita in sugar beet infected fieldswithout serious effects on crop performance which eventually results in augmented yield.