Biological and Chemical Control of the Citrus Nematode, Tylenchulus semipenetrans (Cobb, 1913) on Mandarin in Egypt

An experiment was conducted on 15-year-old mandarin (Citrus reticulata) cv. Baladi trees grafted on sour orange (C. aurantium)rootstock infected with the citrus nematode (Tylenchulus semipenetrans) to evaluate potential effect of seven treatments on its management. They were: entomopathogenic nematodes (EPN) in two formulations: Heterorhabditis bacteriophora-infective juveniles (IJs) within infected Galleria mellonella L. cadavers or IJs in water suspensions, as well as Bio-Nematon (Paecilomyces lilacinus), Stanes sting (Bacillus subtilis), Micronema (Serratia sp., Pseudomonas sp., Azotobacter sp., B. circulans and B. thuringiensis), Nema Plus Zero (a.i. 2.4-dihydroxybenzene 12.5%, 2.4-dichloro-propene and Inert Ingredients 81.5%) and Carbofuran (furadan) in addition to the untreated check. All the tested materials suppressed T. semipenetrans populations and increased fruit yield. Micronema, which had the above-mentioned biocontrol agents, resulted to the highest fruit yield (229%) of control yield. Nematode levels were 20 and 26% of control levels, 27 weeks following treatment with Bio-Nematon and Stanes sting, respectively. The tested materials reduced all T semipenetrans life stages but the magnitude of the reduction differed with time of sampling, life stage and the applied material.