BIOLOGICAL CONTROL OF THE CITRUS NEMATODE,TYLENCHULUSSEMIPENETRANS ATTACKING CITRUS SINENSISNAVAL ORANGE TREES

Sweelam, M.E.; Abokorah, M. S.; Taka, Safaa M. Abo; Ellatief, Seham M. Abd-

doi:10.21608/mjapam.2019.123021

BIOLOGICAL CONTROL OF THE CITRUS NEMATODE,TYLENCHULUSSEMIPENETRANS ATTACKING CITRUS SINENSISNAVAL ORANGE TREES

Document Type : Original Article

Authors

Faculty of Agriculture, Menoufia University, Egypt.

10.21608/mjapam.2019.123021

Abstract

This work was conducted to study the biological control of citrus nematode Tylenchulus semipenetrans infesting citrus orchards at Menoufia University. The experiments were applied at the citrus experimental farm of the Faculty of Agriculture, Menoufia governorate on, Citrus sinensis (naval orange) and in the Biological Control Laboratory of Faculty of Agriculture, Menoufia University. Citrus trees naturally infested with citrus nematode Tylenchulus semipenetrans were chosen to conduct a biological control experiment by soil application of the mycorrhizal fungus; Glomus mosseae which was obtained from Cairo Mircen, Ain Shams University, Egypt, mychorrhiza inocula were introduced around the trees trunks (1×108 spores/ml) and was flattened with soil at the rate of 25 ml / tree. Also, the nematophagous fungus, Arthrobotrys conoides was obtained from Agricultural Botany Department, Faculty of Agriculture, Menoufia University. Spore suspension was adjusted to a concentration of 1×108 spores/ml distilled water at a rate of 50 ml/ tree. In addition, local bacterial strain of Azotobacter chroococcum, was obtained kindly from Pharmaceutical Department National Research Center, Giza, Egypt, the bacterial strain contained 107cell/ml and applied at the rate of 50 ml/ tree. TervigoTM is a suspension concentrate (SC) containing 20g/L abamectin with the addition of an iron chelate Fe-EDDHA 400g/L produced by Syngenta East Africa Ltd was applied at the rate of 25 ml per tree. The above materials were app < /span>lied singly or in combinations, monthly soil samples were taken to laboratory where nematodes were extracted, identified and counted until the end of the experiments. The obtained results indicated that the nematophagous fungus, Arthrobotrys conoides treatment recorded the highest reduction percentages of citrus nematode as 66.5 % compared to other bioagents when singly applied. Application of the three bioagents when applied together (A. conoides, G. mosseae, A. chroococcum) recorded the highest reduction percentages against citrus nematode recording 84.5 %, compared to 82.7 % at the nematicide, Tervigo. The treatment of Mycorrhizal fungus, Glomus mosseae recorded the least reduction percentages of citrus nematode as 46.1 %. The treatment of the three bioagents when applied together recorded the highest increase in number of fruits per branch as 200 %, in addition the treatment caused 84.6 % increase in the weight of orange fruit, also, the treatment increased the fruit yield by 108.9 % compared to control trees.

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