Identification Of Nematode Species On Ficus Carica And Chemical Control Of Fig Root-knot Nematode Disease In Fujian Province

Ficus carica,the common fig,is a rapidly growing tree with long full fruit period and good economic benefits.The planting area of fig in Fujian Province has been growing increasingly,and it become an emerging and popular economic fruit tree for rural revitalization over recent years.The yellowing and decline disease of fig has been increasing in recent years and becoming the bottleneck for the fig production development in Fujian Province.The research on distribution and damage of plant nematodes on fig were done during the year from 2019 to 2021,and control experiment for fig root knot nematode disease has also been done.The main findings of the study are as follows:Meloidogyne incognita on fig has been first reported in Fujian Province,and It may also be an important cause of decline in fig yellowing.The research results showed that fig root knot nematode disease was commonly distributed in all fig producing region.The distinctive symptoms of root-knot nematodes infestation on fig consist of galls on primary and secondary roots,rootting roots with heavy infestations,stunted plants,chlorotic leaves and reduced yields.The species of root knot nematodes from different main fig production areas in Fujian Province have been identified as M.incognita by morphological characteristics and measurements.The rDNA-28S-D2D3,rDNA-ITS,mtDNA-COIIand mtDNA-NAD5 regions of the nematodes has been sequenced.The species has also been identified as M.incognita based on phylogenetic trees which constructed based on the above target genes using Bayesian Inference(BI)and Maximum Likelihood(ML).The populations of root knot nematode were further confirmed with M.incognita specific primers Mi-F/Mi-R.This is first report Meloidogyne sp.on fig in Fujian Province.Species of other plant pathogenic nematodes have been identified on fig.Based on morphological and molecular characteristics,6 species belonging to 6 genera were identified as follows:Helicotylenchus dihystera,Rotylenchulus reniformis,Pratylenchus coffeae,Tylenchorhynchus annulatus,Xiphinema hunaniense,Aphelenchus avenae.Of them,H.dihystera,T.annulatus,R.reniformis and X.hunaniense are first reported on fig in China.Furthermore,H.dihystera are the dominant species.In soil samples,its isolated frequency is 48.1%,followed by 35.9% for R.reniformis,25.0% for T.annulatus and 25.0% for P.coffeae.The potential damage of H.dihystera,R.reniformis and P.coffeae should be paid more attention to.The control experiment for root knot nemaode disease of fig has benn done.The research results showed that the main transmission way of root knot nematode transported to virgin land was infested fig seedlings carried with infested soil.Based on growth characteristics of fig and the discipline of occurence and development of M.incognita,The results show that 30 days after field application in early spring,the population development of second stage of juvenile could been significantly inhibited by Fluopyram(41.7% SC)at 0.5 m L/ per plant and0.5m L/ per plant,and by Thiazophos(10% GR)at 15 g/per plant.The root knot nematode control efficacy of the above-mentioned treatments approached to 88.9%,73.7%,57.9% respectively after field application,while it was only 21.1% by Avermectin(5% EC).This indicates that,low dosage of Fluopyram(41.7% SC)may be an effective nematicide forthe control of fig root knot nemaode disease.