Application Of Single And Mixed Xinjunan Against Root Knot Nematode Disease And Root Rot Disease On Tomato

Root-knot nematode disease and root-rot disease are two important soilborn diseases that seriously damage the vegetables production in greenhouse.They often happen at the same time and easy to form complex infection,which seriously threaten the production of tomato and other vegetables and then cause huge economic losses.Currently,chemical control is still the major measure for disease management.But there is lack of agents for both controlling root-knot nematode disease and root-rot disease domestic and overseas.Our laboratory have found that xinjunan had certain toxicity to Meloidogyne incognita and Fusarium oxysporum f.sp.radicis-lycopersici,but the efficacy on the two diseases is unknown.In this study,the safety dosage of xinjunan,its toxicity to M.incognita and F.oxysporum f.sp.radicis-lycopersici and the synergistic ratio of xinjunan combined with fluopyram and pyraclostrobin for controlling tomato root-knot nematode and root-rot diseases in pot and field conditions were determined.The major results are as follows:1.At the dosages of 200,100,and 50 mg a.i./plant,Xinjunan were safe to three varieties of transplanted tomato seedlings by root irrigation.When xinjunan was applied at planting stage,the three doses of xinjunan had no significant effects on the growth of plant height and stem diameter of seedling（Zhuofen and Vienna 2）after 7-day and 15-day treatments.After 7days of treatment,xinjunan had no significant effects on the growth of tomato（398）plants,while xinjunan at 100 mg a.i./plant and 200 mg a.i./plant（0.2236 cm）had significant effects on the growth of tomato plants,after 15 days of treatment.When xinjunan was applied at 7 d after planting stage,the three dosages of xinjunan had no significant effects on the growth of plant height and stem diameter of tomato（Zhuofen,398,Vienna 2）after 7-day.After 15 days of treatment,xinjunan had significant effects on the growth of tomato（Zhuofen and 398）plants,while xinjunan at 100 mg a.i./plant and 200 mg a.i./plant（6.45 cm）had significant effects on the growth of tomato（Zhuofen）plants,while xinjunan at 50 mg a.i./plant and 100mg a.i./plant（10.08 cm）had significant effects on the growth of tomato（398）plants.In addition,xinjunan had no significant effects on the growth of tomato（Vienna 2）plants after15 days of treatment.2.Xinjunan had effect on J2 stage of M.incognita at 24h,with LC₅₀ of 57.66μg/m L.The combination of xinjunan with fluopyram at ratios of 1:5 and 20:1 showed synergistic activity against M.incognita J2 with CTC of 148.23 and 134.13.The EC₅₀ value of xinjunan for against F.oxysporum f.sp.radicis-lycopersici was 45.07μg/m L.The synergistic effect of xinjunan and pyraclostrobin was favorable at ratios of 5:1 and 20:1,which had SR were 2.32and 2.82,respectively.The pot and field experiments were carried out based on the above-mentioned four synergistic ratios.3.The pot experiments indicated that xinjunan combined with fluopyram（20:1）at dosage of 100 mg a.i./plant had the highest efficacy（57.40%）for controlling root-knot nematode diseases after 30 days of treatment.Xinjunan combined with fluopyram（1:5）at dosage of 4 mg a.i./plant had the highest efficacy（67.87%）for the management of root-rot disease after 30 days of treatment in the mixtures group.Xinjunan combined with pyraclostrobin could reduce the both diseases severity with incidence lower than 40%,which showed no significantly difference with that of the xinjunan.Additionally,there was no significant difference between once treatment in planting and twice treatment of at planting and 30 d after planting.4.The field experiments indicated that xinjunan combined with fluopyram at ratio of20:1（100 mg a.i./plant）had the most satisfactory efficacy（67.93%）for the control of root-knot nematode disease after 90 days of treatment,which had no significant difference with that of fluopyram treatment.But the application dosage of fluopyram can be reduced by52.4%.It showed that xinjunan combined with fluopyram or pyraclostrobin had unfavorable efficacy for controlling root-rot disease after 90 days of treatment that with efficacy less than40%.There was no significant difference between once treatment in planting and twice treatment of at planting and 30 d after planting.In conclusion,xinjunan combined with fluopyram could apply for controlling root-knot nematode disease,while xinjunan or xinjunan combined with pyraclostrobin could not be applied for controlling root-rot disease.