Inhibitory Effect of 16 Fungicides on Persimmon Anthracnose Pathogen Colletotrichum horii

Xianmei YU Changming HOU Kunpeng ZHANG Hao ZHAI Yanan MA Miao AN Chengxiang AI

AbstractIn this research, the inhibitory effect of 16 fungicides on Colletotrichum horri causing persimmon anthracnose was investigated using mycelial growth method and spore germination method. The results showed that among the 16 tested fungicides, 10% of Difenoconazole WG, 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70% of Mancozeb WP, 430 g/L of Tebuconazole SC, 50% of Prochlorazmanganese chloride and 400 g/L of Flusilazole EC achieved the best inhibitory effect on mycelial growth of C.horri, with the inhibition rate of 100%; 70% of Polyram WG, 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70% of Mancozeb WP, 50% of Chlorobromoisocyanuric acid AF, 50% of Triram WP and 400 g/L of Flusilazole achieved the best inhibitory effect on spore germination of C. horri, with the germination rate of 0. In conclusion, 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70% of Mancozeb WP and 400 g/L of Flusilazole EC achieved the best inhibitory effect both in mycelial growth and spore germination, which could be used as the preference fungicides for the control of persimmon anthracnose, and 70% of Polyram WG and 50% of Triram WP achieved the secondly best inhibitory effect, which could be used as alternative fungicides. The results of this research could provide scientific evidence for the effective control of persimmon anthracnose, and more optional pesticides for utilization in the production practice of persimmon industry.

Key wordsPersimmon anthracnose; C.horri; Inhibitory fungicides; Fungicides screening in laboratory



Received: August 9, 2018Accepted: October 25, 2018

Supported by Key R & D Program of Shandong Province（2018GNC110013）; the Innovative Project of Forestry Science and Technology of Shandong Province of China（LYCX04201823）; Agricultural Improved Seed Project of Shandong Province（2016LZG012）.

Xianmei YU (1976-), female, P.R. China, associate professor, PhD, devoted to research about disease control of fruit trees and soil microorganism; Changming HOU（1983-）, male, P.R. China, assistant professor, master, devoted to research on fruit trees. #These authors contributed equally to this work. *Corresponding author: Chengxiang AI (1975-), male, P. R. China, associate professor, master, devoted to research about persimmon resources and breeding. Email: chengxiang_1975@163.com.

Persimmon anthracnose induced by Colleltrichum horii is a kind of destructive disease in its production, is nearly distributed in main persimmon cultivation region of China, and seriously inhibits sustainable development of persimmon industry in China［1-2］. Based on enhancing cultivation management measures and improving plants ability of disease resistance, prevention and control of persimmon anthracnose are still dominant by chemical agents, and common fungicides include Prochloraz, Difenoconazole, Tebuconazole, Mancozeb, Thiophonatemethyl, Chlorothalonil, Carbendazim, Iprodione, Anilazine and Paclobutrazol［3-10］. However, continuous and unreasonable use of chemical pesticides not only causes pesticide residue and environmental pollution, but also makes the pathogen produce resistance and declines control effect［9-10］. Therefore, it is necessary to screen more and effective fungicides for reasonable mixing and rotation, to delay or reduce the production of drug resistance, prolong use life of fungicides, and finally reach the target of effectively preventing and controlling disease. Based on mycelial growth rate method and spore germination method, inhibition effect of 16 common fungicides on C. horii causing persimmon anthracnose was studied, which aimed to screen effective inhibitory fungicides, and provide scientific basis and test data for effective prevention and control of persimmon anthracnose.

Materials and methods

Materials

Persimmon anthracnose pathogen C. horii was isolated and conserved by the research group. 16 kinds of fungicides and their manufacturers were shown as Table 1.

Determination of inhibitory effect of fungicides

Mycelial growth inhibition test

Mycelial growth rate method was used. Under sterile condition, corresponding fungicides were added before PDA medium concreted based on recommended concentration in the field to prepare the fungicidecontaining medium plate. After the medium was solidified, fungus cake with the diameter of 5 mm was inoculated to the middle of fungicidecontaining medium plate, while PDA medium not containing fungicide was taken as the control, and each treatment was repeated for three times. After cultivated for 5 d in 25 ℃ of constanttemperature incubator, colony diameter was measured by cross method, and mean of colony diameter in each treatment was calculated. According to below formula, inhibitory rate of mycelial growth by each fungicide was calculated.

Inhibitory rate of mycelial growth (%)=［(diameter of control colony-diameter of treated colony)/(diameter of control colony-diameter of fungus cake)］×100%.

Spore germination test

1.0×106 spores/ml of conidia suspension was made. 40 μl of spore suspension and fungicide liquid (2 times of recommended concentration) were taken for mixing, and then it was dropped on clean single concave slide. After that, it was cultivated in 25 ℃ of constanttemperature incubator, while sterile water was control. After cultivated for 8 h, it was observed under microscope, and germination rate of conidia in each treatment was calculated.

Data processing

Statistics and analysis of test data were conducted by DPS 9.5 and Microsoft Excel 2013.

Table 116 kinds of common fungicides and their manufacturers

FungicideManufacturerDilution times

50% Carbendazim WPWeihai Hanfu Biological and Chemical Medication Co., Ltd.800

1.5% Polyoxin DPYanbian Chunlei Biochemical Reagent Co., Ltd.600

77% Copper calcium sulphate WPIndustrias Quimicas del Valles S.A. Spain400

95% Posetylaluminium WPZhejiang Jiahua Chemical Co., Ltd.100

70% Polyram WGBASF Corporation Germany500

22% Carbendazim+8% Tebuconazole (Fulian)Jiangsu Rotam Chemistry Co., Ltd.1 200

10% Difenoconazole WGSyngenta Biotechnology Co., Ltd. Swiss7 000

33.5% Copper quinolate SCZhejiang Hisun Chemical Co., Ltd.2 000

25% Bromothalonil ECJiangsu Tuoqiu Agrochemicals Co., Ltd.3 000

70% Mancozeb WPXian MPC Stock Co., Ltd.1 200

430 g/L Tebuconazole SCBayer Crop Science4 000

250 g/L Hexaconazole SCTaiwan Jiatai Enterprise Co., Ltd.5 000

50% Chlorobromoisocyanuric acid AFNanjing Nannong Pesticide Technology Development Co., Ltd800

50% Prochlorazmanganese chlorideNanjing Redsun Co., Ltd.1 200

400 g/L Flusilazole ECDupont Company America10 000

50% Triram WPHebei Zanfeng Bioengineering Co., Ltd.1 600

Results and analyses

Inhibition of 16 tested fungicides on mycelial growth of persimmon anthracnose pathogen

Seen from Table 2, 250 g/L of Hexaconazole SC, 70% of Polyram WG, 22% of Carbendazim +8% of Tebuconazole (Fulian), 50% of Triram WP, 10% of Difenoconazole WG, 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70% of Mancozeb WP, 430 g/L of Tebuconazole SC, 50% of Prochlorazmanganese chloride and 400 g/L of Flusilazole EC had the best inhibitory effect, and inhibitory rate of mycelial growth was 95.63%-100.00%, with insignificant difference, which were significantly higher than that of other fungicides. Inhibitory rates of mycelial growth by 1.5% of Polyoxin DP, 95% of Posetylaluminium WP and 50% of Chlorobromoisocyanuric acid SP were respectively 61.94%, 63.11% and 62.70%, with insignificant difference. The inhibitory rate of mycelial growth by 77% of Copper calcium sulphate WP and 50% of Carbendazim WP was lower than 50%, with worse inhibitory effect and significant difference, which was significantly lower than that by other fungicides.

Impact on conidial germination of persimmon anthracnose pathogen by 16 tested fungicides

Seen from Table 2, after 16 tested fungicides were used to treat conidia of persimmon anthracnose pathogen, germination rate of spore had extremely significant difference. Among them, 70% of Polyram WG, 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70% of Mancozeb WP, 50% of Chlorobromoisocyanuric acid AF and 50% of Triram WP achieved the best inhibitory effect on spore germination of C. horri, with the germination rate of 0. Inhibitory effect of 400 g/L of Flusilazole EC took second place, and germination rate of spore in the treatment was 3.33%, with insignificant difference from prior three kinds of fungicides, but they were all significantly lower than other fungicides. Germination rates of spore by 1.5% of Polyoxin DP and 77% of Copper calcium sulphate WP were respectively 5.67% and 7.33%, and they also had stronger inhibition effect on germination of C. horii conidia. 50% of Carbendazim WP, 95% of Posetylaluminium WP, 10% of Difenoconazole WG and 250 g/L of Hexaconazole SC had the worst inhibitory effect, and germination rate of conidia was close to and even higher than that of control.

Table 2Impact on mycelium growth and conidial germination of persimmon anthracnose pathogen by 16 tested fungicides

FungicideInhibitory rateof myceliumgrowthGerminationrate of spore

Contrast-62.33±0.58 Cc

50% Carbendazim WP11.61 d57.67±0.58 Dd

1.5% Polyoxin DP61.94 b5.67±0.58 Ii

77% Copper calcium sulphate WP40.71 c7.33±0.58 Hh

95% Posetylaluminium WP63.11 b69.33±1.15 Bb

70% Polyram WG97.27 a0.00 Jj

22% Carbendazim+8% Tebuconazole(Fulian)98.09 a32.67±0.58 Ff

10% Difenoconazole WG100.00 a66.67±1.00 Bb

33.5% Copper quinolate SC100.00 a0.00 Jj

25% Bromothalonil EC100.00 a0.00 Jj

70% Mancozeb WP100.00 a0.00 Jj

430 g/L Tebuconazole SC100.00 a20.33±0.58 Gg

250 g/L Hexaconazole SC95.63 a75.33±1.53 Aa

50% Chlorobromoisocyanuric acid AF62.70 b0.00 Jj

50% Prochlorazmanganese chloride100.00 a47.33±0.58 Ee

400 g/L Flusilazole EC100.00 a3.33±0.58 Jj

50% Triram WP99.18 a0.00 Jj

Different capital letters in the same row showed extremely significant difference (P<0.01), while different lowercase letters showed significant difference (P<0.05).

Conclusions and discussions

Chemical agent is still main means of current disease prevention and control. In recent years, there are some reports on agent screening of persimmon anthracnose pathogen. From 7 common fungicides, Qu et al.［3］ screened 4 fungicides (Carbendazim, Difenoconazole, Tebuconazole and Flusilazole), which had obvious inhibitory effect on persimmon anthracnose pathogen C. gloeosporioides. Xi［12］ found that Thiabendazole and Carbendazim had the best inhibitory effect on persimmon anthracnose pathogen, and inhibitory rate was more than 90%, followed by Tebuconazole and Difenoconazole. In the field, 500 times of 80% Fu?Fuxin liquid had the best prevention and control effect, and control rate was 74.89%. But 70% of Thiophonatemethyle, 50% of Carbendazim and 80% of Mancozeb had worse prevention and control effect, and control rate was less than 50%. Via indoor toxicity determination and field control test, Deng et al.［13］ found that 25% of Prochloraz EC (2 000 times) and 25 g/L of Fludioxonil SC (1 000 times) had better inhibitory effect on persimmon anthracnose, and their prevention and control effects were respectively 49.10% and 47.76%.

In most reports, EC50 and inhibition rate of mycelial growth were taken as screening basis for inhibition effect of fungicides［3,8-10,12］, while spore germination which was important influence factor in pathogen infecting process also could be as important screening basis. Based on inhibition rate of mycelial growth and germination rate of spore, Wu et al.［11］ screened 5 fungicides (250 g/L of Propiconazole EC, 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70% of Mancozeb WP and 50% of Thiophonatemethyl WP) from 22 fungicides by common agent concentration in field production, which had better inhibitory effects on mycelial growth and conidial germination of pear anthracnose pathogen.

In this paper, based on mycelial growth rate method and spore germination method, the inhibitory effect on persimmon anthracnose pathogen by 16 kinds of common fungicides was analyzed. It was found that the inhibitory effects on mycelial growth and conidial germination of persimmon anthracnose pathogen by different chemical agents were various. Among them, 250 g/L of Hexaconazole SC, 70% of Polyram WG, 22% of Carbendazim+8% of Tebuconazole (Fulian), 50% of Triram WP, 10% of Difenoconazole WG, 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70% of Mancozeb WP, 430 g/L of Tebuconazole SC, 50% of Prochlorazmanganese chloride and 400 g/L of Flusilazole EC had better inhibitory effect on mycelial growth of persimmon anthracnose pathogen, while 7 kinds of fungicides had better inhibitory effect on germination of conidia. But some fungicides had strong inhibitory effect on mycelial growth of persimmon anthracnose pathogen but lower inhibitory rate of spore germination, such as 250 g/L of Hexaconazole SC, 22% of Carbendazim+8% of Tebuconazole (Fulian), 10% of Difenoconazole WG, 430 g/L of Tebuconazole SC and 50% of Prochlorazmanganese chloride. Some fungicides could effectively inhibit spore germination but had worse inhibitory effect on mycelial growth, such as 50% of Chlorobromoisocyanuric acid AF. Comprehensively considering the inhibitory effects on mycelial growth and conidial germination by the fungicides, it was thought that 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70% of Mancozeb WP and 400 g/L of Flusilazole EC had best inhibitory effect in 16 kinds of test fungicides, which could be taken as preferred agents, while 70% of Polyram WG and 50% of Triram WP achieved the secondly best inhibitory effect, which could be used as alternative fungicides.

References

［1］ ZHANG JZ. Anthracnose of persimmon caused by Colletotrichum gloeosporioides in China［J］. Asian and Australasian Journal of Plant Science and Biotechnology, 2008, 2(2): 50-54.

［2］ XIE L, ZHANG JZ, CAI L, et al. Biology of Colletotrichum horii, the causal agent of persimmon anthracnose［J］. Mycology: An International on Fungal Biology, 2010, 1: 4, 242-253.

［3］ QU JL, WU HB, FAN K, et al. Biological characteristics of Collelotrichum gloeosporioides and inhibitory effects of several fungicides［J］. Chinese Journal of Pesticide Science, 2012, 14(5): 503-509. (in Chinese).

［4］ LIU J, LIU HT, WANG SF. Prevention and control measures of persimmon anthracnose［J］. Journal of Shandong Forestry Science and Technology, 2004(6): 78. (in Chinese).

［5］ LI XM, DING XY. Impact of paclobutrazol on Diospyros nitida growth［J］. China Forestry Science and Technology, 2008, 22(5): 101-103. (in Chinese).

［6］ GENG QQ. Occurrence features and control methods of persimmon anthracnose［J］. Hebei Fruits, 2012(5): 53. (in Chinese).

［7］ LIU SZ. Prevention and control techniques of persimmon anthracnose［J］. Shanxi Fruits, 2013(4): 54. (in Chinese).

［8］ GAO YY, HE LF, LI BX, et al. Identification of the pathogen causing pepper anthracnose in Shandong Province and screening of highly effective fungicides［J］. Scientia Agricultura Sinica, 2017, 50(8): 1452-1464. (in Chinese).

［9］ HUA YG, JIANG LY, LIN FP, et al. Fungicides screening trial against persimmon anthracnose in lab［J］. Forest Pest and Disease, 2001, 20(6): 11-13. (in Chinese).

［10］ XUE J, TIAN ZL, LIU DY, et al. Occurrence rule and control test of persimmon anthracnose［J］. Shanxi Fruits, 2003(4): 5-7. (in Chinese).

［11］ WU LQ, ZHU LW, HENG W, et al. Identification of Dangshan pear anthracnose pathogen and screening fungicides against it［J］. Scientia Agricultura Sinica, 2010, 43(18): 3750-3758. (in Chinese).

［12］ XI H. Investigation, identification and control of persimmon anthracnose in China［D］. Luoyang: Henan University of Science and Technology, 2015. (in Chinese).

［13］ DENG QE, DING XY, XU JQ, et al. Screening of fungicides to pathogens of persimmon anthracnose［J］. Forest Research, 2017, 30(1): 160-165. (in Chinese).

Editor: Ping SONGProofreader: Xinxiu ZHU

Xianmei YU et al. Inhibitory Effect of 16 Fungicides on Persimmon Anthracnose Pathogen Colletotrichum horii



(Continued from page 30)