生长季苹果枝干轮纹病病菌分生孢子释放的决定性因素_英文_.pdf

Decisive Factors of Conidia Release of Botryospha eria berengeriana during Growing Season WANG Ye HU Tong le CAO Ke qiang Institute of Plant Protection Hebei Agricultural University Baoding 071001 China Abstract Objective The study aimed to explore the release conditions for the conidia of Botryosphaeria berengeriana and understand the release dynamic of conidia Method The systematical survey on the release conditions for the conidia of B berengeriana were conducted in two growing seasons in 2008 and 2009 combined with the collection of meteorological data around conidia release period the weather conditions causing large amount release of B berengeriana were analyzed Result During a growing season the conidia of pathogen appeared several large release peaks Under the suitable temperature when the precipitation lasted for 4 h the conidia of B berengeriana began to release with large amount the amount of conidia reached the peak after release and trended to be stable during 4 12 h which significantly reduced after 24 h tended to dis appear after 36 h and completely disappeared after 72 h Conclusion The dominant factor affecting B berengeriana conidia release in large a mount was precipitation while the lasting time of precipitation played a decisive role Key wordsBotryosphaeria berengeriana de Not f sp piricola Conidia release Precipitation lasting time Decisive factor Received May 15 2010Accepted August 25 2010 Supported by State Apple Industry Technology System Project nyb cytx 08 04 01 Corresponding author E mail wangye19841224 163 com Apple is the plant belonging to Malus Rosaceae which is one of the fruit trees with the longest cultivation history the lar gest area and the highest yield in China and the whole world Ring spot in apple tree twing is one of the most serious disea ses in apple production It is an important disease caused by Botryosphaeria berengeriana de Not F sp in apple bran ches the incidence is in branches dark brown water soaking or small ulcer spots are formed with lenticels as the center which are slightly uplifted showing verrucous round The le sions then lost water and are depressed the edges are cracked and outstanding with flat circle shape When multiple lesions gather together the bark of large branches in trunk are rough so it is called rough skin disease Fig 1 The dis ease mainly occurs in Asian countries such as Japan China North Korea and South Korea which also have been found in Europe and America 1 3 Since 1970s with the change of main cultivation varieties the cultivation areas of the suscepti ble varieties but with high quality have continuously expanded which have caused large amount of fruits rot before and after picking and has gradually become the prominent issue in fruit production Fig 2 The main inoculum causing rotten fruits is the conidia diffused by B berengeriana In recent years there have been many reports about ring spot in apple fruit including identification of pathogen 4 6 infection mechanism 7 8 inci dence law 9 10 and control 11 etc but the reports on ring spot in apple tree twing are mainly investigation report 12 13 efficacytrials 14 15 channels ofinvadingbranch 16 and time 17 while the research on conidia spreading condition and law of pathogen in branches is rare 18 Exploring the spreading condition of B berengeriana conidia and understanding the re lease dynamic of conidia has important guiding significance for disease prevention Therefore author conducted the research on the factors affecting the release of B berengeriana conidia in apple growing season Fig 1Apple ring spot in trunk Fig 2Apple ring spot in fruit Plant Diseases and Pests2010 1 5 34 37 1Materials and Methods 1 1Tested sitesSample park in Hebei Agricultural Univer sity was selected as the test site there were 150 apple trees which were 16 year old trees of different varieties and more than 80 tree had different levels of ring rot in branches 1 2System monitoring of conidia release of B berengeri anaFrom the early June to the late September in 2008 and growing season in 2009 middle April to late September 5 apple trees which had been infected by B berengeriana were randomly selected in sample park of Hebei Agricultural Universi ty the variety was Fushi home made wide mouth plastic bot tles the mouth was contacted with branches were hanged un der the branches with intensive lesions and rainwater was col lected each tree had two plastic bottles in different directions to collect water After each rainfall the rainwater would be collected and centrifuged 5 000 r min 1 ml distilled water was used to float precipitation and 20 l was taken out and observed under microscopy The number of B berengeriana conidia in the samples were counted and the total number of B berengeri ana conidia in the collected rainwater were calculated 1 3Relationship between conidia release and moisturiz ing time of the treeFive diseased apple trees respectively numbered No 1 No 2 No 3 No 4 No 5 had been ran domly selected in sample park of Hebei Agricultural University since July 2 2009 500 ml water was used to spray the tree trunk with the length of 30 cm and large area of lesions and gauze was used to wrapped for maintaining moisture which was removed after a certain time Another 500 ml water was used to spray the moisture maintaining part and the water flowing down was collected After centrifugation 1 ml distilled water was added to make precipitation float then 20 l was taken out and observed under microscopy and the number of B berengeriana conidia in the samples were counted Washing and observation process was conducted every two hours in the first 12 hours which was conducted every 12 h from 12 to 72 h After 72 h observation was conducted every 5 d and the number of B berengeriana conidia were calculated 1 4Acquisition of meteorological dataMeteorological da ta system was obtained from CR1000 data acquisition unit Ac quisition unit was composed with air temperature and humidity sensors HMP45C rainfall tube TE525MM soil moisture sensor 109 soil moisture sensor CS616 CFM100 stor age module and 1G CF card which could be used to measure the factors such as air temperature humidity soil tempera ture soil moisture and rainfall etc Daily meteorological data were directly send to computer for analysis from apple orchard through wireless transmission 2Results and Analysis 2 1Dispersal law of B berengeriana conidia in growing seasonThe dates of B berengeriana conidia release in rainy day of growing season in 2008 with the lasting time and quan tum of precipitation were plotted in Fig 3 Horizontal axis in Fig 3 represented the date of precipitation As shown in Fig 3 conidia had been captured in the fruit orchard in the early June Although some precipitation appeared the amount was con stantly small A very large peak of conidia release appeared on June 21 the amount of conidia in precipitation reached 47 spore ml Subsequently although there was rainy day the a mount of conidia maintained at a lower level for 20 d 20 days later the second peak appeared on July 11 Similar to the a bove condition 18 days later the third peak appeared on July 29 then the release amount of conidia gradually decreased and disappeared in early September Fig 3Conidia release condition of B berengeriana under different precipitation conditions in 2008 We also could see from Fig 3 that although the rainy days in growing season were more the release amount of conidia was not equal which was not necessarily proportional to the a mount of precipitation and the release of conidia seemed to be carried out in batches After release for one time another large amount of conidia release would appeared after about 15 days if there was rainy day Release condition of B berengeriana conidia in growing season in rainy day in 2009 and the data of precipitation and precipitation time were mapped and shown in Fig 4 Horizontal axis in Fig 4 represented the date of precipitation As shown in Fig 4 conidia also had been captured in the fruit orchard in the early June and the first conidia release peak appeared on June 6 Five conidia release peak appeared during the whole grow ing season and the interval of release peak was about 15 days The two precipitations on July 23 and 24 were almost the 53WANG Ye et al Decisive Factors of Conidia Release of Botryosphaeria berengeriana during Growing Season same but only small amount of B berengeriana conidia was observed in the precipitation on July 23 while the amount of conidia observed in the precipitation on July 24 was 17 times than that observed on July 23 Precipitation on July 23 lasted for three hours while it lasted for ten hours on July 24 this indi cated that precipitation was the necessary precondition of massive release of conidia and the decisive factors whether conidia could release with large amount was the lasting time of precipitation Fig 4Conidia release condition of B berengeriana under different precipitation conditions in 2009 2 2Relationship between B berengeriana conidia re lease and moisturizing time of treeMoisturizing time of tree and conidia release condition of pathogen since July 2 2009 was combined to draw chart Fig 5 As shown in Fig 5 pyc nidium of pathogen would start to release conidia after tree moisturizing for 2 h the amount of conidia reached peak and tended to be stable during 4 12 h which significantly reduced after 24 h then tended to disappear after 36 h and completely disappeared after 72 h The above condition indicated that B berengeriana conidia began to release after at least 2 h the amount of release conidia could reach the peak within 4 h Conidia release of disease tumor in the same tree section had the consistent trend release process was basically completed within 24 h under continuous moist condition In the same growing season the sporulation of disease tumor in the same tree section was more than once which might have several sporulation processes If the same part of the same tree was moisturized for 4 h every five days after 72 h large amount of conidia would be collected again after 15 d Fig 5Relationship between conidia release and moistur izing time of tree 3Discussion System observation data of B berengeriana conidia re lease in two consecutive growing season in apple orchard and tree moisturizing test found that the dominant factors affecting B berengeriana conidia release in large amount was precipita tion while the lasting time of precipitation played a decisive role When the temperature was suitable and the precipitation lasted for 4 h the conidia of B berengeriana would largely re lease conidia release reached the peak during 4 12 h and gradually decreased which basically disappeared after 36 h Experiment also found that the interval of twice conidia release with large amount was about 15 d under the natural condition the precondition of conidia release with large amount each time was the continuous precipitation lasted for over 4 h Many previous studies showed that precipitation was the dominant factorleading to prevalentoftheotherdisea ses 19 20 however these studies mostly emphasized the rela tionship between the amount of precipitation and the occurrence and development of disease while precipitation lasting time was rarely considered The study comprehensively analyzed the effects of precipitation and precipitation lasting time on B berengeriana conidia release and the results showed that the heavy precipitation per unit time with short lasting time had less effect on pathogen conidia release than the relatively small precipitation per unit time with long lasting time the environ mental demand characteristics was similar with Apple Alternaria Blotch with large amount conidia production and release 21 From further studies on tree moisturizing conidia could not re lease with large amount until it had been moisturized for 4 h therefore the heavy rain with short lasting time was not condu cive to the release of pathogen conidia The season with large amount of B berengeriana conidia release and the required environmental conditions were con firmed which had important guiding significance for the preven tion of B berengeriana From current production if rough bark had formed it was difficult to eradicate using direct spraying or smearing fungicidemethod spraying fungicide to protect bran ches and prevent large infection of pathogen conidia was the key to prevent B berengeriana Therefore spraying protect before precipitation in the growing season from June to August should be paid special attention if spraying protect before pre 63Plant Diseases and Pests2010 cipitation had not done and the lasting time of precipitation was over 4 h fungicide should be timely sprayed to eradicate the newly infected pathogen Since the results are based on the data of two years it is necessary to conduct study on the production and release of conidia in order to provide theoretical basis for prediction and prevention of B berengeriana References 1 BEOWN EA BRITTON KO Botryosphaeria diseases of apple and peach in southeastern United States J Plant Disease 1986 70 480 484 in Chinese 2 HWANG BK LEE YS Biochemical characteristics of apple rot caused by Macrophoma sp II Phenolic compound content in infec ted fruits J Korean J Plant Pro 1982 21 4 222 226 3 BROWN EA HENDRIX FF Pathogenicity and histopathology of Botryosphaeria dothidea on apple stems J Phytopathology 1981 71 375 379 4 CHEN C Research progress of apple fruit ring rot J Acta Phyto pathologica Sinica 1999 29 3 193 196 in Chinese 5 LIU GQ FAN YS ZHU SH et al Study on genetic variation of ap ple fruit ring rot in China by RAPD technology J Developmental and Reproductive Biology 2001 2 58 64 in Chinese 6 HUANG CY LIU KQ RAPD analysis of the pathogenic fungi of ap ple ring rot J Acta Phytopathologica Sinica 2001 2 164 169 7 LI GX SHEN YB GAO YM et al Study on the infection mecha nism of apple ring rot disease J Journal of Fruit Science 2007 24 1 16 20 in Chinese 8 LI GX YANG H GAO SH et al The effects of infection of Botryo sphaeria berengriana f sp piricola on cell membrane permeability and defendant enzymes in different resistance cultivars of apple J Journal of Plant Protection 2006 2 127 130 in Chinese 9 XU JY ZHOU ZQ YAN ZH et al Occurrence regularity of apple ring rot disease J Journal of Fruit Science 1992 1 43 46 in Chinese 10 LI MN WANG JY ZHOU ZS et al Study on infection regularity of Botryosphaeria berengeriana on apple fruit and its influencing factor J China Fruits 2001 5 10 14 in Chinese 11 HOU BL WANG JZ ZHU JH et al Occurrence and control of ap ple ring rot disease J China Fruits 1998 2 42 43 in Chi nese 12 GAO YM SHEN YB WANG BS et al Occurrence condition sur vey of apple trunk canker and internal bark necrosis J China Fruits 2005 5 50 53 in Chinese 13 GAO YM SHEN YB ZHANG EY et al Study on the occurrence rule and condition of fungi type apple rough bark disease J Jour nal of Anhui Agricultural Sciences 2007 3 751 754 in Chi nese 14 YANG WH LIU KQ Resistance detection of Botryosphaeria beren geriana f sp piricola to carbendazim and thiophanate methyl J Journal of Plant Protection 2002 2 191 192 in Chinese 15 GAO YM LI GX SHEN YB et al Suitable fungicides and their combination for control of apple fruit canker disease Physalospora piricola J Journal of Fruit Science 2006 3 401 405 in Chinese 16 LI GX GAO YM YANG H et al Observation of infection ap proach of Botryosphaeria berengriana f piricola on apple stem un der scanning electron microscope J Journal of Fruit Science 2005 2 169 171 in Chinese 17 ZHOU ZQ HOU H FENG GX et al Infection period of Botryo sphaeria berengeriana f sp piricola on apple branches J Journal of Fruit Science 2006 6 843 845 in Chinese 18 WANG HQ FAN YS ZHU SH et al Pycnidium opening dispersed spore regularity of appl