苹果霉心病病原研究

１９８９－１９９３年，在甘肃苹果产区采集红星或元帅品种病果和无症状果实，逐果取果心组织分离，获得３０余个真菌分离物，以链格抱（Ａｌｔｅｒｎａｒｉａａｌｔｅｒｎａｔａ）出现率最高，占５１．３％；其次为粉红单端孢（Ｔｒｉｃｈｏｔｈｅｃｉｕｍｒｏｓｅｕｍ）、棒盘孢（Ｃｏｒｙｍｅｕｍｓｐ．）、节孢状镰刀菌（Ｆｕｓａｒｉｕｍａｒｔｈｒｏｓｐｏｒｉｏｉｄｅｓ）、狭截盘多毛孢（Ｔｒｕｎｃａｔｅｌｌａａｎｇｕｓｔａｔａ）等，依次占１１．８％、１２．０％、８．９％、７．９％。每个单果大多是只能分离出一种菌，少数出现２一３种菌。不同症状的果实，出现的真菌种类不同，霉心果以链格孢出现率最高，占６０％－８０％；心腐果中链格孢出现率显著较少，占１０％－３０％；而粉红单端孢、节孢状镰刀菌、棒盘孢、狭截盘多毛孢等５种菌的出现率较高，占７．８％－２５．５％。用果心不带菌的果实人工接种，对１２种分离物进行致病性测定看出，不同菌株之间致病力有明显差异，致心腐的病菌主要有５种，分别是粉红单端孢、棒盘孢、节孢状镰刀菌、狭截盘多毛孢和一种不产孢的浅色丝状菌。链格孢主要致霉心症状。混合接种试验表明，如有几种真菌进入果心，则致病性强的一种首先占据优势，?

Studies on Causal Agent of Apple Mouldy Core and Core Rot

Aprogram to investigate causal agent of apple mouldy core andcore rot in Tiansbui was conducted since1989 to l993. More than 30 kinds of fungal isolates were isolated from core region of Starking apple fruits,with or without symptoms,in which Alternaria alternata was predominant(5l.3%of the total number),llowed byTrichothecium roseum(ll.8%),Cerpecom sp.(12.0%), Fusarium arthrosporioides( 8.9%),and Truncatella angustata(7.9%).From a carpel cavity of individual healthy fruit without symptom,2 to 3 kinds of fungal isolates may be observed,nevertheless,from the core region of individual diseased fruit with mouldy core or core rot symptom only one kind of fungalisolate can be obtained in most cases. The proportion of main kind of isolates varied with the type of symptom of diseasedfruit. From mouldy core tissues,the A. altemata occupied about 60%-80%, but it was less in core rot region(l0%-30%)in which T. roseum, Ceryneum sp.,F,arthrosporioides,and T. angustata appeaered more frequently(7.8%-25.5%). In anartificial inoculation trials by injecting spore or hyphal fragment suspension of l2 kinds of isolates into carpel cavities of Rallsapple fruits, in which none of fungal residents were present,it showed that the pathogenicity of different isolates varied sig-nificantly. Pathogens causing core rot symptom included T. roseum, Coryneum sp.,F,arthrosporioides, and T. angutata,in contrast to A. alternata caused mouldy core mainly. Results of combined inoculation indicated that when more than one iso-lates had been injected into carpel cavities, the more virulent pathogen colonized predominantly, and the less virulent onescould hardly be obtained in reisolation.