CHE REFERENCE LIBRARY - ZetaTalk

t:ERTAIN Ei,EMENTS IN NlrRSERY PRACTICE 201is often the chief cause of the dropping of currant leaves andinay be destruc%ivc also on gooseberries.Ihmipfio~r. .-.--- The septoria leaf-spot disease causes ratherlarge angular lesions with grayish centers and brown borders.Wit.hin tile grayish center of old spots may bc~ observed severalminute black specks. The spots may be few or many on theleaf ; whm they al*e numerous, the leaf turns yellow and fallsprematurely- (Figs. 2 15,Zlti). The septorialeaf-spot is tlisting&liedeasil>- from hheantluxc~nosc disease bythtl much larger andwell-defined lesions,with characteristiclight-colored centers.Ccr~usr. - The diseaseis caused by thefungus A~1yms]dllr~clbntJ ross7i It1 r ilr . The minuteblack specks inthe center of the okI FI(;. 2l(i. Sty\tori:t Icnf-spot of currnnt andgoos~bcrry.sp0t.s are fruit~ingbodies (pycnidki) of the fungus. The pycnidia contain sporeswhich a,re disseminateci by the wind a,nd rain, and are thus ameans for further spread of the fungus. Falling 011 currant orgooseberry leaves, the spores germinate a,nd produce new infections. The fungus lives over winter in t.he old leaves onthe ground and in the spring sptxG1 spores nre produced that&tack the new foliage. As with most leaf-spot fungi, heavyrains, followed by da~up cloudy weather, grea’tly augmentthe sprk2acl of this p;krasite.C’orrtrol. -- hkasures suita,ble for the anthracnose diseasecontrol a.lso the septoria leaf-spot. The first application