CCP 02-23-1987 - Laserfiche WebLink

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, . , OAK ANTHRACNOSE--Oak anthracnose is a fungal leafspot disease which - occurs mainly on white oaks but also on bur oaks. It typlcally appears as large lrregular light brown spots, which..y coalesce and encompass the majorlty of the leaf surface. Disease de"elopllent 15 fa"ored by . cool wet weather, especially early in the season. Bllghted leaves may fal,. and twigs may be lnfected or killed by the fungus. This disease may be confused with oak wUt, but there are features which readily distinguish the two: 1) Oak anthracnose ls lOst s.".r. on White oaks whereas oak wilt h ~st severe on red oaks. 2) Oak anthracnose will produce fndiyidual blotches on leayes, often In the center of tile leaf. Although blotches .y coalesce, causing large areas of browning, tile browning will not be restricted to the ..rllins only, as is the ease with oak wilt. 3) Symptoms of oak anthracnose are .ost severe on tile lower, inside branches where the hUlridity le"el realfns hfgher. Sympt08s of oak wl1 t wll1 appear on the extrlllitles of branches, often in the upper crown. Although it may be unsightly. oak anthracnose seldom causes .ore than lIinor damage to an established, Ileal thy tree, and chllllcal control is not usually necessary. If defo11atlon occurs early in the season. the tree can usually produce .ore leaves. though the second f1 ush may consist of smaller and fewer lenes. If a tree suffers severe . defollation for several yeaTS In a TOW. branch dleback may occur. Slnce the fungus overwinters in Infected leayes and twigs, lt is hel pful to remove and destroy fallen leayes In the autumn and to prune out dead branches. Remember, do not prune oalts in Aprl1. May, or June because of the danger of attracting the beetles which spread the oak wi 1t fungus. Trees that have been defoliated, or wlth dead twigs and branches from previous infections. IIlght benefit from a spring application of fertilizer to Increase Yisor. lIater the trees during dry periods, if practical. Chemical control may be advisable on a tree which has been defoliated for several years in a row, or on a young. newly transplanted tree, especia lly one 1 nfected 1n the previous year. fungicides should be applied just after bud break and repeated two to three times at 7 to 10 day intervals if the weather is wet. A spray prograll begun before the onset of symptoms, as a prevent1ve measure. will be much ~re effective than one begun after SymptllllS are obvious. BellOll11, tribasic copper sulfate, and Bordeaux lIixture include fungicides labeled for control of anthracnose on oak. ---.- ..- - - .-_..~~------~ RED OAK GROUP _'TE 0,,", GIllU' . ~thrrn Red OIk Nonhern Pin o,k ... Dol Whnll! Oat ''''. J. D....rm of .he four MetIJ\ common........... in.......