Apply chlorothalonil or mancozeb when needles are half elongated and again 3 wks. October Symptoms Several months after infection, needles turn lavender in color. Tiny black fruiting structures form in rows on either side of the midvein on the underside of the needle. Large patches of needless areas develop on the tree. Sporulation May and September Favorable envrionment Free moisture on the needles.
Management Make two applications of chlorothalonil.