QuestionWe believe our blue spruce has the Rhizosphaera needle cast disease. Half of the bottom branchs around the 25-30 ft. spruce look just like pictures we have seen of this disease. If we get fungicide spray and it stops this disease will the bottom branchs which have turned mostly brown and lost their needles get new growth or will the branchs eventually die. Thank you for your time and any info you can give us.
AnswerNo the branches that have lost their needles will not leaf out again. Hardwood trees have the capability to leaf out but conifers do not. IF there is still green needles on the branches I would remove the dead and dying needles and treat with the fungicide. This may help keep the spores from spreading to the green needles.
Severe infections should be sprayed with chlorothalonil (Daconil), thiophanate methyl (Cleary 3336), or copper-containing fungicides registered for use against this disease. Spray when the needles are half-elongated and again when fully elongated. A minimum of two years of treatment is recommended because of the organism's life cycle.
