Plant Diseases/sago palm


I have had my sago palm for about 15yrs. Recently the fronds have yellowed, there are some black spots on them and they are all just drooping over.  I repotted it about 5 months ago and not sure if that affected the plant. Please help.

Dear Denise, It sounds like your sago is suffering from a fungus.  It may have additional problems, but it definitely has a fungus.  For a fungicide, I suggest a product containing the ingredient proprioconazole in the list of active ingredients.  Spray the plant thoroughly, to the point of dripping, and let it dry.  You may need to spray 2 or 3 times about a week apart to control the fungus.  In addition, I would trim off the yellowing fronds.  Many sagos (including mine) will suffer some yellowing during the winter months due to freezing temperatures and dying older fronds.  You also need to check the upper and lower surfaces of the fronds to see if they are bumpy.  Bumps on sago leaves are an indication of scale insects.  The scale is an unmoving insect that hides under the hard shells or scales making them hard to kill.  I mention this because sagos are very susceptible to these insects.  If you do see the presence of scale, you need to also get a horticultural oil to spray with.  Horticultural oils (sometimes called lightweight or summer oils or dormant oils) are different from other types of oil, so be sure to use one designated for spraying plants.  You can mix the horticultural oil with the proprioconazole when you spray and treat both problems at the same time.  You will know that the scale is dead if a moderate stream of water sprayed on the leaves a few days after spraying will easily dislodge the bumps.  In addition to both these problems, you may have a bit of problem from the replant and/or watering.  When repotting, be sure to only go up one size or so in the pot size, and make sure the plant is firmly pressed into the soil.  Keep the stem uncovered.  Also, be sure to water the plant thoroughly each time, and let the water drain completely out of the bottom.  If the plant is kept with a plant saucer underneath, be sure that the saucer stays completely dry after watering.  Water standing in plant trays is a leading cause of plant death.  At any rate, this should completely address the issues with your sago palm.  If there is anything you need further information on, or you are not sure of some direction, please let me know.  I am available to answer your plant questions anytime.  I hope this information helps.  Good luck, Melissa

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Melissa Johnston


Plant diseases, landscaping, tropical plants, roses, herbs, plant care, grafting, horticulture, plant identification, anything about plants I can likely answer.


35 years experience in various plant businesses, 1984 Certified Texas Master Gardener.

Master Gardener Association of Texas charter member

none as of yet, but I have a plant q&a book I am in process of submitting.

Magna cum laude graduate of Texas A&M, 1978

Awards and Honors
Plant growing awards, highest grade for Texas Master Gardener graduates.

Past/Present Clients
Past member of and was very highly rated. Owned landscape company in the past, Almost Paradise, and was very successful despite little equipment, no help, and no advertising. Lived well for two years until 9/11.

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