Plant Diseases/Apple


Hi, I have planted apple trees this winter and I want to know what  precaution should I take to make them healthy. How to fertilize and spray them. What are the diseases that can infect trees and how to save them.

Dear Vivek,
There are several different sprays to spray apples with in order to get insect and disease free apples.  
1.    During the dormant season, when apples and leaves have fallen, clean up the ground of leaves, do any necessary pruning, and spray the tree with dormant oil, perhaps every two weeks if you see any bugs or have had diseases.  This will kill overwintering eggs of aphids, mites and control some diseases.
2.   When the tree starts showing green growing tips, spray the tree with sulfur (but not within three weeks of spraying with oil) for disease prevention; also spray with insecticidal soap or NEEM oil if aphids or mites are a problem.
3.   During the time from leaves to bloom, spray with sulfur (but not lime sulfur) for disease prevention; NEEM oil if you have aphids, mites or other bugs, Bacillus thuriengensis  for pest caterpillars (donít mix this with the sulfur spray, apply those separately).
4.   During first bloom, spray with sulfur and Bacillus if necessary, but donít use anything else to avoid any injury to bees.  Only spray with sulfur or Bacillus if you need to during this time.
5.   Petal fall is when the flowers are dropping off of the tree and are no longer being pollinated.  Now is when you can repeat the spray with sulfur and Bacillus again, and then spray with those 7-10 days later if needed or begin weekly kaolin clay spraying.  Kaolin clay products can be sprayed on weekly to keep away apple maggots and other apple pests.  
6.   When the fruit is set and begins developing, keep a close watch out for any signs of disease.  You will want to spray with sulfur spray or Bordeaux if you see any signs of disease on either the fruit or the leaves, every 10-14 days as fruits develop.  Stop spraying 30 days before expected harvest.  
In addition, if you have cedar trees nearby, you are in danger of developing cedar apple rust, so eliminate those plants if possible.  If not, you will have to spray with fungicide to control this.  The time to spray will be from silver tip (when the tree is almost out of being dormant and the tip of the buds are silver before they turn green with the first leaves), again after petal fall, and another spray again 10 days later.  In addition, any remaining cedar trees should be looked at, and collect and destroy any galls in the trees.
  In addition, keeping your orchard clean and free of old leaves and weeds is very important to get the best apples.  I know it sounds like a lot, but remember, some of the additional spraying you only need to do if you see problems, like bugs and spots on fruit or leaves.
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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