Plant Diseases/apple


Hi,i have sprayed caustic soda on apple trees two years back,is it safe to spray again with caustic soda.what is role of caustic soda.

Dear Vivek, Generally the caustic soda can be used to remove lichens from tree bark.  It is also used to control insect pests but to make sure that most pests are not overwintering on your fruit trees, make sure there is no loose bark on any of the trees, because insects will be hiding there.  Also make sure that your orchard is as clean as possible.
A soap spray made with natural ingredients is highly effective in controlling aphids, mites and thrips in fruit orchards. The spray does not harm the spiders in fruit trees. To make the spray, add a 2/3 grated soap cake in 1 gallon of hot water. Add 1 tsp. white oil, 1 1/4 cup used cooking oil and 2 tsp. caustic soda to the hot mixture. Cool to room temperature and spray on affected tree parts. Do not spray on the trees during warmer periods of the day. White oil is an organic insecticide made with mixing 1 cup vegetable oil, 1 cup water and 2 tsp. dish soap. Caustic soda, also known as "lye," can easily be obtained at any chemical supply store.
I hope this information helps.  Happy New Year!  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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