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Q&A Home

Barbara writes,

How much Merit 75 WP do I need per gallon of water for tall bearded iris that have iris borers?

Do I drench the rhizomes and spray the foliage? How much liquid per plant and how often. There are tiny grubs already in the lower part of the leaves.


Apply 3 to 4 level teaspoons of MERIT 75 WP per 1000 sq ft. The amount of water you use will be up to you, though we recommend using at least 2 gallons of water per 1000 sq ft. Apply as a broadcast treatment and incorporate into the soil. When the application is made to established plants, optimum control will be attained if area is irrigated thoroughly after application. Complete instructions can be found on page 4 of the product label.

Answer last updated on: 06/05/2010

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