ISD For Citrus Trees: Information On ISD Tags On Citrus

By Darcy Larum, Landscape Designer

You’ve just purchased a lovely little lime tree (or other citrus tree). While planting it, you notice a tag stating “ISD Treated” with a date and also a treatment expiration date. The tag may also say “Retreat before Expiration.” This tag may leave you wondering, what is an ISD treatment and how to retreat your tree. This article will answer questions about ISD treatment on citrus trees.

What is an ISD Treatment?

ISD is an acronym for imidichloprid soil drench, which is a systemic insecticide for citrus trees. Citrus propagating nurseries in Florida are required by law to use an ISD treatment on citrus trees before selling them. ISD tags on citrus trees are put on to let the buyer know when the tree was treated and when the treatment expires. It’s recommended that the consumer treat the tree again before the expiration date.

While ISD treatment on citrus trees helps control aphids, whiteflies, citrus leaf miners and other common plant pests, its main purpose is to prevent the spread of HLB. Huanglongbing (HLB) is a bacterial disease affecting citrus trees that is spread by the Asian citrus psyllid. These psyllids can inject citrus trees with HLB while they feed on the leaves. HLB causes citrus foliage to turn yellow, fruit to not properly form or ripen, and eventually death to the whole tree.

Tips on ISD Treatment for Citrus Plants

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The Asian citrus psyllid and HLB have been found in California, Florida, Texas, Louisiana, Alabama, Georgia, South Carolina, Arizona, Mississippi and Hawaii. Like Florida, many of these states are now requiring treatment of citrus trees to control the spread of HLB.

ISD for citrus trees usually expires about six months after they were treated. If you have purchased an ISD treated citrus tree, it is your responsibility to retreat the tree before the expiration date.

Bayer and Bonide make systemic insecticides specifically for treating citrus trees to prevent the spread of HLB by Asian citrus psyllids. These products can be purchased at garden centers, hardware stores or online.

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