Dead Gypsy Moth Larvae on Burlap Sprayed With Deltamethrin

Dead Gypsy Moth Larvae

These newly hatched gypsy moth larvae all died as they tried to go up this cedar tree, and past the burlap sprayed with Deltamethrin.


We first heard about Deltamethrin when reading the June, 2007 issue of Smithsonian Magazine. The magazine had an an article about former president Jimmy Carter giving out bed nets in Ethiopia to help people protect themselves from mosquitos and the malaria disease they may cause.

Since mosquitoes that transmit malaria bite only at night, the protection provided by sleeping under an insecticidal net can be crucial in preventing the disease. Hung over sleeping areas and tucked under the mattress, the nets are made from insecticide-coated fabric that kills insects that land on it as they attempt to bite the sleeper below. The insecticide used is Deltamethren.

We wondered if spraying Deltamethrin on the burlap strips, we placed around trees, would kill Gypsy Moths that would walk on it. We tried it, and it did - see above photo.

Deltamethrin is a pyrethroid insecticide. Pyrethoids are synthetic compounds made to mimic the pyrethrins that are isolated from chrysanthemum flowers. According to Wikipedia, synthetic pyrethoids are a member of one of the safest classes of pesticides.

Suspend SC

Suspend SC Insecticide provides Deltamethrin in a concentrated suspension of pure micro-crystals. The micro-crystals give Suspend SC a long residual, and instead of being absorbed into porous materials, they stay on the surface. As a result, insects continue to contact them long after the insecticide has been applied. Yet Suspend SC leaves no visible residue, has virtually no odor, and won't clog spray equipment. Suspend SC is a long lasting residual that lasts up to 3 months after application

Suspend SC is supplied in concentrated form. It must be diluted by mixing it with water. It is then applied to the burlap strips using an ordinary garden sprayer.

Back in 2007 it was difficult to find a source to buy Deltamethrin. But now it can be obtained from

Follow this link to see: Suspend SC available on