Spinosad

Spinosad is an organic insecticide originally made out of fermented bacteria found in soil where sugarcane was grown. Actually, it was first found in a rum still. Bootleg bacteria, anyone?

Let me start by saying that anything called insecticide, organic or otherwise, is deadly to something. That’s the point, right? Since not all insects are our enemies, that can be a problem. Before we explore the benefits of spinosad, let’s keep in mind that spinosad can be highly toxic to honey bees and other pollinators, under certain conditions. Now let’s find out how it works and how we can use it safely. 

How spinosad works

Spinosad works by messing with an insect’s neurological system, creating hyperactivity, tremors, and muscle contractions. Ultimately, the insects go into seizures and then become paralyzed, out of pure exhaustion, and then they die. Insects can be affected by eating or touching this insecticide. Chemically, there are over 20 different natural forms of spinosads and 200 different synthetic forms. These synthetic forms are called spinosyns. The spinosad formulas that you can buy are made from two of the synthetic types, spinosyn A and spinosyn D. 

Uses of spinosad

Spinosad is used on a large number of crops, against many types of insects, including:

• Moths and butterflies (Lepidoptera)
• Flies, mosquitoes, gnats, midges, and beneficial hoverflies (Diptera)
• Thrips (Thysanoptera)
• Beetles (Coleoptera)
• Crickets, grasshoppers, and katydids (Orthoptera)
• Sawflies, wasps, bees, and ants (Hymenoptera)

Safe use of spinosad

According to the University of California Dept. of Agriculture & Natural Resources (UCANR), spinosad has a residual toxicity that can last anywhere between 3 hours to more than 24 hours, depending on application rates and formulation. UCANR recommends using 1.25 to 3 ounces per acre. That sure doesn’t work out to be very much for my little 1/5 acre property! As with any other insecticide, it is probably a good idea to stay out of the area yourself for the same time frame. You know, just in case. Spinosad should not be used within 24 hours of harvesting.

Protecting pollinators from spinosad

Spinosad is sold under several different brand names, including Bull’s Eye, Entrust, Natular, Protector Pro, and Success. To reduce the risk to honey bees and other pollinators:

• Do not apply spinosad while plants are blooming
• Only apply spinosad in late evening, night, or early morning
• Use the least possible amount
• Do not apply spinosad while there is wind
• Do not apply spinosad near bee hives

If you really must use an insecticide, spinosad is probably a better choice than non-organic products that build up in the soil and encourage the evolution of resistant species. Personally, I prefer tolerating a little bit of damage, monitoring regularly, and handpicking the pests I see. It’s not as effective as, say DDT, in the short run, but it serves me best in the long haul.