Dandruff Control For Insect Pests

A metallic element used to help control dandruff might also make insect pests resilient to microbial control methods, a new study suggests.

Insect scientists Kent Shelby and Holly Popham of the USDA's Agricultural Research Service studied the effects of higher-than-average dietary levels of selenium on two pest moths--the cabbage looper and the tobacco budworm.

High levels of selenium are toxic to both pests and beneficial insects, but the study results indicate that moderate dietary levels of the chemical might actually strengthen insect immunity. The researchers found that insects with higher selenium levels demonstrated greater resistance to baculoviruses--a group of viruses that cause insects to sicken, stop eating, and die.

If selenium boosts the pests' immunity, it could also decrease the effectiveness of baculoviruses and other microbial biological control agents used to control and reduce insect populations.

Selenium application is often used as a control agent, but Shelby and Popham suggest than an insufficient does might be benefiting the pests instead of wiping them out.

--Bjorn Carey

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