When to scout for soil insect pests

Damage from soil-dwelling insect pests, such as wireworms and white fringed beetles, typically develops in the first three to four weeks following transplant. Scout plants for at least month following transplant.

What part of the plant to scout for soil insect pests

Soil-dwelling insect pests damage roots and stems, so damage is not visible at the surface.

How to scout for soil insect pests

Plants that appear stressed or stunted can be dug up and observed for either chewing and boring damage or insect presence.  Be aware that other issues can cause plant stunting, including herbicide damage or carryover, some insecticides, salt injury from granular fertilizer, and weather.  Rule out these potential causes of injury before digging large numbers of plants.

Soil insect pest thresholds

Rescue treatments, or treatments applied after damage occurs, are not effective for soil insects in tobacco.  However, because damage from soil insects is relatively rare in tobacco, preventative insecticide use pretransplant is also not recommended unless a field has a history of soil insect damage.  Crop rotation is another means of soil insect control.

If greater than 10% of plants are killed due to soil-dwelling insect feeding, replanting is recommended.  If less than 10% of plants die due to insect feeding, replanting is not necessary.