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Angie Peltier


Angie Peltier
Former Extension Educator, Commercial Agriculture



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Hill and Furrow

Current topics about crop production in Western Illinois, including field crops research at the NWIARDC in Monmouth.
Figure. Mesh pheromone trap used to trap European corn borers and corn earworm at the NWIARDC.
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Pheromone insect trapping

Posted by Angie Peltier - Insects

What are pheromones?

What does your dog have in common with common insect pests? Pheromones. Pheromones are chemicals used in non-verbal communication among individuals of the same species. Pheromones can influence behavior or development. One type of pheromone, sex pheromones, is emitted by female insects to attract mates.

How can we use pheromones?

We can use synthetic insect sex pheromones to attract insects to the traps that we have set up in strategic areas of NWIARDC. Different trap designs are used to take advantage of the behavior of specific insects: sticky traps, mesh traps or even modified milk jugs filled with an antifreeze solution.

Pheromone traps can be used to determine thresholds for both scouting and chemical control. For example: for black cutworms, trap data is used to determine when peak moth flight occurred. This data, in combination with pest degree days (a measure of pest development based on temperature) accumulated after this peak, allow entomologists to predict when cutworms will begin cutting. This information will alert producers and CCAs to begin scouting. Scouting will help to determine whether black cutworm populations and damage in a field has reached the threshold to consider chemical control.

A handy tool developed by the Illinois State Water Survey and Entomologists from the Department of Crop Sciences at the University of Illinois, can be used to calculate pest degree days for insect pests.

Pheromone trapping at the NWIARDC

In 2012, black cutworm trapping began in late March and ended in late May. The peak flight came early on during the trapping period, on April 4 (Figure) and the cutting date to begin scouting was projected to be May 6th. Today, May 31st, 2012, pest degree days have accumulated to 695 since the peak flight. After 640 pest degree days, black cutworms are no longer considered a threat to young corn plants. To compare 2012 to the 11-year average, May 31st would have accumulated 495 degree days. If 2012 were a typical year, cutworms would still be cutting, although cutting activity would be slowing.

Trapping for European corn borers and corn earworms at the NWIARDC began on May 25 (Figure).

Why use pheromone traps?

Many of you might be wondering why it is important to continue to monitor these insect pests with the widespread use of transgenic hybrids carrying the insecticidal Bt (Bacillus thuringiensis) traits. Insect monitoring is still important for several reasons: 1) not everyone plants Bt hybrids; 2) not every Bt hybrid provides protection for every important insect pest. A trait table developed by entomologists Drs. Chris DiFanzo (Michigan State University) and Eileen Cullen (University of Wisconsin) illustrates this point.; 3) even with Bt hybrids control is not absolute, some hybrids don't offer control, but suppression. These hybrids have the potential to be overwhelmed under high insect pressure.; 4) as was observed in 2011 with the Western corn rootworm, insect populations, given the right circumstances, can develop resistance to Bt traits.



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