Meal moth (Pyralis farinalis) commonly found in navel orangeworm pheromone trap.
Figure 1: Meal moth (Pyralis farinalis) commonly found in navel orangeworm pheromone trap.

I have been hearing multiple reports of high counts of Navel Orangeworm (NOW) moths trapped with the new Suterra Biolure. We have placed our traps and have had high trap counts as well. In our liners, however, we have found two different moths – one being NOW  (Amyelois transitella) and the other being a meal moth (Pyralis farinalis). Both of these moths are within the same family (Pyralidae) and can be confused. 

The meal moth can be distinguished from NOW by two features – the light brown color and the dark brown bands on the wings. Speaking with a Suterra rep, this was expected as these moths are attracted to the same sex pheromone as NOW.

Figure 2. Moths circled in red are meal moths, the rest are NOW (Photo by A. Ray)
Figure 2. Moths circled in red are meal moths, the rest are NOW (Photo by A. Ray)

Trap counts can range depending upon location – in one locations we trapped 20 meal moths, while a second location we trapped only 2. Suterra doesn’t know why populations vary, but suspect that proximity to hullers or warehouses might influence populations.  A comparison of meal moths next to NOW in a liner can be seen in figure 2.

We plan to follow the trap counts of NOW, meal moth, and NOW eggs (using egg traps) todetermine if there is any type of relationship. To date, we have found higher NOW moth counts than expected (>30/week), and very low egg counts (<2/week) at two locations. This suggests that the biolure may be more sensitive, but the exact relationship of moth count to NOW infestation is still needed to determine spray thresholds.

 

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