SOUTHEAST: With the sugarcane planting season in full swing and the return of drier weather, growers should be alert to the presence of lesser cornstalk borer (Elasmopalpus lignosellus) in newly emerged stands of plant cane. Unfortunately, this is often only discovered after observing “dead heart” and “shot holing,” at which point yield loss may have already occurred and larvae are usually beyond the reach of most insecticides.
One inexpensive and effective way to monitor lesser cornstalk borer populations is through the use of pheromone traps strategically placed in new plantings. These traps are durable, inexpensive and highly effective at trapping adult moths, which are unique and thus easily identifiable. Monitoring the traps on a weekly basis doesn’t require much time and will provide advance warning of upcoming infestations.
While no treatment threshold currently exists for Florida sugarcane, local experience has shown that when weekly moth counts exceed 40 adults per trap, potential crop damage is imminent and treatment may be warranted. Of course, the ultimate decision to treat depends on a number of other factors such as age of the crop, variety and other agronomic practices that may reduce lesser cornstalk borer pressure.
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Reporting from North Palm Beach, FL