Mar 1, 2022

Data Key to Codling Moth Control

{Sponsored} Maximizing science and minimizing guesswork could be the winning formula to control codling moth in apples and pears. 

Localized degree-day and trap-catch information can help fruit producers make more informed decisions, reduce crop production risk, and improve control of codling moth and other pests. 

While the 2020 and 2021 growing seasons were similarly warm, the frequency of fruit load rejections for Pennsylvania producers differed starkly between the two years. 

“In 2020, Pennsylvania fruit processors rejected almost as many fruit loads as they did in 2005 and 2007, and those were both considered disaster years. Fortunately, in 2021, the numbers of rejected loads were much lower than in 2020,” says Greg Krawczyk, Penn State University tree fruit entomologist. 

In southern Pennsylvania, codling moth flights normally start at the beginning of May with two generations expected per season. In comparison, Oriental fruit moth flights often start three to four weeks earlier. 

“Adult codling moth are active when the temperature is above 62,” says Krawczyk. “Codling moth, when it is flying, responds to the temperature. If it is cool, they are not flying and may not be observed in sex pheromone traps.” 

No matter the year, effective codling moth control requires correct timing and adequate coverage with effective insecticides before pests enter fruit. 

“After egg hatch, the larvae can be inside the fruit in less than 24 hours,” says Krawczyk. 

Seasonal management of codling moth, as recommended by Extension entomologists, generally includes two to three insecticide applications each for the first and second generations. 

In Krawczyk’s bioassay studies, most products within three classes of chemistry effectively controlled codling moth when sprayed at optimum timings. He recommended rotating modes of action, including IRAC Group 5 (Delegate^® WG insecticide), Group 24 (diamides) and Group 32 (granuloviruses). 

Delegate provides a unique mode of action in insecticide rotations because the active ingredient, spinetoram, is the only Group 5 insecticide. Delivering fast knockdown and long-lasting codling moth control, Delegate also controls a broad spectrum of key pests, including Colorado potato beetle, armyworms, leafrollers, thrips, leafminers and more. 

Preliminary laboratory bioassay data on larvae collected during the 2020 and 2021 seasons showed consistent efficacy within each mode of action, with some exceptions. 

Including mating disruption with scheduled insecticide sprays further improved the marketability of apples in Krawczyk’s studies. 

“Every year since 2009, it seems that mating disruption plus insecticides help us keep fruit clean,” he says. 

Unfortunately, very heavy pressure from internal fruit worms during Krawczyk’s 2021 on-farm studies, resulted in some orchards still experiening more than 10% fruit damage at harvest despite the season-long use of mating disruption along with insecticide treatments. 

Because anticipating moth flights is key to codling moth control, entomologists recommend using degree days and trap data to better time insecticide treatments. Krawczyk recommends the Network for Environment and Weather Applications, based at Cornell University, for localized weather and degree-day data. The site offers data from more than 700 weather stations throughout the Northeast and Mid-Atlantic apple-growing regions. 

Visit NEWA.Cornell.edu to view weather-related IPM tools. To learn more about the role Delegate can play in your codling moth control program, visit DelegateWG.Corteva.US. 

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