I believe that apples universally reach full bloom at about 175 DD °F and that codling moths’ first flight (biofix) is about that time. Egg hatch begins around 425 DD °F (biofix + 250 DD °F), which is the traditional timing for first codling moth treatment. What the above article recommends is an early treatment at 375 DD °F to kill eggs before hatching. The author(s) suggest horticultural oil.
Here is a similar recommendation for an early treatment at 275 DD °F with Rimon followed by a delayed treatment at 525 DD °F with any number of other chemicals:
The delayed larvicidal treatment is possible because the early ovicide treatment kills eggs that would have hatched in the period starting at 250 DD °F [from biofix]. Another nice feature of this program is that the delayed application of the larvicide is a more efficient timing than the standard first cover timing of 250 DD °F. Only a small portion of the first generation egg hatch occurs between 250-350 DD °F, ca 15 percent, while more than 50 percent of the hatch occurs over a two to three week period beginning at 350 DD °F. The combined strategy also shortens the period of time that larval control is necessary, presenting an opportunity to reduce the number of sprays needed to achieve control.
- Wise, John, et al. “First Generation Codling Moth Management.” 18 May 2010. Michigan State University Extension. 14 Apr. 2018 <http://msue.anr.msu.edu/news/first_generation_codling_moth_management>.
I should say that I have only ever used the traditional timing with Sevin.
You may be mistaken about your current cumulative DDs. You can check your current cumulative DDs at an airport near you. Please see my previous post.