PestWatch Report for August 21, 2019

 

Sites where sprays are applied may reduce counts, and moving traps close to silking corn will tend to increase the catch. Within the last two weeks, sites exceeding 70 moths/week, suggesting a tight (3-4) day spray interval occurred in Bucks, Erie (from last week), Lancaster, Mifflin, and Union counties.

 

Sites with 36-70 moths/week, suggesting a 4-5 day interval, were reported in Blair, Centre, Erie, Lancaster, Luzern, Northampton, Schuylkill, and York counties. Additional sites had lower counts but still above a spray threshold, and southwestern sites in Indiana and Washington counties stayed below the threshold.

 

 

Populations carrying pyrethroid resistance tends to increase in August. Historically, this problem has been greater in areas to the east of the Appalachians and is well documented this year from Delaware. Non-pyrethroid options include Coragen, Blackhawk, and Radiant. However, these will not control sap beetles, brown marmorated stink bug, or insects feeding on silk (Japanese beetles, adult corn rootworms). Adding a pyrethroid, or the premix Besiege should help with pests that are not “worm” species.

 

European corn borer (ECB) counts are low, except for a site in Susquehanna county based on last week. Sprays targeting CEW will control ECB.

 

Fall armyworm (FAW) captures are rising rapidly in Erie county, but not in the rest of the state. A non-target called Inter-mediate Cucullia, or Intermediate Hooded Owlet, is also showing up in the FAW traps.

 

 

Average weekly catch –7-day moving average. The average catch per night (catch, divided by the number of nights trap-ping), divided by the number of nights where data exist, multiplied by 7. Weeks where all the average-catch-per-night values are nulls are treated as if no data exist for that week.

 

 

THRESHOLDS Reproductive (tassel/silk) and late vegetative corn attract moths. Shorten spray schedules when populations increase. If CEW is not a problem, then consider ECB.