Thirty-three sites reported this week. Nine of the sites had European corn borer (ECB)-E and four sites had ECB-Z. Nineteen sites reported corn earworm (CEW) with eighteen high enough to be on a 3, 4, 5 or 6 day spray interval (see table at bottom of post). Fall armyworm (FAW) was caught at twenty-two sites and Western bean cutworm (WBC) was caught at twenty-two sites. The hybrid ECB moth was not caught at any of the six reporting sites.

NEWA Western bean cutworm flight emergence lookup table.

The graph below shows the average number of moths caught per week throughout the season. WBC peaked the week of August 4th and now CEW and FAW are on the rise. ECB- E had a small peak in June followed by a second smaller peak late July. ECB-Z has been fairly low throughout the season.

Average sweet corn trap catches for all reporting sites from 5.26.20 – 8.18.20.

Dry Bean Western Bean Cutworm Alert
8.18.20
Marion Zuefle, NYS IPM Program and Margie Lund, CVP
(Information and photos from T. Baute, OMAFRA)

This year we are monitoring eight WBC traps placed next to dry bean fields. Dry bean growers should scout adjacent corn for WBC eggs and larvae when cumulative trap catch reaches 50 moths or 7-10 days after peak emergence, and should continue to scout for three weeks, especially if damage has been seen in recent years. Peak flight occurred the first week of August (see graph below).

Average WBC trap catches for the eight sites from 7.7.20 – 8.18.20.

Dry bean pod scouting should begin 7-10 days after peak emergence (given in blue below), in those fields which have accumulated over 50 moths/trap, near fields with high trap counts, or where WBC has been found in bean pods/seeds in recent years.

WBC eggs, laid shortly after moth emergence, take 5-7 days to hatch. Pod feeding typically begins 10 days after peak moth catch. Early feeding by small larvae is generally minor and does not go into the pod. Growers in areas of concern should scout bean pin pods and larger pods for damage/feeding holes. Check 10 spots in a field, 5 plants per spot. WBC larvae hide in the soil during the day and won’t be seen on beans. If you find larvae in the pods during the day they are most likely European corn borer.

Spraying once, 7-10 days after peak emergence/catch, the ideal timing, resulted in almost no damaged pods in a Michigan trial. Delaying a few days resulted in few damaged beans. A pyrethroid insecticide such as Warrior, Asana, Baythroid, etc. is recommended. Organic growers using Pyganic may need more than one spray, and are advised to spray in the evening.

This project is funded by the NYS Dry Bean Industry.